axial skeleton (skull)

maxillarynerve (v2)

This is the second branch of cranial nerve V. It passes through three foramina on its way to the face. It is a sensory nerve to the skin of the face, oral cavity, and teeth.

zygomatic process

As is often the case, this landmark of the temporal bone is named for the bone it articulates with rather than the bone it is part of. It forms the posterior portion of the zygomatic arch and projects anteriorly to where it articulates with the temporal process of the zygomatic bone. This projection is from the squamous portion of the temporal bone. The masseter muscle, which is the prime flexor (closer) of the mandible, attaches to the inferior margin of this landmark.

squamosal suture

Most of this landmark is found between the temporal bone and the parietal bone on each side of the skull. It is an example of a synostosis. This structure starts as a fontanel in the fetus. Technically these are fibrous joints or ligamentous unions. The flexibility that comes about because of these structures is important during birth so that passage through the birth canal will be easier and so that growth can occur after the child is delivered. The fontanels close for the most part by the time the child is a year old. However, complete ossification of the ligaments separating the bones doesn't begin until the individual is in their late twenties and is not complete until the person is in their fifties!

tear ducts

The lacrimal canal holds this structure. It serves to conduct the fluid from the eye into the nasal cavity. It is sometimes called the nasolacrimal duct.

sella turcica

The name of this landmark means Turkish saddle. It is called that because it looks like a saddle (duh). It is part of the sphenoid bone and is of importance because this is where the pituitary gland (hypophysis) is found. It is part of the middle fossa of the cranium. A sheet of dura mater attaches to the posterior margin of this landmark. This sheet is called the tentorium cerebelli that separates the cerebellum from the posterior part of the cerebral hemispheres.

crista galli

The name of this landmark of the ethmoid bone translates to chicken's comb, the fleshy ridge on the top of a chicken's head. It rises superiorly to the cribriform plate on its left and right sides. It extends superiorly between the frontal lobes of the brain. Functionally it is important because an extension or fold of the dura mater, the falx cerebri, is anchored to it and this helps stabilize the position of the brain. Dr. J thinks it is like the sail of the sailboat and the cribriform plate is like the deck of the sailboat.

facial region

The skull is sometimes divided into to areas for study purposes. One of the regions is the cranium and the other is the answer to this clue.

cranium

The skull is sometimes divided into to areas for study purposes. One of the regions is the facial region and the other is the answer to this clue.

auditory ossicles

The three bones of the middle ear are collectively referred to as the answer to this clue. They include the malleus, incus, and stapes. In nursery school we called them the hammer, anvil, and stirrup respectively. Functionally they are important because they amplify the pressure of vibrations of the ear drum associated with sound by about 20 times. There are synovial joints between them and they are suspended in the middle ear by ligaments.

spheniod sinus

There are a pair of this feature immediately inferior and anterior to the sella turcica and they are associated with the sphenoid bone. They are air-filled cavities that are lined with mucous membranes. There are three other pairs of these in the skull. They are not well developed at birth, but enlarge as the child grows and reach full size in adolescence. There are small openings from these features into the nasal cavities. The mucus is propelled into the nasal cavities by cilia. Functionally they are important in the quality of the voice and they also reduce skull weight.

frontal sinuses

There are a pair of this feature immediately superior and medial to the orbits and they are associated with the frontal bone. They are air-filled cavities that are lined with mucous membranes. There are three other pairs of these in the skull. They are not well developed at birth, but enlarge as the child grows and reach full size in adolescence. There are small openings from these features into the nasal cavities. The mucus is propelled into the nasal cavities by cilia. Functionally they are important in the quality of the voice and they also reduce skull weight.

maxillary sinuses

There are a pair of this feature inferior to the orbits and supeiror to the oral cavity. They are associated with the maxillary bone. They are air-filled cavities that are lined with mucous membranes. There are three other pairs of these in the skull. They are not well developed at birth, but enlarge as the child grows and reach full size in adolescence. There are small openings from these features into the nasal cavities. The mucus is propelled into the nasal cavities by cilia. Functionally they are important in the quality of the voice and they also reduce skull weight.

ethmoid sinuses

There are a pair of this feature lateral and superior to the nasal cavities and they are associated with the ethmoid bone. They are air-filled cavities that are lined with mucous membranes. There are three other pairs of these in the skull. They are not well developed at birth, but enlarge as the child grows and reach full size in adolescence. There are small openings from these features into the nasal cavities. The mucus is propelled into the nasal cavities by cilia. Functionally they are important in the quality of the voice and they also reduce skull weight.

