PHYSIOLOGY, AISTD PATHOLOGY OF THE CHIMPANZEE. 365 



ligament is a strong membrane continuing tiie atlanto-axoid 

 ligament from the anterior arch of the atlas up to the anterior half 

 of the circumference of the foramen magnum. The memhrana 

 tectoria continues the posterior common ligament up to the 

 cranial surface of the basi-occiput where it spi-eads out in a fan- 

 shaped manner. The posterior occijnto-axoid ligament (P.O- 

 A.L) is a strong band on each side on the deep aspect of the 

 membrana tectoria. It extends from the antero- lateral part of 

 the vertebral canal to the ba.si-occiput. It passes lateral to the 

 odontoid process and covers the spinal aspect of the lateral part 

 of the transverse ligament and conceals it from view. The 

 transverse liga7nent (T.L) is a strong band running behind the 

 odontoid process. It is attached by its extremities to the inner 

 aspect of the inferior atlantic articular processes. The cruciate 

 ligament has no inferior crus. The superior crus (S.O.C) is 

 broader and shorter than in Man. It runs fi'om the transverse 

 ligament below to the basi-occiput below the membrana tectoria 

 above. The chech ligamsnts (O.L) are more horizontal than in 

 Man. They run from the odontoid to the inner aspect of the 

 occipital condyles. The middle odontoid, ligament runs from 

 the tip of the odontoid to the anterior edge of the foramen 

 magnum. It is stronger and more horizontal than in Man. 

 Capsular ligaments are as usual. As the odontoid runs farther 

 upwards than in Man the ligaments are modified. 



The lumbar vertebrse are connected by the usual capsular 

 ligaments, intervertebral discs and ligaments connecting their 

 processes. 



Ligaments of the Pelvis (text-fig. 37) : — The lumbar vertebrae 

 are included more closely between the ilia than in Man, and the 

 pelvic ligaments differ in several respects. The limiho-inguinal 

 ligaments (L-I.L) consist of an upper horizontal ligament 

 running from the third lumbar transverse process to the inner 

 lip of the crest of the ilium, and a lower fan-shaped one from the 

 fourth lumbar transverse process to the inner lip and inner 

 surface of the ilium. The fibres of these ligaments are con- 

 tinuous ; and the lower one is continuous with the anterior 

 sacro-iliac ligament ( A.S-I.L). The latter is fan-shaped, and runs 

 from the ala sacri to the anterior surface of the ilium, where it 

 spreads out in a fan-shaped manner. Some fibres run along the 

 pelvic brim. The short posterior sacro-iliac ligament is as in 

 Man. It is superficially thickened to iovvo. the oblique posterior 

 sacro-iliac ligament (O.P.S-I.L), w^hich runs fi'om the posterior 

 tubercles of the sacrum to the two posterior iliac spines and the 

 bone between. The great sacro-sciatic ligament (G.S-S.L) runs 

 from the side of the lower sacral and upper coccygeal vertebrae. 

 It narrows and then it expands again on the posterior part of the 

 inner aspect of the ischial tuberosity. A falciform process runs 

 forwards to become the sub-pubic ligament. The ischial spine is 

 slight, but it receives a broad expansion from the great sacro- 

 sciatic ligament, and a cord-like small sacro-sciatic ligament 



