Physician Assistant PAS 701/2/3 PA Examination Question Pool: Abdomen, Pelvis, and Perineum - October 16, 2019 (21 Questions)

Note: The answer guide is not "the answer." For the essay examination, please be prepared to answer questions in prose. The guides are not exhaustive. Your answer does not require that all points in the guide are addressed. Plus, you may receive credit for writing about relevant information not mentioned in the guide. Each question spans multiple lectures. Thus, the placement of a question according to a particular lecture is somewhat arbitrary.

Applied Human Structure and Function PAS-703 Abdomen, Pelvis, and Perineum Examination Preview Four Questions October 16, 2019 – 100 Points Instructions

  • PA_AbPelPer2019Preview.pdf - Expect that grammatical corrections will be applied to the final version of the examination.
  • As was the case for the previous written examination, if one of the 10 questions does not resonate with you, then you may substitute another question from the question pool. Or, you may write a question of your own. The question must be relevant to the subject and of an academic spirit comparable to the question pool. Please avoid being overly redundant with another answered question.
  • Between the four known questions and the opportunity to substitute a question; you currently know 50% of the examination. The remaining 50% of the examination is a wild card. Hmmmmmmm.
  • Please plan on answering all 10 questions, in prose, during the examination time.
  • Notice that each question ends with "Cite an example of clinical relevance." In most cases the clinical relevance is self-evident. Nonetheless, if you have additional comment about clinical relevance; please write a note about it. Especially comment if your laboratory experience has, in any way, inspired your clinical knowledge. This part of the question is aimed at thwarting, or not, current trends in medical education advocating that dissection based anatomy as no longer relevant to clinical practice. Nonetheless, explicitly citing an addition example of clinical relevance is not essential to answering the question.

Fascial Layers of the abdominal wall - Vertebral projections, Dermatomes

Catheterization of the urethra may go awry at the membranous urethra and cause extravasation of urine into the superficial pouch. Discuss the boundaries of Scarpa's fascia and its derivatives with respect to the containment of urine in the male. Specify the fascial layers associated with the accumulation of urine. Discuss whether urine will be found in the ischiorectal fossa. Cite an example of clinical relevance. (10 pts)

General
  • Scarpa's fascia is membranous tela subcutanea. This fascia is capable of holding sutures and defines a potential space between it and deep fascia. This space can be invaded by infection or the extravasation of urine. The tear in the inferior fascia of the urogenital diaphragm transmits urine from the deep pouch to the superficial perineal pouch. The intact superior fascia of the urogenital diaphragm together with the intact superficial perineal fascia will prevent urine from entering the ischiorectal fossa. The accumulation of urine is restricted by the boundaries of Scarpa's (membranous) fascia.
Anterior abdominal wall
  • Between Scarpa's fascia and deep fascia of external oblique
  • Superior: Scarpa's fascia attaches to deep fascia in finger like projections at level of umbilicus
  • Inferior medial: open passage to scrotum
  • Inferior lateral: passage to thigh
  • Lateral: near midaxillary line at the thoracolumbar fascia
  • Medial: along the linea alba, fundiform ligament
  • Anterior: Scarpa's fascia
  • Posterior: deep fascia of external oblique
Thigh
  • Between Scarpa's fascia and fascia lata
  • Inferior: 2 cm below inguinal ligament
  • Superior: open
  • Lateral: iliotibial tract
  • Medial: pubic ramus
  • Anterior: Scarpa's fascia
  • Posterior: fascia lata
Scrotum
  • Between Dartos tunic (Scarpa's derivative) and external spermatic fascia (deep fascia)
  • Superficial: Dartos tunic
  • Deep: external spermatic fascia
Penis
  • Between Colles fascia (Scarpa's derivative) and Bucks fascia (deep fascia)
  • Extends distally toward base of, but not including, the glans
  • Superficial: Colles fascia
  • Deep: Buck's fascia
Urogenital triangle
  • Within superficial pouch between superficial perineal fascia (derivative of Scarpa's fascia) and perineal membrane (deep fascia)
  • Superior: perineal membrane (inferior fascia of the urogenital diaphragm)
  • Inferior: superficial perineal fascia
  • Anterior: open into scrotum
  • Posterior: posterior free edge of urogenital diaphragm, superficial perineal fascia
  • Lateral: conjoint rami
  • Medial: not restricted
Extravasation of urine into the ischiorectal fossa
  • Limited by superior fascia of urogenital diaphragm
  • Limited by superficial perineal fascia (attached to posterior free edge of urogenital diaphragm and conjoint rami)
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Anterior Abdominal Wall Musculature, Rectus Sheath, Collateral Circulation

Review the anatomy of the rectus sheath. Include contents, coverings, fascial boundaries, innervation, vasculature, lymphatic drainage, and relationships. Account for the arrangement of fascial layers superior to and inferior to the arcuate line. What fascial layers are penetrated by a wound, inferior to the arcuate line, that proceeds into the peritoneal cavity? Cite an example of clinical relevance. (10 pts)

General
  • The rectus sheath may be incised for laparotomy. The incision may be midsagittal along linea alba or parasagittal along the rectus abdominis muscle. A mid-line incision may limit bleeding but, invites problems with wound healing, dehiscence, and herniation.
Boundaries
  • Superior: Costal margin and xiphoid process
  • Inferior: Pubic bone and symphysis
  • Anterior: Anterior lamina aponeuroses
  • Posterior: Anterior lamina aponeuroses, transversalis fascia inferior to arcuate line
  • Lateral: Linea semilunaris
  • Medial: Linea alba
Fascia and Fascial Specializations
  • The rectus sheath surrounds the rectus abdominis muscle. Boundaries - superior: costal cartilages, inferior: pubic crest, anterior: anterior lamina rectus sheath, posterior: posterior lamina rectus sheath, medial: linea alba, lateral: linea semilunaris. Contained with the rectus sheath are the rectus abdominis, superior and inferior epigastric vessels, anterior branches of intercostal, subcostal, and iliohypogastric nerves, tendinous intersections.
  • Superficial to deep lateral to rectus sheath: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique - internal oblique - transversus abdominis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • Superficial to deep at rectus sheath superior to arcuate line: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique aponeurosis - internal oblique aponeurosis anterior layer - rectus abdominis - internal oblique aponeurosis posterior layer - transversus abdominis aponeurosis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • Superficial to deep at rectus sheath inferior to arcuate line: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique aponeurosis - internal oblique aponeurosis anterior and posterior layers fused - transversus abdominis aponeurosis - rectus abdominis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • The superficial fascia, starting superior at the level of the umbilicus and extending inferior, is made up of two layers - a fatty layer (Camper's) and a membranous layer (Scarpa's). Scarpas fascia is attached to deep fascia along the linea alba and extends inferiorly onto the penis (Colles), scrotum (Dartos), or labia majora (superficial perineal fascia). Scarpa's fascia contributes the fundiform ligament from the anterior abdominal wall to the dorsum of the penis/clitoris. Most inferior, Scarpa's fascia or its derivatives attach to the posterior free edge of the urogenital diaphragm and to the fascia lata about one inch inferior to the inguinal ligament.
  • The rectus sheath does not have a aponeurotic posterior lamina at levels inferior to the arcuate line and superior to the insertions of the internal oblique. Thus, the posterior lamina is non-muscular inferior to the approximate mid-point between umbilicus and pubic crest and is, again, non-muscular superior to the xiphoid process.
Vasculature Supply
  • Superficial veins - portal system: paraumbilical veins, caval system: lateral thoracic, thoracoepigastric, superficial epigastric, superficial circumflex iliac vein
  • Superficial arteries - superficial circumflex iliac, superficial epigastric, superficial pudendal
  • Caput medusae - paraumbilical veins (portal system) reverse flow, dilate, and shunt to caval system at inferior vena cava (great saphenous - femoral - external iliac - IVC)and superior vena cava (axillary - subclavian - brachiocephalic - SVC)
  • Vessels in the neurovascular plane (deep the internal oblique and superficial to transversus abdominis) - intercostal arteries and veins from lower thoracic levels and lumbar arteries, musculophrenic, deep circumflex iliac artery, iliolumbar artery
  • Vessels within the rectus sheath - superior and inferior epigastric arteries and veins
  • Anterior aortic shunt - subclavian - internal thoracic - superior epigastric - inferior epigastric - external iliac
Contents
  • Arteries and veins: Superior and inferior epigastric vessels, paraumbilical veins
    • Anastomoses
  • Muscles: Rectus abdominis, pyramidalis
    • Breast reconstruction
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Inguinal Canal, Inguinal Hernias, Spermatic Cord, Testis, Development

Indirect inguinal hernias pass into a patent processus vaginalis. Abdominal viscera may move through the processus vaginalis into the scrotum. Review the anatomy of the spermatic cord. Include contents, coverings, fascial boundaries, innervation, vasculature, lymphatic drainage, and relationships. Discuss the pathway and location of an indirect inguinal hernia that has descended into the scrotum. Cite an example of clinical relevance. (10 pts)