temporal bone(s)

There are two of these bones and they are bones of the cranium. They are positioned inferior to the parietal bone and articulate with the parietal bone at the squamosal suture. Anteriorly it articulates with the zygoma, posteriorly with the occipital bone, and inferiorly with the mandible. It forms most of the middle fossa of the cranium. There are a number of landmarks of these bones including: the petrous ridge, the mastoid, zygomatic, and styloid processes, and the mandibular fossa. They also contain the stylomastoid foramen, the internal auditory meatus and external auditory meatus, and forms part of the jugular foramen.

lacrimal bone

There are two of these bones and they are bones of the face. They each contain the lacrimal canal which is functionally important as this is the passage for the tear duct. The canal terminates in the nasal cavity. These bones make up part of the medial wall of the orbit. They contact the maxillary bone anteriorly, the ethmoid bone posteriorly, and the frontal bone superiorly.

palatine bones

There are two of these bones and they are facial bones. They form the posterior third of the hard palate where they articulate with the palatine process of the maxillary bones. The portion of those bones that forms the hard palate is called the horizontal plate. Each bone also has a perpendicular (vertical) plate

inferior conchae

There are two of these bones, one on the lateral wall of each nasal cavity. Functionally they are important because their curved surface causes turbulence as air moves into the nasal cavity. The turbulence helps warm, moisten, and filter the air before it enters the lower respiratory tract. In addition, they help recover moisture and heat during expiration. This is especially important in cold and dry conditions. An additional benefit has been proposed based on a recent finding that the air flow is different for the two nasal cavities. It has been shown that the mucosa that covers the conchae becomes swollen on one side, and then after a few hours the swelling reduces on that side and the other side becomes swollen. A possible advantage of this would be that the sense of smell is better on the swollen side because the air moves more slowly and there is more intense stimulation by scents when air flow is slow. Similar structures are part of the ethmoid bone.

zygomatic bone

There are two of these facial bones. In nursery school we called it the cheekbone. They articulate posteromedially with the sphenoid bone, posterolaterally with the temporal bone, superiorly with the frontal bone and anteriorly with the maxillary bones. This bone is a portion of the bony orbit of the eye. The temporal process is the only landmark of this bone that we will study

Occipital condyles

These are landmarks of the occipital bone and they are functionally important because they articulate with the superior articular facets of the atlas (C1). This joint functions as a hinge joint allowing flexion and extension of the head. When one shakes their head "no" the two bones move as one piece. Dr. J thinks these structures are shaped like the rockers of a rocking chair which facilitates the flexion and extension of the skull relative to the atlas. We find the hypoglossal canal in the lateral base of these landmarks, immediately superior to the articular surface. This foramen is important as it transmits the hypoglossal nerve (XII).

alveoli

These features are found in both maxillary bones and the mandible. They are the depression into which the root of the tooth is anchored.

superior conchae

These landmarks are part of the ethmoid bone, one on the lateral wall of each nasal cavity. They are functionally important because their curved surface causes turbulence as air moves into the nasal cavity. The turbulence helps warm, moisten, and filter the air before it enters the lower respiratory tract. In addition, they help recover moisture and heat during expiration. This is especially important in cold and dry conditions. An additional benefit has been proposed based on a recent finding that the air flow is different for the two nasal cavities. It has been shown that the mucosa that covers the conchae becomes swollen on one side, and then after a few hours the swelling reduces on that side and the other side becomes swollen. A possible advantage of this would be that the sense of smell is better on the swollen side because the air moves more slowly and there is more intense stimulation by scents when air flow is slow. We find olfactory receptors in the epithelium covering the medial surfaces of these landmarks. The ethmoid bone has two other pair of similar structures.

sutures

These landmarks occur where two bones are fused together. This type of joint when found in the skull is referred to as this name. The bones fuse during middle age. Functionally they are important because they help protect the brain.

nuchal lines

These landmarks of the occipital bone are where many muscles and ligaments of the neck and back attach to the skull. Generally areas that serve as points of attachment for muscles have raised bone due to the stress on the bone and the stimulation that causes bone growth. One of them is also known as the external occipital crest and this is formed because of the attachment of the ligamentum nuchae that connects the cervical vertebrae to the skull. There is a superior and inferior pair as well and they form attachments with the muscles and ligaments that stabilize the articulation of the occipital condyles with the atlas, thereby balancing the mass of the head over the cervical vertebrae. The superior pair is adjacent to the external occipital protuberance, while the inferior pair are approximately 2.5 centimeters (1 inch) inferior to the superior pair.

