112 ATLAS AND TEXT-BOOK OF HUMAN ANATOMY. 



Fig. 172. — The anterior longitudinal ligament in the lower thoracic portion of the vertebral column, 

 together with the costo-vertebral ligaments seen from in front (f). 



Fig. 173. — The posterior longitudinal ligament in the lower thoracic and upper lumbar portions of the 

 vertebral column. The vertebral arches have been removed (f). 



Fig. 174. — Horizontal section through an intervertebral fibrocartilage (somewhat enlarged). 



Fig. 175. — Two thoracic vertebrae divided longitudinally in the median line and showing the ligamenta 

 flava. 



Fig. 176. — The ligamenta flava of the thoracic vertebral arches seen from in front, the arches having been 

 separated from the bodies. The left ribs have been disarticulated and removed; the 

 right ones are retained in their natural position (f). 



Fig. 177. — The posterior longitudinal ligament and intervertebral fibrocartilages of the lumbar vertebrae, 

 the vertebral arches having been removed (f). 



Fig. 178. — A longitudinal section taken at about 45 degrees to the median plane through four thoracic 



vertebrae to show the costo-vertebral articulations (f). 

 Fig. 179. — The ligaments of the middle and lower thoracic vertebrae and their ribs, seen from behind (f). 

 Fig. 180. — The ligaments of the middle and lower thoracic vertebrae and their ribs seen from the left side. 



The uppermost rib has been disarticulated and removed (f). 



It widens opposite each intervertebral fibrocartilage, to which it is firmly united, but it is 

 but loosely connected to the bodies of the vertebrae, being separated from them by venous plexuses. 



In addition to the longitudinal ligaments, this group also contains a portion of the supra- 

 spinous ligament. It will be described subsequently, however, together with the interspinous 

 ligaments wdth which it is intimately connected. 



The short ligaments of the vertebral column, connecting contiguous vertebras, are sub- 

 divided into those connecting the arches and those connecting the processes. 



The ligaments between the vertebral arches, the ligamenta flava (Figs. 175 and 176), are 

 strong and are composed almost entirely of elastic tissue, to which they owe their pronounced 

 yellow color and hence their name. They extend anteriorly as far as the posterior margins of 

 the articular capsules of the intervertebral articulations and consequently close the vertebral 

 canal except at the situation of the intervertebral foramina. With the exception of a distinct 

 groove in the median line, their internal surface is absolutely smooth and is directly continuous 

 with the inner surfaces of the vertebral arches. By their elasticity they keep the posterior wall 

 of the vertebral canal smooth during flexion of the vertebral column and they also support the 

 backward movement of the vertebral column during extension. They commence between the 

 second and third cervical vertebrae (sometimes between the first and second) and extend to the 

 last lumbar vertebra, and are strongest below and weakest above. 



The intertranverse ligaments (Figs. 179 and 180) are unimportant and inconstant ligaments 

 connecting the transverse processes of the vertebrae; they are particularly developed in the 

 thoracic and lumbar regions. 



The interspinous ligaments (Fig. 175) connect the spinous processes of contiguous vertebrae 

 and attain their greatest development in the lumbar region. They are continuous anteriorly 

 with the ligamenta flava and posteriorly wdth the supraspinous ligament (Fig. 179) which, con- 

 nects the apices of the spinous processes and forms an independent ligament. The interspinous 



