Chap. IV.] 



THE SKELETON. 



43 



termed the manubrium or handle ; the middle and largest 

 piece, which represents the chief part of the blade, is termed 

 the , gladiolus ; and the inferior piece, which is likened to the 

 point of the sword, is termed 

 the ensiform appendix. On 

 both sides of the upper and 

 middle pieces are notches for 

 the reception of the sternal 

 ends of the costal cartilages. 

 The ensiform appendix is carti- 

 laginous in structure in early 

 life, but is more or less ossified 

 at the upper part in the adult : 

 it has no ribs attached to it. 

 The sternum is about six inches 

 long, being rather longer in the 

 male than in the female. 



The ribs are elastic arches of 

 bone, forming the chief part of 

 the thoracic wall (^vide Fig. 42). 

 They are usually twelve in 

 number on each side. They 

 are all connected behind with 



the vertebrae, and the first seven pairs are connected with the 

 sternum in front through the intervention of the costal carti- 

 lages: these first seven pairs are called from their attachment 

 the vertebro-sternal, or true ribs. The remaining five pairs 

 are termed false ribs; of these, the first three, being attached 

 in front to the costal cartilages, are usually called the vertebro- 

 costal, while the two remaining, being unattached in front, 

 are termed vertebral, or floating ribs. The convexity of the 

 ribs is turned outwards so as to give roundness to the sides of 

 the chest and increase the size of its cavity; each rib slopes 

 downwards from its vertebral attachment, so that its sternal 

 end is considerably lower than its dorsal. The spaces left 

 between the ribs are called the intercostal spaces. 



The skull as a whole. — The skull, formed by the union of 

 the cranial and facial bones already described, is divisible into 

 cranium or brain case, and the anterior region or face. 



The bones of the cranium begin to develop at a very early 



Fig. 43. — Sternum. Front and side 

 view. 



