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AAAC54 21/5/05 10:57 AM Page 122
54 The skull I

Parietal
Coronal suture
Squamous
Frontal temporal
Sphenoid,
greater wing
Ethmoid Lambda
Lacrimal
Occipital Supraorbital foramen Metopic suture (uncommon)
Nasal Position of frontal air sinus
Zygomatic
Frontal
Maxilla
External
auditory Ethmoid
meatus External Lacrimal Orbital plate
of frontal
occipital
Styloid Optic canal Sphenoid,
protuberance
process
Fig.54.1 Superior lesser wing
Skull, side view orbital Sphenoid,
fissure greater wing
Inferior Zygomatic
orbital
fissure Maxilla

Mental foramen
Vomer
Sagittal Fig.54.2 Infra-orbital foramen
suture Skull, anterior view

Occipital Lambda

External
occipital Superior
protuberance nuchal line
Inferior
nuchal line
Foramen
transversarium Mastoid process
Posterior tubercle Transverse process
of atlas of atlas
Tip of dens
Fig.54.3 Spine of axis
Skull, posterior view

The skull consists of the bones of the cranium (making up the vault and cancellous bone (the diploë) which contains red bone marrow and a
the base) and the bones of the face, including the mandible. number of diploic veins. The bones are the frontal, parietal, occipital,
squamous temporal and the greater wing of the sphenoid. The frontal
The bones of the cranium air sinuses are in the frontal bone just above the orbit. The bones are
The vault of the skull separated by sutures which hold the bones firmly together in the mature
• The vault of the skull comprises a number of flat bones, each of skull (Figs 54.1–3). Occasionally the frontal bone may be separated
which consists of two layers of compact bone separated by a layer of into two halves by a midline metopic suture.
122 Head and neck