_Toes._
Digitorum 14
—
30
The connection of the bones are in various ways; those connections that
are designed for rest, are by close contact of parts, and are called
_sutures_ or _seams_; such are the bones of the skull with themselves
and the face. Those connections which are designed for motion are called
_articulation_. Some of the articulations have but an obscure motion, as
the ribs with the back-bone, and the back with itself, &c. Others have
an angular motion, as the elbows and knees; and others again have an
universal motion, as the arm-bone with the shoulder, and the thigh bone
with the hip. The _sutures_, and such connections as have no motion, are
merely dovetailed into one another in close connection; but those
articulations that are designed for motion are connected by cartilages,
either in close contact, or so as to move slippery over one another.
The ligaments are those tough tendinous parts, by which the
articulations designed for motion are joined together; at some parts
they cover the joints only, and at others, they are immediately fastened
to each other, besides the external coverings; those ligaments are very
strong and elastic, and have a close connection with the nerves that
pass by them.
The surrounding ligaments of all moveable joints, form a _capsular-bag_,
which contains a slippery liquor, called _synovia_, that lubricates the
ends of the bones covered with _cartilages_, that they may move with
ease and agility over one another.
_Muscles_ are the fleshy parts on the human body, appointed for motion.
They are a composition of arteries, veins, nerves, and tendons.
Muscles are generally divided into two kinds; those for necessary or
involuntary motion, and those for voluntary. Some again are fastened at
each end to some of the bones at their extremity, and contract
themselves in a straight direction; others again are annular, or in the
form of a ring; and by this manner open and shut. The first kind are
generally divided into three parts, the head, belly, and tail. The whole
muscle begins and ends in a tendon, by which it is fastened to the part
it is designed to move; which, when the belly of the muscle contracts
itself, must consequently draw both bones nearer together, fastened to
the head and tail; and thus performs the motion. Some of these muscles
act in consort, and others in opposition to each other.
The tendons are the principal parts of the muscle; and that part
thereof, as before observed, which is fastened in the bones, namely, at
the head and tail of the muscle, and is the chord, as it were, by which
the limb is brought into motion.
A tendon is a hard, substantial, flexible, and elastic body, which, at
the head of the muscle, is very compact; but as it enters the muscle,
spreads its fibres over the whole body, gathers again at the tail, in as
compact a manner as it began, and continues in this chord-like texture
till it fastens itself at its appropriated place.[7]
Footnote 7:
It must be observed however, that tendons take on many various forms,
as different as the muscles; which would be too tedious here to
particularize.
The tendons and ligaments are of equal substance, and differ in nothing
but their various uses; namely, the ligaments to connect the
articulation; and the tendons, or the ends of the muscles, to give
motion. The muscles are a composition of the tendinous fibres,
plentifully intermixed with small ramifications of blood vessels; all
which compose the fleshy part thereof. Hence, the tendons being white
and hard, the muscles gradually grow softer and redder in the middle of
them; and they verge gradually to become tendinous at the tail, the same
as the head.
Hence, from the close texture of the tendons, they are very painful when
wounded, or otherwise hurt; but as the muscles are softer and more
pliable, their wounds and other accidents are of less consequence, and
not so dangerous as the former.
The number of muscles are undetermined, for though the principal muscles
are so distinct that they cannot be mistaken as to their form and use,
yet there is so great a number of small ones, or so many of the great
ones capable of being subdivided again, that anatomists have not, as
yet, agreed about their number.
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