UE Innervations Flashcards
Axillary nerve sensory and motor innervation
C5-6
Branch of posterior cord
Motor:
Teres minor
Deltoid
Sensory:
Upper lateral cutaneous n. of arm - skin to lower half deltoid, upper LH of tricep
Cause of axillary n. injury
shoulder dislocation
surgical neck of humerus fx
sxs:
“square shoulder” - deltoid m. atrophy
Sensory loss over lower half of deltoid
Radial nerve motor innervation (12)
C5-8, T1
Branch of posterior cord
Motor:
triceps
anconeus
brachioradialis
supinator
Extensor capri radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris
Extensor digitorum
Extensor digiti minimi
Extensor pollicis longus
Extensor indicis
Abductor pollicis longus
Broad overview of actions:
elbow extension
wrist extension
MCP/CMC extension
Radial nerve sensory innervation
C5-8, T1
Branch of posterior cord
Lower lateral cutaneous nerve of arm - skin of lower half of lateral side of arm
Posterior cutaneous nerve of arm - skin on back of arm
Posterior cutaneous nerve of forearm - skin on back of forearm
Superficial branch - skin of lateral half of dorsum of hand, lateral two and half digits including thumb
Radial nerve injury
Radial tunnel syndrome
- tenderness in extensor m. mass of forearm (distal to lat. epi.)
- long finger extension test reproduces pain
Posterior interosseous nerve syndrome
Wrist drop
Ulnar nerve motor innervation (10)
C7-T1 (main contribution C8-T1)
Branch of medial cord
Motor:
Dorsal interossei (4)
Palmar interossei
Adductor pollicis
Opponens digiti minimi
Flexor digiti minimi
Abductor digiti minimi
Flexor pollicis brevis
Flexor digitorum profundus (medial half)
Flexor carpi ulnaris
Lumbricals 3-4
action overview:
wrist flexion
finger/thumb mvmt
Ulnar nerve sensory innervation
C7-T1 (main contribution C8-T1)
Branch of medial cord
Palmar cutaneous branch - medial 1/2 of palm
Dorsal cutaneous branch - skin of dorsal aspect of medial one and half fingers
Superficial branch - 1/2 of 4th, 5th digit
Ulnar nerve injury
Cubital tunnel syndrome
- compression at cubital tunnel
- paralysis of FCU, FDP, hypothenar eminence, interossei, 3rd/4th lumbricals
- all sensation affected, inability to grip paper
Guyon’s canal syndrome
- sensory changes and progressive weakness of muscles innervated distal to the site
Ulnar claw hand
- hyperextension at 4th, 5th MCP, flexion 4th/5th IP due to weakness of lumbricals and interossei
Median nerve motor innervation (11)
C5-8, T1
Branch from medial and lateral cord
Motor:
Flexor digitorum profundus (radial/lateral half)
Flexor digitorum superficialis
Flexor pollicis longus
Flexor pollicis brevis
Flexor carpi radialis
Pronator quadratus
Abductor pollicis brevis
Pronator teres
Opponens pollicis
Palmaris longus
Lumbrical 1 & 2
action overview:
wrist/finger/thumb flexion
Median nerve sensory innervation
C5-8, T1
Branch from medial and lateral cord
Palmar cutaneous branch - lateral two thirds palm
Palmar digital branches - dorsal tips 1, 2, 3 digits; palmar side of lateral three and half fingers
Median nerve injuries
Pronator teres syndrome
- hypertrophy of pronator teres m. compresses median n.; all other m. and sensation affected
Carpal tunnel syndrome
- median n. compressed under flexor retinaculum of wrist
Ape hand deformity
- wasting of the thenar eminence of the hand occurs b/c of median n. palsy
Musculocutaneous nerve motor (3) and sensory innervation
C5-7
Branch of lateral cord
Motor:
bicep
brachialis
coracobrachialis
action overview:
shoulder/elbow flexion
sensory:
lateral cutaneous n. of forearm - lateral side forearm
Suprascapular nerve motor innervation
C5-6
Branch from upper trunk
Motor:
infraspinatus
supraspinatus
action overview:
shoulder ER and ABD
Upper/lower subscapular nerve motor innervation
C5-6
Branch of posterior cord
Motor:
teres major (lower)
subscapularis (both)
action overview:
shoulder IR, ADD
Lateral pectoral nerve motor innervation
C5-7
Branch of lateral cord
Motor:
pectoralis major
