The middle cranial fossa, deeper than the
anterior cranial fossa
The anterior cranial fossa is a depression in the floor of the cranial base which houses the projecting frontal lobes of the brain. It is formed by the orbital plates of the frontal, the cribriform plate of the ethmoid, and the small wings and fr ...
, is narrow medially and widens laterally to the sides of the
skull
The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...
. It is separated from the
posterior fossa by the
clivus and the
petrous crest.
It is bounded in front by the posterior margins of the lesser wings of the
sphenoid bone, the
anterior clinoid processes
In the sphenoid bone, the posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes ...
, and the ridge forming the anterior margin of the
chiasmatic groove
The superior surface of the body of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove, prechiasmatic sulcus), above and behind which lies the optic c ...
; behind, by the superior angles of the petrous portions of the temporal bones and the
dorsum sellæ
The dorsum sellae is part of the sphenoid bone in the skull. Together with the basilar part of the occipital bone it forms the clivus.
In the sphenoid bone, the anterior boundary of the sella turcica is completed by two small eminences, one on ...
; laterally by the temporal squamæ, sphenoidal angles of the parietals, and greater wings of the sphenoid. It is traversed by the squamosal, sphenoparietal, sphenosquamosal, and sphenopetrosal sutures.
It houses the
temporal lobes
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The temporal lobe is involved in pro ...
of the brain and the
pituitary gland
In vertebrate anatomy, the pituitary gland, or hypophysis, is an endocrine gland, about the size of a chickpea and weighing, on average, in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain. The ...
.
A middle fossa craniotomy is one means to surgically remove acoustic neuromas (
vestibular schwannoma
A vestibular schwannoma (VS), also called acoustic neuroma, is a benign tumor that develops on the vestibulocochlear nerve that passes from the inner ear to the brain. The tumor originates when Schwann cells that form the insulating myelin sheath ...
) growing within the internal auditory canal of the temporal bone.
Middle part
The middle part of the fossa presents, in front, the
chiasmatic groove
The superior surface of the body of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove, prechiasmatic sulcus), above and behind which lies the optic c ...
and
tuberculum sellae
The tuberculum sellae (or the tubercle of the sella turcica) is a part of the sphenoid bone
The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of ...
; the chiasmatic groove ends on either side at the
optic foramen
The ''optic foramen'' is the opening to the optic canal. The canal is located in the sphenoid bone; it is bounded medially by the body of the sphenoid and laterally by the lesser wing of the sphenoid.
The superior surface of the sphenoid bone is b ...
, which transmits the
optic nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual information from the retina to the brain. In humans, the optic nerve is derived fro ...
and
ophthalmic artery
The ophthalmic artery (OA) is an artery of the head. It is the first branch of the internal carotid artery distal to the cavernous sinus. Branches of the ophthalmic artery supply all the structures in the orbit around the eye, as well as some s ...
to the
orbital cavity
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , o ...
.
Behind the optic foramen the
anterior clinoid process
In the sphenoid bone, the posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes ...
is directed backward and medialward and gives attachment to the
tentorium cerebelli
The cerebellar tentorium or tentorium cerebelli (Latin for "tent of the cerebellum") is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.
Structure
The cerebellar tentorium is an arch ...
.
Behind the tuberculum sellæ is a deep depression, the
sella turcica
The sella turcica (Latin for 'Turkish saddle') is a saddle-shaped depression in the body of the sphenoid bone of the human skull and of the skulls of other hominids including chimpanzees, gorillas and orangutans. It serves as a cephalome ...
, containing the
fossa hypophyseos
The sella turcica (Latin for 'Turkish saddle') is a saddle-shaped depression in the body of the sphenoid bone of the human skull and of the skulls of other hominids including chimpanzees, gorillas and orangutans. It serves as a cephalome ...
, which lodges the
hypophysis, and presents on its anterior wall the
middle clinoid processes
The anterior boundary of the sella turcica is completed by two small eminences, one on either side, called the middle clinoid processes. It is found lateral to the sella turcica.
Etymology
Clinoid likely comes from the Greek root ''klinein'' or ...
.
The
sella turcica
The sella turcica (Latin for 'Turkish saddle') is a saddle-shaped depression in the body of the sphenoid bone of the human skull and of the skulls of other hominids including chimpanzees, gorillas and orangutans. It serves as a cephalome ...
is bounded posteriorly by a quadrilateral plate of bone, the
dorsum sellae
The dorsum sellae is part of the sphenoid bone in the skull. Together with the basilar part of the occipital bone it forms the clivus.
In the sphenoid bone, the anterior boundary of the sella turcica is completed by two small eminences, one on ...
, the upper angles of which are surmounted by the posterior clinoid processes: these afford attachment to the tentorium cerebelli, and below each is a notch for the
abducent nerve
The abducens nerve or abducent nerve, also known as the sixth cranial nerve, cranial nerve VI, or simply CN VI, is a cranial nerve in humans and various other animals that controls the movement of the lateral rectus muscle, one of the extraocul ...
.