maxillae (maxillarybones)

These two bones are considered part of the face. They form the upper jaw, as well as the anterior two thirds of the hard palate. They also form the lateral walls of the nasal cavities, and a portion of the bony orbit of the eye. They have a number of landmarks including: sinuses, alveoli, and the palatine processes. In addition they have the infraorbital foramina and form part of the inferior orbital fissure. All facial bones except the mandible articulate with these bones.

Parietal bone(s)

These two bones are cranial bones. They articulate anteriorly with the frontal bone at the coronal suture, posterior with the occipital bone at the lambdoidal suture, and inferiorly with the temporal bone at the squamosal suture. They also articulate with each other along the sagittal suture on the superior surface of the skull.

middle conchae

These two landmarks are part of the ethmoid bone, one on the lateral wall of each nasal cavity. Their curved surface causes turbulence as air moves into the nasal cavity. The turbulence helps warm, moisten, and filter the air before it enters the lower respiratory tract. In addition, the conchae help recover moisture and heat during expiration. This is especially important in cold and dry conditions. An additional benefit has been proposed based on a recent finding that the air flow is different for the two nasal cavities. It has been shown that the mucosa that covers the conchae becomes swollen on one side, and then after a few hours the swelling reduces on that side and the other side becomes swollen. A possible advantage of this would be that the sense of smell is better on the swollen side because the air moves more slowly and there is more intense stimulation by scents when air flow is slow. The ethmoid bone has two other pair of similar structures that are superior to this pair

nasal bones

These two small bones are considered facial bones. They form the bridge of the nose. They articulate with the maxillary bones laterally, the perpendicular plate of the ethmoid bone posteriorly, and the frontal bone superiorly. Inferiorly cartilages that form most of the external nasal skeleton attach to these bones.

hyoid bone

This bone does not articulate with any other bones. It is held in place by ligaments to the styloid process of the temporal bone and the thyroid cartilage of the larynx. It also has muscle attachments. In spite of the fact that is not attached to the skull, it is considered part of the axial skeleton, specifically part of the skull. It has a shape similar to the mandible, suggesting a common origin. Functionally it is important because it is the origin of muscles that move the larynx during the act of swallowing.

ethmoid bone

This bone is a single bone of the cranium. It is anterior to the sphenoid and posterior to the nasal bones. It forms most of the area between the nasal cavity and the orbit of the eye. It has a number of landmarks associated with it including: crista galli, cribriform and perpendicular plates, a pair of sinuses, superior and middle conchae.

Incus

This bone is one of the three auditory ossicles. In nursery school we called it the anvil. Functionally it is important because in association with the other ossicles it helps amplify the pressure of vibrations associated with sound by about 20 times.

stapes

This bone is one of the three auditory ossicles. In nursery school we called it the stirrup. The base of this bone contacts the oval window, a hole in the medial wall of the middle ear. Functionally it is important because in association with the other ossicles it helps amplify the pressure of vibrations associated with sound by about 20 times.

malleus

This bone is one of the three auditory ossicles. These three bones are located in the middle ear which is within the temporal bone. When we were in nursery school we called this bone the hammer. The "handle" of this bone attaches to the eardrum. Functionally it is important because in association with the other ossicles it helps amplify the pressure of vibrations associated with sound by about 20 times.

frontal bone

This bone is unusual in several respects. Firstly, it is two bones in the fetus while it is considered a single bone in the adult. It forms part of the cranium and also forms part of the face. It is one of the four bones that we study that contains a paranasal sinus. It also has the second foramen that the ophthalmic nerve passes through to reach the facial region.

hypoglossal nerve (XII)

This cranial nerve is found in the anterior triangle of the neck. It runs with an artery that has a different name, but their names translate to the same meaning. It is a motor nerve

optic nerve (II)

This cranial nerve is the sensory nerve for vision. It passes through the optic canal to and from the eye

Inferior orbital fissure

This feature is formed by the sphenoid bone, maxillary, palatine, and zygomatic bones. It provides for passage of the maxillary nerve and is the second foramen that nerve passes through.

superior orbital fissure

This feature is part of the sphenoid bone. It provides for passage of four cranial nerves, the lowest number of which is III.

