The Axial Skeleton forms the longitudinal axis of the body and is comprised of 3 parts:
- Vertebral Column
- Bony Thorax
The skull is comprised of 8 cranial bones and 14 facial bones. The bones are joined by sutures - the mandible is the only skull bone connected by a freely moving joint. There are hollow portions of the bones surrounding the nasal cavity called paranasal sinuses which help to lighten the skull and amplify sound as we speak.
There are 3 tiny bones in each ear that function in hearing.
Found in the anterior cervical region is the hyoid bone. It is the only bone in the body that does not articulate with another bone. It serves as a moveable base for the tongue and aids in swallowing and speech.
The ribcage protects major organs. It consists of 3 parts: sternum (3 fused bones), ribs & thoracic vertebrae. The 12 pairs of ribs are subdivided by structure into:
True ribs (pairs 1-7)
False ribs (pairs 8-12) do not attach directly to sternum
Floating ribs (pairs 11-12) have no ventral attachment
The spine extends from the skull to the pelvis and provides support for the axial skeleton. The spine is comprised of 26 vertebral bones separated by cartilaginous intervertebral discs. There are 7 cervical vertebrae, 12 thoracic vertebrae and 5 lumbar vertebrae. Inferior to the lumbar vertebrae are 5 vertebrae which have fused to form the sacrum. Inferior to that is the coccyx (tailbone) which has formed by the fusion of 3-5 vertebrae.