Bones of the Skull and Cranial Anatomy

Vocabulary flashcards generated from lecture notes covering embryologic divisions, cranial sutures, fontanels, craniosynostosis, sinus anatomy, and landmark structures of the head and neck.

Sutures

Immovable fibrous joints unique to the skull between skull bones that allow for brain growth during childhood and adolescence and fuse completely by around age 20.

Neural crest

Embryologic tissue that forms the anterior part of the skull.

Paraxial mesoderm

forms the posterior part of the skull.

Neurocranium

The cranium; the functional division of the skull that protects the brain, subdivided into a roof (calvarium) and a base.

Calvarium

The roof of the neurocranium that protects the brain from above

• frontal

• parietal

• occipital bones.

Viscerocranium

The skeletal face comprised of 14 individual bones that support soft tissues of the face and house the

• orbits

• nasal cavity

• oral cavity

• and sinuses.

Fontanels

Incompletely fused joints manifesting as wide membranous gaps between skull bones in an infant that fuse within 18 months of birth.

Frontal fontanel

located at the junction of coronal and Sagittal suture

Occipital fontanelle

located at the junction of lamboid and sagittal (posterior)

Frontal suture

closes within 3-9 months.

Coronal suture

fuses the frontal bone with the two parietal bones.

Sagittal suture

fuses both parietal bones together.

Squamous suture

Fuses the parietal bone with the temporal bone.

Lambdoid suture

Fuses the occipital bone with the two parietal bones.

Bregma

Where coronal and sagittal sutures intersect

Lambda

Where sagittal and lambdoid sutures intersect

Craniosynostosis

premature closure of fontanels and/or sutures where cranial skeletal growth lags behind brain growth.

Scaphocephaly

early closure of the sagittal suture

• resulting in a skull that becomes elongated in an anteroposterior (AP) direction.

Brachycephaly

early closure of the coronal and lambdoid sutures

• causing the skull to grow vertically tall and elongate superior-inferiorly.

Plagiocephaly

early closure of the coronal and lambdoid sutures on just one side of the skull

• resulting in asymmetrical distortion.

Sinuses

pouches originating from the lateral nasal wall that extend into the frontal, ethmoid, sphenoid, and maxilla bones to reduce

• skull weight

• assist in voice resonance

• thermal insulation

• pressure regulation

• defense.

Alveolar process

The portion of the mandible that supports the teeth, whose development, full presence, or age-related resorption dictates the angle of the mandible throughout life.

Lafort fracture lines

weak horizontal lines of fracture in the skull that act as common sites of fracture and serve as surgical guides during orthognathic surgery.

Pterion

The weakest region of the lateral calvaria where the frontal, parietal, sphenoid, and temporal bones articulate.

What bones make up the orbit

FM, plesz

frontal, maxillary, palatine, lacrimal, ethmoid, sphenoid, and zygomatic

Ethnoid bones

1. Crita gallia

2. uncinate process

3. cibriform plate

4. superior and middle nasal conchae

Crista galli

Crest of the ethmoid bone (meaning 'crest of the rooster') that projects upward to attach to the falx cerebri of the dura mater.

Uncinate process

A sickle-shaped extension of the ethmoid bone that directs sinus drainage to the middle meatus.

Cribriform plate

where cranial nerve I (olfactory nerve) passes.

Superior and middle nasal conchae

curled bone that directs airflow through the nose

Sphenoid bone

1. Sella turcicia

2. Clinoid process

3. lesser wing

4. greater wing

Sella turcica

A saddle-shaped depression in the sphenoid bone that houses the pituitary gland.

Clinoid processes

Four central extensions of the sphenoid bone surrounding the sella turcica that attach to the dura mater.

Nasal septum

Vertical wall separating right and left of nasal airway,

composed of

1. septal cartilage

2. the perpendicular plate

3. the vomer bone.

Semilunar hiatus

Opening located within the middle nasal meatus through which the middle ethmoid air cells, maxillary sinus, and frontal sinus drain.