Aditus to mastoid antrum
The medial wall and part of the posterior and anterior walls of the right tympanic cavity, lateral view.
Coronal section of right temporal bone.
Latin	aditus ad antrum mastoideum
Gray's	subject #230 1042

The entrance to the antrum is a large irregular aperture, which leads backward from the epitympanic recess into a considerable air space, named the tympanic or mastoid antrum.

The antrum communicates behind and below with the mastoid air cells, which vary considerably in number, size, and form; the antrum and mastoid air cells are lined by mucous membrane, continuous with that lining the tympanic cavity.

On the medial wall of the entrance to the antrum is a rounded eminence, situated above and behind the prominence of the facial canal; it corresponds with the position of the ampullated ends of the superior and lateral semicircular canals.

[edit] See also

• aditus
• mastoid antrum

[edit] External links

• Description at umich.edu
• http://www.dartmouth.edu/~humananatomy/figures/chapter_44/44-5.HTM

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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

v • d • e Bones of head and neck: the neurocranium of the skull (TA A02.1.01-07, GA 2.129-155) Occipital Squama external (Inion/External occipital protuberance, Nuchal lines) · planes (Occipital, Nuchal) · internal (Cruciform eminence, Internal occipital protuberance, Sagittal sulcus, Internal occipital crest) Lateral parts Condyle (Condyloid fossa, Condylar canal) · Hypoglossal canal · jugular (Jugular process, Jugular tubercle) Basilar part Pharyngeal tubercle Other Foramen magnum (Basion, Opisthion) Parietal Parietal eminence · Temporal line · Parietal foramen Frontal Squama Frontal suture · Frontal eminence · external (Superciliary arches, Glabella) · foramina (Supraorbital, Cecum) · Zygomatic process · internal (Sagittal sulcus, Frontal crest) Orbital part Ethmoidal notch · Lacrimal fossa · Trochlear fovea · Frontal sinus · Frontonasal duct Temporal Squama Articular tubercle · Suprameatal triangle · Mandibular fossa · Petrotympanic fissure · Zygomatic process Mastoid part Mastoid foramen · Mastoid process (Mastoid cells) · Mastoid notch · Occipital groove · Sigmoid sulcus · Mastoid antrum (Aditus) Petrous part Carotid canal · Facial canal (Hiatus) · Internal auditory meatus · Cochlear aqueduct · Stylomastoid foramen fossae (Subarcuate fossa, Jugular fossa) · canaliculi (Inferior tympanic, Mastoid) · Styloid process · Petrosquamous suture (note: ossicles in petrous part, but not part of temporal bone) Tympanic part Suprameatal spine Sphenoid Surfaces Superior surface: Sella turcica (Dorsum sellae, Tuberculum sellae, Hypophysial fossa, Posterior clinoid processes) · Ethmoidal spine · Chiasmatic groove · Middle clinoid process · Petrosal process · Clivus Lateral surface: Carotid groove · Sphenoidal lingula Anterior surface: Sphenoidal sinuses Great wings foramina (Rotundum, Ovale, Vesalii, Spinosum) · Spine · Infratemporal crest · Sulcus for auditory tube Small wings Superior orbital fissure · Anterior clinoid process · Optic canal Pterygoid processes fossae (Pterygoid, Scaphoid) · pterygoid plates (Lateral, Medial) · Pterygoid canal · Hamulus Other Body · Sphenoidal conchae Ethmoid Plates Cribriform plate (Crista galli, Olfactory foramina) · Perpendicular plate Surfaces Lateral surface Orbital lamina · Uncinate process Medial surface Superior nasal concha · Superior meatus · Middle nasal concha · Middle meatus Labyrinth Ethmoid sinus · ethmoidal foramina (Posterior, Anterior)

v • d • e Sensory system: Auditory and Vestibular systems (TA A15.3, GA 10.1029) Outer ear Pinna (Helix, Antihelix, Tragus, Antitragus, Earlobe) • Ear canal • Auricular muscles Eardrum (Umbo, Pars flaccida) Middle ear Tympanic cavity Labyrinthine wall/medial: Oval window · Round window • Secondary tympanic membrane • Prominence of facial canal • Promontory of tympanic cavity Membranous wall/lateral Mastoid wall/posterior: Mastoid cells • Aditus to mastoid antrum • Pyramidal eminence Carotid wall/anterior Tegmental wall/roof: Epitympanic recess Jugular wall/floor Ossicles Malleus (Neck of malleus, Superior ligament of malleus, Lateral ligament of malleus, Anterior ligament of malleus) · Incus (Superior ligament of incus, Posterior ligament of incus) · Stapes (Anular ligament of stapes) Muscles Stapedius · Tensor tympani Eustachian tube Bony part of pharyngotympanic tube · Cartilage of pharyngotympanic tube (Torus tubarius) Inner ear/ (membranous labyrinth, bony labyrinth) Auditory system Cochlear labyrinth General cochlea Scala vestibuli • Helicotrema • Scala tympani • Modiolus • Cochlear cupula Perilymphatic space Perilymph • Cochlear aqueduct Cochlear duct / scala media Reissner's/vestibular membrane • Basilar membrane Endolymph • Stria vascularis • Spiral ligament Organ of Corti: Stereocilia • Tectorial membrane • Sulcus spiralis (externus, internus) • Spiral limbus Vestibular system/ Vestibular labyrinth Static/translations/vestibule/endolymphatic duct: Utricle (Macula) · Saccule (Macula, Endolymphatic sac) · Kinocilium · Otolith • Vestibular aqueduct • Canalis reuniens Kinetic/rotations: Semicircular canals (Superior, Posterior, Horizontal) • Ampullary cupula • Ampullae (Crista ampullaris) ear navs: anat/pathways/physio/dev, noncongen/congen, eponymous signs, proc