On either side of the sella turcica is the
carotid groove
The carotid groove is an anatomical groove in the sphenoid bone located above the attachment of each great wing of the sphenoid bone. The groove is curved like the italic letter f, and lodges the internal carotid artery and the cavernous sinus
...
, which is broad, shallow, and curved somewhat like the italic letter ''f''.
It begins behind at the
foramen lacerum
The foramen lacerum ( la, lacerated piercing) is a triangular hole in the base of skull. It is located between the sphenoid bone, the apex of the petrous part of the temporal bone, and the basilar part of the occipital bone.
Structure
The foram ...
, and ends on the medial side of the anterior clinoid process, where it is sometimes converted into a foramen (carotico-clinoid) by the union of the anterior with the middle clinoid process; posteriorly, it is bounded laterally by the
lingula.
This groove lodges the
cavernous sinus
The cavernous sinus within the human head is one of the dural venous sinuses creating a cavity called the lateral sellar compartment bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.
Structure
The cave ...
and the
internal carotid artery, the latter being surrounded by a plexus of
sympathetic nerves.
Lateral parts
The lateral parts of the middle fossa are of considerable depth, and support the
temporal lobes
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The temporal lobe is involved in pro ...
of the
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...
.
They are marked by depressions for the brain convolutions and traversed by furrows for the anterior and posterior branches of the
middle meningeal vessels.
These furrows begin near the
foramen spinosum
The foramen spinosum is a hole located in the greater wing of the sphenoid. It is located posterolateral to the foramen ovale and anterior to the sphenoidal spine. It allows the passage of the middle meningeal artery, middle meningeal vein and ...
, and the anterior runs forward and upward to the sphenoidal angle of the parietal, where it is sometimes converted into a bony canal; the posterior runs lateralward and backward across the
temporal squama and passes on to the parietal near the middle of its lower border.
The following apertures are also to be seen.
In front is the
superior orbital fissure, bounded above by the small wing, below, by the
great wing, and medially, by the body of the
sphenoid; it is usually completed laterally by the
orbital plate of the
frontal bone
The frontal bone is a bone in the human skull. The bone consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bony part of the forehead, pa ...
.
It transmits to the
orbital cavity
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , o ...
the
oculomotor
The oculomotor nerve, also known as the third cranial nerve, cranial nerve III, or simply CN III, is a cranial nerve that enters the orbit (anatomy), orbit through the superior orbital fissure and innervates extraocular muscles that enable mo ...
, the
trochlear, the
ophthalmic division of the
trigeminal
In neuroanatomy, the trigeminal nerve ( lit. ''triplet'' nerve), also known as the fifth cranial nerve, cranial nerve V, or simply CN V, is a cranial nerve responsible for sensation in the face and motor functions such as biting and chewing; ...
, and the
abducent nerves
The abducens nerve or abducent nerve, also known as the sixth cranial nerve, cranial nerve VI, or simply CN VI, is a cranial nerve in humans and various other animals that controls the movement of the lateral rectus muscle, one of the extraocula ...
, some filaments from the
cavernous plexus
The cavernous nerve plexus (also called the Walther plexus) is situated below and medial to that part of the internal carotid artery which is placed by the side of the sella turcica in the cavernous sinus, and is formed chiefly by the medial div ...
of the sympathetic, and the orbital branch of the
middle meningeal artery
The middle meningeal artery ('' la, arteria meningea media'') is typically the third branch of the first portion of the maxillary artery. After branching off the maxillary artery in the infratemporal fossa, it runs through the foramen spinosum t ...
; and from the orbital cavity a recurrent branch from the
lacrimal artery
The lacrimal artery is an artery of the orbit. It is a branch of the ophthalmic artery. It accompanies the lacrimal nerve along the upper border of the lateral rectus muscle, travelling forward to reach the lacrimal gland. It supplies the lacri ...
to the
dura mater
In neuroanatomy, dura mater is a thick membrane made of dense irregular connective tissue that surrounds the brain and spinal cord. It is the outermost of the three layers of membrane called the meninges that protect the central nervous system. ...
, and the
ophthalmic veins
Ophthalmic veins are veins which drain the eye.
More specifically, they can refer to:
* Superior ophthalmic vein
* Inferior ophthalmic vein
The inferior ophthalmic vein is a vein of the orbit that - together with the superior ophthalmic vein ...
.
Behind the medial end of the
superior orbital fissure is the
foramen rotundum
The foramen rotundum is a circular hole in the sphenoid bone of the skull. It connects the middle cranial fossa and the pterygopalatine fossa. It allows for the passage of the maxillary nerve (V2), a branch of the trigeminal nerve.
Structure
T ...
, for the passage of the
maxillary nerve
In neuroanatomy, the maxillary nerve (V) is one of the three branches or divisions of the trigeminal nerve, the fifth (CN V) cranial nerve. It comprises the principal functions of sensation from the maxilla, nasal cavity, sinuses, the palat ...
.
