The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . thatthe spinal column is not straight, but formsa series of curves. In the neck, and inthe abdomen, the convexity of the curves isforward, while in the chest, and in the pel-vis, it is backward. These curves giveadditional elasticity to the column, andwith .the aid of the elastic cartilages givegreat protection to the brain from suddenjars. Each bone in the spinal column iscalled a vertebra, from a Latin wordsignifying to turn, as a joint. Thus atranslation or definition of the wordwould be, u a joint
The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . thatthe spinal column is not straight, but formsa series of curves. In the neck, and inthe abdomen, the convexity of the curves isforward, while in the chest, and in the pel-vis, it is backward. These curves giveadditional elasticity to the column, andwith .the aid of the elastic cartilages givegreat protection to the brain from suddenjars. Each bone in the spinal column iscalled a vertebra, from a Latin wordsignifying to turn, as a joint. Thus atranslation or definition of the wordwould be, u a joint of the spinal col-umn. Each vertebra has within ita large opening, through which passesthe spinal cord. The vertebrae areheld together by ligaments, and areso placed, one directly over the other,that the central openings form a con-tinuous canal extending the entirelength of the spinal column. This iscalled the spinal canal; it furnishes a :? Fig. 54. The spinal column. The right sideof the figure is toward the back of the body. TlIK SKELETON. 167 Between the ver- This clastic firm protection to the spinal cord tebrae are discs, or cushions, ofcartilage resembles rubberin its elasticity. Its greatuse can be appreciatedwhen it is stated thatthe combined thickness ofall these cushions is oversix inches. They greatlydiminish the shock and jarthat comes to the body fromjumping and running. Nearly all the vertebrasresemble those shown inFigs. 56 and 57. Fig. 56illustrates a vertebra ofthe neck, as viewed fromabove. The long process,C, is the one that is soeasily felt at the back of the neck. The darkly shadedoval portion at the top of the figure, immediately infront of the opening for the spinal cord, is the place ofattachment of the elastic cartilage. Fig. 57 representsa vertebra lower down the spinal column, and viewedfrom the side. A represents the front of the vertebra,and the place where the cartilage is attached. The longprocess, B, extends backward and downward,
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysiology, bookyear1
