86 ISCHIUM OS PU.BIS. 



crest, and the anterior inferior spinous process; the two processes 

 being separated by a notch for the attachment of the sartorius 

 muscle. This border terminates inferiorly in the lip of the acetabu- 

 lum. The posterior border also presents two projections, the poste- 

 rior superior and the posterior inferior spinous process, separated 

 by a notch. Inferiorly this border .is broad and arched, and forms 

 the upper part of the great sacro-ischiatic notch. 



The ischium is divisible into a thick and solid portion the body, 

 and into a thin and ascending part the ramus; it may be consi- 

 dered also, for convenience of description, as presenting an external 

 and internal surface, and three borders, posterior, inferior, and 

 superior. 



The external surface is rough, for the attachment of muscles.; and 

 broad and smooth above, where it enters into the formation of the* 

 acetabulum. Below the inferior lip of the acetabulum is a notch, 

 which lodges the obturator externus muscle in its passage outwards 

 to the trochanteric fossa of the femur. The internal surface is 

 smooth, and somewhat encroached upon at its posterior border by 

 the spine. 



The posterior border of the ischium presents towards its middle a 

 remarkable projection, the spine. Immediately above the spine is 

 a notch of large size the great sacro-ischiatic, and below the spine 

 the lesser sacro-ischiatic notch; the former being converted into a 

 foramen by the lesser sacro-ischiatic ligament, gives passage to the 

 pyriformis muscle, and to the gluteal vessels and nerve, pudic vessels 

 and nerve, and ischiatic vessels and nerves ; and the lesser com- 

 pleted by the great sacro-ischiatic ligament, to the obturator internus 

 muscle, and to the internal pudic vessels and nerve. The inferior 

 border is thick and broad, and is called the tuberosity. The surface 

 of the tuberosity is divided into three facets; one anterior, which is 

 rough for the origin of the semi-membranosus; and two posterior, 

 which are smooth, and separated by a slight ridge for the semi-ten- 

 dinosus and biceps muscle. The inner margin of the tuberosity is 

 bounded by a sharp ridge, which gives attachment to a prolongation 

 of the great sacro-ischiatic ligament. The superior border of the 

 ischium is thin, and forms the lower circumference of the obturator 

 foramen. The ramus of the ischium is continuous with the ramus 

 of the pubis, and 'is slightly everted. 



The pubis is divided into a horizontal portion or body, and a de- 

 scending portion or ramus; it presents for examination an external 

 and internal surface, a superior and inferior border, and symphysis. 



The external surface is rough, for the attachment of muscles; and 

 prominent at its outer extremity, where it forms part of the acetabu- 

 lum. The internal surf ace is smooth. The superior' border is marked 

 by a rough ridge the crest ; the inner termination of the crest is the 

 angle; and the outer end, the spine or tuberosity. Running out- 

 wards from the spine is a sharp ridge, the pectineal line or linea 

 ilio-pectinea, which marks the brim of the true pelvis. In front of 



