Abductor: hint that this muscle does the action of Abduction which means to 'take away from the mid-line of the body'
Pollicis: referring to the thumb
Longus: there is likely a shorter version of this muscle (when we cover the four short muscles of the thumb - you will meet the 'short version' of this muscle: Abductor Pollicis Brevis)
This long muscle of the thumb starts from about half way up the back of the forearm (the posterior side) then turns into a skinny tendon that attaches right where the wrist meets the thumb (aka carpo-metacarpal joint)
Official Attachment Points:
Origin: Posterior surface of the radius and ulna & the interosseous membrane
Insertion: Base of the first metacarpal
Break it down:
radius and ulna = forearm bones
interosseous membrane = is a connective tissue between the radius and ulna
metacarpal = our metacarpals are our finger bones between the wrist and the actual fingers (phalanges) so the metacarpals are located pretty much in the palm of your hand!)
Also, this muscle is deep to (meaning it lives underneath) the wrist extensors!
a) Abducts the thumb at the carpo-metacarpal joint
b) extends the thumb at the carpo-metacarpal joint