General
  • The spermatic cord is the pedicle of testis. Beginning at the deep ring, the spermatic cord transmits the contents of the deep ring from the abdominopelvic cavity to the scrotum.
  • The pathway from the deep ring to the scrotum marks the "descent" of the testis.
  • A peritonealized surface of the testis causes a trailing diverticulum know as the processes vaginalis.
  • Applied to the anterior aspect of the testis is the visceral layer of tunica vaginalis.
  • The deep ring marks the beginning of the inguinal canal and is located: at the mid-inguinal point; lateral to the inferior epigastric artery; and slightly more than 1 cm superior to the inguinal ligament.
  • At the deep ring the spermatic cord receives the internal spermatic fascia derived from transversalis fascia. Within the inguinal canal the internal oblique contributes the fascia.
  • The cord exits the inguinal canal by way of the superficial ring.
  • The superficial ring, a defect in the external oblique aponeurosis, contributes the external spermatic fascia.
  • The testis, at the distal extent of the cord, ultimately resides within the scrotum. It is tethered to the most inferior aspect of the scrotum by the scrotal ligament.
  • The external spermatic fascia (deep fascia) is opposed to Dartos fascia (superficial fascia).
Internal Spermatic Fascia
  • Structures that pass through the deep ring were retroperitoneal and reside within the internal spermatic fascia derived from transversalis fascia.
  • processes vaginalis - a trailing diverticulum of peritoneum that accompanies the testis during the "descent."
  • Distally, within the scrotum, the processes vaginalis opens into the tunica vaginalis
  • Extraperitoneal connective tissue
  • Testicular artery - paired branches from lumbar aorta near renal arteries
  • Testicular vein - proximally the testicular vein may consist of 3-4 veins
  • Distally the testicular surrounds the testicular artery forming the pampiniform plexus veins numbering 10 to 12 veins
  • Left testicular vein drains into left renal vein and the right testicular vein drains into the inferior vena cava near the renal artery
  • Testicular lymphatic drainage - drainage to upper lumbar nodes, to lumbar lymph ducts, to cisterna chyli
  • Testicular autonomic plexus - sympathetic preganglionic cell bodies in IMLCC T10(11-12)
    • Sympathetic postganglionic cell bodies in superior mesenteric ganglion
    • Parasympathetic preganglionic fibers derived from the vagus nerve
  • Afferent "pain" fibers following sympathetic pathways to spinal levels T10(11-12)
  • Vas deferens - under sympathetic control, the walls (2-3 mm thick) of the vas deferens contract to discharge spermatozoa
  • Within the cord the Vas deferens lies posterior to the testicular artery
  • Distally, the Vas deferens forms the tail of the epididymis at the posterior inferior pole of testis
  • Further distally the tail gives way to the body and then to the head of the epididymis at the posterior superior pole
  • Deferential artery - branch of the internal iliac artery that supplies the vas deferens and anastomoses with the testicular artery
  • Deferential autonomic plexus - derived from the superior/inferior hypogastric autonomic plexus to prostatic plexus
    • Parasympathetic preganglionic fibers possibly derived from pelvic (S2-4)
    • Afferent "pain" fibers following sympathetic pathways to spinal levels T10(11-12)
  • Deferential lymphatic drainage - drainage to internal iliac nodes, to lumbar lymph ducts, to cisterna chyli
  • Genital branch of genitofemoral nerve - mediates efferent component of reflex
  • Cremasteric artery - branch of inferior epigastric artery supplies the tunics
Cremasteric fascia
  • Superficial to the internal spermatic fascia and deep to the external spermatic fascia
  • Derived from internal oblique muscle, the fascia contributes to the cord within the inguinal canal
  • Genital branch of the genitofemoral nerve - provides somatic motor supply
  • Cremasteric artery - branches provide vasculature to the fascia
External Spermatic Fascia
  • Superficial to the cremasteric fascia and is the outer most tunic
  • Derived from the external oblique, the external spermatic fascia extends to the cord beyond the superficial ring
  • Within the scrotum the external spermatic fascia is deep to Dartos tunic
Path of indirect inguinal hernia
  • An indirect hernia follows the embryologic "descent" of the testis indirectly out the superficial ring by way of the deep ring.
  • A patent processes vaginalis allows herniated material to pass through the deep ring lateral to the inferior epigastric artery
  • Herniated material passes through the inguinal canal and out the superficial ring - superior and medial to pubic tubercle
  • Distally, the hernia is arrested by the tunica vaginalis (PA students are requested to post bail on behalf of an herniated intestine.)
  • In the case of herniated intestine, visceral peritoneum is directly opposed to visceral and parietal tunica vaginalis
  • Palpation of the hernia occurs at the anterior aspect of the testis within the scrotum
  • The long and curvaceous path of an indirect hernia make strangulation a distinct possibility
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Laparotomy, Umbilical Ligaments and Folds, Survey of Abdominal Viscera

Review the anatomy of the anterior abdominal wall. Include structure, supports, relationships, vasculature, innervation, and lymphatic drainage. Cite an example of clinical relevance. (10 pts)

General
  • Between the costal margins and the bony pelvis
  • Muscular - relaxes on distension and contracts on compression
  • Compression raises intra-abdominal pressure to stabilize vertebral column - increasing muscle tone is a treatment for back pain
  • Compression protects abdominopelvic viscera from injury
  • Forced expiration of the lungs and evacuation of pelvic viscera
  • Neurovascular plane - between internal oblique and transversus abdominis
Muscles
  • External oblique - origin: iliac crest for trunk flexion (ribs for compression), insertion: lower 7 ribs (iliac crest for compression), inferior free edge is inguinal ligament, anterior half is aponeurosis contributing to rectus sheath and linea alba and attaching to pubic crest
  • Internal oblique - origin: lateral two-thirds inguinal (different accounts), iliac crest, and thoracolumbar fascia, insertion: lower 3 ribs, anterior half is aponeurosis contributing to rectus sheath and conjoined tendon
  • Transversus abdominis - origin: inguinal ligament lateral to internal oblique, inner lip iliac crest, thoracolumbar fascia, lower six costal cartilages, inserts upon itself by way of the rectus sheath and linea alba
  • Rectus abdominis - origin: pubic crest, insertion: 5, 6, and 7 costal cartilages, tendinous intersections divide muscle into sections, pyramidalis
Ligaments and Folds
  • Linea alba - midline raphe: intertwining of aponeurotic fibers from external oblique, internal oblique, and transversus abdominis
  • Inguinal ligament - inferior aspect of the external oblique aponeurosis
  • Lacunar ligament - external oblique, medial boundary of femoral ring
  • Pectineal ligament - external oblique, posterior boundary of femoral ring
  • Conjoint tendon - fusion of internal oblique and transverses abdominis to pectin pubis, guards against direct inguinal hernia
  • Median umbilical ligament - obliterated urachus (allantois)
  • Medial umbilical ligaments - obliterated umbilical arteries
  • Lateral umbilical fold (inferior epigastric artery)
  • Fundiform ligament - derived from Scarpa's fascia and supporting the dorsum of the penis/clitoris to the inferior aspect of linea alba
  • Medial and lateral crura - contribute to anterior wall of inguinal canal and to the margin of the superficial ring, external oblique, external oblique
  • Intercrural fibers - contribute to anterior wall of inguinal canal and approximate the medial and lateral crura, external oblique
  • Reflected inguinal ligament - posterior/inferior wall of superficial ring, external oblique
Fascia and Fascial Specializations
  • The rectus sheath surrounds the rectus abdominis muscle. Boundaries - superior: costal cartilages, inferior: pubic crest, anterior: anterior lamina rectus sheath, posterior: posterior lamina rectus sheath, medial: linea alba, lateral: linea semilunaris. Contained with the rectus sheath are the rectus abdominis, superior and inferior epigastric vessels, anterior branches of intercostal, subcostal, and iliohypogastric nerves, tendinous intersections.
  • Superficial to deep lateral to rectus sheath: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique - internal oblique - transversus abdominis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • Superficial to deep at rectus sheath superior to arcuate line: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique aponeurosis - internal oblique aponeurosis anterior layer - rectus abdominis - internal oblique aponeurosis posterior layer - transversus abdominis aponeurosis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • Superficial to deep at rectus sheath inferior to arcuate line: epidermis - dermis - campers fascia (fatty) - Scarpa's fascia (membranous) - deep fascia - external oblique aponeurosis - internal oblique aponeurosis anterior and posterior layers fused - transversus abdominis aponeurosis - rectus abdominis - transversalis fascia - extraperitoneal connective tissue - parietal peritoneum
  • The superficial fascia, starting superior at the level of the umbilicus and extending inferior, is made up of two layers - a fatty layer (Camper's) and a membranous layer (Scarpa's). Scarpas fascia is attached to deep fascia along the linea alba and extends inferior onto the penis (Colles), scrotum (Dartos), or labia majora (superficial perineal fascia). Scarpa's fascia contributes the fundiform ligament from the anterior abdmominal wall to the dorsum of the penis/clitoris. Most inferiorly, Scarpa's fascia or its derivatives attach to the posterior free edge of the urogenital diaphragm and to the fascia lata about one inch inferior to the inguinal ligament.
  • The rectus sheath does not have a aponeurotic posterior lamina at levels inferior to the arcuate line and superior to the insertions of the internal oblique. Thus, the posterior lamina is non-muscular inferior to the approximate mid-point between umbilicus and pubic crest and is, again, non-muscular superior to the xiphoid process.
Nerves and innervation
  • Motor - lower intercostal nerves (T6-11), subcostal, iliohypogastric - travel in neurovascular plane and pierce linea semilunaris
  • Sensory - lower intercostal nerves (T6-11), subcostal, iliohypogastric - travel in neurovascular plane and pierce linea semilunaris, anterior intercostal nerves, T8 at xiphysternal region, T10 at umbilicus, and T12 at suprapubic region, subcostal at pubic ridge
Inguinal Fossae
  • Supravesical (direct inguinal hernia)
  • Medial inguinal fossa (direct inguinal hernia)
  • Lateral inguinal fossa (indirect inguinal hernia)
Vascular Supply
  • Superficial veins - portal system: paraumbilical veins, caval system: lateral thoracic, thoracoepigastric, superficial epigastric, superficial circumflex iliac vein
  • Superficial arteries - superficial circumflex iliac, superficial epigastric, superficial pudendal
  • Caput medusae - paraumbilical veins (portal system) reverse flow, dilate, and shunt to caval system at inferior vena cava (great saphenous - femoral - external iliac - IVC)and superior vena cava (axillary - subclavian - brachiocephalic - SVC)
  • Vessels in the neurovascular plane (deep the internal oblique and superficial to transversus abdominis) - intercostal arteries and veins from lower thoracic levels and lumbar arteries, musculophrenic, deep circumflex iliac artery, iliolumbar artery
  • Vessels within the rectus sheath - superior and inferior epigastric arteries and veins
  • Anterior aortic shunt - subclavian - internal thoracic - superior epigastric - inferior epigastric - external iliac
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Peritoneum, Visceral Ligaments, Mesentery, Greater Omentum, Peritoneal Sacs

