Innervation Of The Upper Limb.

Front 1

CERVICAL PLEXUS

Back 1

Derived from:
Spinal nerve roots C1, C2, C3, C4

Supplies:
Head & top of shoulder.

Front 2

BRACHIAL PLEXUS

Back 2

Derived from:
Spinal nerve roots C5, C6, C7, C8, T1

Supplies:
Upper limb from just below the top of the shoulder.

Front 3

AXILLARY NERVE

Back 3

Derived from:
C5, C6

Supplies:
Deltoid
Teres minor
Upper triceps

Front 4

RADIAL NERVE

Back 4

Derived from:
C5, C6, C7, C8, T1

Supplies:
LARGEST SUPPLY --> posterior compartment (extensors) of the arm & forearm.

Front 5

MUSCULOCUTANEOUS

Back 5

Derived from:
C5, C6, C7

Supplies:
Anterior compartment (flexors) of the arm.

Front 6

MEDIAN NERVE

Back 6

Derived from:
C6, C7, C8, T1

Supplies:
Anterior compartment of the forearm.
Pronators
Flexors
Thenar muscles
Lateral 2 lumbricals

Front 7

ULNAR NERVE

Back 7

Derived from:
C7, C8, T1

Supplies:
Flexor carpi ulnaris
Medial 1/2 of flexor digitorum profundus
Medial 2 lumbricals
Interossei
Hypothenar muscles
Adductor pollicis

Front 8

AXILLARY NERVE LESION

Back 8

Site of injury:
Axilla

Paralysis:
Deltoid

Motor loss:
Humeral abduction

Sensory loss:
Over lower deltoid

Front 9

MUSCULOCUTANEOUS NERVE LESION

Back 9

Site of injury:
Axilla

Paralysis:
Arm flexors

Motor loss:
Weak forearm flexion & supination

Sensory loss:
Lateral forearm

Front 10

RADIAL NERVE LESION

Back 10

Site of injury:
1) Axilla
2) Cubital fossa

Paralysis:
1) Supinator & extensors
2) All except triceps

Motor loss:
1) Weak supination, loss of extension
2) Weak supination

Sensory loss:
Lateral dorsum of hand

Front 11

MEDIAN NERVE LESION

Back 11

Site of injury:
1) Elbow
2) Wrist

Paralysis:
1) Pronators, most flexors, thenar mm., lumbricals.
2) Thenar mm.

Motor loss:
1) Loss/impaired wrist & digit flexion, loss of opposition & precision grip
2) Loss of opposition & precision grip

Sensory loss:
Dorsum of lateral 3 digits

Front 12

ULNAR NERVE LESION

Back 12

Site of injury:
1) Above elbow
2) Wrist

Paralysis:
1) FCU, medial FDP, hypothenar mm., adductor pollicis, lumbricals, interossei
2) As above, except FDP

Motor loss:
1) Impaired hand function, "claw hand" & loss of power grip
2) Impaired flexion of 4th & 5th digits.

Sensory loss:
Palmar & dorsal surfaces of lateral 2 digits.