DOI Page / Citation link:
https://doi.org/10.11588/diglit.20658#0047
ANATOMY,
33
head to the lower part of the body ; and is divided principally into two parts, the upper of which is
called the true vertebra, and the lower one the false vertebra, from the joints being immoveable
in the adult. It is upon the bones of the spine that the body turns. The true vertebras are subdivided
into three classes, the cervical, dorsal, and lumbar vertebras.—The false vertebras consist of the os
sacrum and os coccygis. The bones of the spine are united together by a ligament, which in adult
age acquires the consistence of a cartilage ; it is of an elastic nature, and forms a kind of partition
between the different vertebras, by which means the several motions of the trunk are performed with
facility. This cartilaginous substance in advanced age becomes shrivelled, and loses much of its
elasticity ; which is the reason old people stoop, and decrease in stature. The bones of the spine
are also connected with each other, both externally and internally, by many strong ligaments.
Eaehoone of the spine may be considered with regard to its body, processes, and cavities.
Each body somewhat resembles part of a cylinder cut off transversly ; but is convex before,
and concave behind, where it assists in forming the cavity of the spine.
The processes are seven in number in each vertebras, viz. one at the back part, which, from its
shape and direction, is called the spinous process. On each side of which are two others, called,
from their situation, transverse processes. And four others, called oblique, or articular processes,
from their situation : they are much smaller than the spinous or transverse one. Two are placed
on the upper and two on the lower part of each vertebra: the two superior processes of one verte-
bra being articulated with the two inferior ones of the next.
The cavities of the vertebras coincide with one another, and form along bony channel, in which
the spinal marrow is placed. There are also four notches in each vertebra, two at the upper, and
two at the lower end, and between the oblique processes and the body of the bone. These inden-
tions corresponding with each other, form a foramen, or passage, for several vessels and nerves.
The cervical vertebras, or vertebras of the neck, consist of seven bones, or of a firmer texture
than those of the other parts of the spine ; they serve to facilitate the motions of the head, in
which they very often all assist.
The dorsal vertebras are twelve in number, and of a middle size, betwreen those of the neck and
loins. On each side, at the upper and under part of each of these vertebras, are two considerable
depressions,the one in the lower vertebras, uniting with the one above it, and thus form articulating
cavities for the reception of the heads of the ribs; and, at the fore part of the transverse processes
of each, except the two last, is an articulating surface, for admitting the tuberosity of the ribs.
The lumbar vertebras are five in number. They differ from the vertebras of the back, only in
being of a larger size, and having their spinous processes placed at a greater distance from each
other; which is necessary for the freedom of their articulation, as the most considerable motions
of the trunk are performed by these bones.
The os sacrum is nearly of a triangular figure; the inferior part bent a little forwards. On
the superior part there are two oblique processes, articulated with the last lumbar vertebras. It
has also generally three small spinous processes on its posterior convex side, which are filled up
and covered with muscular and tendinous parts.—This bone is united laterally to the ossa inno-
minata, or hip-bones ; and its inferior part to the coccyx.
The os coccyx, or os coccygis, is also nearly triangular in its form, being broadest at its upper
part: and growing narrower towards its apex, where it is not bigger than the little finger. It de-
rives its name from its supposed resemblance to the beak of a cuckoo. It differs from the vertebras
k greatly,
33
head to the lower part of the body ; and is divided principally into two parts, the upper of which is
called the true vertebra, and the lower one the false vertebra, from the joints being immoveable
in the adult. It is upon the bones of the spine that the body turns. The true vertebras are subdivided
into three classes, the cervical, dorsal, and lumbar vertebras.—The false vertebras consist of the os
sacrum and os coccygis. The bones of the spine are united together by a ligament, which in adult
age acquires the consistence of a cartilage ; it is of an elastic nature, and forms a kind of partition
between the different vertebras, by which means the several motions of the trunk are performed with
facility. This cartilaginous substance in advanced age becomes shrivelled, and loses much of its
elasticity ; which is the reason old people stoop, and decrease in stature. The bones of the spine
are also connected with each other, both externally and internally, by many strong ligaments.
Eaehoone of the spine may be considered with regard to its body, processes, and cavities.
Each body somewhat resembles part of a cylinder cut off transversly ; but is convex before,
and concave behind, where it assists in forming the cavity of the spine.
The processes are seven in number in each vertebras, viz. one at the back part, which, from its
shape and direction, is called the spinous process. On each side of which are two others, called,
from their situation, transverse processes. And four others, called oblique, or articular processes,
from their situation : they are much smaller than the spinous or transverse one. Two are placed
on the upper and two on the lower part of each vertebra: the two superior processes of one verte-
bra being articulated with the two inferior ones of the next.
The cavities of the vertebras coincide with one another, and form along bony channel, in which
the spinal marrow is placed. There are also four notches in each vertebra, two at the upper, and
two at the lower end, and between the oblique processes and the body of the bone. These inden-
tions corresponding with each other, form a foramen, or passage, for several vessels and nerves.
The cervical vertebras, or vertebras of the neck, consist of seven bones, or of a firmer texture
than those of the other parts of the spine ; they serve to facilitate the motions of the head, in
which they very often all assist.
The dorsal vertebras are twelve in number, and of a middle size, betwreen those of the neck and
loins. On each side, at the upper and under part of each of these vertebras, are two considerable
depressions,the one in the lower vertebras, uniting with the one above it, and thus form articulating
cavities for the reception of the heads of the ribs; and, at the fore part of the transverse processes
of each, except the two last, is an articulating surface, for admitting the tuberosity of the ribs.
The lumbar vertebras are five in number. They differ from the vertebras of the back, only in
being of a larger size, and having their spinous processes placed at a greater distance from each
other; which is necessary for the freedom of their articulation, as the most considerable motions
of the trunk are performed by these bones.
The os sacrum is nearly of a triangular figure; the inferior part bent a little forwards. On
the superior part there are two oblique processes, articulated with the last lumbar vertebras. It
has also generally three small spinous processes on its posterior convex side, which are filled up
and covered with muscular and tendinous parts.—This bone is united laterally to the ossa inno-
minata, or hip-bones ; and its inferior part to the coccyx.
The os coccyx, or os coccygis, is also nearly triangular in its form, being broadest at its upper
part: and growing narrower towards its apex, where it is not bigger than the little finger. It de-
rives its name from its supposed resemblance to the beak of a cuckoo. It differs from the vertebras
k greatly,