THE BONES. 77 



The a r ex of the cavity is almost immnveabk; the rest of the part, and 

 particularly of the basis, by means of the ribs, very moveable. It is expanded 

 in inspiration, contracted during expiration. 



In the foetus are: 1. The diameters from before to behind 

 greater than the transverse diameter, the Sternum projects, on 

 account of the size of the heart and the thymus gland. 



2. The vertical diameter shorter, since the diaphragm projects 

 high upwards. 



3. The ribs slightly curved, the fossse pulmonales not yet 

 developed, as the lungs have not yet respired. 



4. The inferior opening larger in all directions, on account of 

 the large size of the Liver. 



88. The Pelvis, 



formed of 1. The Sacrum and Coccyx ; 



2. The hip, or unnamed bones, ossa coxarum, s. innominata, 

 two. 



It lies below the fifth lumbar vertebra, at the side and before 

 the inferior parts of the vertebral column ; contains a portion of 

 the intestinal canal, and especially the organs of procreation [with 

 those of micturition], 



89. Os coxx, Hip bones, 



occupy the anterior sides of the Pelvis, are flat, and consist, be- 

 fore the age of puberty, of three separate bones, the Ilium, 

 Ischium, and Pubes, which are united together by their thickest 

 parts in the Acetabnlum. 



Connection : behind with the os sacrum, before and below 

 with each other, laterally with the thigh bones. 



90. 1. Os Ilium, 



is the largest and broadest piece ; the most superior, and forms 

 the lateral wall of the Pelvis ; extends from the Sacrum to the 

 superior third of the Acetabulum : 



a. External surface; undulating, with 1 to 2 lineae arcuatse externse, for 

 glutaeus medius and minimus ; and a few foramina for vessels. 



b. Internal surface; with linea arcuata interna, the limit between the 

 superior part, for m. Iliacus internus, which is the lateral wall of the great 

 pelvis, and the inferior portion, that of the lesser pelvis. Behind: tuber 

 Ilium and fades auricularis, the articular surface for the Sacrum. 



c. Crest of the hip, Crista llii, is the superior S-shaped border, for m. 

 latissimus dorsi, and quadrat us lumborum,- with, 1. labiurn externum, for 

 obliq. externus; 2. tab. internum, for m. transvers. abdum.; 3. linea interme- 

 dia, for m. obliq. internus. 



d. Anterior border, descending at an obtuse angle with the Spina llei ant. 



