Radi 106 Book Flashcards Chapter 11 (facial bones, sinuses) and Chapter 18

the organs of hearing and equilibrium are the main structures found within the

petrous portion of the temporal bones

the three divisions of the ear are

• external

• middle

• internal portions

The external ear begins with the

auricle or pinna on each side of the head

EAM is the

opening or canal of the external ear

the mastoid process and mastoid tip of the temporal bone are

posterior and inferior to the EAM

the meatus narrows as it meets the

tympanic membrane or eardrum

Middle ear

irregularly shaped, air-containing cavity located between the external and internal ear portions

What are the three main parts of the middle ear

• tympanic membrane

• three small auditory ossicles

• tympanic cavity

The tympanic cavity is divided further into two parts; what are they

• tympanic cavity proper

• attic or epitympanic recess

The drum crest or spur is a

sharp, bony projection that separates the EAM from the epitympanic recess

the tympanic cavity communicates

anteriorly with the nasopharynx by way of the eustachian tube or auditory tube

Eustachian tube

passageway between the middle ear and the nasopharynx. Approximately 1 ½ inches long and serves to equalize the pressure within the middle ear to the outside atmospheric air

ears popping is caused by

pressure being adjusted internally in the middle ear to prevent damage to the eardrum

Mastoid

second direct communication into the middle ear occurs posteriorly to the mastoid air cells.

Aditus

opening between the epitympanic recess and the mastoid portion of the temporal bone

connects directly to a large chamber within the mastoid portion called the antrum

antrum

connects to the various mastoid air cells

encephalitis

serious infection of the brain

what prevents encephalitis from occuring

thin plate of bone that forms the roof of the antrum, auditus, and attic area of the tympanic cavity called the tegmen tympani

Auditory Ossicles

three small bones that are prominent structures within the middle ear

Malleus

“means hammer” attached to the inside surface of the tympanic membrane. Head of it articulates with the central ossicle, the incus

Stapes

smallest of the three auditory ossicles the incus connects to it. The footplate of it is attached to another membrane called the oval window, which leads into the inner ear

The internal ear contains essential sensory apparatus of both

hearing and equilibrium

the inner ear is divided into two main parts

• Osseous or Bony Labyrinth

• Membranous Labyrinth

Osseous Labyrinth

bony chamber that houses the membranous labyrinth, a series of intercommunicating ducts and sacs

The Osseous or Bony labyrinth divide into three shaped parts

• Cochlea

• Vestibule

• Semicircular Canals

Round Window or Cochlear window is shown

at the base of the cochlea

What contains the oval window or vestibular window

vestibule

what are the three semicircular canals

• superior

• posterior

• lateral semicircular canals

the semicircular canals relate to the sense of

direction or equilibrium

the cochlea relates to the sense of

hearing

How many facial bones are there

14

Maxillary bones

largest immovable bones of the face

Each maxilla assists in the formation of three cavities of the face

• mouth

• nasal cavity

• one orbit

What are the two palatine processes also called

hard or bony palate

Cleft palate

opening between the palatine processes that is caused by incomplete joining of the two bones

Zygoma

located lateral to the zygomatic process of each maxilla. Form the prominence of the cheeks and make up the lower outer portion of the orbits

Projecting posteriorly from the zygoma is a slender process that connects with the zygomatic process of the temporal bone to form the

zygomatic arches

Each Zygoma articulates with

Three cranial bones (frontal, sphenoid, temporal) and one facial bone (maxilla)

Lacrimal Bones

small, thin bones located in the medial wall of each orbit, contributing to the structure of the tear duct system.

Nasal Bones

two fused of these bones form the bridge of the nose and are variable in size. Lie anterior and superiomedial to the fontal process of the maxillae and inferior to the frontal bone.

Lacrimal Bone articulates with

two cranial bones (frontal and ethmoid) and two facial bones (maxilla and inferior nasal concha)

Each Nasal bone articulates with

two cranial bones (frontal and ethmoid) and two facial bones (maxilla and adjacent nasal bone)

Inferior nasal conchae

two platelike, curved bones that project from the lateral walls of the nasal cavity on each side and extend medially

What are the 3 pairs of nasal conchae

• super (part of the ethmoid bone)

• medial (part of the ethmoid bone)

• inferior (consists of separate facial bones)

What does the inferior nasal conchae articulate with

one cranial bone (ethmoid) three facial bones (maxilla, lacrimal, palatine)

What does the palatine bone articulate with

two cranial bones (sphenoid and ethmoid) and four facial bones (maxilla, inferior nasal conchae, vomer, and adjacent palatine)

What two bones form the bony nasal septum

ethmoid and vomer

Vomer

thin, triangular bone that forms the nasal septum. Surface of this are marked by small, furrow-like depressions for blood vessels, a source of nosebleed with trauma to the nasal area.

