226 THE ARTICULATIONS OF THE HORSE 
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, 7. 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 bone 
Bifurcation of suspensory 
ligament 
Bifurcation of common digital artery 5 
: ; ; : Capsule of fetlock joint (proximal 
pouch) 
Medial digital artery S d 
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 
Oblique or middle distal sesomoid 
ligament 
Straight or superficial distal 
sesamotd ligament 
Lateral ligament of pastern joint 
Distal end of digital sheath 
Suspensory ligament of navicular 
bone 
Dorsal branch of digital artery 
Volar branch of digital artery 
Distal annular ligament of digit (cut 
and reflected) 
Fic. 241.—Derp Dissection or DistaLt Part or Ricut Fore Limp or Horse, SHowrne Jornts AND LIGAMENTS; 
Posterior View. 
1, Cartilage of third phalanx; 2, flexor surface of navicular 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 wider above than below.! It is attached above to the bases of the sesa- 
moid bones and the intersesamoid ligament, below to the complementary fibro- 
eartilage 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~ 
1'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. 
