Nerves Of The Upper Limb

Front 1

Objectives

Back 1

1) Identify the 3 cords of the brachial plexus
2) name and identfy the terminal branches of the brachial plexus
3) state the innervation of all the upper limb muscles or muscle groups
4) describe the position of the upper limb nerves and their relationship to other structures

Front 2

Trapezius Muscle

Back 2

1) innervated by Accessory Nerve CN XI

Front 3

Brachial Plexus

1 of 2

Back 3

1) Provides innervation for all muscles (except trapezius) involved in movement of upper limb
2) fomed by spinal nerves C5 - C8, T1
a) nerves have motor fibers for both flexor (anterior) & extensor (posterior( muscles
b) anterior & posterior components seperated out from each spinal nerve & segregated together into named peripheral nerves

Front 4

Brachial Plexus

2 of 2

Back 4

3) spinal nerves form 3 trunks:
a) Superior (upper) trunk - junction of C5+C6
b) middle trunk - C7 only
c) Inferior (Lower) trunk - junction of C8+T1
4) anterior & posterior nerve components seperate from trunk & reunite to form brachial cords:
a) lateral cord - anterior components from superior & middle trunks
b) medial cord - anterior cmponents from inferior trunk
c) posterior components from superior, middle, & inferior trunks
--cords named for their positional relationship to axillary artery

Front 5

Peripheral Nerves derived from Spinal Nerves

Back 5

a) Dorsal Scapular Nerve
1) runs inferiorly along medial border of scapula
2) innervates levator scapulae & rhomboid major & minor muscles
b) Long Thoracic Nerve
1) runs inferiorly along lateral chest wall
2) innervates serratus anterior muscle

Front 6

Peripheral Nerve Derived from Brachial Trunk

Back 6

a) Suprascapular Nerve fro superior trunk
1) passes through suprascapular notch at superior border of scapula
2) innervates supraspinatus muscle in supraspinous fossa
3) passes around base of spine of scapula to innervate infraspinatus muscle in infraspinous fossa

Front 7

Peripheral Nerve derived from Posterior Cord

Back 7

a) Subscapular Nerve
1) pass posteriorly to enter deep sides of subscapularis and teres major muscles
b) Thoracodorsal nerve
1) runs inferiorly along lateral body wall
2) innervates latissimus dorsi muscle - runs across deep side of muscle
c) axillary nerve - wraps around posterior-lateral humerus to innervate deltoid & teres minor muscle
d) radial nerve - to all muscles of posterior arm and posterior forearm

Front 8

Nerves derived from lateral cord

Back 8

a) lateral pectoral nerve - to pectoralis major muscle
b) musculocutaneous nerve - to all 3 anterior compartment muscles of arm
c) lateral root of median nerve

Front 9

Nerves derived from Median Cord

Back 9

a) median pectoral nerve - to pectoralis major & pectoralis minor muscles
b) medial root of median nerve
c) ulnar nerve

Front 10

Median Nerve:

Back 10

a) derived from lateral and Medial cords
b) innervates most flexor muscles of forearm & thenar muscles of hand
-- key landmarks: musculocutaneous nerve, medial & lateral roots of median nerve, & ulnar nerve together form capital "M" as nerve exits brachial plexus

Front 11

Terminal Branches of the Brachial Plexus
x 5
1) Axillary Nerve

Back 11

a) emerges in posterior shoulder region through quadrangular space
b) borders of quadrangular space:
1) teres major muscle - inferior
2) teres minor muscle - superior
3) long head of triceps brachii muscle - medial
4) humerus - lateral
c) innervates teres minormuscle as it passes through quadrangular space
d) passes posterior & lateral to humerus - encircles humerus deep to deltoid muscle
e) innervates deltoid muscle from deep side

Front 12

Terminal Branches of the Brachial Plexus
x 5
2) Radial Nerve

Back 12

a) passes around medial, posterior, & lateral humerus along radial (spiral) groove
1) innervates all 3 heads of triceps brachii muscle
b) crosses elbow joint anterior to lateral epicondyle of humerus
1) does not pass through cubital fossa
c) runs down posterior forearm - supplies all muscles of extensor forearm
d) sends sensory branches to posterior-lateral hand (does not innervate any hand muscles)
1) sensory to lateral side posterior (dorsal) hand & posterior side of digits 1-3

Front 13

Terminal Branches of the Brachial Plexus
x 5
3) Musculocutaneous Nerve

Back 13

- to flexor muscles of arm (brachium)
a) passes through coracobrachialis muscle
b) innervates coracobrachialis, brachialis, & biceps brachii muscles

Front 14

Terminal Branches of the Brachial Plexus
x 5
4) Ulnar Nerve

Back 14

a) down medial side of proximal arm, then around into posterior compartment
1) no branches in arm (no innervations)
b) crosses elbow, posterior to medial epicondyle of humerus ("funny bone")
c) runs down medial forearm, deep to felxor carpi ulnaris muscle
1) innervates flexor carpi ulnaris & medial 1/2 (ulnar side) of flexor digiorum profundus
d) crosses anterior-medial wrist to enter hand - superficial to flexor retinaculum
1) in hand, supplies all muscles of hypothenar compartment (abductor digiti minimi, flexor digiti minimi, opponens digiti minimi) and most muscles of central compartment (adductor pollicis, dorsal & palmar interosseous muscles, 3rd & 4th lumbrical muscle)
2) cutaneous (sensory) innervation to medial hand (both palmar & dorsal sides) and both sides of digits 4 and 5

Front 15

Terminal Branches of the Brachial Plexus
x 5
5) Median Nerve
1 of 2

Back 15

a) arm - runs with neurovascular compartment of medial arm (with brachial artery & vein)
no branches in arm (no innervation)
b) passes through cubital fossa (region anterior to elbow) ; boundaries:
1) lateral - brachioradialis muscle (origin = lateral epicondyle of humerus)
2) medial - pronator teres muscle (origin = medial epicondyle of humerus)
3) roof - bicipital aponeurosis (biceps brachii muscle to medial antebrachial fascia)
c) median nerve runs down central forearm - deep to flexor digitorum superficials
1) supplies 6 1/2 muscles of flexor forearm (all muscles not supplied by ulnar nerve - pronator teres, flexor carpi radialis, palmaris longus, flexor digitorum superficialis, flexor pollicis longus, pronator quadratus, and lateral (radial) 1/2 of flexor digitorum profundus)

Front 16

Terminal Branches of the Brachial Plexus
x 5
5) Median Nerve
2 of 2

Back 16

d) median nerve crosses anterior wrist - passes deep to flexor retinaculum (through the carpal tunnel)
e) in hand, median nerve supplies:
1) motor innervation to muscles of thenar compartment - abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
2) motor innervation to 1st & 2nd lumbrical muscles
3) cutaneous innervation to lateral palm and anterior side of digits 1-3

Front 17

Carpal Tunnel Syndrome

Back 17

1) carpal tunnel - formed by the "U" shaped arrangment of carpal bones, roofed by flexor retinaculum
2) passing through carpal tunnel are median nerve & 9 tendons (4 tendons from flexor digitorum superfcialis, 4 tendons fro flexor digitorum profundus, 1 tendon from flexor pollicis longus)
3) carpal tunnel syndrome produced by compression of median nerve within carpal tunnel; nerve compression my result from:
a) inflammation & swelling of flexor muscle tendons (due to repetitive use)
b) dislocation or fracture of carpal bones
c) arthritis in wrist joint
4) results in paralysis of thenar muscles and thus decreased mobility of thumb, and/or pain, tingling, or numbness on anterior (palmar) sides of digits 1-3