The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . nary, — boththe head and the atlasrotating on the pivotof the axis. They alsoshow how the head canbend forward and back-ward, while the atlas re-mains fixed and immov-able upon the axis. Itis one of the most curiousand wonderful mechan-isms of the body. The Ribs. There aretwelve ribs on each sideof the body. The ribs are so curved that each makesan elastic arch of bone. Behind, the ribs are attached to the spinal column. Tnfront, the first seven are at-tached to the sternum, bymeans of cartilages. The
The essentials of healthA text-book of anatomy, physiology, hygiene, alcohol, and narcotics . nary, — boththe head and the atlasrotating on the pivotof the axis. They alsoshow how the head canbend forward and back-ward, while the atlas re-mains fixed and immov-able upon the axis. Itis one of the most curiousand wonderful mechan-isms of the body. The Ribs. There aretwelve ribs on each sideof the body. The ribs are so curved that each makesan elastic arch of bone. Behind, the ribs are attached to the spinal column. Tnfront, the first seven are at-tached to the sternum, bymeans of cartilages. Thenext three are fastened toeach other by cartilages;while the last two have noattachment in front, hencethey are called the floating-ribs. The Thoracic Cavity. Thethoracic cavity is inclosed bythe spinal column behind, the sternum in front, the ribs Fig. 58. The atlas, or the firstvertebra, viewed from above : (1) theprocess of the axis ; (2) the openingfor the spinal cord; (3) the places onwhich the sknll rests. The dottedline represents a ligament which holdsthe process, (1), in Fig. 59. The axis, or the sec-ond vertebra, viewed from theside : (1) the process on whichthe atlas turns seen also at 1,(Figs. 58, and 60) ; (2) the placeon which the atlas rests. 170 THE ESSENTIALS OF HEALTH. on the sides, and the diaphragm below. The spaces be-tween the ribs are filled in with muscular tissue, so thatsurrounding the thoracic cavity there is a complete wall,formed partly of bone and partly of muscle. All that part
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectphysiology, bookyear1
