THE ARTICULATIONS OF THE PELVIC LIMB 229 
ulnare, radiale), are short, strong bands which are attached above in the depressions 
on either side of the lower part of the second phalanx, under cover of the cartilage 
of the third phalanx. They widen below and end in the depressions on either 
side of the extensor process and on the anterior end of the cartilages. 
The collateral sesamoidean or suspensory navicular ligaments, medial and 
lateral (Lig. sesamoideum collaterale ulnare, radiale),! are strong, somewhat elastie 
bands, which form a sort of suspensory apparatus for the third sesamoid. They are 
attached superiorly in and above the depressions on each side of the distal end of 
the first phalanx and are here partly blended with the collateral ligaments of the 
pastern joint. They are directed obliquely downward and backward, and end 
chiefly on the ends and proximal border of the distal sesamoid, but detach a 
branch to the axial surface of each cartilage and angle of the third phalanx. 
The phalango-sesamoidean or distal navicular ligament (Lig. phalangeo-sesa- 
moideum) reinforces the capsule distally. It is a strong layer of fibers which 
extend from the distal border of the distal sesamoid to the flexor surface of the third 
phalanx. 
Movements.—The chief movements are flexion ana extension. In the stand- 
ing position the jomt is extended. During volar flexion a very small amount of 
lateral movement and rotation can be produced by manipulation. Dorsal flexion 
is very limited. 
Dorsal flexion appears to be checked mainly by the deep flexor tendon, since in cases of rup- 
ture of the latter the toe turns up. The mobility of the posterior part of the socket for the second 
phalanx (formed by the distal sesamoid) diminishes concussion when the weight comes on the foot 
LIGAMENTS OF THE CARTILAGES OF THE THIRD PHALANX 
In addition to the bands mentioned above, which attach the cartilages to the 
extremities of the navicular bone, there are three ligaments on either side which 
attach the cartilages to the phalanges. 
An ill-defined elastic band passes from the middle part of the border of the first 
phalanx to the upper part of the cartilage, detaching a branch to the digital cushion. 
A short, strong band connects the anterior extremity of the cartilage with the 
rough eminence on the second pha- 
lanx in front of the attachment of the 
collateral ligament of the coffin joint. 
The lower border of the cartil- 
age is covered in part by fibers which 
attach it to the angle of the third 
phalanx. 
Ventral sacro-iliac ligament 
Tuber 
Coxe 
THE ARTICULATIONS OF THE 
PELVIC LIMB 
THE SACRO-ILIAC ARTICULATION 
This joint (Articulatio sacro- 
me a ae ne Fic. ee gee eee PH TIGUUATION OF HEED on 
. (Adapted from Schmaltz, Atlas d. Anat. 
sacrum and ilium. These surfaces d. Pferdes.) 
| are not smooth in the adult, but are 
marked by reciprocal eminences and depressions, and are covered by a thin layer of 
cartilage. The joint cavity is a mere cleft, and is often crossed by fibrous bands. 
Sacro-iliac 
articulation 
* These are termed the postero-lateral ligaments by M’Fadyean. Functionally they are 
Suspensory ligaments of the nayicular bone. 
