In the adult? Describe the acetabulum. 93. Describe the sacrum. Explain fig. 12. 94. Describe the coccyx.
CHAPTER V.
ANATOMY OF THE BONES, CONTINUED
95. The bones of the upper and lower limbs are enlarged at each extremity, and have projections, or processes. To these, the tendons of muscles and ligaments are attached, which connect one bone with another. The shaft of these bones is cylindrical and hollow, and in structure, their exterior surface is hard and compact, while the interior portion is of a reticulated character. The enlarged extremities of the round bones are more porous than the main shaft.
96. The UPPER EXTREMITIES contain sixty-four bones—the Scap´u-la, (shoulder-blade;) the Clav´i-cle, (collar-bone;) the Hu´mer-us, (first bone of the arm;) the Ul´na and Ra´di-us, (bones of the fore-arm;) the Car´pus, (wrist;) the Met-a-car´pus, (palm of the hand;) and the Pha-lan´ges, (fingers and thumb.)
97. The CLAVICLE is attached, at one extremity, to the sternum; at the other, it is united to the scapula. It is shaped like the Italic ∫. Its use is to keep the arms from sliding toward the breast.
98. The SCAPULA is situated upon the upper and back part of the chest. It is flat, thin, and of a triangular form. This bone lies upon and is retained in its position by muscles. By their contractions it may be moved in different directions.
99. The HUMERUS is cylindrical, and is joined at the elbow with the ulna of the fore-arm; at the scapular extremity, it is 40 lodged in the glenoid cavity, where it is surrounded by a membranous bag, called the capsular ligament.