36 ANTHROPOLOGY. 
a sitting posture. Between the spine and the tuberosity is the lesser sciatic © 
notch, eee one into a foramen by the great sciatic ligament. The third - 
process is the ramus, ascending from the tuber Sahus and inwards, and — 
joining the descending ramus of the pubes. | 
The os pubis (pl. 122, fig. 5°) is situated at the anterior part of the pelvis, 
and is smaller than he ilium or ischium. It may be divided into the body | 
and processes. ‘The body is the most external portion, and constitutes the 
internal and superior part of the acetabulum. From the body the first pro- 
cess, the horizontal ramus, proceeds forwards and outwards, grooved beneath 
where it bounds the obturator foramen. At the internal extremity of this 
ramus is the second process, the tuberosity or spine. This is a prominent 
tubercle, into which Poupart’s ligament is inserted. The third process, the 
crest, leads transversely inwards from this spine, and at its internal end is 
the fourth process, the symphysis. From the lower end of the symphysis 
descends the fifth process, the inferior or descending ramus; this, with the 
ramus of the opposite pubes, forms the arch of the pubes; the outer edge 
of the ramus assists in bounding the thyroid hole. 
b. The Pelvis as a whole. Considering in the next place the pelvis as a 
whole, we commence with the acetabulum (pl. 123, fig. 48”), constituted by 
the junction of the bodies of the three bones. It is surrounded by a promi- 
nent border with a deep notch or deficiency internally, and two others of — 
less extent, inferiorly and superiorly. The great notch which is opposite 
the thyroid foramen, between the ischium and pubes, is converted into a 
foramen by a ligament passing between these two bones. The cotyloid 
cavity (fig. 45°) in the acetabulum for the reception of the head of the 
thigh bone, is of a hemispherical form, and about two inches and a half in 
diameter. | 
The obturator, or thyroid foramen, is situated at the inner side of the ace- 
tabulum and at an inferior level, and is the large anterior hole in ae pelvis 
bounded by the ischium and ee 
The superior circumference or base of the pelvis is formed on each side 
by the crest of the ium; posteriorly by the promontory of the sacrum, 
anteriorly by the iliac spines, ilio-pubal eminences, the intervening grooves, 
and the crests and symphysis of the pubic bones. The lower or perineal 
circumference (strait, or outlet, of the pelvis) is directed downwards and a 
little forwards; bounded by the rami of the pubes, the rami and tuberosities 
of the ischium, the coccyx, and in the recent state by the sacro-sciatic 
ligament of each side. When, as in the artificial skeleton, the latter are 
removed, this strait presents three notches: first, the arch of the pubes, 
triangular and placed beneath the symphysis; second and third, the sacro- 
sciatic notches between the sacrum and os mnominatum of each side. - 
Kach of these is divided into a superior and an inferior by the sciatic 
heaments. 
The internal surface of the pelvis is divided into two parts by the ilio- 
pectineal line. The upper of these parts, properly part of the abdomen, is 
known as the false pelvis, the inferior being the true. The latter is a sort 
of curved canal, wider about the centre than at either end; with smooth | 
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