Peptic ulcer disease may erode the posterior wall of the stomach and release stomach contents into the lesser sac. Define the boundaries (including spaces and/or recesses) of the lesser sac. Account for the progression from dull pain to sharp pain once the stomach wall perforates. Discuss the pathway of spilled stomach contents that pass from the lesser sac into the greater sac, and the location of these contents with respect to body position. Cite an example of clinical relevance. (10 pts)

General
  • The lesser sac is a diverticulum in the superior region of the peritoneal cavity. Communicates with the greater sac via the epiploic foramen. For the most part, the lesser sac is posterior to the stomach and liver, anterior to the pancreas and diaphragm, superior to the duodenum, pancreas, and transverse mesocolon, inferior to the liver and diaphragm, left of the caudate, and right to the gastrolienal and lienorenal
Superior recess
  • Posterior to liver, begins at epiploic foramen
  • Anterior - caudate lobe of liver and lesser omentum
  • Posterior - diaphragm
  • Superior - diaphragm
  • Inferior - lesser recess
  • Right - liver, ligamentum venosum
  • Left - splenic recess
Inferior recess
  • Inferior to the right gastropancreatic fold (common hepatic a.)
  • Anterior - hepatoduodenal ligament, duodenum, gastrocolic ligament
  • Posterior - pancreas, tail of pancreas enters lienorenal ligament
  • Superior - superior recess
  • Inferior - transverse mesocolon
  • Right - liver
  • Left - gastrolienal ligament
Splenic recess
  • Left of gastroepiploic fold (left gastric a.)
  • Anterior - stomach, gastrocolic ligament (greater omentum)
  • Posterior - aorta, left suprarenal gland, upper pole left kidney, splenic a., diaphragm
  • Superior - liver and diaphragm
  • Inferior - inferior recess
  • Right - caudate lobe, superior recess
  • Left - gastrolienal and lienorenal ligaments
Epiploic foramen
  • Communication between lesser and greater sacs
  • Anterior - hepatoduodenal ligament
  • Posterior - inferior vena cava
  • Superior - caudate lobe liver
  • Inferior - duodenum
  • Right - opening into hepatorenal recess and right paracolic gutter
  • Left - lower recess of lesser sac
Pathway of Spilled Contents
  • Person rolls to the right - contents of lesser sac enter the greater sac via the epiploic foramen
  • Person returns to supine - contents enter the hepatorenal recess
  • Person stands - contents follow the right paracolic gutter to the pelvic basin and the rectouterine or rectovesical pouch
  • General discussion of abdominopelvic gutters
Somatic afferent innervation
  • parietal peritoneum of the posterior wall innervated by thoracoabdominal nerves
Sharp pain
  • Irritation of the parietal peritoneum of the posterior wall activates somatic afferent activity in the thoracoabdominal nerves (intercostals, subscostals, iliohypogastric, ilioinguinal) and possibly phrenic nerve.
Vascular supply
  • Vascular supply is by regional arteries and veins (optional)
  • Posterior - splenic av
  • Anterior - common hepatic, right gastric, left gastric, arteries
  • Inferior - right and left gastroepiploic arteries and veins, supra- and retroduodenal arteries and veins
  • Superior - inferior phrenic av
  • Left - short gastric arteries and veins
  • Right - right and left gastric arteries and veins
Lymphatic drainage
  • Follows vascular supply
  • paraaortic nodes to lumbar trunks to cisterna chyli
  • diaphragmatic border involves mediastinal and axillary nodes (anterior wall vasculature)
Autonomic Innervation
  • sympathetic preganglionic fibers - mostly from greater and lesser (cell bodies in imlcc of T5-11)
  • sympathetic postganglionic fibers - mostly from celiac plexus (cell bodies in celiac ganglion)
  • parasympathetic preganglionic fibers - from vagus nerve (cell bodies in dorsal motor nucleus of vagus nerve)
  • parasympathetic postganglionic fibers - intrinsic ganglia
Visceral afferent innervation
  • "pain" follows sympathetic pathways to spinal levels T5-11
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Survey of foregut, midgut, hindgut, Celiac Trunk, Stomach, Spleen, Liver, Gall bladder

Review the anatomy of Part I (cap) of the duodenum with respect to structure, relationships, innervation (sensory and motor), vasculature, lymphatic drainage, support (visceral and fibrous). Cite an example of clinical relevance. (10 pts)

Part 1
  • Relationships and boundaries
    • Vertebral level L1 (transpyloric plane)
    • Posterior
      • Inferior vena cava
      • pancreas, bile duct, gastroduodenal a.
    • Anterior
      • liver and gall bladder
    • Superior
      • margin of epiploic foramen
    • Inferior
      • transverse mesocolon and right colic flexure
    • Medial
      • pancreas, stomach, lessor omentum
    • Lateral
      • second part of duodenum and gall bladder
  • Contents and Special Features
    • Forms the duodenal cap
    • No plicae circulares
      • Smooth walled
    • Receives stomach contents directly via pylorus
      • high acidity may cause ulceration
    • partly intraperitoneal
      • attachment of hepatoduodenal ligament (lessor omentum)
      • attachment of greater omentum
  • Vascular Supply
    • gastroduodenal artery
      • Superior part by supraduodenal arteries and veins
      • Inferior part by retroduodenal arteries and veins
      • Superior anterior and posterior pancreaticoduodenal arteries
    • Veins follow similar pathways and drain into the hepatic portal vein.
  • Innervation
    • Parasympathetic
      • preganglionic fibers derived from vagus nerve and travel in celiac mesenteric plexuses.
      • postganglionic fibers located in intrinsic ganglia of the duodenum
    • Sympathetic
      • preganglionic fibers (IMLCC T5-T9) travel in greater splanchnic nerve
      • pierce crura of diaphragm and enter celiac ganglia on sides of aorta near celiac arterial trunk
      • postganglionic fibers derived from cell bodies located in celiac ganglia
      • travel to duodenum along arterial extensions of the celiac mesenteric plexuses
  • Lymphatic drainage
    • primary drainage into pyloric nodes and right gastroepiploic nodes
    • celiac nodes to intestinal lymph trunk and to cisterna chyli
  • Support
    • pylorus and hepatoduodenal ligament

Review the anatomy of Part II (descending) of the duodenum with respect to structure, relationships, innervation (sensory and motor), vasculature, lymphatic drainage, support (visceral and fibrous). Cite an example of clinical relevance. (10 pts)

