ANATOMY. 



gans of sense. Those of the ribs are 

 found by long maceration to consist of 

 concentric oval laminae. In some there 

 are tendinous fibres intermixed ; as in 

 those of the vertebrae. 



Anatomists divide cartilages into two 

 kinds ; the temporary and the permanent. 

 The former are confined to the earlier 

 stages of existence : the latter common- 

 ly retain their cartilaginous structure 

 throughout every period of life. 



The temporary cartilages are those in 

 which the bones of the body are formed. 

 They are hence called by the Latin wri- 

 ters ossescentes. All the bones of the body, 

 except the teeth, are formed in a ivdus of 

 cartilage. The form of the bone, with its 

 various processes, is accurately repre- 

 sented in these cartilaginous primordia ; 

 and it is the substance alone which 

 changes. 



The permanent cartilages are of vari- 

 ous kinds. We find them composing the 

 external ear, external aperture of the nos- 

 trils ?.'vl eye-lids. The larynx is entirely 

 composed of this substance ; and the tra- 

 chea, with its branches, is furnished with 

 cartilaginous hoops, by which these tubes 

 fire kept permanently open, for the ready 

 passage of air to and from the lungs. 



The bodies of the vertebrae are joined 

 by large masses of a peculiar substance ; 

 p'artaking of the properties and appear- 

 ance of cartilage and ligament, which 

 allow of the motions of these parts on each 

 other, without weakening the support that 

 is afforded to the upper parts of the body 

 in general, and to the head in particular, 

 by the vertebral column. These carti- 

 lages impart a great elasticity to the spine; 

 by which the effects of concussion from 

 jumping, from falls, &c. are weakened, 

 and destroyed, before they can be propa- 

 gated to the head. When the body has 

 been long in an erect position, the com- 

 pression of these cartilages, by the supe- 

 rior parts, diminishes the height of the 

 person. They recover theirformer length, 

 when freed from this pressure : hence a 

 person is taller when he rises in the morn- 

 ing, than after sustaining the fatigues of 

 the day, and the difference has sometimes 

 amounted to an inch. 



Cartilages are sometimes interposed be- 

 tween the articular surfaces of bones, 

 where they fill up irregularities, that 

 might otherwise impede the motions of 

 the part; and increase the security of the 

 joint, by adapting the articular surfaces 

 to each other. 



The articular surfaces of bones are, in 

 .very instance, covered by a thin crust of 



cartilage, having its surface most exqui~ 

 sitely polished, by which all friction in the 

 motions of the joint is avoided, and the 

 ends of the bones glide over each other 

 with the most perfect facility. 



Nomenclature of bones. The processes 

 or apophyses of bones bear different 

 names, according to their figures. Hence 

 we find them described under the terms* 

 of head (roundish ball;) condyle (a flat- 

 tened head;) neck; tuberosity ; spine; 

 &c. others have particular names from 

 supposed resemblances. 



The cavities or depressions of bones 

 are called cotyloid, when deep ; glenoid, 

 when shallow. Again, we have pits, iur- 

 rows, notches, sinuosities, fossae, sinuses, 

 foramina, and canals. 



Connection of bones. Anatomists have 

 divided these into three classes: Symphy- 

 sis, Synarthrosis, and Diarthrosis. 



The term symphysis merely denotes 

 the union of the conjoined bones, without 

 any reference to peculiar form or motion; 

 hence it is divided, accordingto the means 

 by which it is affected, into. 



1. Synchondrosis, where cartilage is 

 the connecting medium : this is exempli- 

 fied in the junction of the ribs and ster- 

 num ; of the bodies of the vertebrae ; and 

 of the ossapubis: 



2. Synneurosis or syndesmosis ; where 

 ligaments are the connecting bodies, as 

 in all the moveable articulations: 



3. Syssarcosis ; where muscles are 

 stretched from one bone to another. 



The synarthrosis, or immoveable con- 

 junction of bones, consists of, 



1. Suture ; where the bones are mutu- 

 ally indented, as if sewn together : 



2. Harmonia ; where the conjunction is 

 effected by plane surfaces : 



3. Gomphosis; where one bone is fixed 

 in another, as a nail is in a board. The 

 teeth afford the only specimen : 



4. Schindylesis ; where the edge of one 

 bone is received into a groove in another: 

 as the nasal plate of the ethmoid, in the 

 vomer. 



Diarthrosis, or moveable conjunction of 

 bones. The conjoined parts of the bones 

 are covered with a smooth cartilage, and 

 connected by one or more ligaments. It 

 has three subdivisions j viz. 



1. Enarthrosis, or ball and socket; 

 where a round head of one bone is re- 

 ceived into a cavity of another, and con- 

 sequently is capable of motions in all di- 

 rections; 



2. Arthrodia ; where the cavity is more 

 superficial, and much motion not allowed: 



3. Ginglymus ; where the motions arc 



