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|Bone: Mastoid process|
|Side view of head, showing surface relations of bones. (Mastoid process labeled near center.)|
|Latin||processus mastoideus ossis temporalis|
|Gray's||subject #34 141|
The mastoid process is a conical prominence projecting from the undersurface of the mastoid portion of the temporal bone. It is located just behind the external acoustic meatus, and lateral to the styloid process. Its size and form vary somewhat; it is larger in the male than in the female.
The term “mastoid” is derived from the Greek word for “breast,” a reference to the shape of this bone. The temporal bone contains another protrusion, the styloid process, located in close proximity to the mastoid process. The styloid process also serves as a point of attachment for muscles and has a distinctive pointed shape akin to that of a stylus, explaining the origins of the name.
This part of the skull projects from the temporal bone and is roughly pyramidal or conical in shape. One important role for this bone is as a point of attachment for several muscles - the splenius capitis, longissimus capitis, digastric posterior belly, and sternocleidomastoid. These muscles are one reason the mastoid process tends to be larger in men, because men have bigger muscles as a general rule and thus require larger points of attachment.
The mastoid process is absent or rudimentary in the neonatal skull. It forms postnatally, as the sternocleidomastoid muscle develops and pulls on the bone.
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.
occipital bone: Foramen magnum | Squama occipitalis (Inion | Nuchal lines | Planum occipitale | Planum nuchale | Cruciform eminence | Internal occipital protuberance | Sagittal sulcus | Internal occipital crest)
parietal bone: Parietal eminence | Temporal line | Parietal foramen
frontal bone: Squama frontalis (Frontal suture | Frontal eminence | Superciliary arches | Glabella | Supraorbital foramen | Zygomatic process | Sagittal sulcus | Frontal crest | Foramen cecum)
temporal bone: Squama temporalis (Articular tubercle | Suprameatal triangle | Mandibular fossa | Petrotympanic fissure) | Mastoid portion (Mastoid foramen
sphenoid bone: Sphenoidal sinuses | Ethmoidal spine | Optic foramen | Sella turcica | Fossa hypophyseos | Dorsum sellae | Posterior clinoid processes | Carotid groove | Lingula sphenoidalis | Sphenoidal conchæ | Great wings (Spina angularis | Foramen rotundum | Foramen ovale | Foramen Vesalii | Foramen spinosum | Infratemporal crest | Sulcus tubae auditivae | Small wings | Superior orbital fissure | Anterior clinoid process | Optic foramen)
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