Part II
  • Relationships and boundaries
    • Vertebral level L1-L3
    • Posterior - hilum of right kidney
    • Anterior - attachment of transverse mesocolon
    • Superior - liver
    • Inferior - jejunum
    • Medial - pancreas and common bile duct
    • Lateral = right colic flexure
  • Contents and Special Features (3 pts)
    • Beginning of plicae circulares
    • Minor duodenal papilla - accessory pancreatic duct
    • Major duodenal papilla - chief pancreatic duct
      • Sphincter of Oddi
      • Ampulla of Vater
  • Vasculature and lymphatic supply
    • Superiorly from gastroduodenal artery
      • Superior anterior and posterior pancreaticoduodenal arteries
    • Inferiorly from superior mesenteric artery
      • Inferior anterior and posterior pancreaticoduodenal arteries
    • Veins follow similar pathways peripherally but drain into portal vein centrally.
    • Lymphatic drainage
      • primary drainage into pyloric nodes and right gastroepiploic nodes
      • celiac nodes to intestinal lymph trunk and to cisterna chyli
  • Innervation
    • Parasympathetic
      • preganglionic fibers derived from vagus nerve and travel in celiac and superior mesenteric plexuses.
      • postganglionic fibers located in intrinsic ganglia of the duodenum
    • Sympathetic
      • preganglionic fibers from greater splanchnic (T5-T9) and lesser splanchnic (T10-T11) nerves
        • travel to celiac and superior mesenteric ganglia respectively
      • postganglionic fibers from celiac and superior mesenteric ganglia
        • travel to duodenum along arterial extensions of the celiac and superior mesenteric plexuses
  • Support
    • retroperitoneal - extraperitoneal connective tissue
    • head of pancreas and common bile duct

Review the anatomy of Part III (horizontal) of the duodenum with respect to structure, relationships, innervation (sensory and motor), vasculature, lymphatic drainage, support (visceral and fibrous). Cite an example of clinical relevance. (10 pts)

Part III
  • Structure and relations,
    • These superior mesenteric artery branches from the aorta near the L2 vertebral level. It courses inferiorly and anterior resulting in the formation of a "V" by the superior mesenteric artery and the aorta.
    • Crossing the aorta just inferior to the branching of the superior artery is the left renal vein. The horizontal portion of the duodenum crosses the aorta immediately inferior to the left renal vein at the L3 level.
    • A swelling of the superior mesenteric artery near its origin from the aorta or a swelling of the aorta just distal to the origin of the superior mesenteric artery could compress the left renal vein and the duodenum.
    • Vomiting, left kidney problems, and varicoceles of the pampiniform plexus could result.
  • Innervation (similar to part II with a bias toward superior mesenteric plexus)
    • Sympathetic
      • Preganglionic cell bodies - IMLCC of T10-11
        • fibers travel within lesser splanchnic n.
      • Postganglionic cell bodies - Superior mesenteric ganglion
        • fibers travel with extensions of superior mesenteric plexus along inferior anterior/posterior pancreaticoduodenal arteries.
    • Parasympathetic
      • preganglionic cell bodies in dorsal motor nucleus of vagus nerve
        • preganglionic fibers travel through super mesenteric ganglion without synapsing and contribute to superior mesenteric plexus
    • General visceral afferent fibers follow sympathetic (pain) and vagal (visceral reflexes) pathways.
  • Vasculature and lymphatic supply
    • Inferior anterior/posterior pancreaticoduodenal arteries and veins
      • arteries. from superior mesenteric artery from aorta
      • veins. from superior mesenteric vein from portal v.
    • lymphatic drainage to superior mesenteric nodes to intestinal trunk to lumbar trunk to cisterna chyli
  • Support
    • retroperitoneal - extraperitoneal connective tissue
  • Clinical significance
    • A swelling of the superior mesenteric artery near its origin from the aorta or a swelling of the aorta just distal to the origin of the superior mesenteric artery could compress the left renal vein and the duodenum.
    • Vomiting and left kidney problems could result.
    • Varicoceles of pampiniform plexus.

Review the anatomy of Part IV (ascending) of the duodenum with respect to structure, relationships, innervation (sensory and motor), vasculature, lymphatic drainage, support (visceral and fibrous). Cite an example of clinical relevance. (10 pts)

Part IV
  • Structure and relations
    • The 4th part of the duodenum is located at the level of the second lumbar vertebra and crosses the anterior surface of the aorta. It is the last part of the duodenum and ends at the duodenojejunal junction where the suspensory ligament of Treitz marks the end of the retroperitoneal course of the duodenum and the beginning of the intestinal mesentery. Crossing anteriorly is the transverse mesocolon and gastrocolic ligament and stomach. Superiorly is the body of the pancreas. posteriorly and to the left is the hilum of the left kidney. Paraduodenal recesses are sometimes present. These recesses can entrap viscera.
  • Innervation
    • The autonomic nerve supply is from the superior mesenteric plexus. Preganglionic sympathetic fibers within the lesser splanchnic nerve are derived from cell bodies in the intermediolateral cell columns of spinal cord levels T10 and T11. Postganglionic fibers arise from cell bodies in the superior mesenteric ganglion. These fibers help form the superior mesenteric plexus. Parasympathetic preganglionic fibers travel with branches of the vagus nerve to enter into the superior mesenteric plexus. The parasympathetic postganglionic cell bodies are located in enteric ganglia within the wall of the duodenum.
    • General visceral afferent fibers follow sympathetic (pain) and vagal (visceral reflexes) pathways
    • Sympathetic
      • Preganglionic cell bodies - IMLCC of T10-11
        • fibers travel within lesser splanchnic n.
      • Postganglionic cell bodies - Superior mesenteric ganglion
        • fibers travel with extensions of superior mesenteric plexus along inferior anterior/posterior pancreaticoduodenal arteries.
    • Parasympathetic
      • Preganglionic cell bodies in dorsal motor nucleus of vagus nerve
        • preganglionic fibers travel through super mesenteric ganglion without synapsing and contribute to superior mesenteric plexus
      • Postganglionic cell bodies in enteric ganglia
  • Vasculature and lymphatic supply
    • The chief arterial supply is from the inferior anterior and posterior pancreaticoduodenal arteries arising from the trunk of the superior mesenteric artery. Additional supply may come from the first jejunal artery. The venous drainage follows the same named arteries and empty into the portal vein by way of the superior mesenteric vein.
    • The primary lymph drainage is into superior mesenteric and upper lumbar nodes and the intestinal lymph trunks into the cisterna chyli.
  • Support
    • ligament of Treitz
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Small and Large Intestine, Appendix, Paracolic Gutters

Review the anatomy of the transverse colon. Include structure, support, relationships, innervation, vasculature, and lymphatic drainage. Cite an example of clinical relevance. (10 pts)

General
  • The transverse colon is an intraperitoneal segment of the large bowel. It spans from the right colic flexure to the left colic flexure. Surgical access to the lesser sac is provided by the gastrocolic ligament. The transverse colon divides the greater sac into supracolic and infracolic compartments.
Structure
  • Layers - from inner to outer
    • Mucosa (columnar epithelium) - no villi in large intestine
    • Submucosa (vascular and submucosal nerve plexuses) - padding between mucosa and muscular layer
    • Tunica muscularis - inner circular and outer longitudinal smooth muscle, myenteric plexus, peristalsis
    • Mesothelium and connective tissue
    • Serosa - visceral peritoneum covers the transverse colon except at the attachment of transverse mesocolon
  • Teniae coli - 3 longitudinal bands of smooth muscle
  • Haustra coli - sacculations caused by the teniae coli being shorter than the gut tube
  • Appendices epiploicae - fat appendages hanging from the teniae coli
  • Caliber is generally larger than the small intestine
Support
  • Right
    • Superior aspect of retroperitoneal ascending colon, cradled by right lobe of liver
    • Right hepatocolic ligament
  • Middle
    • Transverse mesocolon attaches to posterior abdominal wall crossing right kidney, duodenum, IVC, aorta, pancreas, left kidney
    • Gastrocolic ligament provides anchoring to the stomach
  • Left
    • Phrenicocolic ligament
Relationships
  • Right - level of L2
    • Superior - liver, gallbladder, descending duodenum
    • Inferior - coils of jejunum and ileum
    • Anterior - costal margin, diaphragm, liver
    • Posterior - diaphragm, right kidney, inferior vena cava, pancreas, quadratus lumborum
    • Lateral left -
    • Lateral right - liver, right paracolic gutter, hepatorenal recess
  • Middle - level of L1-2
    • Superior - stomach, gastrocolic ligament, liver, lesser sac
    • Inferior - coils of jejunum and ileum
    • Anterior - greater omentum, costal margin, diaphragm, falciform ligament
    • Posterior - pancreas (head, body, and tail), horizontal duodenum, aorta, superior mesenteric artery, intestinal mesentery
    • Lateral left - left colic flexure (see below)
    • Lateral right -right colic flexure (see above)
  • Left - level of T12-L1
    • Superior - spleen, diaphragm
    • Inferior - jejunum, descending colon, left paracolic gutter
    • Anterior - diaphragm
    • Posterior - diaphragm, left kidney, quadratus lumborum
    • Lateral left - phrenicocolic ligament, superior aspect of left paracolic gutter
    • Lateral right -
Innervation
  • Right Side
    • Parasympathetic
      • Preganglionic
        • Vagus nerves
        • Preganglionic pathway - vagus nerves, superior mesenteric ganglion (no synapse), superior mesenteric plexus, right and middle colic arteries
      • Postganglionic
        • Enteric ganglia at the target
        • Cell bodies in submucosal layer - postganglionic fibers contribute to submucous plexus, enteric plexus
    • Sympathetic
      • Preganglionic
        • Cell bodies within intermediolateral cell column (IMLCC) of T10-11
        • Preganglionic fiber path - ventral root to spinal nerve, to ventral ramus, white ramus communicans, thoracic sympathetic trunk, thoracic splanchnic nerves, lesser splanchnic nerve
      • Postganglionic
        • Cell bodies in the superior mesenteric ganglion
        • Postganglionic fiber pathway - superior mesenteric plexus, right colic artery, middle colic artery, enteric plexus
    • Visceral Afferent
      • High threshold (pain)
        • Follow sympathetic preganglionic and sympathetic postganglionic pathways
      • Low threshold (homeostatic)
        • Follow the vagus nerves
  • Left Side
    • Parasympathetic
      • Preganglionic
        • Pelvic splanchnic nerves
        • Preganglionic pathway - IMLCC S2-4, pelvic splanchnic nerves, inferior hypogastric plexus, left hypogastric nerve, sigmoid mesocolon, retroperitoneal along medial margin of descending colon, left transverse mesocolon
      • Postganglionic
        • Enteric ganglia at the target
        • Cell bodies in submucosal layer - postganglionic fibers contribute to submucous plexus, enteric plexus
    • Sympathetic
      • Preganglionic
        • Cell bodies within intermediolateral cell column (IMLCC) of L1-3
        • Preganglionic fiber path - ventral root to spinal nerve, to ventral ramus, white ramus communicans, lumbar sympathetic trunk, lumbar splanchnic nerves, aoric plexus, inferior mesenteric ganglia (synapse here)
      • Postganglionic
        • Cell bodies in the inferior mesenteric ganglia
        • Postganglionic fiber pathway - inferior mesenteric plexus, left colic artery, enteric plexus
    • Visceral Afferent
      • High threshold (pain)
        • Follow sympathetic preganglionic and sympathetic postganglionic pathways
      • Low threshold (homeostatic)
        • Follow parasympathetic preganglionic pathway (see parasympathetic preganglionic pathway)
Vasculature
  • Provided by the blood supply of midgut and hindgut, venous drainage is into portal system
  • Right
    • Right colic artery/vein from superior mesenteric artery/vein
      • Retroperitoneal up to right colic flexure
      • Contributes to marginal artery/vein
  • Middle
    • Middle colic artery/vein from superior mesenteric artery/vein
      • Travels through to transverse mesocolon
      • Contributes to marginal artery/vein
  • Left
    • Left colic artery/vein from inferior mesenteric artery/vein
      • Retroperitoneal up to left colic flexure
      • Contributes to marginal artery/vein
Lymphatic drainage
  • Intestinal nodes to central nodes (superior and inferior mesenteric nodes) to intestinal lymph trunks to cisterna chyli
  • Right
    • Paracolic nodes to superior mesenteric nodes
  • Middle
    • Paracolic nodes to superior mesenteric nodes
  • Left
    • Paracolic nodes to inferior mesenteric nodes

