Spinodeltoid muscle (cat only)

Dscn1794.jpg (77035 bytes) Dscn1795.jpg (72353 bytes) Dorsolateral view, left side

Cat information:
spinodeltoid (cat only corresponds
        to the posterior portion of the deltoid)
origin:  middle third of the spine of scapula
insertion:  deltoid ridge of humerus
nerve:  axillary
action:  flexes and rotates humerus (arm)

14.gif (23095 bytes) Lateral view, right side Posterior view of origin, right side
Anterior view of insertion, right side Posterior view of insertion, right side

Human information:
spinodeltoid (cat only corresponds
        to the posterior portion of the deltoid
        which is pictured above)
origin:  inferior margin of spine of scapula
insertion:  deltoid tuberosity of humerus
nerve:  axillary (C5 and C6)
action:  abducts (horizontal abduction),
        laterally (externally) rotates and extends
        shoulder (humerus or arm)

Dr. J likes to tell his students that the spinodeltoid looks a bit like a football!  If you don't like that analogy you can decide what it looks like to you, a gum drop for example.  This is one of the five muscles in the group we refer to as the muscles that move the arm (not including the rotator cuff muscles).  The above drawings of the origin and insertion might help visualize this information (red is the origin, blue the insertion).  The origin included here is for the middle and posterior divisions of the deltoid.  The other two divisions will be discussed with their corresponding cat muscles.

COPYRIGHT 2009 by William C. Johnson II
ALL RIGHTS RESERVED!

Home