نظام الهيكل العظمي عند الحصان skeletal system in the horse

The skeleton of the horse has three major functions in the body. It protects vital organs, provides framework, and supports soft parts of he body. Horses have 205 bones, whichare divided into the appendicular skeleton (the legs) and the axial skeleton (the skull, vertebral column, sternum, and ribs).
Both pelvic and thoracic limbs contain the same number of bones, 20 bones per limb.
Bones are connected to muscles via tendons and other bones via ligaments.
Bones are also used to store minerals, and are the site of red blood cell formation.
[Curves
Viewed laterally the vertebral column presents several curves, which correspond to the different regions of the column, and are called cervical, thoracic, lumbar, and pelvic.

The cervical curve, convex forward, begins at the apex of the odontoid (tooth-like) process, and ends at the middle of the second thoracic vertebra; it is the least marked of all the curves.

The thoracic curve, concave forward, begins at the middle of the second and ends at the middle of the twelfth thoracic vertebra. Its most prominent point behind corresponds to the spinous process of the seventh thoracic vertebra. This curve is known as a tt curve.

The lumbar curve is more marked in the female than in the male; it begins at the middle of the last thoracic vertebra, and ends at the sacrovertebral angle. It is convex anteriorly, the convexity of the lower three vertebrae being much greater than that of the upper two. This curve is described as a lordotic curve.

The pelvic curve begins at the sacrovertebral articulation, and ends at the point of the coccyx; its concavity is directed downward and forward.

The thoracic and pelvic curves are termed primary curves, because they alone are present during fetal life. The cervical and lumbar curves are compensatory or secondary, and are developed after birth, the former when the child is able to hold up its head (at three or four months) and to sit upright (at nine months), the latter at twelve or eighteen months, when the child begins to walk.


[ Names of individual vertebrae
Individual vertebrae named according to region and position, from superior to inferior

Cervical – 7 vertebrae (C1-C7)
C1 is known as "atlas" and supports the head, C2 is known as "axis"
Possesses bifid spinous processes, which is absent in C7
Small-bodied
Thoracic – 12 vertebrae (T1-T12)
Distinguished by the presence of costal facets for the articulation of the heads of ribs
Body is intermediate in size between the cervical and lumbar vertebrae
Lumbar – 5 vertebrae (L1-L5)
Has a large body
Does not have costal facets nor transverse process foramina
Sacral – 5 (fused) vertebrae (S1-S5)
Coccygeal – 4 (3-5) (fused) vertebrae (Tailbone

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