Extrinsic Muscles of the Thumb Flashcards
What are the attachments of flexor pollucis longus?
O: anterior surface of radius - between radial tuberosity and pronator quadratus & adjacent interosseous membrane
I: palmar surface of base of distal phalanx of thumb
what is the nerve supply of flexor pollucis longus?
Anterior interosseous branch of median nerve C8, T1
what is the action of flexor pollucis longus?
Flexion of the IP joint @ thumb
Flexes MCP and wrist o
Functional activity of flexor polluclis longus?
Gripping small object
What is the DOF of flexor pollicis longus?
inferomedially
How does flexor pollucis longus cross the wrist joint?
in the main compartment carpal tunnel, in its own synovial sheath
What are the attachments of extensor pollicis longus?
O: middle 1/3rd posterior surface of ulna and adjacent interosseous membrane
I: dorsal surface of base of distal phalanx of thumb
What is the nerve supply to extensor pollicis longus?
posterior interosseous branch of radial nerve - C7, c8
what is the action of extensor pollicis longus?
extends 1st IP, MCP, CMC and wrist joint abducts the wrist
what is the function of extensor pollicis longus?
releasing grip
How does extensor pollucis longus cross the wrist joint?
in the 3rd compartment of the extensor retinaculum - in its own synovial sheath
what are the attachments of extensor pollucis brevis?
O: middle 1/3 posterior surface of radius and interosseous membrane
I: dorsal surface base of proximal phalanx of thumb
what is the nerve supply of extensor pollicis brevis?
posterior interosseous nerve C7, C8
what is the action of extensor pollucis brevis?
Extends CMC and MCP joints of thumb
Helps to extend and abduct wrist
what is a function of extensor pollucis brevis?
release of grip
