Muscles Week 12 Flashcards
What is the origin of the Extensor Pollicis Longus?
Posterior middle 1/3 of ulna and interosseous membrane
Where does the Extensor Pollicis Longus insert?
Distal phalanx of thumb
What is the action of the Extensor Pollicis Longus?
Extension of thumb (CMC, MCP, IP joints); assists in extension and radial flexion of wrist
What is the innervation of the Extensor Pollicis Longus?
Radial nerve
What is the origin of the supinator?
Lateral epicondyle of humerus and supinator crest of lateral ulna (near radial notch)
Where does the supinator insert?
Proximal 1/3 of radial shaft
What is the action of the supinator?
Supination of forearm
What is the innervation of the supinator?
Radial nerve
Where is the supinator located in relation to other muscles?
Deep to the forearm extensors and superficial to the head of the radius
What is the origin of the Abductor Pollicis Longus?
Posterior surfaces of ulna, radius, and interosseous membrane (middle 1/3 of forearm)
Where does the Abductor Pollicis Longus insert?
Base of 1st metacarpal (lateral side)
What is the primary action of the Abductor Pollicis Longus?
Abduction of thumb (CMC joint)
Also: radial deviation of wrist, assists with extension and rotation of thumb, and flexion/supination of hand at wrist.
Which nerve innervates the Abductor Pollicis Longus?
Radial nerve
What is the origin of the Extensor Pollicis Brevis?
Posterior distal 1/3 surface of radius & interosseous membrane
Where does the Extensor Pollicis Brevis insert?
Base of proximal phalanx of thumb
What is the action of the Extensor Pollicis Brevis?
Extension of proximal phalanx & 1 metacarpal of thumb (mild radial flexion of wrist)
Which nerve innervates the Extensor Pollicis Brevis?
Radial nerve
What is the origin of the Extensor Pollicis Longus?
Posterior middle 1/3 of ulna and interosseous membrane
Where does the Extensor Pollicis Longus insert?
Distal phalanx of thumb
What is the action of the Extensor Pollicis Longus?
Extension of thumb (CMC, MCP, IP joints); assists in extension and radial flexion of wrist
What is the innervation of the Extensor Pollicis Longus?
Radial nerve
What is the origin of the Extensor Indicis?
Posterior distal 1/3 of ulna and interosseous membrane
Where does the Extensor Indicis insert?
Base of middle and distal phalanx of index finger (via extensor expansion & extensor digitorum muscle tendon)
What is the action of the Extensor Indicis?
Extension of index finger (MCP, PIP, DIP)
Weak extension of hand and adduction of index finger
What is the innervation of the Extensor Indicis?
Radial nerve
What is the origin of the Flexor Pollicis Longus?
Radius (middle 1/3 anterior surface) and interosseous membrane
What is the insertion point of the Flexor Pollicis Longus?
Base of distal phalanx of thumb (anterior aspect)
What is the primary action of the Flexor Pollicis Longus?
Flexion of thumb (CMC, MCP, IP joints)
Also crosses wrist joint for weak wrist flexion.
Which nerve innervates the Flexor Pollicis Longus?
Median nerve
