226 



THE ARTICULATIONS OF THE HOESB 



considerable elasticity, and is the highly modified interosseous medius muscle. It 

 consists mainly of tendinous tissue, but contains a variable amount of striped mus- 

 cular tissue, especially in its deep part and in young subjects. Its principal func- 

 tion is to support the fetlock, i. e., to prevent excessive dorsal flexion of the joint 

 when the weight is put on the limb. The branches which join the common exten- 

 sor tendon limit volar flexion of the interphalangeal joints in certain phases of move- 

 ment. 



The distal sesamoidean ligaments are three in number. The superficial or 



Large metacarpal bone 

 Lateral small metacarpal hone 



Bifurcation nf co»imon digital artery 

 Medial digital artery 



Oblique or middle distal sesamoid 

 ligament 

 Straight or superficial distal 

 sesamoid ligament 



Distal annular ligament of digit {cut 

 and reflected) 



Bifurcation of suspensory 

 ligament 



Capsule of fetlock joint {proximal 



pouch) 

 Sesamoid groove 



Volar annular ligament of fetlock 

 {cut and reflected) 



Lateral sesamoid ligament 

 Stump of proximal digital annular 



ligament 

 Extensor branch of suspensory 



ligament 

 Volar ligaments of pastern joint 



Insertion of superficial flexor 



tendon 

 Fibrous plate 

 Deep flexor tendon 



Lateral ligament of pastern joint 

 _^ _^ ^ Distal end of digital sheath 



^ Suspensory ligament of navicular 



':'^rT bone 



Dorsal branch of digital artery 

 Volar branch of digital artery 



Fig. 241. — Deep Dissection of Distal Part of Right Fore Limb of Horse, Showing Joints and Ligaments; 



Posterior View. 



1, Cartilage of third phalanx; 2, fle.xor surface of na\dcular bone; 3, distal navicular ligament; 4, insertion of 

 deep flexor tendon. Small arrows point to openings made in capsules of pastern and coffin joints. (After Schmaltz, 

 Atlas d. Anat. d. Pferdes.) 



straight sesamoidean ligament (Lig. sesamoideum rectum) is a flat band and is 

 somewhat witler above than below. ^ It is attached above to the bases of the sesa- 

 moid bones and the intersesamoid ligament, below to the complementary fibro- 

 cartilage of the proximal end of the second phalanx. The middle sesamoidean 

 ligament is triangular, with thick, rounded margins (Ligg. sesamoidea obliqua) and 

 a thin central portion.^ Its base is attached to the sesamoid bones and intersesa- 



' This is often called the Y-shaped ligament — a rather undesirable name, since it is not 

 bifurcate. 



- It is also called the V-shaped ligament. 



