Cribriform plate
Encyclopedia
The cribriform plate of the ethmoid bone
(horizontal lamina) is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities
.
Projecting upward from the middle line of this plate is a thick, smooth, triangular process
, the crista galli
, so called from its resemblance to a rooster
's comb.
The long thin posterior border of the crista galli serves for the attachment of the falx cerebri
.
Its anterior border, short and thick, articulates with the frontal bone, and presents two small projecting alæ, which are received into corresponding depressions in the frontal bone and complete the foramen cecum
.
Its sides are smooth, and sometimes bulging from the presence of a small air sinus in the interior.
On either side of the crista galli, the cribriform plate is narrow and deeply grooved; it supports the olfactory bulb
and is perforated by foramina for the passage of the olfactory nerves. The foramina in the middle of the groove are small and transmit the nerve
s to the roof of the nasal cavity; those at the medial and lateral parts of the groove are larger—the former transmit the nerves to the upper part of the nasal septum
, the latter those to the superior nasal concha
.
At the front part of the cribriform plate, on either side of the crista galli, is a small fissure which is occupied by a process of dura mater
.
Lateral to this fissure is a notch or foramen which transmits the nasociliary nerve
; from this notch a groove extends backward to the anterior ethmoidal foramen.
leaking into the nose and loss of sense of smell
.
Ethmoid bone
The ethmoid bone is a bone in the skull that separates the nasal cavity from the brain. As such, it is located at the roof of the nose, between the two orbits. The cubical bone is lightweight due to a spongy construction. The ethmoid bone is one of the bones that makes up the orbit of the eye...
(horizontal lamina) is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities
Nasal cavity
The nasal cavity is a large air filled space above and behind the nose in the middle of the face.- Function :The nasal cavity conditions the air to be received by the other areas of the respiratory tract...
.
Projecting upward from the middle line of this plate is a thick, smooth, triangular process
Process (anatomy)
In anatomy, a process is a projection or outgrowth of tissue from a larger body. The vertebra has several kinds of processes,such as: transverse process, prezygapophysis, postzygapophysis.-Examples:Examples of processes include:...
, the crista galli
Crista galli
The crista galli is a median ridge of bone that projects from the cribriform plate of the ethmoid bone.It is where the falx cerebri attaches anteriorly to the skull....
, so called from its resemblance to a rooster
Rooster
A rooster, also known as a cockerel, cock or chanticleer, is a male chicken with the female being called a hen. Immature male chickens of less than a year's age are called cockerels...
's comb.
The long thin posterior border of the crista galli serves for the attachment of the falx cerebri
Falx cerebri
The falx cerebri, also known as the cerebral falx, so named from its sickle-like form, is a strong, arched fold of dura mater which descends vertically in the longitudinal fissure between the cerebral hemispheres....
.
Its anterior border, short and thick, articulates with the frontal bone, and presents two small projecting alæ, which are received into corresponding depressions in the frontal bone and complete the foramen cecum
Foramen cecum (frontal bone)
The frontal crest of the frontal bone ends below in a small notch which is converted into a foramen, the foramen cecum , by articulation with the ethmoid....
.
Its sides are smooth, and sometimes bulging from the presence of a small air sinus in the interior.
On either side of the crista galli, the cribriform plate is narrow and deeply grooved; it supports the olfactory bulb
Olfactory bulb
The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors.-Anatomy:In most vertebrates, the olfactory bulb is the most rostral part of the brain. In humans, however, the olfactory bulb is on the inferior side of the brain...
and is perforated by foramina for the passage of the olfactory nerves. The foramina in the middle of the groove are small and transmit the nerve
Nerve
A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...
s to the roof of the nasal cavity; those at the medial and lateral parts of the groove are larger—the former transmit the nerves to the upper part of the nasal septum
Nasal septum
The nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....
, the latter those to the superior nasal concha
Superior nasal concha
The back part of the medial surface of the labyrinth of ethmoid is subdivided by a narrow oblique fissure, the superior meatus of the nose, bounded above by a thin, curved plate, the superior nasal concha....
.
At the front part of the cribriform plate, on either side of the crista galli, is a small fissure which is occupied by a process of dura mater
Dura mater
The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...
.
Lateral to this fissure is a notch or foramen which transmits the nasociliary nerve
Nasociliary nerve
The nasociliary nerve is a branch of the ophthalmic nerve. It is intermediate in size between the two other main branches of the ophthalmic nerve, the frontal nerve and the lacrimal nerve, and is more deeply placed.-Path:...
; from this notch a groove extends backward to the anterior ethmoidal foramen.
Pathology
A fractured cribriform plate can result in cerebrospinal fluidCerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
leaking into the nose and loss of sense of smell
Anosmia
Anosmia is a lack of functioning olfaction, or in other words, an inability to perceive odors. Anosmia may be either temporary or permanent. A related term, hyposmia, refers to a decreased ability to smell, while hyperosmia refers to an increased ability to smell. Some people may be anosmic for one...
.