THE HEAD

Introduction to the skull

Superficial face; scalp

Parotid region and deep face

Intracranial cavity; meninges

Eye and orbit

Cranial nerves

Oral cavity and contents

Ear and temporal bone


Introduction to the skull

Development of the skull

Base of skull: endochondral ossification

Bones of calvarium: intramembranous ossification

Bones of the face are partly basal and partly calvarial bones so they ossify both by intramembranous and endochondral ossification.

CALVARIAL BONES

The bones of the cranium and the underlying lobes of the brain have the same name:

At birth, the anterior fontanelle (bregma) is a diamond-shaped area between the 2 frontal bones and the 2 parietal bones. It pulsates and bulges when the baby cries. It closes by 18 months to 2 years.

In an X-ray of the skull, there is the need to differentiate the following normal structures from fractures :

The pineal gland near the center of the brain may contain corpora aranaceae (calcareous granules) and it can be used to detect displacement of the brain.

 

THE CRANIAL FOSSAE: 3 fossae forming 3 steps down to foramen magnum from front to back.

1) Anterior cranial fossa:

2) Middle cranial fossa

The middle meningeal artery enters the skull through the foramen spinosum and its groove can be traced laterally and anteriorly on the squamous portion of the temporal bone before dividing into anterior and posterior (frontal and parietal) branches.

3) Posterior cranial fossa

The posterior cranial fossa contains:

The superior sagittal sinus is continuous with the right transverse sinus whereas the smaller straight sinus is continuous with the left transverse sinus. The right jugular foramen is thus usually larger than the left.

THE EXTERIOR OF THE BASE OF THE SKULL

The internal carotid artery:

THE SKELETON OF THE FACE

In the orbit are found:

The supraorbital, infraorbital and mental foramina, lie on a vertical line and transmit the ophthalmic, maxillary and mandibular divisions of the trigeminal (Vth cranial) nerve.