80 SPECIAL ANATOMY. 



physis of the one side to the ileo-pectineal eminence at the superior border of 

 the Acetabulum of the other. 



b. Cavum pelvis minoris, formed, behind, by the Sacrum and Coccyx, the 

 cavity of which is 4 inches 6 lines, and depth 10 to 12 lines; anteriorly by the 

 ftymphysis and ossa pubis with fomm. obturator; laterally by oss. Ischii. 

 Diameter. 



1. Straight diameter [ant. posterior] = 4^ inches from the centre between 

 the second and third pieces of the Sacrum to the Symphysis pubis. 



2. Transverse diam. = 4 inches between the Spina ischii, before and above 

 them. 



c. Apertura inferior, pelvic outlet, formed by the apex of the coccyx, the 

 Tuber Ischii, and Arcus pubis ; has three notches; arcus pubis and Incisurse 

 ischiadicse. 



1 . Straight diam. [ant. post.] = 3 to 4 inches from the apex of the coccyx 

 to the crown of the pubic arch. 



2. Transverse diam. =4 inches from internal border of one Tuber Ischii to 

 the other. 



3. Oblique diam., two, = 4 inches from the centre of the ligam. sacro-ischi- 

 adic of one to the Tuber Ischii of the other side. 



The axis of the small pelvis, that is, a perpendicular drawn through the 

 centre of the straight diameter, passes above obliquely backwards, below ob- 

 liquely forwards. Inclination. The Promontory lies 3 to 4 inches higher 

 than the superior border of the Symphysis pubis, and the Conjugata therefore 

 makes with a horizontal line an angle of 60. The apex of coccyx lies ^ to 

 1 inch higher than the inferior border of the Symphysis pubis. 



Development of the Bones of the Pelvis. 



Ossification commences in the acetabulum, first, that is, in the 

 body of the Ilium, in the fourth month of the foetus. At the age 

 of puberty the inferior border of the Ischium and the crista Illi 

 first ossify, and the last only unites with the rest of the bone at 

 the twentieth to the twenty-fifth year. 



In young children, and even more in the unborn, the pelvis is 

 relatively much more narrow, and strongly inclined, so that the 

 urinary bladder lies with its whole anterior surface on the abdo- 

 minal parietes, instead of in the lesser pelvis. Characters of the 

 female pelvis, vide 109. 



Bones of the Extremities, Ossa extremitatum. 



A. Thoracic extremities, arms, extremitates superiores, s. tho- 

 racicae, Brachia. 



94. I. Shoulder, Humerus, 



consists of the shoulder-blade and collar-bone. 



1. Scapula, Omoplata, Shoulder-blade. 



Position : behind on the Thorax, behind the second to the 

 seventh ribs on either side of the vertebral column, very move- 

 able. 