Review of the anatomy of the appendix. Include structure, relationships, innervation, vasculature, lymphatic drainage, and support. Account for the progression beginning with dull ache in the lower right quadrant accompanied by paraumbilical referred pain, and then proceeding to acute, localized, and sharp pain. Cite an example of clinical relevance. (10 pts)

General
Structure
Relationships
Innervation
Vasculature
Lymphatic drainage
Support
Clinical
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Duodenum, Pancreas, Portal vein, Portal hypertension

Cirrhosis of the liver limits the passage of portal blood through the sinusoids and into the hepatic veins. Portal hypertension causes retrograde portal blood flow at sites of portacaval anastomoses. Discuss the anatomy and symptoms associated with dilated veins in the vicinity of portacaval shunts. (10 pts)

Caput medusae
  • Paraumbilical veins (portal) and venous drainage of the anterior abdominal wall (caval).
Esophageal varices
  • Esophageal vein (branch of left gastric vein) and venous drainage of the esophageal venous plexus (azygos system to caval).
Internal hemorrhoids
  • Superior rectal vein (portal) and inferior rectal vein (caval).

Review the anatomy of the Pancreas. Include structure, support, relationships, vasculature, innervation, and lymphatic drainage. Cite an example of clinical relevance. (10 pts)

General
The pancreas is a tear-drop shaped finely lobulated glandular structure associated with the duodenum. Named parts include the head, uncinate process, neck, body, and tail. It lies transversely to the anterior surface of the aorta with the neck and uncinate process on the anterior surface of the aorta and IVC. The tail extends laterally to left as far as the lienorenal ligament. The longitudinal extent is about 6 - 8 inches. The width at the head is 2 - 3 inches. The chief and accessory pancreatic ducts discharge digestive enzymes into the duodenum at the major and minor duodenal papilla. The chief pancreatic duct runs the transverse length of the pancreatic tissues and drains toward the ampulla of Vater. In turn, discharge from the ampulla is regulated by the sphincter of Oddi. The accessory pancreatic duct drains the superior aspect of the head.
Structure
  • The pancreas is located retroperitoneal and forms much of the floor of the lesser sac
  • The head extends from the right side of the L1-3 lumbar vertebrae
  • The head is cradled by all parts of the duodenum in the comfortable embrace of a "C"
  • The head, neck crosses the IVC, the anterior vertebral bodies of L1-3 and the aorta
  • The body crosses the duodenojejunal junction
  • The neck, body, and tail extend to the left as far the the hilum of the spleen
  • The uncinate process creates the pancreatic incisure at the inferior border of the head
  • The pancreatic incisure "takes a bite" out of the superior mesenteric vein and artery (vein to right of artery)
  • The uncinate process lies posterior to the superior mesenteric vein and artery
Relationships
  • Transverse mesocolon crosses lower aspect of head and inferior margin of neck and body
  • Anterior surface faces lessor sac and stomach - incision of gastrocolic ligament provides surgical access
  • Anterior surface of head touches all four parts of duodenum
  • Posterior to the head is the hilum of the right kidney along with the right renal vessels
  • Posterior to the head is the common bile duct on the right and the portal vein to the left
  • Posterior to the neck is the inferior vena cava and the aorta
  • Posterior to the body is the left kidney, suprarenal gland, and right crus of the diaphragm
  • The celiac trunk is immediately superior to the upper margin of the head and neck
  • The splenic artery runs retroperitoneal along the superior margin of the neck, body, and crosses anterior to tail
  • The common hepatic artery crosses the anterior surface of the upper margin of the head to the right side
  • The splenic vein runs directly posterior to the neck and body
  • The inferior mesenteric vein crosses the posterior surface of the lower margin of the neck
Vasculature
  • Head - arterial arcades from the celiac (foregut) and superior mesenteric arteries (midgut)
    • the superior anterior and posterior pancreaticoduodenal arteries from the gastroduodenal artery
    • the inferior anterior and posterior pancreaticoduodenal arteries from the superior mesenteric artery
  • Neck - dorsal pancreatic artery from aorta
  • Body - great pancreatic artery from splenic artery
  • Tail - caudal pancreatic arteries from splenic artery
    • The inferior pancreatic artery, an anastomotic network within the pancreas, provides all tissues
    • Venous drainage follows arterial channels to eventually drain into the SMV, splenic vein, and portal vein
Lymphatic drainage
  • Lymphatic drainage tends to follow blood vessels
  • Superior margin of head into celiac nodes
  • Inferior margin of head into superior mesenteric nodes
  • Anterior surfaces into pyloric nodes
  • Body and tail into pancreaticolienal nodes along splenic vessels and into celiac nodes or upper lumbar nodes
  • paraaortic nodes drain into lumbar lymph ducts and then into cisterna chyli
Innervation
  • Celiac plexus innervates superior head and neck as well as the body and tail
  • Superior mesenteric plexus innervates the inferior head
  • Sympathetic preganglionic cell bodies - IMLCC of T5-9 to fibers in greater splanchnic nerve
  • Sympathetic postganglionic cell bodies - celiac ganglion to fibers in celiac plexus
  • Sympathetic preganglionic cell bodies - IMLCC of T10-11 to fibers in lesser splanchnic nerve
  • Sympathetic postganglionic cell bodies - superior mesenteric ganglion to fibers of superior mesenteric plexus
  • Parasympathetic preganglionic cell bodies - dorsal motor nucleus vagus nerve to fibers of celiac and superior mesenteric plexuses
  • Visceral afferent pain - follow thoracic to spinal levels T5-11
Clincal Relevance
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Posterior Abdominal Wall, Aorta, Kidneys, Suprarenal glands, Diaphragm, Lumbar Plexus

Review the anatomy of the left kidney. Include structure, innervation, vasculature, lymphatic drainage, and relationships. Cite an example of clinical relevance. (10 pts)

