THE LIGAMENTS. 103 



2. Lig. annulare, consisting of transverse fibres, the rings passing round the 

 borders of the articular surfaces. 



3. Lig. arcualum inferius s. triangulare or sub-pubic, beneath the symphysis, 

 triangular, continuation of the Lig. inteross., forms the superior border of the 

 pubic arch; proceeds from one ramus descend, pub. to the other. 



b. The ram. coxarum with the vertebral column, symphysis 

 sacro-iliaca. 



The articular surfaces of the Sacrum and Ilium, superficies 

 auriculares, covered with cartilage and with a thin Synovial cap- 

 sule, which in children and pregnant women is more distinct, are 

 united by a slight layer of fibro-cartilage with gelatinous sub- 

 stance, and form an amphiarthrosis. Contributing to strengthen 

 the articulation there are : 



1. Ligg. sacro-iliaca vaga anterior a, short, transverse and oblique from the 

 superior surface of the Sacrum to the internal of the Ilium, they blend with 

 the memb. oss. sacri propria. 



2. Ligg. sacro-iliaca vaga posteriora, short, crossed, filling up the fossa be- 

 tween the posterior surface of the Sacrum and tuber oss. ilium. 



3. Ligg. pelvis, s. ileo-sacra postica, two ; thick, on the posterior side of the 

 pelvis ; longum arising from spina ilei postei'. super. breve arising from spina 

 ileipost. infer. Both are attached to the proc. transversus of the third and fourth 

 sacral vertebrae. Sometimes three lateral bundles pass from the hip-bone to 

 the proc. transvers. of the first and second sacral piece. 



4. Lig. ileo-lumbalia s. pelvis anterior; lies over the sacro-iliac symphysif; 

 springs from proc. transv. of the fifth or fourth lumbar vertebra. Lig. superitts 

 is fixed to the posterior part of the crista Ilei. Lig. inferius is attached broad 

 upon the superior surface of the Sacrum and the internal of the Ilium, close 

 to the spina ilei poster, super. 



c. Of the sacrum and coccyx a symphysis, which often ossi- 

 fies ; in very moveable coccyges, a synovial capsule. Between 

 the articular surfaces a delicate layer of fibro-cartilage. Liga- 

 ments. 



1. Ligg. sacro-coccygea postica longa. from the border of the exit of the Ca- 

 nalis sacralis, which they close, diminishing upon the posterior surface of the 

 coccyx, for m. glutcri maximi. 



2. Ligg. sacro-coccygea post, brevia, below the last, passing from the cornua 

 of the Sacrum to that of the coccyx ; are often ossified. 



3. Ligg. sacro-coccygea antica, from the apex of the sacrum to that of the 

 coccyx, in front; often wanting. 



4. Membr. ossis sacri propria, covers the anterior surface of the Sacrum, is 

 above covered by lig. longitudinale anterius. 



d. Ligaments for the purpose of limiting the pelvic cavity. 



1. Lig. obturatorium, consists of aponeurotic bundles which cross in all di- 

 rections, closing an egg-shaped opening ; it is perforated at its superior margin 

 by a foramen for art., ven., nerv. obturator, and serves to give attachment to the 

 m. obturatores externus et internus. 



2. Ligg. sacro-ischiadica ma jus et minus. 



a. Majus s. post. s. tuberoso-sacnvm arises from the internal lip of the tuber 



