Note: Scroll over or tap on the image to see the labels.

Note: Scroll over or tap on the image to see the labels.

The skull (cranium) is divided into 2 main sections:

• Neurocranium:
  
• Bony part that covers the brain and its membranous coverings, the cranial meninges, proximal portions of the cranial nerves, and vasculature of the brain.
  
• Made up by 8 bones (ethmoidal, frontal, occipital, sphenoidal & the 2 sets of parietal and temporal bones)
  
• Viscerocranium:
  
• Represents the bones of the anterior part of the skull Made up by 15 bones (ethmoid, mandible, & vomer along with 2 sets of maxilla, nasal, inferior nasal conchae, lacrimal, palatine and zygomatic bones

Other important aspects of the skull include:

• Calvaria:
• Formed by the flat bones (frontal, temporal and parietal and are united by a fibrous interlocking sutures).  Note: During early childhood the sphenoid and occipital bones are united by hyaline cartilage known as synchondroses.
  
• Pneumatized Bones:
• These are bones with air cells or sinus which are thought to reduce to the weight of the head and include the ethmoid, frontal, temporal, and sphenoid.  The ethmoid and sphenoid are known to contain the sinuses.

The following foramen are seen on the anterior skull view:

• Supraorbital foramen
• Zygomatic foramen
• Infraorbital foramen
• Mental foramen

Nerves exit out of the foramen.

There are a few clinical applications related to cranial (or skull) anatomy that are important to consider:

• Malar Rash = The is the rash seen on the skin of the face that is distributed in the area overlying the zygomatic bones in patients with SLE (systemic lupus erythematosus).  It gets this name because the zygomatic bones were once called the malar bones. 
• Mental Foramen = Extraction of the teeth can result in the bone to resorb in that area. If all of the teeth are extracted in the area of mental foramen it can sometimes disappear and cause damage to the nerve exiting the foramen.  If patients have dentures on this can put additional pressure on the nerve and thus cause pain with chewing.  In addition, if all of the teeth are extracted in the mandible this can decrease the vertical dimensions of the face causing an overclosure effect. 
• Le Fort Fractures = This is a fracture involving the maxilla and is broken down into 3 different variations. 
• Supraorbital Margin & Supracillary Arches  = The supracilliary arches make up the bone rim just above the supraorbital margin by forming a sharper rim.  When this area receives a direct injury the skin will commonly lacerate.

To see other related content select an item from below:

• Anatomy: Skull Posterior View
• Anatomy: Skull Inferior View 
• LaForte Fractures
  

Editors:  Anthony J. Busti, MD, PharmD, FNLA, FAHA
Last Updated:  June 2015