Arm anatomy + brachial plexus Flashcards Preview

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Flashcards in Arm anatomy + brachial plexus Deck (20):

what structures are injured from sudden upward jerking motion of arm (e.g. bracing fall by grabbing tree branch)

lower trunk of brachial plexus - C8-T1
median and ulnar nerves are damaged (some radial)
lumbercals of hand and all interosseous muscles don't work - TOTAL CLAW hand (difficulty with fine finger movements)
sensory loss over medial hand and forearm


associated symptoms from shoulder dislocation and fracture to the proximal humerus?

axillary nerve damage - weakness of deltoid and teres minor - can't abduct arm


what is commonly injured with axillary lymph node removal?

long thoracic nerve - paralysis of serratus anterior
winged scapula and impaired arm abduction beyond 90 degrees


what is consequence of injury to musculocutaneous nerve?

impaired arm flexion at the elbow and impaired supination (biceps, brachialis, coracobracialis)


fraction to the midshaft of the humerus injurs what nerve?

radial nerve

wrist drop (paralysis of wrist extensors), impaired

extension of the arm (triceps and brachioradialis)

and posterior foram and dorsolateral hand sensory loss


initial abduction is mediated by _____
horizontal abduction is mediated by _____ and ____
above horizontal abduction is mediated by ____ and __

supraspinatus + deltoid
serratus anterior + trapezius


what two muscles are innervated by the suprascapular nerve?

suprascapular muscle => abduction
infraspinatus muscle => lateral rotation


what is damaged by supracondylar fracture of humerus?

proximal median nerve injury (C5-T1) - loss of thumb opposition, wrist flexion, flexion of lateral fingers and loss of lumbercals of 2nd and 3rd digits


2nd and 3rd fingers stay extended when trying to make a fist. What is the injury?

proximal median nerve injury - supracondylar fracture of humerus


2nd and 3rd fingers remain flexed while hand in relaxed. What is the injury?

distal median nerve injury (e.g. wrist laceration)


what injury could cause loss of thenar muscle group, loss of opposition abduction and flexion of thumb, with no sensory loss?

palm laceration that damages recurrent branch of medial nerve


pt. presents with flattened deltoid, loss of arm abduction at shoulder (>15 degees) and loss of sensation over deltoud muscle and lateral arm. What was the injury?

fractured surgical neck of humerus or anterior dislocation of the shoulder -- damage to axillary nerve


What nerve and artery are located near:

axilla/lateral thorax

long thoracic nerve, lateral thoraci artery


What nerve and artery are located near:

surgical neck of humerus

axillary nerve, posterior circumflex artery


What nerve and artery are located near:

midshaft of humerus

radial nerve, deep brachial artery


What nerve and artery are located near:

distal humerus/cubital fossa

median nerve, brachial artery


What nerve and artery are located near:

popliteal fossa

tibial nerve, popliteal artery


What structures does the median nerve travel through in the forarm before reaching the carpel tunnel and passing under the flexor retinaculum?

gains access to the forarm at the medial aspect of the antecubital fossa and immediately courses between the humeral and ulnar heads of the pronator teres muscle at the very proximal foram. It then travels between the flexor digitorum superficialis and flexor digitorum profundus along the arm before entering the wrist withing the flexor retinaculum.

proximal median nerve injury may result from supracondylar humerus fracture or entrapment between the pronator teres

findings: sensory loss in the median nerve distribution with weakness on thumb flexion/opposition, flexion of the second/third digits and weakness with wrist flexion/abduction


what nerve penetrates the coracobrachialis muscle and intially corses between the biceps brachii and coracobrachialis muscle before descending toward the elbow between the biceps and brachials muscles? injury would cause ____?

musculocutaneus nerve

paralysis of elbow flexors (biceps, brachialis and coracobrachialsis) and loss of sensation over the lateral forearm.


what nerve travels through the supinator muscle?

radial nerve

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