CHAP, iv.]- THE SKELETON OF THE LIMBS. 107 



by a notch (the ^cotyloid notch). There is no perforation in the 

 acetabulum, but its surface just within the notch is depressed, the 

 depression affording attachment to the very strong ligamentum teres 

 (or round ligament) which goes from it to the head of the thigh- 

 bone. 



Enclosed by the ilium, ischium, and pubis, there is an oval space 

 called the obturator foramen, one such being placed on each side of 

 the pubic symphysis (0). 



The concavity in the posterior border, between the posterior 

 spinous process of the ilium and the spine of the ischium, is called 

 the greater ischiatic notch ; the other concavity, between the spine of 

 the ischium and the tuberosity of that bone, is called the lesser 

 ischiatic notch. 



The width from side to side of the pelvis is about equal to its 

 depth from the brim of the pubis to midway between the tuberosities 

 of the ischia. Either of these dimensions is much less than half 

 the greatest extent of the ossa innominata. 



13. The FEMUR is a bone of about the same length as the ulna, 

 and, like the humerus, is more or less cylindrical, with a rounded 

 head above (to fit into the acetabulum), and with an expansion 

 below with two articular surfaces. 



The shaft, which is nearly straight, is smooth in front, but has an 

 oblique ridge behind, termed the lima aspcra, which is most marked 

 about half-way up the bone (la). 



At the upper end of the shaft are two conspicuous projections. 

 The external one of these (projecting from the outer margin of the 

 bone, which it continues upwards), is called the great, or peroncal 

 trochanter (gt). The internal projection, which is much smaller, 

 more conical, and rounded, stands out from the inner and hinder 

 side of the bone, and is called the lesser, or tibial trochanter (It). 



Between the two trochanters, on the hinder side of the femur, a 

 bony prominence extends, which is termed the posterior inter- 

 trochanteric ridge (r) ; and a very slightly marked line, the anterior 

 inter-trochantcnc ridge, also connects the two trochanters on the 

 front surface of the femur. 



On the inner and hinder side of the great trochanter is a pit, 

 termed the trochantcnc fossa (/). 



From between the inter-trochanteric ridges a narrower portion of 

 bone, compressed antero-posteriorly, projects inwards, forming a 

 slightly obtuse angle with the shaft. This is called the neck of the 

 femur (ri). It ends in a rounded head (forming a large part of a 

 sphere) which (h) fits into the acetabulum. 



On the hinder part of the inner side of the head of the femur 

 there is a very distinctly marked depression, or pit, which serves for 

 the attachment of the ligamentum teres (p). 



On the outer side of the hinder part of the femur, a little below 

 the great trochanter, is a more or less marked vertical ridge, which 

 serves for the insertion of the gluteus maximus muscle. 



At the lower end of the femur are two rounded prominences, 



