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 coUaterale ulnare, radiale),^ are strong, somewhat elastic 

 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 third 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 joint 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 oases of rup- 

 ture of the latter the toe turns up. The mobihty 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 hgaments 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. 



Veidnd sacru-iliiic ligament 



The Articulations of the 



Pelvic Limb _,, ,.ai«_ „ .,. 



THE SACRO-ILIAC ARTICULATION fi: 'imr articulation 



This joint (Articulatio sacro- 

 iliaca) is a diarthrosis formed be- 

 tween the auricular surfaces of the 

 sacrum and ilium. These surfaces 

 are not smooth in the adult, but are 



marked by reciprocal eminences and depressions, and are covered by a thm layer of 

 cartilage. The joint cavity is a mere cleft, and is often crossed by fibrous bands 



Fig. 243. — Left Sacho-iliac AsTicnLATioN op Horse; Ax- 

 TEKIOR View. (Adapted from Schmaltz, Atlas d. Anat. 

 d. Pferdes.) 



1 These are termed the postero-lateral ligaments by M'Fadyean. 

 suspensory Hgaments of the navicular bone. 



Functionally they are 