hard palate

This feature is the bony portion of the roof of the oral cavity. It is formed anteriorly by the palatine processes of the two maxillary bones and posteriorly by the horizontal plates of the two palatine bones. Functionally it is important because it separates the nasal cavities from the oral cavity. This separation is important to keep food out of the air passages and it also is essential to form suction as when drinking with a straw.

anterior fossa

This feature of the skull is made up of the frontal bone, cribriform plate of the ethmoid bone, and the lesser wing of the sphenoid bone. The frontal lobes of the brain are superior to it.

middle fossa

This feature of the skull is made up of the greater wing of the sphenoid bone and the temporal bone. The temporal lobes of the brain are superior to it.

posterior fossa

This feature of the skull is made up of the temporal bone and occipital bone. The cerebellum, pons, and medulla oblongata are superior to it.

hypoglossal canal

This foramen has appreciable depth and is found in the occipital bone on the lateral surface of the foramen magnum. It provides a passage for cranial nerve XII.

jugular foramen

This foramen is between the temporal and occipital bones. The glossopharyngeal (IX), vagus (X), spinal accessory (XI), and internal jugular vein all pass through this foramen.

infraorbital foramen

This foramen is found in the maxillary bone, just inferior to the orbit. It is the third foramen through which the maxillary nerve (V2) passes to the face

Foramen ovale

This foramen is found in the sphenoid bone on the middle fossa of the cranium. It is the first foramen that the mandibular nerve passes through as it leaves the cranium.

optic canal

This foramen is found in the sphenoid bone. Its name suggests that this is an opening with appreciable depth. It houses the optic nerve (II). Note that if you pass a wooden applicator stick through this landmark on each side, the sticks crisscross inside the cranium.

supraorbital foramen (notch)

This foramen is in the frontal bone and it is the second foramen that the ophthalmic nerve passes through as it travels to the face.

foramen magnum

This foramen is part of the occipital bone. Several structures pass through it. They include the medulla oblongata and the meninges that surround it, the ascending portions of the spinal accessory nerves (XI), and the two vertebral arteries. The medulla oblongata connects to the spinal cord.

foramen rotundum

This foramen of the sphenoid bone houses the maxillary nerve (V2) as it passes toward the infraorbital foramen of the maxillary bone. This is the first of the three foramina it passes through.

stylomastoid foramen

This foramen provides for passage of the cranial nerve VII out of the skull and onto the face. It is found in the temporal bone.

coronoid process

This is a landmark of the mandible. It extends superiorly from the anterior portion of the ramus. It is functionally important as the point of attachment of the temporalis muscle. Although we will not study this muscle, it is important in elevation and retraction of the mandible. Technically, its name translates to mean resembling a crown.

pterygoid process

This is a landmark of the sphenoid bone and there is one on both sides. There is a medial and lateral plate for each of them. They project inferiorly from the greater wing. The medial plate articulates with the perpendicular plate of the palatine bones anteriorly. This landmark is the origin for the pterygoid muscles that close the mandible. It is also associated with the soft palate.

vomer

This is a single bone of the face. It Is of functional importance because it forms the inferior portion of the nasal septum. It starts as a large portion of that septum posteriorly and then narrows to a point at is anterior end, often being called plow shaped.

mandible

This is a single bone of the face. It articulates with the mandibular fossa of the temporal bone and irritation of this joint leads to the condition known as TMJ syndrome. It has a number of landmarks associated with it including: rami, alveoli, coronoid and condyloid processes, mandibular fossa, body, and the mandibular (sigmoid) notch. It also houses two important foramina, the mandibular and mental foramina. We find that it is actually two bones in the fetus.

Olfactory nerve (I)

This is the first cranial nerve. It is sensory for the sense of smell and it passes through the many foramina of the cribriform plate of the ethmoid bone.

mental foramen

This is the last (third) foramen that the mandibular nerve (V3) passes through as it courses away from the brain.

alveolar process

This is the name for the portion of the two maxillary bones and the mandible that contain the alveoli for the teeth.

mandibular foramen

This is the second foramen that the mandibular nerve (V3) passes through as it moves toward the mental foramen. It is part of the mandible. Dentists usually try to anesthetize this nerve near this foramen when working on teeth in the mandible.

mandibular nerve (v3)

This is the third branch of cranial nerve V. It passes through three foramina on its way to the face. It is a mixed nerve serving the muscles of mastication as well as sensory to the skin of the face, anterior two thirds of the tongue (general senses, not taste), and teeth.

mandibular (sigmoid) notch

This landmark is a concavity on the mandibular ramus between the condyloid and coronoid processes.

external occipital protuberance

This landmark is a raised area on the midline of the occipital bone where the posterior wall meets the base of the skull. It is medial to the two superior nuchal lines. It is at the superior extent of the ligamentum nuchae that connects the cervical vertebrae to the skull.

