Petrotympanic fissure

Anatomic feature of the human skull

Petrotympanic fissure
Left temporal bone. Outer surface. (Petrotympanic fissure is labeled at left, fourth from top.)
The right membrana tympani with the malleus and the chorda tympani, viewed from within, from behind, and from above. (Glaserian fissure labeled at center left.)
Details
Identifiers
Latin	fissura petrotympanica
TA98	A02.1.06.074
TA2	717
FMA	55463
Anatomical terms of bone [edit on Wikidata]

The petrotympanic fissure (also known as the squamotympanic fissure or the glaserian fissure) is a fissure in the temporal bone^[1] that runs from the temporomandibular joint to the tympanic cavity.^[2]

The mandibular fossa is bounded, in front, by the articular tubercle; behind, by the tympanic part of the bone, which separates it from the external acoustic meatus; it is divided into two parts by a narrow slit, the petrotympanic fissure.

It opens just above and in front of the ring of bone into which the tympanic membrane is inserted; in this situation it is a mere slit about 2 mm. in length. It lodges the anterior process and anterior ligament of the malleus, and gives passage to the anterior tympanic branch of the internal maxillary artery.

Eponym

It is also known as the "Glaserian fissure", after Johann Glaser.^[3]

The contents of the fissure include communications of cranial nerve VII to the infratemporal fossa. A branch of cranial nerve VII, the chorda tympani, runs through the fissure to join with the lingual nerve providing special sensory (taste) innervation to the tongue. Anterior tympanic artery and tympanic veins also pass through the structure. Petrotympanic fissure contains some of the fibers of the anterior ligament of malleus, which run on the base of skull and eventually attach onto the spine of sphenoid bone.

References

This article incorporates text in the public domain from page 140 of the 20th edition of Gray's Anatomy (1918)

^ Petrotympanic+fissure Archived October 9, 2016, at the Wayback Machine at eMedicine Dictionary
^ Eckerdal O (1991). "The petrotympanic fissure: a link connecting the tympanic cavity and the temporomandibular joint". Cranio. 9 (1): 15–22. doi:10.1080/08869634.1991.11678343. PMID 1843474.
^ "Glaserian fissure". Medcyclopaedia. Retrieved 2008-03-07.^{[dead link]}

External links

Anatomy figure: 30:06-09 at Human Anatomy Online, SUNY Downstate Medical Center
Anatomy photo:30:os-0108 at the SUNY Downstate Medical Center

Neurocranium of the skull

Occipital

Squamous part	external Inion/External occipital protuberance Occipital bun External occipital crest Nuchal lines Suprainiac fossa planes Occipital Nuchal internal Cruciform eminence Internal occipital protuberance Internal occipital crest Groove for transverse sinus
Lateral parts	Condyle Condyloid fossa Condylar canal Hypoglossal canal jugular Jugular process Jugular tubercle
Basilar part	Pharyngeal tubercle Clivus
Other	Foramen magnum Basion Opisthion

Parietal

Frontal

Squamous part	Frontal suture Frontal eminence external Superciliary arches Glabella foramina Supraorbital foramen Brow ridge Foramen cecum Zygomatic process internal Sagittal sulcus Frontal crest
Orbital part	Ethmoidal notch Fossa for lacrimal gland Trochlear fovea Frontal sinus Frontonasal duct

Temporal

Squamous part	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 of 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 Supreme nasal concha Superior nasal concha Superior meatus Middle nasal concha Middle meatus
Labyrinth	Ethmoid sinus ethmoidal foramina Posterior Anterior

Foramina of the skull (and canals, fissures, meatus, and hiatus)

Anterior cranial fossa

to Orbit:	ethmoidal foramina anterior posterior
to Nasal cavity:	olfactory foramina (CN-I) foramen cecum

Middle cranial fossa

to Orbit:	optic canal (CN-II) superior orbital fissure (CN-III,IV,V1,VI)
to Pterygopalatine fossa:	foramen rotundum (CN-V2) pterygoid canal
to Infratemporal fossa:	foramen ovale (CN-V3) foramen spinosum/carotid canal
other:	foramen lacerum hiatus for greater petrosal nerve hiatus for lesser petrosal nerve sphenoidal emissary foramen

Posterior cranial fossa

internal auditory meatus/facial canal/stylomastoid foramen (CN-VII,VIII)
jugular foramen (CN-IX,X,XI)
foramen magnum (CN-XI)
hypoglossal canal (CN-XII)
condylar canal
mastoid foramen

Orbit

to Nasal cavity:	nasolacrimal canal
to face:	supraorbital notch foramen infraorbital foramen groove zygomatic foramen -facial -temporal
to Pterygopalatine fossa:	inferior orbital fissure
other:	Inferior orbital fissure Fossa for lacrimal sac

Pterygopalatine fossa

to Nasal cavity:	sphenopalatine foramen
to Oral cavity:	greater palatine canal foramen lesser palatine canals foramina
to Infratemporal fossa:	pterygomaxillary fissure
to Nasopharynx:	palatovaginal canal