Muscles of the Shoulder

[Up] [extrinsicmm.] [intrinsicmm.] [arteries] [nerves] [Equine digit]

[joints]  [image 1]  [image 2]  [image 3]  [image 4]   [brachium]  [forearm]

In this image, the head is still to the left, but the forelimb has been elevated so that the elbow is up and we are viewing the medial aspect of the limb. The very small muscle A originates on the corocoid process of the scapula and inserts on the lesser tubercle of the humerus. Muscle A is the coracobrachialis muscle and muscle B is the biceps brachii muscle. Both of these muscles are innervated by the musculocutaneous nerve. In the dog, both of these muscles extend the shoulder, but since the coracobrachialis muscle is minor and flexes the shoulder in some species (such as the horse), don't concern yourself with its function in this course. Also, we will concern ourselves more with the action of the biceps brachii muscle on the elbow.

Muscle C is the subscapularis muscle, and is innervated by subscapular nerves. Muscle D is the teres major muscle, and like the teres minor and deltoideus muscles, it is innervated by the axillary nerve and acts to flex the shoulder. Muscle E is the transected latissimus dorsi muscle.

[Up] [extrinsicmm.] [intrinsicmm.] [arteries] [nerves] [Equine digit]