Coronal suture

This landmark is found between the frontal bone and the two parietal bones. It is an example of a synostosis. This structure starts as a fontanel in the fetus. Technically these are fibrous joints or ligamentous unions. The flexibility that comes about because of these structures is important during birth so that passage through the birth canal will be easier and so that growth can occur after the child is delivered. The fontanels close for the most part by the time the child is a year old. However, complete ossification of the ligaments separating the bones doesn't begin until the individual is in their late twenties and is not complete until the person is in their fifties!

lambdoidal suture

This landmark is found between the occipital bone and the two parietal bones. It is an example of a synostosis. This structure starts as a fontanel in the fetus. Technically these are fibrous joints or ligamentous unions. The flexibility that comes about because of these structures is important during birth so that passage through the birth canal will be easier and so that growth can occur after the child is delivered. The fontanels close for the most part by the time the child is a year old. However, complete ossification of the ligaments separating the bones doesn't begin until the individual is in their late twenties and is not complete until the person is in their fifties!

sagittal suture

This landmark is found between the two parietal bones. It is an example of a synostosis. This structure starts as a fontanel in the fetus. Technically these are fibrous joints or ligamentous unions. The flexibility that comes about because of these structures is important during birth so that passage through the birth canal will be easier and so that growth can occur after the child is delivered. The fontanels close for the most part by the time the child is a year old. However, complete ossification of the ligaments separating the bones doesn't begin until the individual is in their late twenties and is not complete until the person is in their fifties!

styloid process

This landmark is part of the temporal bone and is anteromedial to the mastoid process. As is the case with many processes, it forms where muscles attach to the bone. It is the origin of the styloglossus, stylohyoid, and stylopharyngeus muscles. It also serves as a point of attachment for the stylohyoid and stylomandibular ligaments.

mastiod process

This landmark is part of the temporal bone. It is the insertion for the sternocleidomastoid muscle. In fact it is this muscle that causes this landmark to develop. Several other muscles that you will not be responsible for also attach to this landmark. As a group these muscles are responsible for rotation or extension of the head.

Palatine process of the maxilla

This landmark of each of the maxillary bones makes up the majority (about 67 to 75%) of the hard palate on each side. Along the midline these two landmarks of the left and right maxillary bones articulate with each other. They articulate posteriorly with the horizontal plate of the palatine bone on each side. The shelf that they form is part of the roof of the oral cavity as well as part of the floor of the nasal cavities.

cribriform plate

This landmark of the ethmoid bone has the foramina through which fibers of the olfactory nerve (I) pass into the nasal cavities on either side. This is somewhat unusual as instead of there being one foramen on each side, there are many foramina, giving this landmark the appearance of a sieve. We find olfactory receptors in the epithelium covering the inferior surfaces of this landmark. It is found on either side of the crista galli, thereby forming part of the anterior fossa of the cranium. Remember that Dr. J likes to draw the analogy between parts of the ethmoid bone and a sailboat. The crista galli is like the sail of the sailboat and this landmark is like the deck of the sailboat.

orbital plate

This landmark of the frontal bone forms a large portion of the anterior fossa of the skull as well as most of the roof of the orbit of the eye.

condyloid process

This landmark of the mandible extends superiorly from the ramus of the mandible. It includes the head of the mandible which is functionally important as this is where the mandible articulates with the mandibular fossa of the temporal bone. This is known as the temporomandibular joint. This joint includes an articular meniscus and functions primarily as a hinge joint, although the mandible can be moved in protraction and retraction. The neck of the mandible is also part of this landmark and it serves as the insertion for the lateral pterygoid muscle.

body

This landmark of the mandible has alveoli that secure the teeth. It is made up of two portions, inferiorly its base and the superior portion, called the alveolar part of the mandible. Remember that although we consider this to be one piece extending to the left and right sides, it was two bones in the fetus. We find the mental foramen in the anterior portion of this landmark, this being where the mandibular nerve (V3) emerges onto the face.