Structure
  • Medial and lateral margins
  • Hilum and renal sinus
  • Fibrous capsule
  • Cortex and medulla
  • Pyramids and renal papilla
  • Minor and major calyx
    • Two or more minor calyces form a major calyx
    • Major calyces combine to form the renal pelvis
  • Renal pelvis
    • Extends through hilum to become the ureter
Position
  • paravertebral gutters
  • 11th thoracic to 3rd lumbar vertebra
Relations to peritoneum and fascia
  • perirenal fat - into renal sinus
  • renal fascia - condensation of ECT, open inferiorly (support and spread of infection)
  • pararenal fat - outside renal fascia, envelopes suprarenal gland and kidney
Relations to surrounding viscera (left kidney)
  • Superior - suprarenal gland
  • Inferior - false pelvis
  • Posterior - diaphragm, lumbocostal trigone, 11-12 ribs, quadratus lumborum, psoas major
  • posteromedial - medial and lateral arcuate ligaments, subcostal nerve, iliohypogastric nerve
  • anteromedial - aorta
  • Anterior - suprarenal g., omental bursa, stomach and lienorenal ligament, spleen, tail of pancreas, left colic flexure, intestine, descending colon
Relations at the hilum
  • Anterior to posterior - renal vein, renal artery, renal pelvis
Sensory and motor innervation
  • preganglionic sympathetic fibers - IMLCC of T10-12, synapse in aorticorenal ganglion
  • postganglionic sympathetic fibers - renal plexus
  • sensory - T10 - L1, follow renal plexus, referred pain
Vascular supply
  • Left renal vein - crosses aorta in "nutcracker", anterior to renal artery,
  • Left renal artery at level of L3,
Lymphatic drainage
  • lumbar nodes
Clinical Relevance
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Autonomic Innervation to Foregut, Midgut, Hindgut, and Pelvis

(Note: The anatomy of the autonomic nervous system (ANS) applies to all regions of anatomy. Thus, the ANS applies to all questions in the examination pool.)
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Skeleton, Anal triangles, Ischiorectal fossa, Female and Male Perineum

Discuss the boundaries and contents of the ischiorectal fossa, fascial specializations, vasculature, innervation, lymphatic drainage, the relationship of the ischiorectal fossa to the superficial and deep pouches, and provide an explanation of your observation that urine does not accumulate in the superficial pouch. Cite an example of clinical relevance. (10 pts)

General
  • Wedge shaped area located between the ischial tuberosities and the anorectal canal and consisting of a posterior recess and an anterior superior recess.
Boundaries of Anterior Superior Recess
  • Superior - inferior fascia of the pelvic diaphragm, most lateral and superior is arcus tendineus
  • Inferior - superior fascia of the urogenital diaphragm
  • Anterior - fusion of superior fascia urogenital diaphragm (transverse perineal ligament) with inferior fascia of pelvic diaphragm at the pubic bone
  • Posterior - open into the posterior recess of the ischiorectal fossa
  • Lateral - inferior - conjoint ramus, intermediate - obturator internus muscle
  • Medial - fusion of the inferior fascia of the pelvic diaphragm with superior fascia urogenital diaphragm at urogenital hiatus
Boundaries of Posterior Recess
  • Superior - inferior fascia of the pelvic diaphragm
  • Inferior - medial: perianal skin, lateral: gluteus maximus
  • Anterior - superior to posterior free edge urogenital diaphragm: anterior superior recess of the ischiorectal fossa, inferior to posterior free edge of urogenital diaphragm: superficial perineal fascia (Dartos)
  • Posterior - gluteus maximus
  • Lateral - gluteus maximus
  • Medial - anal canal
Fascial specializations
  • Arcus tendineus - thickening of obturator internus fascia, faces pelvic cavity on superior aspect and ischiorectal fossa on inferior aspect
  • Pudendal canal - thickened covering of obturator internus fascia over falciform edge along medial ischial tuberosity forms osseofibrous pudendal canal from lesser sciatic foramen to the posterior free edge of the urogenital diaphragm at the conjoint ramus
Contents and relationships
  • Loose areolar fat - accommodate distention
  • Anal canal
  • Pudendal nerve and branches - inferior rectal, perineal, posterior scrotal, dorsal nerve
  • Internal pudendal artery and branches - inferior rectal, perineal, posterior scrotal, dorsal artery, deep artery, artery to the bulb
Fascial Barriers to the Superficial Pouch
  • Infection does not spread from the ischiorectal fossa into the superficial pouch because Scarpa's fascia attaches to the posterior free edge of the urogenital diaphragm. This attachment provides part of the anterior border of the ischiorectal fossa at levels inferior to the posterior free edge of the urogenital diaphragm.
Fascial Barriers to the Deep Pouch
  • Infection does not spread from the ischiorectal fossa into the deep pouch because the superior fascia of the urogenital diaphragm provides a fascial barrier between the anterior superior recess of the ischiorectal fossa and the deep pouch.
Clinical Relevance
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Pelvic Fascia and Peritoneum, Vagina, Uterus, Ovaries

Review the anatomy of the prostate. Include structure, supports, relationships, vasculature, innervation, and lymphatic drainage. Cite an example of clinical relevance. (10 pts)

Structure
  • The prostate, a walnut sized structure located superior to the pelvic floor and inferior to the neck of the bladder, is uniquely in the male. The glandular structure is encapsulated in a shiny capsule that is, in turn, surrounded by a thickened periprostatic fascia derived from pelvic visceral fascia. The posterior aspect of this fascia is especially thickened and is named the fascia of Denonvillier. A considerable amount of smooth muscle within the stroma adds firmness to the gland. Glandular follicles drain by way of 15 - 20 prostatic ducts into the prostatic sinuses of the prostatic urethra.
  • The median lobe of the prostate is posterior to the prostatic urethra. This lobe includes the ejaculatory ducts, seminal colliculus, urethral crest, and most distal aspect of the uvula. Benign prostatic hypertrophy commonly affects the median lobe. In addition to the median lobe, there designated two lateral lobes and an anterior lobe. There are no anatomical landmarks delineating the lobes.
  • The prostatic urethra occupies about 2.5 cm of the central prostate. The superior posterior wall receives a projection of the uvula that becomes the urethral crest within the prostatic urethra. Approximately one-third of the way into the prostatic urethra the urethral crest widens for 2-4 mm to form the seminal colliculus. The ejaculatory ducts empty into the prostatic urethra on either side of the seminal colliculus. Lateral to the seminal colliculus the posterior wall deepens posteriorly to the form the prostatic sinuses receiving the prostatic ducts. The utricle, thought to be a vestigial uterus in the male, might be visible on the anterior surface of the seminal colliculus.
Support
  • Puboprostatic ligament - Condensation of pelvic visceral fascia secures prostate to anterior pelvic wall
  • Lateral ligaments - Condensation of pelvic visceral fascia secures prostate to lateral pelvic wall
  • Median umbilical ligament - obliterated urachus secures bladder, and thus prostate, to anterior abdominal wall
  • Levator prostatae muscle - fibers of pubococcygeus insert into the prostatic fascia and capsule
Relationships
  • Inferior - superior fascia fascia of the pelvic diaphragm located at the urogenital hiatus of the urogenital diaphragm
  • Superior - neck of the bladder and the uvula
  • Anterior - inferior aspect of the pubic symphysis
  • Posterior - rectum, rectovesical space
  • Posterior/superior - ampulla of ductus deferens, ureter, seminal vesicle
  • Lateral - pelvic diaphragm, superior aspect of conjoint rami, pelvic wall
Vasculature of prostate
  • The arterial supply to the prostate is derived from the inferior vesicle, middle rectal, and inferior rectal (internal pudendal) arteries. Each of these arteries is a branch of the internal iliac artery
  • The prostatic venous plexus is superficial to the capsule and deep to prostatic fascia. It receives the deep dorsal vein of the penis and the vesicle venous plexus. Venous drainage to internal iliac veins follow the aforementioned arterial pathways. There is free drainage by the lateral sacral veins into the internal vertebral venous plexus. This drainage is thought to account for the propensity of prostatic cancers to metastasize to the vertebral column.
Innervation of prostate
  • The prostatic autonomic plexus is derived from the inferior hypogastric plexus. Preganglionic sympathetic cell bodies are located in the IMLCC of L1-2. Preganglionic fiber pathways involve the superior hypogastric plexus and the right and left hypogastric nerves. Further, preganglionic fibers can follow the common iliac plexus to the internal iliac plexus and arrive at the prostatic plexus by way of the arterial supply. Postganglionic sympathetic cell bodies are thought to be located in unnamed ganglia distributed throughout the inferior hypogastric plexus. Additionally, preganglionic fibers within the sacral sympathetic trunk contribute sacral splanchnic nerves to the inferior hypogastric plexus.
  • Parasympathetic preganglionic cell bodies are located in the IMLCC of S2-4. Pelvic convey preganglionic fibers to the inferior hypogastric plexus. Postganglionic cell bodies are located in enteric ganglia at the target location.
  • The inferior hypogastric plexus form extensions that spread out over the pelvic organs. The prostatic autonomic plexus forms a collection of nerves the run along the lateral aspect of the prostate and onto the the membranous urethra to enter the cavernous tissue of the perineum. The cavernous nerves provide the parasympathetic innervation to the helicine arteries. To avoid impotency, it is essential that the cavernous nerves are preserved during prostatic surgery.
Lymphatic drainage
  • The internal tissues of the prostate have relatively little lymphatic drainage. For this reason, it is thought that metastatic disease reaches the vertebral column through venous channels (see above).
  • The prostatic capsule and fascia drain into internal iliac nodes to common iliac, to lumbar, to cisterna chyli.
Clinical Relevance

