Radial Nerve : Course, Motor, Sensory & Common Injuries

Radial Nerve: The radial nerve is a major peripheral nerve of the upper limb. It originates from the brachial plexus, carrying fibers from the ventral roots of spinal nerves C5, C6, C7, C8 & T1.

Course of the Radial Nerve

It passes behind the axillary artery next through the triangular interval to access posterior compartment of the arm
It then turns around the spiral groove of the humerus among profunda brachii artery, between the heads of the triceps
It enters antecubital fossa in front of the lateral epicondyle of humerus, within brachialis and brachioradialis muscles. Next its branches in the proximal forearm into two terminal branches:
Next its branches in the proximal forearm into two terminal branches:

Deep branch (motor supply) – pierces supinator muscle and descends along posterior interosseous membrane with the posterior interosseous artery

Superficial branch (sensory supply) – descends under the brachioradialis muscle to end in dorsum of the hand.

Sensory Supply of the Radial Nerve

Posterior aspect of arm and forearm
Lateral ⅔ of the dorsum of the hand
Proximal dorsal aspect of lateral 3½ fingers (thumb, index, middle and half of the ring finger)

Motor Supply of the Radial Nerve

Guides

Opponens Digiti Minimi : Origin, Insertion, Action & Nerve Supply

Pectoralis Minor: Origin, Insertion, Nerve Supply & Action

Phalanges Bones Anatomy

Cervical Spine: Overview, Gross Anatomy

Posterior compartment of the arm muscles
Triceps muscle –adducts and extends shoulder, extends the elbow
Posterior compartment of the forearm muscles
Brachioradialis muscle- elbow flexes
Anconeus muscle – elbow extends, stabilizes the elbow joint
Supinator muscle – supination of the forearm
Extensor carpi radialis longus and brevis muscles– abduct and extend the wrist
Extensor carpi ulnaris muscle – extends and adducts the wrist
Extensor digitorum, extensor indicis, extensor pollicis brevis and longus and extensor digiti minimi muscles – extend the thumb and fingers at MCPJs and IPJs
Abductor pollicis longus muscle – abducts the thumb

Common Radial nerve injuries

Pressure of crutches on armpits (“crutch palsy“)
Somebody else falling asleep with their head lying on patient’s arm ( “honeymoon palsy“)
The patient falling asleep with hanging arm over the back of the chair, classically whilst drunk (“Saturday night palsy“)

Upper Extremity Muscle Atlas