Label:
skeleton system,
swf
The skull consists of 34 bones and contains four cavities: the cranial cavity, the orbital cavity, oral, and the nasal cavity. The cranial cavity encloses and protects the brain and it supports several sense organs. The orbital cavitity surrounds and protects the eye. The oral cavity is a passage way into the respiratory and digestive systems. The nasal cavity leads into the respiratory system, and includes extensive paranasal sinuses. The nasal cavity contains turbinate bones that protect the mucous membrane that lines the cavity from warm inspired air. The skull consists of fourteen major bones
- Incisive bone (premaxillary): part of the upper jaw; where the incisors attach
- Nasal bone: covers the nasal cavity
- Maxillary bone: a large bone that contains the roots of the molars
- Mandible: lower portion of the jaw; largest bone in the skull
- Lacrimal bone: contains the nasolacrimal duct, which carries fluid from the surface of the eye, to the nose
- Frontal bone: creates the forehead of the horse
- Parietal bone: extends from the forehead to the back of the skull
- Occipital bone: forms the joint between the skull and the first vertebrae of the neck (the atlas)
- Temporal bone: contains the eternal acoustic meatus, which transmits sound from the ear to the cochlea (eardrum)
- Zygomatic bone: attaches to the temporal bone to form the zygomatic arch (cheek bone)
- Palatine bone: forms the back of the hard palate
- Sphenoid: formed by fusion of the foetal basisphenoid and presphenoid bones, at the base of the skull. Can become fractured in horses that rear over backwards.
- Vomer: forms the top of the inside of the nasal cavity
- Pterygoid: small bone attached to the sphenoid that extends downward
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