454 LIGAMENTS OF THE SPINE. 



articulating with the sacrum. Upon each side of the base at 

 Fio 131 ^ s posterior part, a small process or cornu arises 

 to unite with a similar one upon the sacrum, 

 forming a foramen for the passage of the fifth 

 sacral nerve. The three lower pieces diminish 

 in size to the last, and in old age, as already 

 stated, become firmly fused together and also 

 with the sacrum, presenting one solid piece. 



The anterior or pelvic surface of the coccyx is smooth, 

 concave, and marked by three transverse lines, denoting its 

 original separation into four pieces. This surface supports 

 the rectum. The posterior surface is rough, presenting 

 ridges and tubercles to which ligaments and muscles are 

 attached. 



The coccyx is light and spongy. Its development is from 

 four points, one to each piece. Ossification in the coccyx is 

 noticed soon after birth in the first piece, from five to ten 

 years in the second ; from ten to fifteen in the third ; and 

 from fifteen to twenty in the fourth piece ; the several pieces 

 unite in pairs the first in order are the two first pieces, 

 then the third and fourth, and lastly the second and third; 

 and between forty and sixty years the coccyx becomes 

 united with the sacrum. Its union with the sacrum by 

 fusion, is much earlier in the male than in the female. 



LIGAMENTS OP THE SPINE COMMON ARTICULATIONS OF THE 

 VERTEBRAL COLUMN. 



1. The anterior vertebral ligament, (Fig. 132,) as its name 

 implies, is situated on the front surface of the spinal column, 

 extending from the axis to the sacrum, and consists of fibres 

 which are broad and strong, increasing in breadth as they 

 descend, and adhering more strongly to the intervertebral 

 matter, than to the bodies themselves. The fasciculi of 

 this ligament vary in length and thickness. The super- 

 ficial fibres are long and run to several vertebras. The 



FIG. 131 represents a front view of the Coccyx. 1 Upper articular surface 

 for last lumbar vertebra. 2 Cornu of coccyx. 3 Transverse process. 444 

 Margin of the four bones. 



