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
- 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
- Abductor Pollicis Longus
- Abductor Digiti Minimi
- Abductor Pollicis Brevis
- Adductor Pollicis
- Anconeus
- Biceps Brachii
- Brachioradialis
- Brachialis
- Coracobrachialis
- Deltoid
- Extensor Carpi Radialis Longus
- Extensor Carpi Radialis Brevis
- Extensor Carpi Ulnaris
- Extensor Digitorum
- Extensor Digiti Minimi
- Extensor Indicis
- Extensor Pollicis Longus
- Extensor Pollicis Brevis
- Flexor Carpi Radialis
- Flexor Carpi Ulnaris
- Flexor Digitorum Profundus
- Flexor Digitorum Superficialis
- Flexor Digiti Minimi Brevis
- Flexor Pollicis Brevis
- Flexor Pollicis Longus
- Infraspinatus
- Interosseous Muscles, Dorsal
- Interosseous Muscles, Palmar
- Levator Scapulae
- Latissimus Dorsi
- Opponens Digiti Minimi
- Opponens Pollicis
- Pectoralis Major
- Pectoralis Minor
- Palmaris Longus
- Pronator Quadratus
- Pronator Teres
- Rhomboid Major and Minor
- Subscapularis
- Supinator
- Serratus Anterior
- Supraspinatus
- Trapezius
- Triceps Brachii
- Teres Major
- Teres Minor
