78 SPECIAL ANATOMY. 



sup., for m. sartorius, tensor fascism lalx and inferior, for m. rectus femoris; 

 between the two spines and below the spina inferior, a notch, for m. lliacus, 

 terminates in the anterior horizontal ramus of the pubes, where is the emi- 

 nentia ileo-pectinaea. 



e. Posterior border, with Spina ilei post. sup. ; inferior ; Incisura semi- 

 lunaris. 



f. Inferior border, from the Spina poster, infer., presents . Incisura ischia- 

 dica major, for m. pyriformis, art. and nerv. glutseux, iachiadicus, and pudend. 

 communis. 



91. 2. Os ischii, seat bone, for m. levator ani. 

 The most inferior portion ; below and behind the Ilium. 



a. Corpus, the inferior portion of the acetabulum. Internal surface smooth, 

 forms the inferior portion of the small pelvis. Posterior border with Spina 

 ischii, the limit between Incisura ischiadica major and minor, for m. gemellus 

 super., coccygeus and, Ligam. spinoso-sacrurn. Anterior border, commence- 

 ment of the obturator foramen. 



b. Ramus descendens, short and thick. Posterior border forms the Incisura 

 ischiadica minor, for m. obturator internus, art., ven., nerv. pudendus commit- 

 nis, from Spina ischii to Tuber ischii, for m. gemellus infer., quadratus ferno- 

 ris, semitendinosus, semimembranosus, biceps, transversus perinsei, Ligam. 

 tuber oso-sacrum. Anterior border, sharp, assists in forming obturator foramen. 



c. Ramus ascendens ascends from Tuber ischii forwards and inwards, for 

 m. ischio'Cavemosus. Internal border forms the internal part of the obturator 

 foramen. External border a part of the Pubic arch. 



92. 3. Os pubis s. pectinis, 

 in the anterior region of the pelvis. 



a. Corpus the inner third portion of the acetabulum with Eminentia tfco 

 pectincza, for crural artery above the Acetabulum. 



b. Ramus horizontalis, for m. rect. abdom., pyrarmdali? above. Superior 

 border, sharp, Pecten s. Crista pubis, for Pedinceus m., a continuation of linea 

 arcuata, terminates in Spina pubis, for ligam. Pouparti. Inferior border, the 

 superior part of the obturator foramen. 



c. Ramus descendens for m. adduct, gracilis, descends from the Spina pubis. 

 to meet the ram. ascend, of the Ischium. External border forms the internal 

 of the obturator foramen; internal border, with that of the other side, the 

 pubic symphysis, over this angulus pubis, superior; beneath it the superior 

 portion of the pubic arch. 



Acetabulum, the hemispherical, hollow surface, in which the body of the 

 three bony pieces meet together, lies on the external side of the pelvis ob- 

 liquely outwards and downwards, and is destined for the reception of the 

 thigh bones. Its crescentic, sharp edge, supercilium, has below and internally 

 a deep Incisura acetabuli, for the vessels of the joint to enter, and is still more 

 deepened by a tendinous ring, labrum cartilagineum. Above is a horizontal 

 groove, for tendo redifemor., beneath a deeper, for tendo obturator externi. The 

 whole external surface is covered with cartilage, that is the fades lunata, to the 

 small Fovea for the attachment of the ligam. teres. The internal surface 

 turned towards the small pelvis is rather curved downwards and backwards, 



