120 



LIGAMENTS OF THE VERTEBRAL COLUMN. 



Fig. 52.* 



When the intervertebral substance is bisected either horizontally or 

 vertically, it is seen to be composed of a series of layers of dense 

 fibrous tissue, separated by interstices filled with the softer kind. 

 The central part of each intervertebral disc is wholly made up of this 

 softer fibrous cartilage, which has the appearance of a pulp, and is so 

 elastic as to rise above the level of the section as soon as its division 

 is completed. When examined from the front, the layers are found 



to consist of fibres passing ob- 

 liquely between the two verte- 

 brae, in one layer passing from 

 left to right, in the next from 

 right to left, alternating in each 

 successive layer. 



ARCHES. The ligamenta 

 subftava are two thin planes, 

 of yellow fibrous tissue, situa- 

 ted between the arches of each 

 pair of vertebrae, from the axis 

 to the sacrum. From the im- 

 bricated position of the laminae 

 they are attached to the poste- 

 rior surface of the vertebra be- 

 low, and to the anterior sur- 

 face of the arch of the vertebra 

 above, and are separated from 

 each other at the middle line by a slight interspace. They coun- 

 teract, by their elasticity, the efforts of the flexor muscles of the 

 trunk ; and by preserving the upright position of the spine, limit 

 the expenditure of muscular force. They are longer in the cervical 

 than in the other regions of the spine, and are thickest in the lumbar 

 region. 



The ligamenta subflava are in relation by both surfaces with the 

 meningo-rachidian veins, and internally they are separated from the 

 dura mater of the spinal cord by those veins and some loose areolar 

 and adipose tissue. 



ARTICULAR PROCESSES. The ligaments of the articular processes 

 of the vertebrae are loose synovial capsules which surround the articu- 

 lating surfaces. They are protected on their external side by a thin 

 layer of ligamentous fibres. 



SPINOUS PROCESSES. The inter-spinous ligaments are thin and 

 membranous, and are extended between the spinous processes in the 

 dorsal and lumbar regions. They are thickest in the latter region ; 

 and are in relation with the multifidus spinae muscle at each side. 



vertebrae, is seen at 4, by the side of the narrow and unattached portion of the 

 ligament. 



* An internal view of the arches of three vertebrae. To obtain this view the 

 laminae have been divided through their pedicles. 1. One of the ligamenta 

 subfiava. 2. The capsular ligament of one side. 



