Side view of skull. Mastoid process shown in red.
|Latin||processus mastoideus ossis temporalis|
The mastoid process projects from the temporal bone in the skull and is roughly pyramidal or conical in shape. It is also filled with sinuses, or mastoid cells. On the medial side of the mastoid process is a deep groove, the mastoid notch, for the attachment of the digastric muscle. Medial to this is a shallow furrow, the occipital groove, which lodges the occipital artery.
Variation in humans
Its size and form vary somewhat; it is larger in the male than in the female.
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 rule and thus require larger points of attachment.
The term “mastoid” is derived from the Greek word for “breast,” a reference to the shape of this bone.
- Animation. Left temporal bone.
- Base of skull. Mastoid process labeled at middle left.
- Close up of the right side of the skull. Mastoid process at left.
- Mastoid process labeled at bottom.
- Mastoid process labeled bottom right.
- Base of skull. Muscle attachments are shown in red lines.
- Side view of head, showing surface relations of bones. (Mastoid process labeled near center.)
|Wikimedia Commons has media related to Mastoid process.|
- lesson5 at The Anatomy Lesson by Wesley Norman (Georgetown University)
- Diagram - #5 (source here)
- Anatomy diagram: 34257.000-1 at Roche Lexicon - illustrated navigator, Elsevier