lesser wing

This landmark of the sphenoid bone forms part of the anterior fossa of the cranium as well as part of the orbit. Although some authors describe it as horn shaped, Dr. J thinks it resembles the cranial end of a manta ray. The projections that form a border with the middle fossa are known as the anterior clinoid process. This process serves as point of attachment for a sheet of dura mater that separates the cerebellum from the posterior portion of the cerebral hemispheres.

greater wing

This landmark of the sphenoid bone forms the anterior part of the middle fossa of the cranium. The foramen rotundum and foramen ovale are both found in this landmark. It can also be seen on the surface of the skull anterior to the temporal bone.

petrous ridge

This landmark of the temporal bone is important as it is the border between the middle fossa and posterior fossa of the cranium. Within this portion of the temporal bone are cavities that form the inner and middle ear. The sharp portion of the ridge is a point of attachment for a membrane that stabilizes the brain. It gets its name from the fact that it is irregular like a rocky wall.

mandibular fossa

This landmark of the temporal bone is important because this is one articular surface of the temporomandibular joint. This is the surface that the head of the condyloid process of the mandible articulates with. Although this is technically a hinge joint, it may also be rotated, depressed, elevated, protracted and retracted. These additional motions are helpful when positioning food on the occlusal surfaces of the teeth. There is a meniscus cartilage associated with this joint. This joint may become problematic for some people resulting in TMJ syndrome.

temporal process

This landmark of the zygomatic bone is another example of a structure that is named for the bone it articulates with rather than the bone it is part of. It forms the anterior portion of the zygomatic arch and projects posteriorly to where it articulates with the zygomatic process of the temporal bone. The masseter muscle, which is the prime flexor (closer) of the mandible, attaches to the inferior margin of this landmark.

facial nerve (VII)

This nerve is both motor and sensory. It also has parasympathetic functions controlling the lacrimal gland, as well as the mandibular and sublingual salivary glands. It leaves the cranium by way of the internal auditory meatus and then exits from the skull via the stylomastoid foramen. We observed this nerve on the lateral portion of the face where the two branches bracket the masseter muscle.

lacrimal canal

This opening has appreciable depth and it holds the lacrimal duct. The duct serves to conduct the fluid from the eye into the nasal cavity. The duct is sometimes called the nasolacrimal duct.

sphenoid bone

This single bone is considered a cranial bone. It articulates with every other cranial bone. It also articulates with the zygomatic, vomer, maxillary, and palatine bones. It has many important landmarks including: the greater and lesser wings, the sinuses, the sella turcica, and the pterygoid processes. It also has a number of significant foramina including,: rotundum, ovale, the optic canal, the superior orbital fissure, as well as others.

occipital bone

This single bone is part of the cranium. It is found on the posterior side of the skull. It articulates via the lambdoidal suture with the parietal bones. It also articulates with the sphenoid bone, temporal bones, and the atlas. It has a number of landmarks including: nuchal lines, condyles, and the protuberance. It also contains the foramen magnum, hypoglossal canals, and part of the jugular foramina.

zygomatic arch

This structure is made up of two processes from two bones, the zygomatic process of the temporal bone posteriorly and the temporal process of the zygomatic bone anteriorly. Dr. J likes to draw the analogy to a drawbridge with part coming from each end of the bridge. The masseter muscle originates on the inferior margin of this structure. The tendon of the temporal muscle passes deep to it. It is sometimes fractured in automobile crashes or from a blow to the side of the face.

nasalseptum

This structure is primarily made up of two bones and a cartilage. The superior bone is the perpendicular plate of the ethmoid. The inferior bone is the vomer. The remainder is hyaline cartilage and it projects anteriorly. This structure separates the two nasal cavities. The superior portion of the perpendicular plate of the ethmoid bone is covered with epithelial tissue that includes olfactory receptors.

ramus (rami)

We have seen this name used in a number of places in the body. It means a branchlike structure of some larger structure. This landmark of the mandible is a posterior processes that meets the body at the mandibular angle. It is nearly in a sagittal plan. The coronoid and condyloid processes project superiorly from the superior edge of this landmark. The mandibular (sigmoid) notch is between these two processes. The mandibular foramen is on the medial surface of this landmark and it transmits the mandibular nerve (V3) into the mandibular canal. Part of the masseter muscle inserts on the lateral surface of this landmark while the medial pterygoid muscle attaches to the medial surface posteroinferior to the mandibular foramen.