FACTS & HINTS

High-Yield Facts

Anatomic Points

Anewborn's skull is large compared to other parts of the skeleton Facial skeleton small compared to calvaria

Two halves of mandible begin to fuse during first year

The mastoid process is not present at birth but develops in the first 2 years of life The anterior fontanelle:

Adiamond-shaped region covered bya fibrous membrane

Lies at juncture of both frontal with both parietal bones

Ossifies by18 months

Useful for assessing hydration and measuring heart rate and intracranial pressure Enlargement of frontal and facial regions associated with increasing size of paranasal sinuses Vertical growth of face because of dental development

Thinnest part of skull is pterion:

Where parietal bone articulates with greater wing of sphenoid.

Fractures can cause intracranial bleeding as pterion overlies anterior division of middle meningeal arteryand vein.

Clinical Points

Skull (Calvaria) Fractures

Can occur as a result of direct trauma to the head

Can be one of several types:

Depressed

Produced byhard blows in regions where calvaria is thin

Fragment of bone forced inward into brain

Linear

Most frequent

Fracture lines radiate awayfrom point of impact

Comminuted - bone broken into several pieces

Contre-coup

Maybe no fracture at impact site

Brain impacts opposite side of skull and rebounds to site of impact, with resulting bruising

Maybe associated with brain injury

When assessing a patient with a head injurythe Glasgow Coma Scale (GCS) is useful..

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Clinical Points

Le Fort Fractures

Common variants of fractures of the maxillae, naso-orbital complex, zygomatic bones (midface fractures) were classified byLe Fort (surgeon and gynecologist)

Le Fort I :

Horizontal fracture of one or both maxillae at the level of the nasal floor.

Maypresent with crepitus on palpation and epistaxis

Rarelycompromises airway. Le Fort II:

Pyramidal-shaped fracture that includes horizontal fracture of both maxillae, extending superiorlythrough maxillarysinuses, infraorbital foramina, and ethmoids to bridge of nose.

Separates central face from rest of skill

Places the airwayat risk Le Fort III:

Includes fractures of Le Fort II plus horizontal fracture through superior orbital fissures, ethmoid, and nasal bones, great wings of sphenoid bones and zygomatic bones.

Maxillae and zygomatic bones separate from skull

Maycause airwayproblems, nasolacrimal apparatus obstruction, and cerebrospinal fluid (CSF) leakage

Mnemonics

Memory Aids

Memory Aids

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