9S 



THE SKELETON. 



12 



holes which serve to give passage to nerves and blood vessels. 

 One of th^se holes, very much larger than the others, called the 

 occipital hole, foramen occipital*, corresponds with the verte- 

 bral canal, and gives passage to the spinal marrow; and on each 

 side of this great hole we find an eminence called coudule, which 

 serves f >r the articulation of the head upon the vertebral column. 

 29. The trunk is composed of the vertebral column, the ribs 

 an 1 xter num. 



Fig. 33. SO. The vertebral column, or spine, is a species of 

 bony stalk, or stem, which occupies the middle line 

 '( of the back, and extends from the head to the poste- 

 / vc rior extremity of the body, (Fig. 38.); it is formed 

 by the union of small, short bones, 

 called vertebra, (Fig. 39.) and pre- 

 sents throughout its whole length a 

 canal formed by the union of the holes 

 by which each vertebra is pierced ; 

 this canal serves to lodge the spinal 

 marrow. Each of these bones pre- 

 sents in front of the hole, a species of thick, solid disc, 

 called the body of the vertebra, which is very firmly 

 united to the body of the vertebra next to it ; behind, 

 we remark prolongations called transverse and spinous 

 processes which form what is commonly called the spine. 



31. Tlie vertebral column is divided into five regions, namely: 



32. 1st. The cervical region, which constitutes the frame of 

 the neck : in man, and all the other mammalia, it is composed of 

 seven vertebrae, (Fig. 38, tc.) 



33. 2n 1. The dortal, or thoracic region, which gives attach- 

 ment to the ribs which form the ch.rst 9 or thorax; the vertebrae of 

 this region in man, are twelve in number, (Tig. 38, vd.) 



34. 3rd. The lumbar region, which terminates the back below, 

 in man, is composed of five vertebrae, (Fig. 38, vl) 



35. 4th. The .sacral region which articulates with the bones of 

 the hips, is composed, in man, of five vertebrae, so run, or fused to- 

 gether, as to form but a single bone called the sacrum, (Fig, 38, s.) 



Explanation of Fi-j. 3!) A vertebra seen from above, c. ils body, /. a 

 hole flr I he passage of the spinal marrow, at. transverse processes, sp. 

 s-pinal process direct-ed ha 1 k wards. 



29. What part-: compose the trunk? 



30. What is the vertebra, column ? What is found in the vertebral canal? 

 Jl. Into how many parts is the vertebral column divided? 



32 How many vertebrae are found in the cervical region? 



J3. Wnat is the number of dorsal vertebrae? 



34. Wh;it is the number ol lumbar vertebrse? 



35. What is the siortun ? 



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