IS 



VERTEBEAL COLUMN. 



In the groove between the two rows are placed the four 2^osfrrior sacred 

 foramina, which are smaller than the anterior. 



The part of the sacrum external to the foramina constitutes the 

 lateral mass, and is broad and thick superiorly, but narrowed inferiorly. 

 The outer aspect of the upper part presents in front a large uneven 



Fiji. 12. 



Fig. 12. — Sacrum and Coccyx op the 

 Male viewei^ from; behind. (A. T.) i 



1, Bodyoftlie first sacral vertebra; 4, 4, 

 sacral canal ; and behind this, the series of 

 finir united lainina? and spinous processes ; 

 (i, G' line of tubercles corresponding to 

 transverse processes ; 7, 7', line of articu- 

 lar processes, with four adjacent posterior 

 sacral foramina ; I, I, auricular or iliac 

 articular surface ; in the coccyx, c, body 

 of the last vertebi-a ; t, transverse process ; 

 7, coruu or superior articular process. 



surface, covered in the recent 

 state with cartilage, which articu- 

 lates with the ilium, and is called 

 from its shape the aurkular sur- 

 face : behind this it is rough and 

 very uneven, for the attachment 

 of ligaments. Lower down, the 

 margin becomes narrowed and 

 sinuous, terminating in the pro- 

 jection called the inferior laicral 

 angle, below which the breadth of the bone is suddenly contracted so 

 as to form a notch with the adjacent part of the coccyx. 



The hase or upper surface of the first vertebra bears considerable 

 resemblance to the upper surface of the last lumbar. In the middle 

 it presents the reniforra surface of the body, behind which is the 

 triangular aperture of the sacral canal, bounded by the depressed 



Fig. 13. 



Fig. 13. — Upper Surface or Base op the 

 Sacrum of a Male. (A. T.) h 



1, the body ; 4, the foramen, ring, or sacral 

 canal ; f), the spinous process of the first sacral 

 vertebra ; 6, tlie part corresponding to a 

 transverse process, in front of which is the 

 large lateral mass ; 7, 7' the superior and 

 inferior articular jirocesses ; c, the mam- 

 millary tubercle ; /, the accessory tubercle, 

 slightly seen. 



laminre. On each side of the aperture is an articular process, exactly 

 resembling the superior process of a lumbar vertebra. In front of this 

 is a groove which forms part of the last lumbar intervertebral foramen. 

 The external portion of the base presents posteriorly an eminence 

 corresponding to the lumbar transverse process, and in fi'ont of that 

 a large smooth curved surface, continuous with the iliac fossa of the 

 pelvis. 



