ANATOMY. 
gin ous hoops, by which these tubes are kept 
permanently open, for the ready passage of 
air to and from the lungs. 
Tiie bodies of the vertebrae are joined by 
large masses of a peculiar substance, par- 
taking of the properties and appearance of 
cartilage and ligament ; which allow of the 
motions of these parts on each other, with- 
out weakening the support that is afforded 
to the upper parts of the body in general, 
and to the head in particular, by the verte- 
bral column. These cartilages impart a 
great elasticity to the spine ; by which the 
effects of concussion from jumping, from 
falls, &c. are weakened, and destroyed, be- 
fore they can be propagated to the head. 
When the body has been long in an erect 
position, the compression of these cartilages, 
by the superior parts, diminishes the height 
of the person. They recover their former 
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 other- 
wise impede the motions of the part ; and 
increase the security of the joint, by adapt- 
ing the articular surfaces to each other. 
The articular surfaces of bones are, in 
every 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 ac- 
cording to their figures. Hence we find 
them described under the terms of head 
(roundish ball) ; condyle (a flattened head) ; 
neck ; tuberosity ; spine ; &c. others have 
particular names from supposed resem- 
blances. 
The cavities or depressions of bones are 
called cotyloid, when deep ; glenoid, when 
shallow. Again, we have pits, furrows, 
notches ; sinuosities, fossae, sinuses, foramina, 
and canals. 
Connection of bones — Anatomists have di- 
vided these into three classes ; Symphysis, 
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, according to the means by 
which it is effected, into 
1. Synchondrosis, where cartilage is- the 
connecting medium : this is exemplified in 
the junction of the ribs and sternum ; of the 
bodies of the vertebrae ; and of the ossa 
pubis : 
2. Synneurosis or syndesmosis; where 
ligaments are the connecting bodies, as in 
all the moveable articulations : 
3. Syssarcosis ; where muscles are stretch- 
ed from one bone to another. 
The synarthrosis, or immoveable conjunc- 
tion of bones, consists of, 
1. Suture ; where the bones are mutually 
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. 
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 ; viz. 
1. Enarthrosis, or ball and socket ; where 
a round head of one bone is received into a 
cavity of another, and consequently is capa- 
ble of motion in all directions ; 
2. Arthrodia ; where the cavity is more 
superficial, and much motion not allowed ; 
3. Ginglymus ; where the motions are 
restricted to two directions, as in the hinge 
of a door. 
The skeleton consists of an assemblage of 
all the bones in the body, excepting the os 
hyoides. It is said to be a natural skeleton, 
when the bones are connected by means of 
their own ligaments or cartilages ; an artifi- 
cial one, when wire or otter extraneous 
substances are employed. 
It is divided into the head, trunk, and ex- 
tremities. 
The head consists of the cranium and the 
face. The former of these parts consists 
of 1 or 2 ossa frontis; 2 ossa parietalia; 
1 os sphenobasilare ; 2 ossa temporum ; 
2 mallei ; 2 incudes ; 2 stapedes ; and 1 os 
sethmoideum ; on the whole, of 13 or 14 
bones. 
The face has 2 ossa maxillaria superiora ; 
2 ossa palati ; 2 ossa mate ; 2 ossa nasi ; 2 ossa 
lacrymalia; 2 ossa turbinata inferiora ; 1 os 
vomer ; 1 maxilla inferior ; 32 teeth ; on the 
whole, 46 bones. 
The tongue has 5 ossa lingualia. 
The bones of the head are therefore 59 
or 60 ; with the lingual bones 64 or 65. 
In the neck there are 7 cervical verte- 
bra; ; in the chest 1 2 dorsal vertebra;, 24 ribs ; 
N 2 
