62 TOPOGRAPHICAL ANATOMY OF THE 



The supra-spinal ligament (ligamentum supraspinale), like the 

 foregoing, is common to a number of intervertebral joints. About the 

 fourth tlioracic vertebra it is directly continuous with the occipital part 

 of the ligamentum nuchse. Caudal to this point it forms a strong 

 band firmly attached to the extremities of the vertebral spinous 

 processes, varying in its breadth with the variation in expansion of the 

 ends of the processes. 



Thouf^h the yellow and elastic ligamenturri nuchoi,^ a modification 

 of the supraspinal ligament, belongs to the neck, the dissector of the 

 thorax should examine that part of it which is attached to the thoracic 

 vertebrae. The ligament is readily divisible into two portions: (1) A 

 cord-like or funicular occipital part (pars occipitalis), and (2) a lamellar 

 cervical part (pars cervicalis). The occipital part merges gradually 

 into the ordinary supraspinal ligament about the fourth thoracic 

 spinous process, and here forms a flattened cord that, on section, is 

 apparently composed of right and left bands blended in the median 

 plane of the body. In this region (the withers) also the right and left 

 borders of the ligament are continued into lateral expansions, about 

 12-15 cm. wide, that thin out over the surface of the trapezius and 

 rhomboid muscles. A synovial bursa, of variable extent and size, is 

 placed between the ligament and the summits of the thoracic spinous 

 processes over which it passes. 



Only a limited extent of the cervical part of the ligament is 

 associated with the thorax. It is attached by digitations to the spinous 

 processes of the second and third thoracic vertebrae, and can readily be 

 separated into right and left halves. 



Interspinal ligaments (ligamenta interspinalia) fill the intervals 

 between adjacent spinous processes, and consequently vary in dimensions 

 with the length of these processes. It will be noted that the fibres of 

 these ligaments do not take the shortest possible course between two 

 processes, but are disposed obliquely with a slope in a ventral and 

 caudal direction. Further, careful dissection will reveal the fact that 

 each ligament is composed of two layers of fibres — right and left. 



Ligamenta flava- consist of short elastic fibres passing between the 

 opposed borders of adjacent vertebral arches. 



Joint capsules (capsulae articulares), each possessed of a synovial 



linino-, enclose the joints between opposed articular processes. In those 



parts of the vertebral column where movement is most free, the capsules 



are loosest. In the thoracic region, where movement is hampered, the 



capsules are short. 



1 Nucha [L.], the nape of the iieok. 

 - Flavus [L.], yellow. 



