![]() Lateral attachments (from superior to inferior) 1: Posteriorly: squamous part of the occipital bone via the occipitomastoid sutureĪnteriorly: tympanic part of the temporal bone via the tympanomastoid suture Superiorly: mastoid angle of the parietal bone via the parietomastoid suture The mastoid part of the temporal bone articulates with the following bones 1,2: The mastoid contains the mastoid (vertical) segment of the facial nerve canal as well as the mastoid canaliculus, which transmits the Arnold nerve. Around this area is the inconstant mastoid foramen, which transmits an emissary vein and occipital artery branch 1,2. The sigmoid plate is the thin lamina of bone that separates mastoid air cells from the dural venous sinuses. Medial to that is the occipital groove, which is traversed by the occipital artery.Īt the posterior intracranial surface of the mastoid, the sigmoid sulcus lodges the sigmoid sinus and partially the transverse sinus 2. The medial extracranial surface of the mastoid process contains a deep groove called the digastric fossa (mastoid notch), which originates the digastric muscle. The anterior landmark is the MacEwen triangle including the spine of Henle. The lateral extracranial surface of the mastoid is sometimes called the mastoid cortex. The tegmen mastoideum forms part of the floor of the middle cranial fossa, separating the mastoid from the cranial cavity. The roof of the mastoid antrum is called the tegmen mastoideum, which is a posterior extension of the tegmen tympani. Pneumatization extends from the antrum as the mastoid air cells. An irregular cavity within the anterosuperior aspect of the bone is called the mastoid (or tympanic) antrum, which communicates with the attic of the tympanic cavity 1. ![]()
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