Behind and lateral to the foramen rotundum is the
foramen ovale, which transmits the
mandibular nerve, the
accessory meningeal artery
The accessory meningeal artery (also accessory branch of middle meningeal artery, pterygomeningeal artery, small meningeal or parvidural branch) is a branch of the maxillary artery, sometimes derived from the middle meningeal artery.
Course
It ent ...
, and the
lesser superficial petrosal nerve
The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) component of the glossopharyngeal nerve (CN IX), carrying parasympathetic preganglionic fibers from the tympanic plexus to the p ...
.
Medial to the foramen ovale is the
foramen Vesalii, which varies in size in different individuals, and is often absent; when present, it opens below at the lateral side of the
scaphoid fossa
In the pterygoid processes of the sphenoid, above the pterygoid fossa is a small, oval, shallow depression, the scaphoid fossa, which gives origin to the Tensor veli palatini
The tensor veli palatini muscle (tensor palati or tensor muscle of the ...
, and transmits a small vein.
Lateral to the foramen ovale is the
foramen spinosum
The foramen spinosum is a hole located in the greater wing of the sphenoid. It is located posterolateral to the foramen ovale and anterior to the sphenoidal spine. It allows the passage of the middle meningeal artery, middle meningeal vein and ...
, for the passage of the middle meningeal vessels, and a recurrent branch from the mandibular nerve.
Medial to the foramen ovale is the
foramen lacerum
The foramen lacerum ( la, lacerated piercing) is a triangular hole in the base of skull. It is located between the sphenoid bone, the apex of the petrous part of the temporal bone, and the basilar part of the occipital bone.
Structure
The foram ...
; in the fresh state the lower part of this aperture is filled up by a layer of
fibrocartilage, while its upper and inner parts transmit the
internal carotid artery surrounded by a plexus of sympathetic nerves.
The nerve of the
pterygoid canal
The pterygoid canal (also vidian canal) is a passage in the sphenoid bone of the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa.
Structure
The pterygoid canal runs through the me ...
and a meningeal branch from the
ascending pharyngeal artery
The ascending pharyngeal artery is an artery in the neck that supplies the pharynx, developing from the proximal part of the embryonic second aortic arch.
It is the smallest branch of the external carotid and is a long, slender vessel, deeply se ...
pierce the layer of fibrocartilage.
On the anterior surface of the petrous portion of the temporal bone are seen the eminence caused by the projection of the
superior semicircular canal; in front of and a little lateral to this a depression corresponding to the roof of the
tympanic cavity
The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound.
Structure
On its lateral surface, it abuts the external auditory ...
; the groove leading to the hiatus of the
facial canal
The facial canal (''canalis nervi facialis''), also known as the Fallopian canal, is a Z-shaped canal running through the temporal bone of the skull. It runs from the internal acoustic meatus to the stylomastoid foramen. It contains the facial ...
, for the transmission of the
greater superficial petrosal nerve
The greater petrosal nerve (or greater superficial petrosal nerve) is a nerve in the skull that branches from the facial nerve; it forms part of a chain of nerves that innervate the lacrimal gland. The preganglionic parasympathetic axons of this ne ...
and the petrosal branch of the
middle meningeal artery
The middle meningeal artery ('' la, arteria meningea media'') is typically the third branch of the first portion of the maxillary artery. After branching off the maxillary artery in the infratemporal fossa, it runs through the foramen spinosum t ...
; beneath it, the smaller groove, for the passage of the
lesser superficial petrosal nerve
The lesser petrosal nerve (also known as the small superficial petrosal nerve) is the general visceral efferent (GVE) component of the glossopharyngeal nerve (CN IX), carrying parasympathetic preganglionic fibers from the tympanic plexus to the p ...
; and, near the apex of the bone, the depression for the
semilunar ganglion
A trigeminal ganglion (or Gasserian ganglion, or semilunar ganglion, or Gasser's ganglion) is the sensory ganglion at the base of each of the two trigeminal nerves (CN V), occupying a cavity (Meckel's cave) in the dura mater, covering the trigem ...
and the orifice of the carotid canal.
See also
*
Anterior cranial fossa
The anterior cranial fossa is a depression in the floor of the cranial base which houses the projecting frontal lobes of the brain. It is formed by the orbital plates of the frontal, the cribriform plate of the ethmoid, and the small wings and fr ...
*
Posterior cranial fossa
The posterior cranial fossa is part of the cranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum.
This is the most inferior of the fossae. It houses the cerebellum, medulla and pons. ...
References
Additional images
File:Middle cranial fossa - animation.gif, Animation
File:Cranial endobasis of a 19-20 weeks foetus 2.JPG, Middle cranial fossa at human foetus
File:Schädelbasis1.jpg, Base of skull
The base of skull, also known as the cranial base or the cranial floor, is the most inferior area of the skull. It is composed of the endocranium and the lower parts of the calvaria.
Structure
Structures found at the base of the skull are for ...
File:Base of skull 22.jpg, Middle cranial fossa
File:Base of skull 23.jpg, Middle cranial fossa
File:Slide28hhhh.JPG, Middle cranial fossa
External links
*
{{Authority control
Skull