Re: Dr Evey's True/False Questions - Axilla & Brachial Plexus

Comments:
: : 1) Pectoralis major inserts, in part, at the lateral lip of the intertubercular sulcus and, thus, contributes to on osseofibrous tunnel for the tendon of the long head of the biceps. : : T : Agree. : : 2) By definition, the medial lip of the intertubercular sulcus is within the axilla. : : T : Agree. : : 3) The axillary sheath houses the axillary artery and the cords of the brachial plexus. : : T : Agree. : : 4) Roots, trunks, divisions, cords, and branches define the parts of the axillary artery. : : F - the brachial plexus : Agree. : : 5) The ventral root of C7 is both root and a trunk of the brachial plexus. : : T : Agree. : : 6) The brachial plexus receives contributions from the dorsal rami. : : F - only ventral rami? : Agree. Dorsal rami always remain segmental. : : 7) The trunks of the brachial plexus extend into the axilla. : : F - this happens more superiorly (in the neck). By the time the brachial plexus reaches the superior border of the axilla - defined by the clavicle, first rib, and superior border of scapula - it has already been through its roots/trunks/divisions stage and enters the axilla as cords? : Agree. : : 8) The middle subscapular nerve is also known as the thoracodorsal nerve and as the nerve to latissimus dorsi. : : T : Agree. : : 9) The long thoracic nerve innervates serratus posterior inferior and serratus posterior superior and, thus, mediates stability of the scapula. : : F - long thoracic nerve innervates serratus anterior (which stabilizes the scapula). The posterior serrati are innervated by intercostal nerves. : Agree. : : 10) The lower subscapular nerve innervates two muscles and each of these muscles laterally rotate the arm. : : F - both muscles medially rotate the arm (subscapularis and teres major) : Agree. : : 11) The upper subscapular nerve innervates one muscle and this muscle is a medial rotator of the arm. : : T : Agree. : : 12) The medial brachial cutaneous and medial antebrachial cutaneous nerves provide cutaneous sensation to the medial aspects of the arm and forearm respectively. : : T : Agree. : : 13) The median nerve is formed by the medial and posterior roots of the median nerve. : : ??? - it's formed by the medial and lateral cords of the brachial plexus. : False. Agree. Roots of the medial and lateral cords. : : 14) A lesion of the axillary nerve within the axilla will cause uncompensated loss of abduction and medial rotation of the arm. : : F - axillary nerve innervates only deltoid and teres minor, so there will be no loss of medial rotation. There're a few other muscles that are involved in medial rotation (ex: teres major, latissimus dorsi, pec major, subscapularis) There will be a loss of abduction in the 15-90* range, although I'm not convinced the scapular rotators couldn't make up for some of this. : Agree. Except that medial rotation will weakened due to loss of anterior deltoid. Rotation of the scapula does not occur at the glenohumeral joint. No compensation for 15 to 90 deg at glenohumeral joint. : : 15) A lesion of the nerve to the rhomboids (dorsal scapular nerve) proximal to the levator scapulae muscle results in uncompensated loss of retraction of the scapula. : : F - pretty sure trapezius is a strong retractor of the scapula : Agree. : : 16) A lesion of the musculocutaneous nerve within the axilla results in uncompensated loss of elbow flexion. : : F - brachioradialis would still work : Agree. Plus pronator teres, plus flexor carpi ulnaris, plus others. : : 17) A lesion of the posterior cord proximal to the upper subscapular nerve results in uncompensated loss of medial rotation. : : F - lateral pectoral nerve from lateral cord will still work, so pec major can still do medial rotation : Agree. Plus two muscles taking origin from the coracoid process. : : 18)The dorsal scapular nerve arises from the posterior cord of the brachial plexus. : : F - from the C5 root, which is eventually involved in the superior trunk and posterior cord : Agree. : : 19) A lesion of the upper root of the brachial plexus would weaken protraction of the scapula. : : T? - A lesion of the C5 root would weaken protraction through loss of a part of the long thoracic nerve origin. Retraction would be more strongly affected through the loss of the dorsal scapular nerve : : 20The long thoracic nerve is derived from the lower 3 roots of the brachial plexus. : Agree. Long thoracic nerve is from upper roots including C5. : : F - from the upper three roots : : 21) A lesion of the long thoracic nerve would severely weaken protraction of the scapula. : : T : Agree. : : 22) A lesion of the long thoracic nerve would affect complete abduction of the arm. : : T - serratus anterior, which rotates the inferior aspect of the scapula would be affected. : Agree. : : 23) A lesion of the middle subscapular would weaken lateral rotation of the arm. : : F - lat dorsi usually does medial rotation of arm : Agree. : : 24) A lesion of the lower subscapular nerve would weaken medial rotation. : : T - through loss of teres major and parts of subscapularis : Agree. : : 25) A complete lesion of the posterior cord and its branches would cause uncompensated loss of medial rotation. : : F - lateral pectoral nerve to pec major would still be working : Agree. See above. : : 26) A complete loss of the posterior cord and its branches would cause uncompensated loss of arm abduction from approximately 15 - 90 degrees. : : T - since a branch of the posterior cord goes to the deltoid : Agree. : : 27) Entrapment of the suprascapular nerve at the superior transverse scapular notch could cause uncompensated loss of arm abduction from 0 - 15 degrees and compensated loss of medial rotation of the arm. : : T - loss of supraspinatus : Agree. : : 28) A lesion of the lower subscapular nerve would cause weakened (compensated) arm adduction. : : Oh...so that's what compensated means. T - loss of teres major : Agree. Intact: muscles of coracoid process, pec major, lat dorsi, and more. : : 29) A lesion of the axillary nerve would weaken every possible movement at the glenohumeral joint with the exception of abduction from 0 - 15 degrees. : : T - loss of deltoid : Agree. : : 30) A total lesion of the median nerve would cause ape hand. : : T : Agree. Atrophy of thenar eminence and loss of oppenens pollicis results in supinated thumb. : : 31) A total lesion of the ulnar nerve would cause claw hand. : : T : Agree. This is tough to account for. : : 32) A total lesion of the radial nerve would cause wrist drop. : : T : Agree. : : 33) A lesion of the radial nerve at the spiral groove would cause loss of extension at the elbow. : False : : 34) A lesion of the radial nerve at the spiral groove would cause the wrist to be flexed and adducted. : : F - abducted? : True. Why do you predict abducted? You could argue and win for neutral flexion. : : 35) A lesion of the ulnar nerve at the ulnar groove would cause the wrist to be extended and abducted. : : T : Agree. : : 36) A lesion of the ulnar nerve within the anterior compartment of the arm would cause the wrist to be extended and abducted. : : F? - I'm thinking it would be neither, since flexor carpi ulnaris might already have received innervation by the time a more distal injury occurs. : True. Flexor carpi ulnaris muscular branches are near the heads of origin. Anterior compartment of the arm places the ulnar nerve having not even passed the medial intermuscular septum; inches away. : : 37) The ulnar nerve enters the anterior arm by passing through the heads of origin of the flexor carpi ulnaris. : : T : Agree.

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