A & P II / Skull Bones

Fontanel

"fountains" that are "soft spots" Membrane filled spaces that are found in between the cranial bones in newborns and infants where the bone making process is not complete - Allows the cranium to be compressed during birth

8 bones that make up the calvaria

- Frontal Bone (1) - Parietal Bone (2) - Occipital Bone (1) - Temporal Bones (2) - Spenoid Bone (1) - Ethmoid Bone (1)

14 Bones that make up the Visceral Bones

- Maxilla (2) - Maxillae - Zygomatic (Malar Bones) (2) - Nasal Bones (2) - Lacrimal Bones (tear ducts) - (2) - Palatine Bones (2) (L shaped little bones) - Inferior concha (Turbinate) (2) - Vomer (1) -Mandible (1)

Parietal Bones

2 Bones, one on each side of the cerebral cranium, forms most of the lateral wall and part of the roof of the skull. They meet in the midline of the roof to form the sagittal suture.

Nasal fossa or cavities

2 chambers of the nose; they end behind the nasal part of the throat (nasopharynx)

How many Teeth are there

32 bones

Parietal eminence

A bony prominence on each outer surface of the parietal bones. The distance between the 2 eminences is the greatest transverse diameter of the skull, important in childbirth.

Glabella

A flattened area between the frontal eminences and the superciliary arches just superior to the nose.

Supraorbital foramen

A hole within the supraorbital margin just medial to its midpoint in which the supraorbital nerve and artery pass through.

The foramen magnum

A large hole in the inferior part of the occipital bone though which the medulla oblangata and its membranes, the accessory nerve (XI) and the vertebral and spinal arteries pass.

Frontal squama

A scale like plate, which corresponds to the forehead, gradually slopes down from the coronal suture, then turns abruptly downward.

What is a Suture

A seam or stitch - an immovable joint found only between skull bones

The Frontal Bone

A single bone (which in the fetus is 2 seperate bones) forms the forehead and part of the roof of the skull, the superior portion of the orbits (eye sockets), and most of the anterior part of the cranial floor. The frontal bone is divided by a suture at childbirth and by age 6 the two frontal bones unite to make one frontal bone.

Supraorbital Margin

A thickening of the frontal bone inferior to the superciliary arches.

Auditory Ossicles

In the ears - Malleus - Incus - Stapes

Posterolateral fontanel

Mastoid fontanels - paired - located on each side of the skull at the junction of the parietal, occipital, and temporal bones - irregularly shaped - close1-2 months after birth but generally not complete until the age of 1 year

Frontal sinuses

Mucus lined cavities which lie deep to the superciliary arches and act as a sound chamber which gives the voice resonance.

Posterior fontanel

Occipital fontael ; Lambda; between the 2 parietal bones and the occipital bone. Smaller than the anterior fontanel - diamond shaped - closes 2 months after birth

Mouth or oral cavity

Opens behind into the lower part of the throat (oropharynx)

Occipital condyles

Oval processes with the convex surfaces, one on either side of the foramen magnum, which articulates with the depressions on the first cervical vertebra.

Anterolateral fontanel

Sphenoid fontanels; - paired - located on each side of the skull at the junction of the frontal. parietal, temporal, and sphenoid bones - small and irregular shaped - close 3 months after birth

External occipital protuberance

The bony prominence on the outer surface of the squamous part of the occipital in MSP = Inion

6 Primary fontanels

Anterior - Frontal Posterior - Occipital Anterolateral - (paired) Sphenoidal Posterolateral - (paired) Mastoid

The Squamosal part

The flat part at the back of the head.

Nasal Septum

The vertical partition between the 2 nasal fossae

Squama =

scale

Hyoid Bone

usually broken during strangulation

Dura Mater

The outer meninx (covering) of the brain.

Lateral or external canthus

The point at the outer border of the eye where the upper and lower eyelids meet, A landmark in Radiography

Nasion

Bridge of the nose.

Cerebral Cranium

Calvaria 8 Bones

Internal occipital protuberance

Can be seen radiographically.

Orbits

Cavities for the eyeballs

4 Prominent skull sutures

Coronal Suture - Between the frontal & 2 parietal bones Sagittal Suture - Found between 2 parietal bones in the mid-sagittal plain Lambdoidal Suture - Found between the parietal bones and the occipital bone Squamosal Suture - Found between the parietal bone and the temporal bones

Skull

Cranium 22 bones of the skeleton forming the head

Visceral Cranium is also known as the

Facial Bones

Occipital Bone

Forms the posterior part and the lower 1/3rd of the cranial floor. It joins posteriorly with the two parietal bones to form the lambdoidal suture.

Anterior fontanel

Frontal fontanel ; Bregma; between the angles of the 2 parietal bones and the 2 segments of the frontal bone - diamond shaped - closes in 18-24 months

Superciliary arches

Inferior to each frontal eminence. Caused by the projection of the frontal sinuses posterior to the eyebrow.

Frontal eminences

Just above the superciliary arches and below the coronal suture.

Lateral Parts of the occipital bone

Lie on each side of the foramen magnum.

Hypoglossal canal

Located at the base of the occipital condyles, it is the fossa (canal) through which the hypoglossal nerve passes.

Base of the occipital bone

The front part of the foramen magnum which unites with sphenoid bone and forms the floor of the skull.