Monday, 16 June 2014

Extensor Pollicis Longus : (3 of 4 long thumb muscles)

Extensor Pollicis Longus : Let's break it down!

Extensor: this muscle probably extends something!
Pollicis: referring to the Thumb
Longus: usually indicates there is a shorter version of this muscle (next week ;)

This long thumb muscle closely resembles last weeks Abductor Pollicis Longus ,   with it's muscle belly starting just above the wrist on the back of the forearm - only this guy has a longer skinny tendon that reaches to the tip of the thumb! This muscle lives underneath the wrist extensor muscles

Official Attachment Points:

Origin: Posterior surface of the ulna and interosseus membrane

Insertion: Distal Phalange of the thumb

Break it down:
Ulna: the forearm bone on the pinky side! (on the other end, the ulna turns into your elbow!)

Interosseous membrane = is a connective tissue between the radius and ulna 
Distal phalange of the thumb:  whereas the fingers have proximal, middle, and distal phalanges (remember this post?) the thumb has just two : proximal and distal

Muscle Action:

Extends the thumb at the interphalangeal joint 
Just like last week, extension of the thumb is basically a thumbs up!

 Thumbs up for Muscle Monday!  Next week:
 The shorter version of this muscle: Extensor Pollicis BREVIS