262 



FASCIA AND MUSCLES OF THE HORSE 



latissimus dorsi, and tensor fasciae antibrachii muscles, the brachial and deep 

 brachial vessels, and the median and ulnar nerves; behind, the long head, branches 

 of the deep brachial vessels, and the radial nerve. 



Blood-supply. — Deep l^rachial and ulnar arteries. 

 Nerve-supply. — Radial nerve. 



5. Anconeus (M. anconeus parvus s. subanconeus) . — This is a small fleshy 

 muscle which covers the olecranon fossa and is covered by the triceps. It is some- 

 what difficult to separate from the outer head. 



Origin. — The distal third of the posterior surface of the humerus. 



Insertion. — The outer 

 surface of the olecranon. 



Action. — To extend the 

 elbow joint, and to raise the 

 capsule of the joint and 

 prevent its being pinched 

 during extension. 



Structure. — It is almost 

 entirely fleshy, and is ad- 

 herent by its deep face to 

 the joint capsule. 



Relations. — Superfici- 

 ally, the triceps muscle; 

 deeply, the humerus and 

 the elbow joint. 



Blood-supply. — Deep 

 brachial artery. 



Nerve-supply. — Radial 

 nerve. 



Deep flexor tendon 



■Distal end of small metacarpal bone 

 Suspensory ligament 



Branch of stiperficial flexor tendon 

 Distal digital annular ligament 

 - Upper border of lateral cartilage 



Fin. 189. — Digit of Horse, Posterior View. 

 14, Deep flexor tendon; 15, superficial flexor tendon; 16, posterior 

 annular ligament of fetlock; 17 , proximal annular or vaginal ligament 

 of digit; 11, lateral cartilage; 24, plantar cushion. (After EUenberger- 

 Baum, Anat. fiir Kiin.stler.) 



IV. FASCIA AND MUSCLES 

 OF THE FOREARM 



AND MANUS 



The forearm is covered 

 on three sides by the mus- 

 cles of this group, leaving 

 the inner surface of the radi- 

 us for the most part subcu- 

 taneous. The extensors of 

 the carpus and digit lie on the anterior (dorsal) and external part of the region, 

 while the flexors occupy the posterior (volar) surface. 



The fascia of the forearm (Fascia antibrachii) forms a very strong and complete 

 investment for all the muscles of the region. The superficial fascia is thin, and 

 disappears at the carpus by fusing with the deep fascia. The deep fascia is very 

 strong and tendinous in character. It furnishes insertion at its upper and inner 

 part to the tensor fasciae antibrachii and posterior superficial pectoral muscles; 

 at its upper anterior and outer part, to aponeuroses from the mastoido-humeralis 

 and biceps. It is attached at the elbow by its deep face to the outer tuberosities of 

 the humerus and radius, to the ulna, and to the lateral ligaments. On the inner 

 surface of the forearm it blends with the periosteum on the subcutaneous surface 

 of the radius. It is closely adherent to the surface of the extensor muscles, Ijut is 

 rather loosely attached to the flexors. From its deep face are detached inter- 

 muscular septa, which form sheaths for the muscles and are attached to the untler- 

 lying bones. The principal septa are: (a) One wdiich passes between the common 



