Monday, 28 April 2014

Flexor Digitorum Superficialis: a wrist flexor

We're still hanging out in the forearm flexors today! 
Today we'll be getting to know Flexor Digitorum Superficialis!  

  Last week we discussed Flexor Digitorum Profundus.  They perform the same actions, and are located in the same approximate area on the inside of the forearm. Profundus is deeper than Superficialis.  Flexor Digitorum Superficialis is a more 'widespread' muscle.  With muscle attachments there is usually only one origin (the point where the muscle attaches/comes from) but with this one it has TWO points of origin, check it out!

has two heads for ORIGIN:

a) Humero-Ulnar head:  medial epicondyle of the humerus (common flexor tendon- where most of the wrist flexors originate) and the coronoid process of the ulna (a bony bump on the ulna bone just past the elbow!)

b) Radial Head: Proximal 1/2 of the anterior shaft of the radius 

INSERTION point:  
middle phalanges of digits 2-5
 Muscle Actions:  just like her 'deeper sister' Profundus..
1) flexion of digits 2-5 at the MCP, PIP, and DIP joints (what?*)
2) flexion of the hand at the wrist joint (aka radio-carpal joint)

* MCP joint: Metacarpo-Phalangeal joint (where your knuckles are!)
PIP joint: Proximal Inter-phalangeal joint
DIP joint:  Distal Inter-phalangeal joint

I gave a visual of these lil' joints back when we went over the Wrist Extensors of the forearm