Brachial Plexus Innervations

Question 1

Dorsal Scapular N.

pierces scalene muscle

Answer 1

Rhomboids, Levator Scapula

Question 2

Long Thoracic N.

Answer 2

Serratus Anterior

Question 3

Suprascapular Nerve

Passes through the scapular nothc under transverse scapular ligament

Answer 3

supplies supraspinatus m., infraspinatus m.

Question 4

Nerve to Subclavius M.

descends behind clavicle Anterior to brachial plexus & subclavian artery

Answer 4

subclavius muscle

Question 5

Lateral Pectoral Neve

Answer 5

primarily pectoralis major m.
also supplies pectoralis minor m.

Question 6

Musculocutaneous N.

pierces corabrachialis, decends btw BB and Brachialis

Answer 6

Coracobrachialis
BB
Brachialis
in the lateral elbow continues to forearm as lateral antebrachial cutaneous n. supplies cutaneous distributation to lateral forearm. ends in forearm

Question 7

Medial Pectoral N.

Answer 7

Pectoralis minor and pectoralis major (sternocostal part)

Question 8

Medial Brachial Cutaneous Nerve

Answer 8

skin on medial side of arm

Question 9

Medial Antebrachial Cutaneous Nerve

Answer 9

skin on medial side of forearm

Question 10

DOES NOT BRANCH IN THE BRACHIUM

Ulnar N.

Answer 10

descends behind medial epicondyle in a groove, enters forearm by passing btw 2 heads of FCU, crosses wrist & enters hand in guyon’s canal
INNE: FCU, medial part of FDP (tendons on the 4th & 5th digits), hypothenar muscles, medial 2 lumbricals, all interossei, ADD policis, deep head of FPB

Question 11

Runs down anteromedial aspect of the arm, DOESN’T BRANCH IN BRACHIUM

Median Nerve

Answer 11

enters forearm btw humeral & ulnar heads of PT
In the distal cubital fossa gives rise to Anterior Interosseous n. which supplies 1/2 FDP, FPL, PQ
enters palm via carpal tunnel deep to Flx retinaclum
INNE: all anterior muscles of forearm except FCU and ulnar 1/2 FDP, 2.5 thenar m.: AbPB, OP, FPB superficial head, lateral 2 lumbricals, skin of lateral side of palm, palmer side of lateral 3 and 1/2 fingers and the dorsal side of 2nd, 3rd, and 1/2 of 4th finger

Question 12

Upper Subscapular Nerve

Answer 12

upper portion of Subscapularis muscle

Question 13

Thoracodorsal N.

runs along posterior axillary wall to apical part of Latissimus Dorsi

Answer 13

Latissimus Dorsi

Question 14

Lower Subscapular N.

Answer 14

lower part of subscapularis muscle and teres major

Question 15

Axillary N.

winds around surgical neck deep to delt m.

accompanied by posterior circumflex humeral artery

Answer 15

Deltoid
Teres Minor
gives rise to lateral brachial cutaneous n.

Question 16

Arises from posterior cord & largest branch of brachial plexus

Radial N.

gives off posterior brachial cutaneous n. occupies radial groove

gives rise to posterior brachial cutaneous and posterior antebrachial cutaneous n. splits into deep radial n. & superficial radial n.

Answer 16

Deep branch: enters supinator & contonues as PI n.
Superifcial branch: crosses roof of antatomical snuff box
INNE: triceps brachii, anconeus, brachioradialis, ECRL

Question 17

Deep Radial N.

Answer 17

INNE: ECRB, ED, EDM, ECU, SUP

Question 18

Posterior Interosseus N.

Answer 18

EI, ABPL, EPL, EPB