Figure 7.5: There are 206 bones in the adult human skeleton, which can be ’grouped’ into different
categories.
Axial skeleton DUMMY
The axial skeleton forms the central axis of the body and consists of the skull, vertebral
column and rib cage and sternum.
The Skull
The skull consists of thecraniumandfacial bones.
Thecraniumconsists of eight flat bones joined together by immovable joints called sutures.
The cranium surrounds and protects the brain. There is a large opening at the base of the
skull called theforamen magnumthrough which the spinal cord passes. On either side of
the foramen magnum is a projection which articulates with the first vertebra (called theatlas)
to allow for the nodding movement of the head.
Figure 7.6: The cranium.There are 15facial bones. These are irregular bones that include the cheek bones, nasal
bones, temples, upper jaw bone (maxilla)) and lower jaw bones (mandible). The only mov-
able bone is the lower jaw. The upper and lower jaws bear the sockets for the 32 permanent
teeth. The number, type and arrangement of the teeth in an animal is indicated by adental
formula. The human dental formula is: 2.1.2.3/2.1.2.3. This formula represents the numbers
of each type of teeth in half of the upper jaw and half of the lower jaw. This formula tells
Chapter 7. Support systems in animals 197