ANATOMY. 
of which do not reach so far ■; are called the 
false ribs. 
The sternum is a broad and flat bone, 
placed in the front of the chest. It consists 
of two pieces of bone, and of a cartilage 
called the ensiform. The clavicles are arti- 
culated towards its upper parts, and the 
cartilages of the ribs are joined to its sides. 
The pelvis is formed by the two ossa in- 
nominata, or haunch bones, the sacrum, and 
os coccygis. The former are very large and 
flat bones, expanded into a broad surface 
above for the support of the abdominal vis- 
cera, and the attachment of the abdominal 
muscles, and furnished with large tubero- 
sities below, for tlie support of the body in 
the sitting position. Each os innomiiiatum 
is divided into the ilium, ischium, and pubes. 
It is firmly joined to the sacrum behind, and 
to the opposite bone in front by the sym- 
phisis pubis. The conjoined portions form 
an arch, called the arch of the pubes. The 
cavity of the pelvis is much larger in the 
female than in the male, as it holds the 
uterus and vagina in addition to what it con- 
tains in the male, and as the foetus passes 
through it in parturition. 
The bones of the upper extremity are 
distributed into those of the shoulder, arm, 
fore-arm, and hand. 
The shoulder contains -two ; the scapula 
and clavicle. The former is situated at the 
upper and outer part of the chest, and is 
joined to the end of the clavicle. 
The humerus is a long and nearly cylin- 
drical bone, joined by a round head to the 
scapula above, and articulated with the ra- 
dius and ulna below. 
The fore-arm has two bones ; the ulna, 
which is joined by a hinge or ginglymus to 
the humerus ; and the radius, which has a 
cavity 'playing upon a rounded head of 
that bone. The prominent extremity of the 
ulna, which forms the elbow, is called the 
olecranon. The hand is divided into the 
carpus, or wrist, the metacarpus, and the 
fingers and thumb. 
The carpus contains eight bones, disposed 
in two phalanges, of which tiie first forms, 
with the radius, the joint of the wrist, and 
the second is articulated to the metacarpus. 
The bones of the first phalanx are the os 
naviculare, lunatum, cuneiforme, and orbicu- 
lare: those of the second, os trapezium, 
trapezioides, capitatum, and unciforme. 
The metacarpus has five bones, and each 
of the fingers three ; the thumb only two. 
In the lower extremity we have the fe- 
mur, the largest of the cylindrical bones in 
the body. This has a round head, contained 
in a socket of the os irmominatum: the 
great trochanter forms a conspicuous pro- 
cess at the upper and outer part of the bone. 
Below' it lias two condyles, which form part 
of the knee. 
The leg has two bones ; the tibia and fibu- 
la. A large fiat portion of the former, co- 
vered only by skin, is called the shin The 
foot is composed of the tarsus, metatarsus, 
and toes. The tarsus has seven bones:-— 
1. Astragalus, composing the ankle, with 
the lower portion of the tibia and fibula. 
2. Os calcis. 3. Os naviculare. 4. Os 
cuboides. 5, 6, 7. Os-a cuneiformia. The 
metatarsal bones are five in number, and 
the bones of each tog are three, except the 
great toe, which has only two. 
SYNDESMOEOGY, OR DOCTRINE OF THE 
JOINTS. 
Construction of a joint. — The opposed 
surfaces of bones, which form joints, are 
covered by a thin crust of cartdage, most 
exquisitely smooth and polished. Hence 
they move on each other in whatever direc- 
tion their structure admits, without any 
hindrance from friction. They are tied to- 
gether by strong and unyielding cords, re- 
sembling tendons, and known by the name 
of ligaments. These keep the surfaces of 
the ljones together, and restrict their mo- 
tions to certain directions. In order still 
further to promote the facility of motion, 
and to obviate every possibility of friction, 
the cartilaginous surfaces are smeared with 
an unctuous fluid, called synovia, which makes 
them perfectly slippery. This fluid is con- 
fined to the surface of the joint by means of 
a thin and delicate membrane, called the 
capsular ligament, which envelopes the joint. 
It is secreted from portions of a fatty sub- 
stance, called the synovial glands. The liga- 
ments are usually situated on the outside of 
the capsula ; but in many instances they are 
contained in the cavity of the joint, passing 
from the centre of one bone to another. 
These are called interarticular ligaments. 
Particular joints . — Joint of the lower jaw. 
This is formed between the condyle of the 
jaw, and a hollow in the temporal bone. It 
contains a moveable- cartilage, which ren- 
ders the articulation more secure, when the 
jaw is brought forwards on the bone under 
certain circumstances. 
The connection of the head to the verte- 
bra; is effected by means of two prominences 
of the occiput, which are received into cor- 
responding, cavities of the atlas. By this 
joint the nodding motions of the head are 
performed. But the atlas itself turns Uori- 
