Brachial Plexus

Question 0

Long thoracic nerve innervates what muscles? Originate from what cervical spinal disc? What results?

Answer 0

C5, C6, C7
Serratus anterior
Winging of scapula
Difficulty raising arm above 90*

Question 1

Axillary nerve innervates what muscles? Originate from what cervical spinal disc? What results?

Answer 1

C5, C6
Deltoids, teres minor
Affected abduction, horizontal abduction, weak external rotation, sensory loss of deltoid prominence

Question 2

Thoracodorsal nerve innervates what muscles? Originate from what cervical spinal disc? What results?

Answer 2

C5 C6 C7
Latissimus dorsi
Weak arm adduction, hyperext. & int. rot.

Question 3

Anterior thoracic nerve innervates what muscles? Originate from what cervical spinal disc? What results?

Answer 3

C5 C6
Pect major
Weak horizontal add. & diagonal add.

Question 4

Radial nerve innervates what muscles? Originate from what cervical spinal disc? What results? Treatment?

Answer 4

C5,6,7,8 & T1
Triceps
Brachioradialis
Supinator
Extensor Capri brevis, longus, ulnaris
Extensor pollicis longus, brevis, abductor pollicis longus
Extensor digitorum communis, indicis proprius, digiti minimi
Dysfunction: no elbow flexion, wrist drop, forearm pronated, no thumb ext., no mp dip or pip ext., thumb drawn into palm of hand, cannot grasp
Sensory loss on dorsal radial surface of hand
Treatment - dynamic splint

Question 5

Median nerve innervates what muscles? Originate from what cervical spinal disc? What results?

Answer 5

C6,7,8 & T1
Flexor-pronator muscles (pronator teres, pronator quadratus, flexor carpi radialis), muscles on radial side of hand (flexor pollicis longus, thumb intrinsics, flexor digitorum superficialis, flexor digitorum profundus 1,2, lumbricales 1,2)
Dysfunction: weak pronation, weak wrist flexion & radial deviation, hand inclined to ulnar side, “ape hand deformity”, inability to oppose or flex thumb or abduct, weakened grip (esp. thumb & index finger), sensory loss over distal phalanx of 1, 2

Question 6

Ulnar nerve innervates what muscles? Originate from what cervical spinal disc? What results?

Answer 6

C8, T1
Muscles on ulnar side of wrist/hand
Intrinsics of hand & fifth digit
Dysfunction: “claw hand deformity” (due to unopposed extensor action of 4-5th mps), hypothenar & interosseus atrophy, no flexion of dips 3-4th digits, no abduction/adduction of fingers, weak wrist flexion, loss of ulnar deviation, sensory loss on ulnar side of hand

Question 7

Trauma of brachial nerve plexus (10)

Answer 7

Birth injuries
Wounds - suicide attempts
Neck blows
Carrying weight (eg heavy purse)
Fx of humerus
Bullet wounds
Stab wounds
Pressure (eg sleeping)
Crutch palsy
Bone dislocations

Question 8

Diseases of brachial plexus (6)

Answer 8

Neuritis (toxic diabetic infection)
Alcoholism (nerve inflammation)
Tuberculosis of the bone
Rumors
Polyneuritis
Cervical rib