An academic physiology and hygiene .. . is on whichthe uppermost vertebra, the atlas, turns, its front, innersurface being kept in position against the peg by a strongligament. In turning, the head and the atlas-bone movetogether without danger of falling either forward or back-ward, an accident which would immediately destroy life bycrushing the spinal cord. 13. The Thorax or Chest. — The ribs, twenty-four in num-ber, twelve on each side, are divided into two general classes, the true and the are all attached bymovable, flexible jointsto the vertebrae behind,and the uppermost seven
An academic physiology and hygiene .. . is on whichthe uppermost vertebra, the atlas, turns, its front, innersurface being kept in position against the peg by a strongligament. In turning, the head and the atlas-bone movetogether without danger of falling either forward or back-ward, an accident which would immediately destroy life bycrushing the spinal cord. 13. The Thorax or Chest. — The ribs, twenty-four in num-ber, twelve on each side, are divided into two general classes, the true and the are all attached bymovable, flexible jointsto the vertebrae behind,and the uppermost sevenon each side, the true ribs,are separately united bybands of cartilage to thebreast-bone in front. Theremaining five on each sideare called the false ribs, andof these the uppermostthree are joined togetherin front by a common car-tilage and by it to thebreast-bone. The last twoon each side are free infront, and hence areknown as floating-ribs. In general the ribs are flat andcurved, and gradually increase in length from the first to. Framework of the Chest as it appears•when not distorted by tight lacing. — i, thesternum or breast-bone 52,2, the ribs ; 3, thespinal column. THE OSSEOUS SYSTEM. ^5 the seventh. They incline forwards and downwardsfrom the backbone, so that when alternately raised anddepressed in breathing, the capacity of the chest is corre-spondingly increased or diminished. 14. The ribs, the breast-bone, and the upper portions ofthe backbone together form the elastie, bony frame-workof a cage, the thorax or chesty which surrounds and pro-tects the heart, lungs, and large blood-vessels. The inter-stices of this cage-like structure are filled with muscleswhich cover and form with it the walls of the chest. EXPLANATION. This figure represents the sternum, or the place where the collar-bone is where the first rib is joined. gt the number of pieces which are united into , the tip of the sternum. 15. The sternum (Gr. sternon, the b
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Keywords: ., bookcentury1900, bookdecade1900, booksubjecthygiene, booksubjectp
