The head is long and attached to the
neck at its upper end. This is significant because at the very top
of the head, the neckband (nuchal ligament) is fastened to a bony
protrusion that is about two inches long. This neckband then runs
underneath the mane to the top of the withers from where it continues
along the top of the spinal processes to the tail (this part is called
the supraspinous ligament). Between the poll and the withers it looks
and acts like a rope. In the area of the withers and along the spinal
column it connects the tops of the spinal processes with each other
thus acting like an elastic but solid band. The horse’s neck is long
and curved like an S. Both the length and the shape of the neck are
significant factors in the biomechanics of the horse. Another important
feature in the support structure of the horse would be the withers.
They are long processes of the vertebrae at the shoulder and are leaning
backwards. This front part of the horse is supported by two front
legs that are straight. (Do not protest yet, we will come back to
it later.)
At the beginning of the withers the
spinal processes are very long and they gradually become shorter and
lean less backwards until the middle of the back from where the processes
lean forward. They also are slightly increasing in length towards
the croup. The vertebrae that are directly attached to the ribs are
called the thoracic part of the vertebral column. They are followed
by the lumbar region that ends at the croup. Here the ilium is firmly
attached to the spine. The sacral vertebrae are fused in the mature
horse and form the croup. The vertebrae of the tail are called the
caudal vertebrae. What is significant to observe is if we look at
the bottom side of the vertebral column it is almost straight, and
the downward appearance of the back is the result of the increased
length of the spinal processes at the withers and the croup. The hind
legs are attached to the ilium and move from there to the hip joint.
The hind legs are angled in three large joints: the hip, the stifle
and the hock.
After this description I hope you
can envision the skeleton of a horse and see the long head, the long
curved neck, the prominent withers, the sloping back, rising again
to the longer spinal processes of the croup. It is also obvious that
the bones and joints of the hind legs are larger and more angled then
the ones of the front legs. Please finish reading this paragraph and
then draw in simple lines the skeleton of a horse. Emphasize the features
I mentioned as important for the understanding of the horse’s biomechanics.
Add to this skeleton the ligaments of the topline. Let us do this
in color. We will choose green for the ligaments. Next, draw the outline
of a suspension bridge and imagine the two superimposed. The pillars
of the bridge represent the horse’s legs, and the support cables would
be the supraspinous ligament. The nuchal ligament is the cable that
anchors the pillar of the bridge to the ground and the anchor on the
other side of the bridge is, in the horse, a system of muscles that
rotate the hip down and pull the hind leg forward. Look upon the withers
and the longer spinal processes of the croup as a fulcrum and you
can see how tension is put on the supraspinous ligament every time
the hind legs move forward.
In your drawing you likely made several
attempts before it started to look like a horse and even then you
do not have to show it to anybody. In order to make your efforts a
bit more challenging, divide the neck into seven vertebrae. The thoracic
part consist of eighteen vertebrae, the
