OSTEOLOGY AND SYNDESMOLOGY. 35 



cuboid, scaphoid, and three cuneiform; the metatarsus of five, and tlie toes 

 of fourteen : thirty-two bones in all. 



1. The Pelvis {pi 122, fig. 3, k k, pi. 123, figs. 43, 45) is the irregular, 

 circular shaped, bony ring at the lower end of the trunk, formed by the 

 sacrum and coccyx posteriorly, and by the ossa innominata laterally and 

 anteriorly; it contains some of the abdominal viscera and many of the; 

 urinary and generative organs; it also supports the spinal column above,, 

 and transmits the weight to the thigh bones, on which it rests below. The 

 sacrum and coccyx have already been described. As each os innominatum' 

 {pi. 122, fig. 3, k) is divisible in early life into three bones, the ilium, 

 ischium, and pubes, uniting to form the socket for the head of the thigh 

 bone, "we shall first consider these separately, and then as united into one- 

 bone, as in the adult. 



a. The individual hones of the Pelvis. The os ilium {pi. 123, fig. 43") 

 is situated at the upper and outer part of the pelvis, and forms that projec- 

 tion commonly called the hip. It is broad, flat, and triangular, the base 

 above bounded by a semicircular crest, which ends before and behind in 

 processes or tubercles named spinous ; the apex below forming the upper 

 and outer part of the acetabulum or socket; it may be divided into the 

 body, ala, and processes. The body is the inferior narrowed portion ; the 

 ala is the broad, fan-like, semicircular portion which ascends from the body, 

 inclining outwards and a little forwards ; the external surface, or dorsum^ is 

 rough and irregularly convex and concave, with a considerable concavity 

 above the acetabulum (external ilia fossa) and two curved semicircular 

 lines, a superior and an inferior. The internal surface of the ala is divided 

 into three parts : one, superior and anterior, is the iliac fossa ; the second 

 forms about the posterior third of the bone ; and the third is smooth and 

 small, and is the only portion of the ilium that enters into the side of the 

 true pelvis. It is separated from the iliac fossa by a rounded edge (called 

 the ilio-pectineal line), continuous behind with the promontory of the 

 sacrum, and before with a sharper ridge on the pubes. The processes of 

 the ilium are, first, the crest {pi. 123, fi{j. 43°), forming the upper border 

 of the ala ; second, the anterior superior spine, at the anterior extremity of 

 this crest; there is a notch between this and the third process, the anterior 

 inferior spine. Internal to this space is a superficial groove, bounded inter- 

 nally by the ilio-pectineal eminence, which is common to and formed by the 

 union of the ilium and pubes. Fourth, the posterior superior spine is the 

 posterior termination of the crest ; and separated from this by a notch is the 

 fifth process, the posterior inferior spine. 



The ischium {pi. 122, fi,g. 4''*) is placed at the lower, outer, and back 

 part of the pelvis, and presents a body and processes. Tiie body forms the. 

 outer, lower, and back portion of the acetabulum, constituting more than 

 two fifths of it. The processes are, first, the spine {fig. 4'), arising from 

 near the middle of the posterior part, below the sacro-sciatic notch. Be- 

 tween this and the second process is the pulley round which the tendon of 

 the obturator muscle turns. This next process is the tuberosity or tuber 

 ischii {fig. V). On this rough and broad process the body rests when in 



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