Fill in the missing blanks –
The skull consists of: an upper section called the CRANIUM which houses the brain.
The MAXILLA (the upper jaw & nasal chambers)
The MANDIBLE (the lower jaw)
& the HYOID APPARATUS.
These areas - particularly the cranium are joined together by "sutures". Sutures are firm & immovable fibrous joints.
For each of the bones of the skull, describe where you can find them.
Bones of the Cranium
Description
PARIETAL
Forms the dorsal & lateral walls of the cranium
TEMPORAL
Lies below the parietal bone on the caudo-lateral surface of the skull. The tympanic bulla houses the middle ear – this is the most ventral part of the temporal surface.
FRONTAL
Forms the frontal aspect of the cranium – "the forehead". Contains an air filled chamber called the frontal sinus which connects to the nasal chamber.
OCCIPITAL
Lies at the caudal aspect of the base of the skull. Here, there is the foramen magnum through which the spinal cord passes.
SPHENOID
Lies on the ventral aspect of the skull forming a floor of the cranial cavity.
SAGITTAL CREST
A ridge of bone on the dorsal midline surface of the skull
ZYGOMATIC ARCH
An arch of bone which projects laterally from the skull forming the "cheekbone".
LACRIMAL
Lies at the base of the orbit, which houses the eye. The region where tears drain from the eye into the nose.
Skull Shapes can vary in dogs & cats which has resulted in three basic categories – can you name them?
DOLICOCEPHALIC
MESOCEPHALIC
BRACHYCEPHALIC
Within the maxilla of the skull are the sinuses. These are hollow spaces which lighten the skull & provide resonance to the vocal chords. The sinuses are also attached to the upper respiratory tract & provide an area where air can be warmed & moistened.
The mandible consisted of two halves which are held together by connective tissue in the midline rostrally at the mandibular symphysis. Can you name the two parts of the mandible?
BODY & RAMUS
The hyoid apparatus comprises of a series of small bones which together suspend the tongue & larynx from the skull. Small holes known as foramina (singular:foramen) are present in the skull. Name a body structure which can pass through here?
BLOOD VESSELS or NERVES
In dogs & cats, the orbit is not a complete bony circle, but is completed by a ligament – this connects the zygomatic process of the frontal bone to the zygomatic arch.
