Mastoid process

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Mastoid process
Mastoid process - lateral view.png
Side view of skull. Mastoid process shown in red.
Processusmastoideusossistemporalis.PNG
Mastoid process
Latinprocessus mastoideus ossis temporalis
Gray'sp.141
TAA02.1.06.004
FMAFMA:52872
Anatomical terms of bone
 
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Mastoid process
Mastoid process - lateral view.png
Side view of skull. Mastoid process shown in red.
Processusmastoideusossistemporalis.PNG
Mastoid process
Latinprocessus mastoideus ossis temporalis
Gray'sp.141
TAA02.1.06.004
FMAFMA:52872
Anatomical terms of bone

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.

Structure[edit]

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.

Variation[edit]

Its size and form vary somewhat; it is larger in the male than in the female.

Development[edit]

The mastoid process is absent or rudimentary in the neonatal skull. It forms postnatally, as the sternocleidomastoid muscle develops and pulls on the bone.

Function[edit]

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.

History[edit]

Etymology[edit]

The term “mastoid” is derived from the Greek word for “breast,” a reference to the shape of this bone.

See also[edit]

This article uses anatomical terminology; for an overview, see anatomical terminology.

Additional Images[edit]

References[edit]

This article incorporates text from a public domain edition of Gray's Anatomy.

External links[edit]