The petrotympanic fissure (also known as the squamotympanic fissure or the glaserian fissure) is a fissure in the

temporal bone The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples, and house the structures of the ears. ...

that runs from the

temporomandibular joint In anatomy, the temporomandibular joints (TMJ) are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below; it is from these bones that it ...

to the tympanic cavity. The

mandibular fossa The mandibular fossa, also known as the glenoid fossa in some dental literature, is the depression in the temporal bone that articulates with the mandible. Structure In the temporal bone, the mandibular fossa is bounded anteriorly by the art ...

is bounded, in front, by the

articular tubercle The articular tubercle (eminentia articularis) is a bony eminence on the temporal bone in the skull. It is a rounded eminence of the anterior root of the posterior end of the outer surface of the squama temporalis. This tubercle forms the front bou ...

; behind, by the tympanic part of the bone, which separates it from the

external acoustic meatus The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter. Struct ...

; 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 The malleus, or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations f ...

, and gives passage to the anterior tympanic branch of the

internal maxillary artery The maxillary artery supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible. Structure The maxillary artery, the larger of the two terminal branches of the external carotid artery, ...

Eponym

It is also known as the "Glaserian fissure", after Johann Glaser.

The contents of the fissure include communications of cranial nerve VII to the infratemporal fossa. A branch of cranial nerve VII, the

chorda tympani The chorda tympani is a branch of the facial nerve that originates from the taste buds in the front of the tongue, runs through the middle ear, and carries taste messages to the brain. It joins the facial nerve (cranial nerve VII) inside the fa ...

, runs through the fissure to join with the lingual nerve providing special sensory (taste) innervation to the tongue.

Anterior tympanic artery The anterior tympanic artery (glaserian artery) is a small artery in the head that supplies the middle ear. It usually arises as a branch of the first part of the maxillary artery. It passes upward behind the temporomandibular articulation, enters ...

and tympanic veins also pass through the structure. Petrotympanic fissure contains some of the fibers of the

anterior ligament of malleus The ligaments of malleus are three ligaments that attach the malleus in the middle ear. They are the anterior, lateral and superior ligaments. The anterior ligament of the malleus also known as Casserio's ligament is a fibrous band that extends ...

, which run on the base of skull and eventually attach onto the

spine of sphenoid bone The sphenoidal spine (Latin: "''spina angularis''") is a downwardly directed process at the apex of the great wings of the sphenoid bone that serves as the origin of the sphenomandibular ligament. Additional images File:Spine of sphenoid bone. ...

References

External links

* * {{Authority control Foramina of the skull

Eponym

Contents

See also

References

External links