A hysterosalpingogram determines patency of the uterine ostia and uterine tubes. Radiographic contrast is injected into the uterine cavity through the vagina and cervix. If the fallopian tubes are patent, dye fills spills into the abdominal cavity. Blockages are then ruled out as the cause of a patient's infertility. Indicate your understanding of the uterus, uterine tubes, and ovary as to structure, orientation, relationships (anterior, posterior, superior, inferior, medial, lateral), ligamentous support, peritoneal associations, innervation (preganglionic, postganglionic, and visceral afferent pathways), vasculature, and lymphatic drainage. Cite an example of clinical relevance. (10 pts)

Uterus
Structure
  • Pear shaped hollow organ - 8cm long, 5cm wide
  • myometrium and endometrium
  • cervix, body, fundus
  • external os, cervical canal, internal os, uterine cavity
Orientation
  • anteflexed and anteverted (lengthens posterior fornix vagina)
Support
  • intraperitoneal organ
  • Broad ligament - visceral ligament (peritoneum)
    • lateral uterus to parietal peritoneum of lateral pelvic wall
  • fibrous ligaments derived from visceral pelvic fascia
    • uterosacral, pubouteral, and lateral cervical (Cardinal) ligaments
  • round ligament to lateral anterior pelvic brim - anterior lamina broad ligament
  • ovarian ligament to posterior abdominal wall via suspensory ligament ovary
Relationships
  • Anterior: bladder, vesicouterine pouch
  • Posterior: rectum, rectouterine pouch
  • Superior: false pelvis, abdominal cavity
  • Inferior: vagina, posterior fornix, rectouterine pouch
  • lateral: broad ligament, pelvic wall, ovary, uterine tube
Vasculature and lymphatic drainage
  • uterine artery at the cervix and ovarian artery at the fundus
    • ovarian vein to inferior vena cava on right and left renal vein on left
    • uterine venous complex into internal iliac veins.
  • fundus drains lymph to upper lumbar nodes along ovarian vessels
  • Superior body near round ligament drains lymph to superficial inguinal nodes
  • cervix drains lymph toward internal iliac nodes
Innervation
  • sympathetic by way of inferior hypogastric plexus to uterovaginal plexus along uterine a.
    • preganglionic in IMLCC lower thoracic and upper lumbar
    • postganglionic in microscopic ganglia of aortic and hypogastric plexuses
  • parasympathetic: pelvic splanchnic if present
  • sensory pain follow sympathetic pathways (e.g. hypogastric nerves)
Uterine Tube
Structure
  • shaped as a salpinx and about 10 cm long
  • connects uterine cavity to the peritoneal cavity
  • isthmus, ampulla, infundibulum, fimbriae
Orientation
  • courses laterally from fundus of uterus toward pelvic wall
  • intraperitoneal in superior free edge of broad ligament
  • cradles ovary as a posterior relation
Support
  • mesosalpinx - visceral ligament (peritoneum) part of broad ligament
    • continuous with mesovarium
  • ovarian ligament to posterior abdominal wall via suspensory ligament ovary
Relationships
  • Anterior: bladder, vesicouterine pouch
  • Posterior: broad ligament, rectum, rectouterine pouch, ovary
  • Superior: false pelvis, abdominal cavity
  • Inferior: broad ligament, rectouterine pouch
  • lateral: broad ligament, pelvic wall, ovary, ovarian fossa, uterine tube
  • medial: fundus and body of uterus
Vasculature and lymphatic drainage,
  • tubal a., uterine artery at the cervix and ovarian artery at the fundus
  • uterine venous complex to internal iliac veins
  • drains lymph to upper lumbar nodes along ovarian vessels
  • drains lymph to superficial inguinal nodes
  • drains lymph toward internal iliac nodes
Innervation
  • sympathetic by way of inferior hypogastric plexus to uterovaginal plexus along uterine a.
    • preganglionic in IMLCC lower thoracic and upper lumbar
  • postganglionic in microscopic ganglia of aortic and hypogastric plexuses
  • sympathetic by way of ovarian plexus
  • parasympathetic: unknown if present
  • sensory pain follow sympathetic pathways
Ovary
Structure
  • The ovary is roughly cylindrical about 3 cm long and 1 cm in diameter. The visceral peritoneum covering the ovary gives way to a specialized germinal epithelial cell layer. The egg is able to penetrate this layer and enter the peritoneal cavity.
Support
  • The ovary is suspended from the posterior lamina of the broad ligament by the mesovarium -- a peritoneal ligament. Supporting the superior pole of the ovary to the pelvic brim is the suspensory ligament of the ovary. Supporting the inferior pole of the ovary to the lateral uterus is the ovarian ligament.
Relationships
  • Superior to the ovary is the pelvic brim and suspensory ligament
  • Inferior to the ovary is the uterine wall and the ovarian ligament
  • Anterior to the ovary is the broad ligament, uterine tube, and fimbria of uterine tube
  • Posterior to the ovary is the rectum and pelvic floor
  • Medial to the ovary is the pararectal fossa, rectouterine pouch, fundus of the uterus
  • Lateral to the ovary is the ovarian fossa (internal iliac artery and ureter), psoas major muscle, and obturator n.
Innervation (motor and sensory)
  • Parasympathetic preganglionic cell bodies are located in the central gray of the spinal cord (IMLCC) at levels S2-4. Preganglionic fibers enter the inferior hypogastric plexus by way of the pelvic splanchnic nerves. The inferior hypogastric plexus contributes a uterine plexus and then to the ovarian plexus. Postganglionic parasympathetic cell bodies are located in intrinsic ganglia of the ovary. The above pathway assumes that the uterovaginal plexus reaches the ovary. This is not known for certain. Parasympathetic preganglionic fiber contributions from the vagus n. may also follow the ovarian plexus.
  • Sympathetic preganglionic cell bodies are located in the intermediolateral cell column at cord levels T10 (and perhaps T11-12). Preganglionic fibers follow the lesser and least to aortic ganglia near (and including) the superior mesenteric ganglion and the aorticorenal ganglion. Postganglionic fibers from these ganglia enter the aortic plexus and extend along the ovarian artery as the ovarian plexus. Visceral afferent pathways follow the sympathetic pathways up to the T10 spinal level. Additional visceral pathways follow parasympathetic pathways back to the S3-4 spinal levels.
Vasculature
  • The arterial supply is mostly from the ovarian arteries. These are paired arteries arising from the anterolateral surface of the aorta near the level of the third lumbar vertebra. The ovarian veins arise from the inferior vena cava on the right and the left renal vein on the left. Additional blood supply is by ascending branches of the uterine vessels (ovarian branch) that anastomose with the ovarian vascular supply.
Lymphatic drainage
  • Lymph drainage is primarily along the embryological decent of the ovary. This includes upper lumbar nodes in the vicinity of the renal arteries. Much of the vascular supply reaches the ovary through the suspensory ligament.
Prolapse of Uterus
  • Weakening of the ligamentous support of the uterus leads to prolapse
    • most notably, the lateral cervical ligaments are important
Clinical Relevance
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Female and Male Bladder, Rectum, Anal Canal, Urination and Defecation

Review the anatomy of the rectum and anal canal. Include peritoneal relationships, vasculature, lymphatic drainage, innervation, and relationships to surrounding structures and spaces. Cite an example of clinical relevance. (10 pts)

