42 LIGAMENTS AND MUSCLES OF THE HORSE. 



1. AXTEA SPINATUS. 



Origin — From the antea-spinatus fossa and cartilage of pro- 

 longation. 



Insertion — By two tendons, the outer one being attached to 

 the anterior part (summit) of the external trochanter of 

 the humerus, and the inner one to the corresponding part 

 of the internal trochante)'. 



Action. — It extends the vshoulder- joint. 



2. POSTEA-SPINATUS. 



Origin. — From the fossa of the same name, and from the car- 

 tilage of prolongation. 



Insertion. — By two tendons, the deep (or short) one being at- 

 tached just inside of the convexity of the external tro- 

 chanter of the humerus, the long (or superficial) one pas- 

 sing over the convexity, to be inserted into a ridge just 

 below. "^ 



Actio7i. — It abducts the humerus and rotates it outwards. 



3. Deltoid. 



Origin. — From the tubercle on the spine of the scapula, and 

 from the dorsal angle of the same. 



Insertion. — To the deltoid ridge of the humerus. 



Action. — To abduct the humerus and rotate it outwards. Act- 

 ins with the teres internus, it also flexes the shoulder, 



4. Teres Minor. 



Origin. — From the lower part of the posterior border of the 

 scapula, from the rough lines at the lower part of the 

 postea spinous fossa, and from a small tubercle on the 

 outer edge of the glenoid cavity. 



Insertion. — To the deltoid ridge. 



Action. — Like the preceding muscle. 



INTERNAL SCAPULAR REGION. 



L Subscapular is. 3. Coracoliumeralis. 



2. Teres internns {or major). 4. Scajmlolmmeralis posticus. 



