44 



ILLUSTRATED !ST0C:K DOCTOU. 



the spinal marrow. 4 — The .spinal marrow. A — The turbinated bones, 

 or thin, bony plates, in the form of a seroll or horn, found in the iLoH. 

 trils, and serving to give wider distribution to the linmg membrane of the 

 nose. II — The se])tuni nasi, or caitilaginous division between the two nos- 

 trils. C, C — The lips. D. The tongue. E — The epiglottis, or valve of 

 the larynx. F — The traehea, or windpipe. G — The oesophagus or gullet. 



It will be observed that the great object in the formation of the cran- 

 ium, that of furnishing a firm cover and a sure protector of the brain 

 against all ordinary accidents, is secured by the emplo^'ment of nine 

 bones, arranged in this manner : The two frontal bones (a), make up the 

 anterior or forward i)art ; the parietals (b), comprise the upper and cen- 

 tral parts, and cover the outer lobes of the cerebrum ; the occipital bono 

 (d), a single bone of great solidity, is at the back of the head; a little 

 lower, and back of the occipital bone, is the aperture through which 

 the spinal cord, together Avith some nerves and an artery, make their exit 

 from the brain. Here the bone is smooth and rounded for the purpost; 

 of jointing with the atlas, the first bone of the neck. The sphenoid bono 

 (g), forms the inferior and central part of the cranium. The ethmoid 

 (f ), through which the olfactory nerve passes, together with the sphenoid, 

 *s /loted above, assists in upholding the base of the brain. In proximity 

 to the facial bones are found sinuses bearing names derived from their 

 nearness to particular bones. 



The temporal bones forming the sides of the cranium are composed oi' 

 two parts, the squamous, or scaly, and the petrous, or stone-like. The 

 petrou'i portion of the temporal bone -contains the organs of hearing, 

 having upon its inside surface the openings for the passage of the auditory 

 L.crvo ; and upon its outside, large passages for the conveyance of sound 



Pig. 4. Front and back view ov 



THr. lUlNKS OF TH FOOT. 



Fig. 5. Skctional view of thb 



BONES of the foot. 