Deviated nasal septum

clinical condition wherein the nasal septum is deflected or displaced laterally from the midline of the nose

Mandible

largest facial bone and is the only moveable bone in the adult skull

Angle (Gonion)

of the mandible divides each half of the mandible into two main parts; the area anterior to the angle is termed the body and the area superior to each angle is termed the ramus

Alveolar process

ridge that extends along the entire superior portion of the body of the mandible

Mental foramen

passageways for the mental artery and vein and mental nerve

What form the TMJ

tempomandiublar fossa of temporal bone and condyle process

Paranasal Sinuses

large, air-filled cavities of these are sometimes called the accessory nasal sinuses because they are line with mucous membranes

When do paranasal sinuses being to develop

in the fetus, but only the maxillary exhibits a definite cavity at birth

at what age do the other sinuses being to be visible on radiographs

6 or 7

What sinus develops last

Ethmoid

When are all paranasal sinuses fully developed

late teenage years

Maxillary sinuses are the site of

communication is the opening into the middle nasal meatus passageway

Frontal Sinuses are larger in men or women

men

Ethmoid Sinuses

contained within the lateral masses or labyrinths; these air cells are grouped into anterior, middle, and posterior collections but they are intercommunicate

Sphenoid sinus

because it is so close to the base or floor of the cranium, sometimes pathologic processes make their Prescence known by their effect on these sinuses

Drainage pathways of the frontal, maxillary, and ethmoid sinuses make up this, which can become obstructed leading to infection of these sinuses

Osteomeatal complex

ethmoid bullla

receives drainage from the frontal and ethmoid sinus cells, which drains down through the middle nasal meatus into the inferior nasal meatus, where it exits the body through the exterior nasal orifice

how many bones is the orbit composed of

7

Each orbit contains three holes or openings in the posterior portion, these openings provide for

passage of specific cranial nerves

Optic Foramen

small hole in the sphenoid bone that is posterior from the apex

superior orbital fissure

between the greater and lesser wings of the sphenoid bone, located lateral to the optic foramen

Inferior Orbital Fissure

located between the maxilla, zygomatic bone, and greater wing of the sphenoid

Sphenoid Strut

small root of bone that separates the superior orbital fissure from the optic canal

Tripod fracture

blow to the cheek, resulting in fracture of the zygoma in three places- orbital process, maxillary process, and arch

Le Fort Fracture

severe bilateral horizontal fractures of the maxillae

Contrcoup fracture

fracture to one side of a structure that is caused by an impact on the opposite side

Neurons

specialized cells of the nervous system that conduct electrical impulses, each one is composed of a

• axon

• cell body

• dendrite

Dendrites

process that conducts impulses toward the neuron cell body

Axon

process that leads away from the cell body

Dendrites and cell bodies make up

gray matter of the brain and spinal cord

axons make up

white matter

The CNS has two main divisions; what are they

• Briann (occupies the cavity of the cranium

• Spinal Cord (terminates at the lower border of L1, with a tapered area called the conus medullaris. Nerve root extensions of the spinal cord continue down to the first coccyx segment)

Brain and spinal cord are enclosed by three protective coverings or membranes called meninges; what are they

• Dura mater

• Arachnoid

• Pia Mater

Dura Mater

strong, fibrous brain covering has an inner and outer layer. The outer layer adheres closely to the inner table of the cranium or skull

Arachnoid

delicate avascular membrane. Delicate, threadlike trabeculae which attaches it to the pia mater

Pia Mater

very thin and highly vascular and lies next to the brain and spinal cord

Immediately exterior to each meningeal layer is a space or potential space; these are called

• epidural space

• subdural space

• subarachnoid space

Epidural space

between the dura and the inner table of the skull

Subdural space

between the dura and the arachnoid, thin film of fluid and various blood vessels

Subarachnoid Space

between the arachnoid and pia mater, comparatively wide space. Brain and spinal cord normally are filled with CFS

The brain can be divided into three general areas

• forebrain

• midbrain

• hindbrain

the brainstem is comprised of the

midbrain, pons, and medulla (oblongata) which passes through the large openings at the base of the skull, the foramen mangnum, to become the spinal cord. The medulla is the final portion of the brainstem, located at the level of the foramen magnum, the opening at the base of the skull

Each side of the cerebrum is termed a cerebral hemisphere and is divided into five lobes; what are they

• frontal lobe

• parietal lobe

• occipital lobe

• temporal lobe

• insula or central lobe

Corpus Callosum

located deep within the longitudinal fissure, consists of an arched mass of transverse fibers (white matter) connecting the two cerebral hemispheres

The ventricular system of the brain is connected to the subarachnoid space. There are four cavities that are filled with CSF and interconnect through small tubes. What are the four cavities

• Right ventricle

• left ventricle

• third ventricle

• fourth ventricle

CSF is formed in the

lateral ventricles in specialized capillary beds called choroid plexus, which filter the blood to form CSF. 500 mL of CSF is formed daily, only about 140 mL of CSF is present within and around the entire CNS

CSF serves as a

protective role for the CNS

Thalamus

small oval structure that is located just above the midbrain and under the corpus callosum. Consists of two oval masses of primarily gray matter that form part of the walls of the third ventricle

The groups of gray matter of the thalamus serves as a

relay stations for most of the sensory impulses as they pass from the spinal cord and midbrain structures into the cerebral cortex

the thalamus serves as

interpretation center for certain sensory impulses, such as pain, temperature, and touch, and for certain emotions and memory

The thalamus and the hypothalamus make up the

diencephalon portion of the forebrain

Midbrain

short constricted portion of the upper brainstem that connects the forebrain to the hindbrain