chapter 2 anatomy and oral structures

anatomy and oral structures

Cranium

Cranium

the portion of the skull that encloses the brain. Eight bones make up this section of the skull.

temporal

two fan-shaped bones, one on each side of the skull, above the ear

parietal

two bones, one on each side, that make up the roof and side walls covering the brain

frontal

a single bone in the anterior region that makes up the forehead

occipital

one large, thick bone in the lower back of the head that forms the base of the skull and contains a large opening for the spinal cord passage to the brain

ethmoid

a spongy bone located between the eye orbits that helps form the roof and part of the anterior nasal fossa of the skull

sphenoid

a large bat-shaped bone at the base of the skull between the occipital and ethmoid in front, and the parietal and temporal bones at each side.

zygomatic

two facial bones, one under each eye, that form the cheekbone and give character to the face, also called malar bone

maxilla

two large facial bones, one under each eye, that unite in the center in the median suture to form the upper jaw that supports the maxillary teeth in the alveolar process, also present in this bone is the maxillary sinus and the infraorbital frenum under each eye that permits the passage of nerves

palatine

two bones, one left and one right, that unite at the median palaine suture to form the heard palate of the mouth and the nasal floor, present in this bone are multiple foramina, the largest the incisive formen is directly behind the central incisors

nasal

two bones, one left and one right, that join side by side to form the arch or bridge of the nose

lacrimal

two small bones, one each on the inner side or nose site of the orbital cavity, that make up the corner of the eye where the tear ducts are located

inferior concha

two thin scroll-like bones that form the lower part of the interior of the nasal cavity

mandible

the strong, horseshoe-shaped bone that forms the lower jaw

vomer

a single bone that forms the lower posterior part of the nasal septum and separates the nose into two chambers

auditory ossicles

small bones in the ear, are not considered bones of the face or cranium

malleus

the largest of the three ossicles in the middle ear; commonly called the ear mallet

incus

one of the three ossicles in the middle ear; commonly called the anvil

stapes

one of the three ossicles in the middle ear; commonly called the stirrup

hyoid

a horseshoe-shaped bone lying at the base of the tongue, it does not articulate with any other bones

sinus

an air pocket or cavity in a bone that lightens the bone, warms the air intake, and helps form sounds

frontal sinus

larger accessory sinus, located in the frontal bone or the forehead above each eye

ethmoid sinus

multiple, smaller sinuses located in the sphenoid bone situated behind the eyes

maxillary sinus

located in the maxilla; the largest and is called the atrium of highmore; this cavity is easily seen and is used as a landmark for identifying radiographs in the mounting of films

suture

a line where two or more bones unite in an immovable joint, several main sutures are located in the cranium

coronal suture

junction of the frontal and the parietal bones; this area is soft at birth and shortly afterward, and it has been called the babys soft spot or fontanel

sagittal suture

the union line betwwen the two parietal bones on the top of the skull

lambdoid suture

located between the parietal bone and the upper border of the occipital bone

temporoparietal suture

located between the temporal and parietal bones; also known as the squamous suture

process

a projection or outgrowth of bone or tissue

symphysis

in the center of the mandible, forms the chin, and is called the mental or chin protuberance

alveolar process

bone growth or border of the maxilla and the mandible; makes up and forms the tooth socket

condyloid process

posterior growth on the ramus of the mandible; articulates with the temporal bone in the temporomandibular joint (TMJ)

coronoid process

anterior growth on the ramus of the mandible that serves as the attachment position for the temporalis muscle

frontal process

the projection of maxilla meeting with the frontal bone to form the eye orbit

infraorbital process

growth process from the zygomatic bone that articulates with the maxilla to form the lower side of the eye orbit

mastoid process

growth on the temporal bone behind the ear that is used for muscle attachment

pterygoid process

growth of the sphenoid bone extending downward from the bone; the most inferior end of the process is known as the pterygoid hamulus, a hook-like end that serves as a site for muscle attachment

styloid process

small, pointed growth from the lower border of the temporal bone, serves as a bone position for attachment of some tongue muscles.