General Anatomy of the Rectum
  • rectosigmoid junction at S3 extending to tip of coccyx and ending at anorectal junction (pelvic floor)
  • ends 2cm anterior and slightly inferior to the tip of the coccyx
  • passes through pelvic diaphragm before anorectal junction
  • 12 cm long with two convexities to right and one to left
  • transverse folds - two on the right and one on the left (this is variable)
  • teniae coli broaden to form longitudinal muscle layer
  • no haustra or appendices epiploica
  • smooth mucosa
  • distensible at the rectal ampulla
Peritoneal coverings and relations
  • upper 1/3 covered anterior and lateral
  • middle 1/3 covered anterior
  • lower 1/3 not peritonealized
  • peritoneal pouches and fossa
  • ant: rectouterine or rectovesical pouch
  • lateral: pararectal fossae
Relations to surrounding structures
  • Anterior - bladder, vagina, uterus, prostate, seminal vesicle, vas deferens, ureters
  • Posterior - presacral space, sacrum, sacral foramina, sacral plexus, sacral sympathetic trunk, piriformis, middle and lateral sacral arteries
  • lateral (left and right) - inferior hypogastric plexus, pelvic wall and associated structures, appendix on right
  • Superior - sigmoid colon, false pelvis
  • Inferior - anal canal, pelvic floor
Ligaments and support
  • Rectovesical - part of the pubosacral ligamentous complex (derived from pelvic visceral fascia)
  • Rectosacral - part of the pubosacral ligamentous complex (derived from pelvic visceral fascia)
Innervation (no somatic for rectum proper)
  • sympathetic - inhibitory to muscles of the rectal wall
    • Preganglionic: IMLCC L1-3 - white rami - lumbar sympathetic trunk - lumbar splanchnic nerves - aortic plexus - inferior mesenteric ganglion
    • Postganglionic: inferior mesenteric plexus - superior rectal arteries, right and left hypogastric nerves to rectal plexus
  • parasympathetic - relax internal anal sphincter, glandular secretion
    • Preganglionic: pelvic leave ventral rami of S2-4 spinal nerves to enter the pelvic plexus on either side of the rectum (inferior hypogastric plexus)
    • an extension of the pelvic plexus either independently or via the left hypogastric nerve contributes to rectal plexus
    • postganglionic: cell bodies and fibers are located in enteric (intrinsic) ganglia
  • Visceral afferent fibers
    • low threshold (homeostatic) follow parasympathetic pathways
    • high threshold (pain) follow sympathetic pathways
Vasculature Supply
  • Superior rectal arteries pair on lateral posterior rectum - derived from single continuation of inferior mesenteric a - provides superior aspect of rectum
  • Superior rectal vein - drains most of the entire venous plexus of the rectum
  • middle rectal artery - from internal iliac - provides inferior aspect of rectum
  • Inferior rectal artery - from pudendal artery - anastomosis with middle rectal artery
  • median sacral artery at the posterior aspect of the anorectal junction
  • rectal venous plexus drains to prostatic plexus or uterovaginal plexus
  • Inferior rectal and superior rectal veins form an interface between caval and portal drainages
  • epirectal lymph nodes drain superior toward upper lumbar nodes near the inferior mesenteric nodes
  • pararectal nodes drain laterally into internal iliac nodes
General Anatomy of the Anal Canal
  • begins at anorectal junction and ends at anal verge
  • 2.5 - 5 cm long
  • Anterior flexion by puborectal sling (puborectalis)
  • transition from cuboidal to squamous epithelium at the dentate line
  • layers - inner epithelium, vascular subepithelium, internal anal sphincter, external anal sphincter, fibromuscular support tissue
  • Anterior attachment to perineal body
  • Posterior attachment to anococcygeal raphe
  • surrounded by ischiorectal fat
  • rectal circular muscle becomes internal anal sphincter
  • puborectalis is continuous with external anal sphincter
  • anal columns end at anal valves
  • anal valves and sinuses mark the dentate line and the anorectal junction
  • stratified squamous epithelium inferior to dentate line
  • stratified columnar epithelium superior to dentate line
  • anal transition zone (ATZ) not same as dentate line but may include it
  • hemorrhoids of the anal cushions are superior to dentate line and may reflect portal hypertension
Innervation of the Anal Canal
  • distal to dentate line
    • somatic motor and sensory by pudendal nerve
    • defined pain
  • proximal to dentate line
    • visceromotor by autonomic nervous system (see above for rectum)
    • visceral afferent follow autonomic pathways (see above for rectum)
    • "dull ache"
  • external anal sphincter by inferior rectal branches of the pudendal nerve
  • internal anal sphincter by autonomic nerves
Vasculature of the Anal Canal
  • proximal - superior rectal artery/vein and median sacral artery/vein
  • distal - inferior rectal artery/vein from the internal pudendal artery/vein
  • proximal lymphatic drainage - upper lumbar nodes
  • distal lymphatic drainage - superficial inguinal nodes and internal iliac nodes
Clinical Relevance
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Female and Male Internal Iliac Artery, Sacral Plexus, Pelvic Autonomic Plexus


Presacral neurectomy is a surgical removal of the superior hypogastric plexus and the proximal right and left hypogastric nerves as a treatment for intractable pelvic pain. The intent is to disrupt general visceral afferent (GVA) fibers that convey pain information from the pelvic viscera. Sectioning the hypogastric nerves also disrupts a pathway followed by sympathetic fibers from the aortic and superior hypogastric plexus. Thus, presacral neurectomy disrupts sympathetic innervation of the pelvic viscera. Nonetheless, in most cases, the pelvic still respond to sympathetic activation. Explain how the pelvic viscera may still receive sympathetic innervation despite disruption of the hypogastric nerves. (10 pts)

General
  • The superior hypogastric plexus is an extension of the aortic plexus beyond the bifurcation of the aorta at L4. The superior hypogastric plexus is retroperitoneal and anterior to the the 5th lumbar vertebral body.
Composition
  • Postganglionic fibers from the celiac, superior mesenteric, aorticorenal, and inferior mesenteric ganglia
  • Preganglionic fibers from lumbar splanchnic nerves and vagus nerve
Distribution
  • Sympathetic supply to the pelvic viscera
  • Limited parasympathetic supply to the pelvic viscera
Alternative Pathways for Sympathetic supply to the Pelvis
  • Sacral sympathetic trunk
  • Periarterial plexuses
Clinical Relevance

Discuss the anatomy of micturition and defecation. Include autonomic and somatic contributions, structure, fascial coverings, spaces, vasculature, innervation, lymphatic drainage, and relationships. (10 pts)

General
Autonomic and Somatic Control
Structure
Relationships
Innervation
Vasculature
Lymphatic drainage
Support
Clinical
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Female and Male Pelvic Diaphragm

Discuss the anatomy of the pelvic diaphragm. Include structure, fascial coverings, spaces, vasculature, innervation, lymphatic drainage, and relationships. (10 pts)

Structure
  • The pelvic diaphragm is a thin sheet of muscle. The urethra and vagina pass through the pelvic diaphragm at the urogenital hiatus. The anal canal passes through the pelvic diaphragm at the anal triangle. Posterior to the vagina and anterior to the anal canal, the urogenital hiatus is filled by the perineal body and the pubococcygeus muscle. The pelvic diaphragm functions in micturition and defecation by controlling intra-abdominal pressure and the anatomical properties of functional sphincters -- uvula and puborectal sling.
  • The anterior aspect of the pelvic diaphragm is made up of the pubococcygeus, iliococcygeus, and the puborectalis. Collectively, these three muscles constitute the levator ani. Its lateral halves slope inferiorly medially from the arcus tendineus to meet at the midline of pelvic floor. The pubococcygeus and especially the iliococcygeus, upon contracting, raise the pelvic floor. These two muscles are tethered to the coccyx by the anococcygeal raphe and insert upon the lateral aspects of the urethra, prostate, vagina, and anal canal.
  • The puborectalis arises from the pubic bones near the superior aspect of the symphysis. It lies on the inferior surface of the pubococcygeus muscle. Posteriorly, the puborectalis muscle circles the anorectal junction. It is not tethered by the anococcygeal raphe. Thus, when contracted, the puborectalis pulls the rectum anterior and thereby promotes fecal continence.
  • The posterior wall of the pelvic diaphragm is defined by the ischiococcygeus muscle. This muscle is not anatomically favored to directly elevate the pelvic and, thus, is not included as part of levator ani. However, the ischiococcygeus muscle, by virtue of its attachments to the ischial spine and the coccyx acts of approximate these two structures and indirectly assists in elevating the pelvic floor.
Fascial Coverings
  • The superior surface of the pelvic diaphragm is covered by parietal pelvic fascia. This fascia is continuous with the transversalis fascia of the abdominal cavity. The inferior surface of the pelvic diaphragm is covered by the inferior fascia of the pelvic diaphragm. This fascia is continuous with deep fascia of the perineum.
Relationships
  • Superior - immediate is pelvic visceral fascia then the pelvic viscera and the abdominal cavity; retropubic space, presacral space, paravesical space, pubosacral ligamentous complex
  • Inferior anterior - superior fascia urogenital diaphragm
  • Inferior posterior - posterior recess of ischiorectal fossa including fat, gluteus maximus, and perineal skin
  • Lateral - arcus tendineus and obturator internus fascia (obturator nerve, external iliac artery and vein)
  • Anterior - superior aspect of the conjoint rami near pubic symphysis
  • Posterior - piriformis muscle and sacrum (sacral plexus, sacral sympathetic trunk, middle sacral artery, effluents of sciatic foramina)
Vasculature
  • The pelvic diaphragm receives arterial supply from the internal iliac. In particular, the inferior vesical arteries, the middle rectal arteries, the internal pudendal arteries, and the inferior rectal arteries all supply the pelvic diaphragm. Similarly, veins if the same name provide venous drainage.
Innervation
  • The levator ani is innervated by the nerve to levator ani derived from S3-4. Additionally, the perineal surface of the levator ani receives innervation from inferior rectal branches of the pudendal nerve.
  • The ischiococcygeus is supplied by the nerve to ischiococcygeus derived from S4-5.
Lymphatic Drainage
  • Lymphatic drainage from the superior surface (pelvis) follows branches of the internal iliac artery to internal iliac nodes, then to upper lumbar nodes, lumbar lymph ducts, and the cisterna chyli. Other drainages include the sacral nodes and the common iliac nodes.
  • Lymphatic drainage from the inferior surface (ischiorectal fossa) drain to the superficial inguinal lymph nodes and the internal iliac nodes.
Clinical Relevance
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Comments

 
arrowbupTop -- LorenEvey - 05 Oct 2019
Topic revision: r12 - 15 Oct 2019, LorenEvey
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