What is the general function of the muscles of the posterior compartment of the forearm
Extension at the wrist and fingers
Which nerve innervates the muscles of the posterior compartment of the forearm
Radial nerve
What are the superficial muscles of the posterior forearm
Extensor carpi radialis brevis Extensor carpi radialis longus Extensor digitorum Extensor carpi ulnaris Extensor digiti minimi Brachioradialis Anconeus
Which superficial muscles of the posterior forearm share a common tendinous origin
Extensor carpi radialis brevis Extensor digitorum Extensor carpi ulnaris Extensor digiti minimi (At lateral epicondyle)
In the distal forearm, where does the radial artery and nerve lie
Between brachioradialis and deep flexor muscles
Where does brachioradialis originate
Proximal aspect of the lateral supracondylar ridge of humerus
Where does brachioradialis insert
Distal end of the radius, just before the radial styloid process
What is the function of brachioradialis
Flexion at the elbow
What nerve innervates brachioradialis
Radial nerve
Where does extensor carpi radialis longus originate
Supracondylar ridge
Where does the extensor carpi radialis brevis originate
Lateral epicondyle
Where do extensor carpi radialis longus and brevis insert
Metacarpal bones II and III
What is the action of extensor carpi radialis
Extends and abducts the wrist
Which nerve innervates extenor carpi radialis
Radial nerve
Where does extensor digitorum originate
Lateral epicondyle
Where does extensor digitorum insert
Tendon splits into 4 and inserts into the extensor hood of each finger
What is the action of extensor digitorum
Main extensor of the four fingers at MCP and IP joints
Which nerve innervates extensor digitorum
Radial nerve (deep branch)
Where does extensor digiti minimi lie
Medially to extensor digitorum
Where does extensor digiti minimi originate
Lateral epicondyle of the humerus
Where does extensor digiti minimi insert
Extensor hood of the little finger
What is the action of extensor digiti minimi
Extends the little finger
Contributes to extension at the wrist
Which nerve innervates extensor digiti minimi
Radial nerve (deep branch)
Where is extensor carpi ulnaris located
Medial aspect of the posterior forearm
Where does extensor carpi ulnaris originate
Lateral epicondyle of the humerus
Where does extensor carpi ulnaris insert
Base of metacarpal V
What is the action of extensor carpi ulnaris
Extension and adduction of the wrist
Which nerve innervates extensor carpi ulnaris
Radial nerve (deep branch)
Where does anconeus lie
Medially and superiorly in the extensor compartment of the forearm
Blended with the fibres of triceps brachii
Where does anconeus originate
Lateral epicondyle
Where does anconeus insert
Posterior and lateral part of olecranon
What is the action of anconeus
Extends and stabilises elbow joint
Abducts ulna during pronation of forearm
Which nerve innervates anconeus
Radial nerve
What is lateral epicondylitis
Inflammation of the periosteum of the lateral epicondyle - caused by repeated use of superficial extensor muscles
What are the deep muscles of the posterior forearm
Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis
Where does supinator lie
Floor of the cubital fossa
What passes between the two heads of supinator
Deep branch of the radial nerve
Where does supinator originate
Two heads:-
Lateral epicondyle of the humerus
Posterior surface of the ulna
Where does supinator insert
Posterior surface of the radius
What is action of supinator
Supinates forearm
Which nerve innervates supinator
Radial nerve (deep branch)
Where is abductor pollicis longus
Immediately distal to supinator
Where does abductor pollicis longus originate
Interosseous membrane
Adjacent posterior surfaces of the radius and ulna
Where does abductor pollicis longus insert
Lateral side of the base of metacarpal I
What is the action of abductor pollicis longus
Abducts the thumb
Which nerve innervates abductor pollicis longus
Radial nerve (posterior interosseous branch)
Where does extensor pollicis brevis lie
Medially and deep to abductor pollicis longus
Where does extensor pollicis brevis originate
Posterior surface of the radius and interosseous membrane
Where does extensor pollicis brevis insert
Base of the proximal phalanx of the thumb
What is the action of extensor pollicis brevis
Extends thumb at MCPJ and carpometacarpal joints
Which nerve innervates extensor pollicis brevis
Posterior interosseous branch of the radial nerve
Where does extensor pollicis longus originate
Posterior surface of the ulna and interosseous membrane
Where does extensor pollicis longus insert
Distal phalanx of the thumb
What is the action of extensor pollicis longus
Extends all joints of the thumb
Which nerve innervates extensor pollicis longus
Radial nerve
Where does extensor indicis proprius originate
Posterior surface of the ulna and interosseous membrane (distal to extensor pollicis longus)
Where does extensor indicis proprius insert
Extensor hood of the index finger
What is the action of extensor indicis proprius
Extends index finger
Which nerve innervates extensor indicis proprius
Posterior interosseous branch of the radial nerve
What is a sign of radial nerve damage
Wrist drop
Where are the common sites of radial nerve damage
Axilla
Radial groove of the humerus