4 Muscles of the hand and wrist Flashcards
What are the muscles of the posterior forearm known as?
Extensor muscles
Which nerve innervates the muscles of the posterior forearm?
The radial nerve
What are the anatomical groups of the posterior muscles of the forearm?
Superficial muscles
Deep muscles
What are the functional groups of the posterior muscles of the forearm?
Muscles which extend abduct/adduct the hand at the wrist
Muscles which extend the medial four fingers
Muscles which extend the thumb
What are the three muscles which extend and abduct/adduct the hand at the wrist joint?
Extensor carpi radialis longus
Extensor carpi radialis brevis
Extensor carpi ulnaris
Where are the extensor carpi radialis longus in the forearm?
Posterior superficially, laterally
From supracondylar ridge of humerus to Metacarpal II and III
What is the function of the extensor carpi radialis longus?
Extension of the wrist
Abduction of the wrist
What is the innervation of the extensor carpi radialis longus?
Radial nerve
Where are the extensor carpi radialis brevis in the forearm?
Posterior superficial, laterally
From lateral epicondyle of the humerus to Metacarpal II and III
What is the function of the extensor carpi radialis brevis?
Extension of the wrist
Abduction of the wrist
What is the innervation of the extensor carpi radialis brevis?
Radial nerve
Where are the extensor carpi ulnaris in the forearm?
Posterior superficial, medially
From lateral epicondyle of humerus to base of Metacarpal V
What is the function of the extensor carpi ulnaris?
Extension at the wrist
Adduction of the wrist
What is the innervation of the extensor carpi radialis brevis?
Radial nerve
Which muscle in the anterior compartment of the forearm helps extensor carpi radialis longus/brevis with abduction of the wrist?
Flexor carpi radialis
Where is the extensor digitorum in the forearm?
Posterior superficial,
From lateral epicondyle of humerus then passes under extensor retinaculum and splits into four tendons attaching to extensor hoods of fingers
What is the innervation of the extensor digitorum?
Deep brances of radial nerve
What is the function of the extensor digitorum?
Main extensor of fingers at MCP and IP joints
How do you test the function of extensor digitorum?
Pronate forearm and extend fingers against resistance
Where is the extensor incidus proprius in the forearm?
Posterior, deep
From posterior surface of the ulna and interosseus membrane (distal to EPL) to extensor hood of index finger
What is the function of the extensor incidus proprius?
Allows index finger to be independent of other digits in extension
Extension of index finger
What is the innervation of the extensor incidus proprius?
Posterior interosseous branch of radial nerve
Where is the extensor digiti minimi in the forearm?
Posterior, superficial
From lateral epicondyle of humeus to extensor hood of little finger (medial to extensor digitorum)
What is the function of the extensor incidus proprius?
Extension of little finger
Contributes to the extension of the wrist
What is the innervation of the extensor incidus proprius?
Deep branch of radial nerve
What are the three muscles which extend or abduct the thumb?
Abductor pollicis longus
Extensor pollicis brevis
Extensor pollicis longus
Where is the abductor pollicis longus in the forearm?
Posterior deep, immediatley distal to supinator muscle
From interosseous membrane adjecent posterior surface of radius and ulna to lateral part of base of metacarpal I
What is the function of the abductor pollicis longus?
Abduction of the thumb
What is the innervation of the abductor pollicis longus?
Posterior interosseous branch of radial nerve
Where is the extensor pollicis brevis in the forearm?
Posterior, deep (medial and deeper than abductor pollicus longus)
From posterior surface of radius and interosseous membrane to base of proximal phalanx of the thumb
What is the function of the extensor pollicis brevis?
Extension of MCP joint of thumb
Extension of carpometacarpal joints of thumb
What is the innervation of the extensor pollicis brevis?
Posterior interosseous branch of the radial nerve
Where is the extensor pollicis longus in the forearm?
Posterior deep, medial to dorsal tubercle
From posterior surface of ulna and interosseous membrane to distal phalanx of the thumb
What is the function of the extensor pollicus longus?
Extension of all joints of the thumb
Carpometacarpal
Metacarpophalangeal
Interphalangeal
What is the innervation of the extensor pollicus longus?
Posterior interosseus branch of radial nerve
Where is the supinator muscle located?
In floor of cubital fossa (inside of elbow)
How many heads does the supinator muscle have?
2 with deep branch of radial nerve passing between them
Where is the supinator muscle attached?
From lateral epicondyle of humerus and posterior surface of ulna to posterior surface of the radius
What is the function of the supinator muscle?
Supination of the forearm
What is the innervation of the supinator muscle
Deep branch of radial nerve
