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The mastoid process serves for the attachment of the sternocleidomastoid, the posterior belly of the digastric muscle, splenius capitis, and longissimus capitis. On the medial side of the 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 ...
They may excavate the mastoid process to its tip, and be separated from the posterior cranial fossa and sigmoid sinus by a mere slip of bone or not at all. They may extend into the squamous part of temporal bone, petrous part of the temporal bone zygomatic process of temporal bone, and - rarely - the jugular process of occipital bone; they may thus come to adjoin many important structures ...
The petrous and mastoid parts of the temporal bone, which derive from the periotic bone, formed from the fusion of a number of bones surrounding the ear of reptiles. The delicate structure of the middle ear , unique to mammals, is generally not protected in marsupials , but in placentals , it is usually enclosed within a bony sheath called the ...
The two heads are separated from one another at their origins by a triangular interval (lesser supraclavicular fossa) but gradually blend, below the middle of the neck, into a thick, rounded muscle which is inserted, by a strong tendon, into the lateral surface of the mastoid process, from its apex to its superior border, and by a thin ...
The mastoid process is the portion of the temporal bone of the skull that is behind the ear. The mastoid process contains open, air-containing spaces . [ 2 ] [ 3 ] Mastoiditis is usually caused by untreated acute otitis media (middle ear infection) and used to be a leading cause of child mortality.
The mastoid antrum (tympanic antrum, antrum mastoideum, Valsalva's antrum) is an air space in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear via the aditus to mastoid antrum (entrance to the mastoid antrum). These air spaces function as ...
the mastoid portion of the temporal bone. In the adult, it lies 4 cm behind and 12 mm above the center of the entrance to the ear canal . [ citation needed ] Its relation to other anatomical structures is fairly variable.
The mastoid foramen is a hole in the posterior border of the temporal bone of the skull. [1] The opening of the mastoid foramen is an average of 18 mm from the asterion, [2] and around 34 mm from the external auditory meatus. [3] It is typically very narrow. [1] [3] This may be around 2 mm. [3]