The posterior compartment of the forearm - muscles (dave's notes) Flashcards
List the 12 muscles of the posterior compartment of the forearm
Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Aconeus Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis
What is the origin and insertion of brachioradialis?
Origin: The upper two thirds of the lateral supracondylar ridge of the humerus and lateral intermuscular septum
Insertion: Base of the styloid process of the radius
What is the action and innervation of brachioradialis?
Flexes arm at the elbow and brings the forearm into the mid-prone position
Radial nerve.
What is the origin and insertion of extensor carpi radialis longus?
Origin: Lower 2/3rds lateral supracondylar ridge of humerus and lateral intermuscular septum
Insertion: Posterior base of 2nd metacarpal
What is the action and innervation of extensor carpi radialis longus?
Extends and adducts the hand at the wrist
Posterior interosseous nerve
What is the origin and insertion of extensor carpi radialis brevis?
Origin: Common extensor origin
What is the common extensor origin?
What arises here?
The smooth area on the front of the lateral epicondyle The fused tendons of: Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris
What is the action and innervation of extensor carpi radialis brevis?
Extends and adducts the hand at the wrist
Posterior interosseous nerve
What is the origin and insertion of extensor digitorum?
Origin: CEO
Insertion: The extensor expansion of all four fingers, three and four normally fuse with fie only getting a slip
What is the action and innervation of extensor digitorum?
Extends all joints of fingers
Posterior interosseous nerve
What is the origin and insertion of extensor digiti minimi?
Origin: CEO
Insertion: Extensor expansion of the little finger, usually two tendons which are joined by extensor digitorum
What is the innervation and action of extensor digiti minimi?
Extends all the joints of the little finger.
Posterior interosseous nerve
What is the origin and insertion of extensor carpi ulnaris?
Origin: CEO and aponeurotic sheath from the ulna
Insertion: BASE of the 5th ??? via a groove by ulnar styloid
What is the action and innervation of extensor carpi ulnaris?
Extends and adducts the hand at the wrist
Posterior interosseous nerve
What is the origin and insertion of aconeus?
Origin: Smooth surface at the lower extremity of posterior aspect of the lateral epicondyle of humerus
Insertion: Lateral side of olecranon
What is the action and innervation of aconeus?
Weak extensor of the elbow
RADIAL nerve
What is the origin and insertion of supinator?
Origin: Deep part from the supinator crest and fossa of the ulna.
Superficial part from the lateral epicondyle and lateral ligament of the elbow and annular ligament
Insertion: Neck and shaft of the radius
What is the action and innervation of supinator?
Supinates the forearm.
Posterior interosseous nerve
When does supinator act independently?
When the elbow is extended
What is the origin and insertion of abductor pollicis longus?
Origin: The upper posterior surface of the ulna and middle 1/3rd of the posterior surface of the radius and interosseus membrane.
Insertion: Over the tendons of the radial extensors and brachioradialis to the base of the first metacarpal and trapezium
What is the action and innervation of abductor pollicis longus?
Abducts and extends the thumb at the carpometacarpal joint
Posterior interosseous nerve
What is the origin and insertion of extensor pollicis brevis?
Origin: Lower 1/3 of the posterior shaft of the radius and interosseous membrane
Insertion: Over the tendons of the radial extensor and brachioradialis to the base of the proximal phalanx
What is the action and innervation of extensor pollicis brevis?
Extends the metacarpophalangeal joints of the thumb
Posterior interosseous nerve
What forms the radial side of the anatomical snuff box?
Abductor pollicis brevis and extensor pollicis brevis
What forms the ulnar side of the anatomical snuff box?
Extensor pollicis longus
What is the origin and insertion of extensor pollicis longus?
Origin: The middle 1/3rd of the posterior ulna and interosseous membrane
Insertion: Base of the distal phalanx of the thumb
What is the action and innervation of extensor pollicis longus?
Extends the IP and MCP joints of the thumb
Posterior interosseous nerve
What is the origin and insertion of extensor indicis?
Origin: The lower posterior shaft of the ulnar and interosseous membrane
Insertion: The extensor expansion of the index finger
What is the action and innervation of extensor indicis?
Extends all the joints of the index finger
Posterior interosseous nerve
