SACRAL AND COCCYGEAL ARTICULATIONS 213 
and withers it is remarkably modified to form the ligamentum nuchz, which re- 
quires more extended notice. 
The ligamentum nuche is a powerful elastic apparatus, the principal function 
of which is to assist the extensor muscles of the head and neck. It extends from 
the occipital bone to the withers, where it is directly continuous with the lumbo- 
dorsal part of the supraspinous ligament. It consists of two parts—funicular and 
lamellar. The funicular part (Pars occipitalis) arises from the external occipital 
protuberance and is inserted into the summits of the vertebral spines at the withers. 
Two burse are usually found under it in the adult. The atlantal bursa lies be- 
tween the ligament and the dorsal arch of the atlas. The supraspinous bursa is 
usually over the third and fourth thoracic spines, but may be over the second or 
extend to the fifth. Another bursa may be present at the spine of the axis; this is 
between the funicular part and the large digitation attached to the axis. In the 
neck the funicular part consists for the greater part of two bands closely applied and 
attached to each other. Near and at the withers it broadens greatly, forming an ex- 
pansion about five to sixinches (ca. 12 to 15 em.) in width, the lateral margins of which 
are thin and turn down over the trapezius and rhomboideus muscles. Behind the 
higher spines it becomes narrower and thinner, and is continued by the white fibrous 
lumbo-dorsal part.2, A mass of fat and elastic tissue lies upon the ligament as far 
back as the withers. It varies greatly in amount in different subjects, and is most 
developed in stallions of draft breeds, in which it forms the basis of the so-called 
“crest.”” The lamellar part (Pars cervicalis) consists of two lamine separated 
medially by a layer of loose connective tissue. Each lamina is formed of digitations 
which arise from the second and third thoracic spines and from the funicular part, 
are directed downward and forward, and end on the spines of the cervical vertebre, 
except the first and last. The digitation which is attached to the spine of the axis 
is very thick and strong. Behind this they diminish in size and strength; the last 
one, which is attached to the sixth cervical vertebra, is quite thin and feeble, or may 
be absent. 
The interspinous ligaments (Ligg. interspinalia) extend between the spines 
of contiguous vertebre. In the cervical region they are narrow elastic bands, and 
in the thoracic and lumbar regions they consist of white fibers directed obliquely 
downward and backward. 
The intertransverse ligaments (Ligg. intertransversaria) are membranes 
which connect adjacent transverse processes in the lumbar region. 
INTERTRANSVERSE ARTICULATIONS 
These joints (peculiar to equidz) are diarthroses formed by the transverse 
processes of the fifth and sixth lumbar vertebrae and between the latter and the ale 
of the sacrum. A similar joint between the fourth and fifth lumbar processes is 
frequently present. The articular surfaces have an elongated oval form, the 
anterior one being concave and the posterior one convex. The capsule is tight, 
and is reinforced ventrally. 
SACRAL AND COCCYGEAL ARTICULATIONS 
In the foal the bodies of the five sacral vertebra form joints which resemble 
somewhat those in the posterior part of the lumbar region. These joints are in- 
in dissecting-room subjects these bursse and the adjacent structures are commonly the seat 
or pathological changes. They appear to be the starting-point of “poll evil” and “‘fistulous 
withers.” Subcutaneous burse may be found over the ligament at the withers. 
* No natural line of demarcation exists between the igamentum nuche and the lumbo-dorsal 
part . ube supraspinous ligament, since the change from the elastic to the white fibrous structure 
is gradual. 
