Brachial Plexus

Question 1

Nerve Roots for Each Trunk

Answer 1

Upper - C5 and C6
Middle - C7
Lower - C8 and T1

Question 2

Order of Brachial Plexus

Answer 2

Randy Travis Drinks Cold Beer

Roots Trunks Divisions Cords Branches

Question 3

3 Cords Sources

Answer 3

Lateral - Upper and Middle so C5-C7
Posterior - All 3 so C5-T1
Medial - Lower so C8 and T1

Question 4

Axillary N./Branch (cord and roots source, 2 innervates)

Answer 4

Posterior cord, but C5 and C6 for some reason

Innervates deltoids and teres minor

Question 5

Radial N./Branch (cord and roots source, 2ish innervates)

Answer 5

Posterior cord, C5-T1

Extensors and triceps

Question 6

Musculocutaneous N./Branch (cord and roots source, 3 Innervates)

Answer 6

Lateral cord, C5-C7

Flexors. Biceps, brachialis, cricobrachialis

Question 7

Median N./Branch (cord and roots source, 2 innervates)

Answer 7

Lateral and Medial Cords, C5-T1

Pronator, thenar muscles of hand

Question 8

Ulnar N./Branch (cord and roots source, 2 innervates)

Answer 8

Medial cord, C8-T1

Interosseus and hypothenar (pinky) m.s

Question 9

Long Thoracic N. Roots and Innervation

Answer 9

C5-C7, serratus anterior

Question 10

Erb (-Duchenne) Palsy (what it is, where, causes)

Answer 10

“Waiter’s tip”
Traction or tear of upper trunk, C5-6
Caused by trauma/motorcycle in adults or NEWBORN LATERAL TRACTION OF NECK ON DELIVERY
Damage deltoid, spinatuses, biceps, so can’t abduct (arm at side), get medial rotation and pronation and other shit to have waiter’s tip out the back

Question 11

Klumpke Palsy (what is/where, causes)

Answer 11

Traction or tear of lower trunk, C8-T1. Lose intrinsic hand muscles: lumbricals, interossei, thenar, hypothenar so get total claw hand bc lumbricals normally flex MCP joints and extend DIP and PIP joints
Infants - upward force on arm during delivery or adults - grabbing a tree branch when falling

Question 12

Thoracic Outlet Syndrome

Answer 12

Cervical rib or pancoast tumor compresses lower trunk and subclavian vessels. Hypertrophy of anterior scalenes can also do

Question 13

Winged Scapula

Answer 13

Lesion of long thoracic nerve (axillary node dissection, stab wounds) so can’t innervate Serratus anteriors

Question 14

Axillary Injury Cause

Answer 14

Fractured surgical neck of humerus or dislocation of humerus, causes drop in deltoid

Question 15

Musculucutaneous Injury

Answer 15

Loss of forearm flexion and supination and sensation of lateral forearm

Question 16

Radial N. Injury (2 causes and signs)

Answer 16

Midshaft fracture of humerus (spinal groove) or Saturday night palsy from falling asleep with arm over chair
Lose extensors of forearm/wrist so wrist drop
Lose brachioradialis
Lose sensation of posterior arm

Question 17

Median Nerve Injury (2 causes and signs)

Answer 17

Supracondylar fracture of humerus (proximal lesion) and carpal tunnel syndrome/wrist laceration (distal lesion)
“Ape hand and Pope’s blessing”
Lose wrist flexion, lumbricals of 2nd and 3rd digits
Also loss of sensation over thenar eminence (& atrophy)
Tinel sign (tingling on percussion) in carpal tunnel

Question 18

Ulner Injury

Answer 18

Fracture of medial epicondyle of humerus

Ulnar claw on digit extension, lose hypothenar stuff

Question 19

Recurrent branch of median nerve Injury

Answer 19

Superficial laceration of palm, get “Ape Hand,” loss of thenar muscle group

Question 20

Artery that Runs with Long Thoracic N.

Answer 20

Lateral Thoracic a.

Question 21

Artery with Axillary N.

Answer 21

Posterior circumflex

Question 22

Artery with Radial N.

Answer 22

Deep brachial a., in spinal groove with it

Question 23

Artery with Deep Branch of Radial n.

Answer 23

Posterior interosseus a.

Question 24

Artery with Median n.

Answer 24

Brachial a.