Anatomia

ANATOMY OF THE SKULL.
It is a vault that houses and protects the brain and is composed of eight cranial bones (four hits and four pairs) linked via immovable joints called sutures, covered withperiosteum and middle layer made ​​of a spongy tissue called diploe.

ODD BONES.
1. Frontal bone, occupies the front of the skull articulates with the parietal right and left.
2. Ethmoid bone,forms the outer wall of the nasal cavity and articulates with the sphenoid body.
3. Sphenoid bone, occupying the anterior and middle skull base, is formed by a body that contains the sphenoidsinuses which houses the pituitary gland within the sella.
4. Occipital bone forms the greater part of the posterior fossa.

PAIRED BONES.

1. Parietal bone, form the side walls and roof of thecranial vault.
2. Temporal bone, located on the bottom and side of the skull between the
occipital bone, parietal and sphenoid, this highlights the mastoid process, styloid and zygomatic,contains the essential organs of hearing.

Meninges.

Conjunctive wraps to protect the various organs of the central nervous system and are responsible for covering the brain, spinal cord and cranial andspinal nerves.
Dura, fibrous outer casing is very resistant lining the cranial cavity.
Pia mater, is closely lining the bone.
Arachnoid: double-bladed serous layer, located between the dura andpia mater, is separated from the latter by the subarachnoid space.
Cerebrospinal fluid.

CIRCLE OF WILLIS.

It is a crown of arterial systems that form an anastomosis at the base of the skull isformed by the anterior communicating artery, posterior and proximal portions of the anterior cerebral arteries, middle and posterior.

Anterior communicating artery: This artery joins medially androstral cerebral arteries.
Posterior communicating artery: arises from the internal carotids, run caudally and medially and anastomose with the proximal portions of the posterior cerebral arteries....