Major Branches of the Brachial Plexus

Musculocutaneous Nerve

arises from the lateral cord of the brachial plexus

• spinal nerve contributions from C5-C7

• travels through the axilla and enters the arm

• pierces through the coracobrachialis

• sensory innervation of lateral forearm

• innervates the biceps brachii, brachialis and coracobrachialis

• TERMINATES INTO LATERAL ANTEBRACHIAL CUTANEOUS NERVE

Axillary Nerve

arises directly from the posterior cord of brachial plexus

• cord contributions from C5 and C6

• exits axilla via the quadrangular space and travels with posterior humeral circumflex artery

• motor innervations to posterior/lateral shoulder

• innervates the deltoids and teres minor

• TERMINATE INTO THE SUPERIOR LATERAL CUTANEOUS NERVE OF THE ARM (sensory) 

Median Nerve

arises from medial and lateral cords of the brachial plexus

• cord contributions from C5-T1

• exits axilla at inferior margin of teres major to enter the arm, pass down medial arm w/ brachial artery

• doesn’t innervate anything in the arm

• innervation to the anterior forearm and hand

• 
  

Branches of Median Nerve

Motor Branches:

• Median recurrent branches (thenar muscles)

• palmer digital branches

• LOAF Muscles: Lateral two lumbricals, opponens pollicis, abductor pollicis brevis, flexor pollicis brevis

Sensory Branches:

• palmar cutaneous branch:

• palmar digital cutaneous branch: innervates the thumb, fingers 2,3, and half of 4

Carpal Tunnel Syndrome

compression of the median nerve in the carpal tunnel

symptoms: numbness, tingling

Motor Innervation of Median Nerve

innervates all flexor muscles of forearm expect flexor carpi ulnaris and medial portion flexion flexor digitorum profundus (FDP)

• Primary

  • pronator teres

  • flexor carpi radialis

  • palmaris longus

  • flexor digitorum superficialis

• Anterior Interosseous branch

  • lateral half of flexor digitorum profundus (digits 2 and 3)

  • flexor pollicis longus

  • pronator quadratus