THE BONES. 33 



whatever the deficiency was in Adam's own person, it has not de- 

 scended to his male children. 



The ribs become gradually longer from the first to the seventh, 

 and from that shorter again to the twelfth. The ten upper ribs are 

 connected to the sternum or breast-bone in front, by means of their 

 cartilages, which it has already been remarked, give elasticity to 

 the walls of the chest. The lowest two, which are not attached in 

 front, are called the floating ribs. The heads of the ribs behind 

 are connected to the vertebra by a kind of hinge joint, which 

 allows the ribs to move up and down in the action of breathing. 

 Each rib passes from its attachment downwards, outwards, and 

 forwards ; so that when lifted up by the muscles of inspiration it 

 at the same time is carried outwards, and so enlarges the capacity 

 of the chest. 



The sternum or breast-bone is about seven inches long, about two 

 broad above, and one below, and ends in a movable point formed 

 of cartilage. It is smooth and convex in front, gives the pro- 

 minence to the front of the chest, and projects conspicuously in 

 some individuals, who are thence commonly called pigeon-breasted. 

 It has the cartilages of the ribs inserted into its edges ; it has a 

 hollow in its upper part to make room for the trachea or windpipe 

 to pass down behind it, and to its two upper corners the two collar- 

 bones are attached. 



The chest viewed as a whole, is conical, the apex of the cone 

 being above, and the base below ; the aperture above is small, 

 about four inches across, and twa from before backward, allowing 

 the windpipe and oesophagus, or gullet, and the great veins of the 

 arms and head to pass down, and their arteries to pass up. The 

 inferior opening of the chest is large, and is filled by a muscle 

 named the diaphragm, a Greek word which literally means the par- 

 tition, because it separates the belly from the chest ; forming a roof 

 for the one, and a floor for the other. The chest is considerably 

 deeper behind than in front, and the edges of the cartilages of the 

 ribs can be felt, and in a thin person seen, passing upwards from 

 the flanks, and meeting at an angle at the breast-bone, leaving a 

 hollow between them, which is known as the pit of the stomach. 



The next division of the trunk is called the pelvis or basin, which 

 consists of a circle of large ffrm bones, situated between the lower 

 portion of the trunk and the inferior extremities. They are the 

 sacrum, the coccyx, the ilium, the ischium, and the pubis. The 

 ilium forms the upper, the ischium the lower, while the pubis is 

 3 