foramen

an opening or hole in the bone for nerve and vessel passage

magnum foramen

opening in the occipital bone for spinal cord passage; largest of all foramina

mandibular foramen

located on the lingual side of the ramus of the mandible; permits nerve and vessels passage to teeth and mouth tissues

mental foramen

opening situated on left and the right anterior areas of the mandible; used for passage of nerve and vessels

lingual foramen

small opening in the center of the mental spine for nerve passage to the incisor area

incisive foramen

opening in the maxilla behind the central incisors on the eye orbit

supraorbital foramen

an opening in the frontal bone above the eye orbit

infraorbital foramen

an opening in the maxilla under the eye orbit

palatine foramen

anterior and posterior openings in the hard palate

zygomaticofacial foramen

an opening in the zygomatic bone

periosteum

forms a lining on all surfaces, except the areas of articulation

lining mucosa

mucous membrane that lines the inner surfaces of the lips and the cheeks

masticatory mucosa

elastic type of mucous membrane that undergoes stress and pull; located around the alveolar area of the teeth and lines the hard palate

specialized muscosa

smoother muscous tissue found on the dorsal side of the tongue

ramus

ascending part of the mandible that arises from the curved, lower arch

angle of the mandible

area along the lower edge of the mandible where the upward curve of the mandible forms

sigmoid notch

S-shaped curvature between the condyle and coronoid processes; upper border of the mandible; also called the mandibular notch

mylohyoid ridge

bony ridge on the lingual surface of the mandible

oblique line

slanted, bony growth ridge on the facial side of the mandible

retromolar area

space located to the rear of the mandibular molars

glenoid

aka mandibular fossa; the condyle of the mandible rests in this depression of the temporal bone

articular eminence

forms the anterior boundary of the fossa and helps maintain the mandible in position

meniscus

an articular disc

synovial fluid

cushions and lubricates the joints that works in a hinge-action movement

mastication

chewing

temporal mastication

elevates and lowers the jaw and can draw the mandible backward

masseter mastication

the muscle that closes the mouth; the principle mastication muscle

internal pterygoid mastication

muscle that opens the jaw and thrusts the mandible forward; assists with lateral movement

orbicularis oris muscle

aka the kissing muscle; a circular muscle surrounding the mouth that compacts, compresses and protrudes the lips

buccinator muscle

principal cheek muscle; compresses the cheek, expels air through the lips and aids in food mastication

mentalis muscle

muscle of the chin (mental) that moves the chin tissue and raises or lowers the lower lip

olfactory nerve

sensory, smell

optic nerve

sensory, vision

oculomotor nerve

motor, upper-eyelid and eyeball movement

trochlear nerve

motor, eye movement and sensation

trigeminal nerve

motor/sensory, dental and face nerve

abducens nerve

motor, lateral eye sense and movement

facial nerve

motor, taste sense and facial expression

vestibulocochlear nerve

motor, equilibrium, hearing, sensation

glossopharyngeal nerve

motor, taste sensation, swallowing, regulation of oxygen and carbon dioxide breaths

vagus nerve

motor, taste sensation of epiglottis, pharynx, blood pressure, smooth muscle of gastrointestinal system, heart rate, digestion

accessory nerve

motor, body sensation, muscles of shoulders

hypoglossal nerve

motor, body sensation, tongue movement in speech and swallowing

trigeminal nerve

the most important nerve connected with dentistry, fifth cranial nerve

gasserian/ semilunar ganglion

mass of nerves

ophthalmic division of trigeminal nerve

smallest of the three divisions; a purely sensory nerve that has three branches

lacrimal nerve (ophthalmic division)

carries sensations from the lacrimal gland and eye conjunctiva

frontal nerve (ophthalmic division)

carries sensation from the forehead, scalp, upper eyelid, and nasal root

nasociliary nerve (ophthalmic division)

carries sensations from the nose, eye, and eyebrow

maxillary division of the trigeminal nerve

a sensory division of the trigeminal nerve that has several branches

anterior palatine (maxillary)

carries sensations from the hard palate, periosteum, and mucous membrane of the molars and premolar teeth; sometimes considered the greater palatine nerve

middle palatine (maxillary)

carries sensation from the soft palate, the uvula, and upper or soft part of the palate, along with the posterior palatine nerve; may be grouped as lesser palatine nerves

posterior palatine (maxillary)

carries sensation from the tonsils and the soft palate

nasopalatine (maxillary)

carries senasation from the nose and the anterior area of the palate

infraorbital (maxillary)

subdivides into three parts

anterior superior alveolar branch (infraorbital)

carries sensation from the maxillary centrals, laterals, and canines

middle superior alveolar branch (infraorbital)

carries sensation from the maxillary premolars and the mesiobuccal root of the maxillary first molar

posterior superior alveolar branch (infraorbital)

carries sensations from the maxillary second and third molar, and the remaining roots of the maxillary first molar

zygomatic nerve (maxillary)

carries sensation from the lacrimal and upper cheek

sphenopalatine (maxillary)

sensory nerve ending from the maxillary anterior mucosal and palatine tissues

mandibular division of the trigeminal nerve

mixed nerve division that registers sensation and causes movement. Consists of several branches