Skull (Part III)

zygomatic arch and infratemporal crest divide

temporal fossa from infratemporal fossa

zygomatic arch is made of

temporal process of zygomatic bone and zygomatic process of temporal bone

infratemporal crest divides

greater wing of sphenoid bone from lateral pterygoid process of sphenoid bone

bones that form pterion

• frontal bone

• parietal bone

• greater wing of sphenoid bone

• squamous part of temporal bone

parts of bones that form pterion form the

medial boundary of temporal fossa

superior temporal line marks

superior boundary of temporal fossa

superior temporal line is attachment site for

temporal fascia

inferior temporal line is attachment site for

temporalis m.

infratemporal fossa is bounded laterally by

ramus of mandible

infratemporal fossa is bounded anteriorly by

infratemporal surface of maxilla

posterior superior alveolar foramina

small hole(s) on infratemporal surface of maxilla that transmits posterior superior alveolar nerves and arteries

infratemporal fossa is bounded medially by

lateral pterygoid plate of sphenoid bone

infratemporal surface of maxilla is limited superiorly by

inferior orbital fissure

infratemporal surface of maxilla is limited medially by

pterygomaxillary fissure

pterygomaxillary fissure is continuous with

inferior orbital fissure

pterygomaxillary fissure is passageway between

pterygopalatine and infratemporal fossa

pterygomaxillary fissure forms lateral wall of

pterygopalatine fossa

pterygopalatine fossa serves as

major neurovascular crossroad between oral cavity, nasal cavity, nasopharynx, orbit, masticator space, and middle cranial fossa

infratemporal fossa is bounded posteriorly by

styloid process of temporal bone

infratemporal fossa is bounded superiorly by

greater wing of sphenoid bone and associated features

mandibular division of trigeminal nerve (V3) enters cranial cavity via

foramen ovale

middle meningeal artery enters cranial cavity through

foramen spinosum

petrotympanic fissure

narrow crevice between petrous and tympanic parts of temporal bone that provides passageway for chorda tympani nerve

articular tubercle

lateral bony prominence on root of zygomatic process of temporal bone

articular eminence

anterior slope of mandibular fossa

sphenoid spine

small downward projection from greater wing of sphenoid bone that is attachment site for sphenomandibular ligament

bony nasal septum is formed by

vomer and perpendicular plate of ethmoid bone

conchae

lateral walls of nasal cavities that project into nasal cavity

superior and middle nasal concha are features of

ethmoid bone

lateral to middle nasal concha are

uncinate process and bulla of ethmoid bone

ethmoidal bulla

elevation produced by middle ethmoidal air cells

uncinate process

curved, hook-like process

perpendicular plate of palatine bone

contributes to lateral nasal wall

sphenoethmoidal recess

space located superior to superior nasal concha and anterior to sphenoid bone

sphenopalatine foramen

hole between perpendicular plate of palatine bone and medial pterygoid plate on lateral nasal wall

sphenopalatine foramen is passageway between

pterygopalatine fossa and nasal cavity

ethmoid sinuses

extensive permeations of air spaces in ethmoid bone

vaginal process of temporal bone

inferior projection from temporal bone that is immediately anterior to styloid process

vaginal process of temporal bone is attachment site for

muscles associated with tongue and larynx

sphenoid bone has two bilateral pterygoid processes that project downward

medial and lateral pterygoid processes

inferior head of lateral pterygoid muscle attaches to

lateral surface of lateral pterygoid process

deep head of medial pterygoid muscle attaches to

medial surface of lateral pterygoid process

hamulus of medial pterygoid plate

hook-like process that acts as pulley for tensor veli palatine tendon to glide around

pterygoid fossa (purple star on diagram)

V-shaped divergence of medial and lateral pterygoid plates

pterygoid notch (red arrow on diagram)

inferior bony deficiency between medial and lateral pterygoid plates

scaphoid fossa

shallow, boat-shaped depression posterior to root of medial pterygoid plate

scaphoid fossa is muscle attachment site for

tensor veli palatini m.

pterygoid canal

horizontal channel that transmits nerve of pterygoid canal

palatovaginal canal (yellow arrow on diagram)

horizontal channel between vaginal process of sphenoid bone and perpendicular plate of palatine bone

palatovaginal canal transmits

pharyngeal nerve and pharyngeal branch of sphenopalatine artery

ala of vomer

superior, thick, horizontal projections that articulate with sphenoid bone

incisive canal

opening in anterior part of intermaxillary suture, posterior to maxillary central incisors

incisive foramen is located at

junction between primary and secondary palates

posterior nasal spine

median projection from posterior border of hard palate

greater palatine foramen

hole in palatomaxillary suture that transmits nerves and vessels onto hard palate

pyramidal process of palatine bone

posterior and lateral projection from junction of horizontal and perpendicular plates of palatine bone

pyramidal process of palatine bone serves as

attachment site for deep head of medial pterygoid m.

lesser palatine foramen

small holes in pyramidal process of palatine bone that transmit nerves and vessels onto soft palate

choana

paired openings that provide communication between nasopharynx and nasal cavities

choana is bound medially by

vomer

choana is bound superiorly by

ala of vomer and vaginal process of sphenoid bone

choana is bound laterally by

medial pterygoid plate

choana is bound inferiorly by

horizontal plate of palatine bone

maxillary tuberosity

rounded eminence on inferior part of infratemporal surface of maxilla; located posterior to last molar

maxillary tuberosity serves as attachment site for

superficial head of medial pterygoid m.

interalveolar septum

thin plate of bone separating two adjacent alveoli

alveolar jugum

vertical grooves or pits on outer surface of alveolar process formed by roots of two adjacent teeth

interradicular septum

thin plate of bone separating roots within a single alveoli

gomphosis

fibrous joint in skull that joins tooth and alveolar sockets

piriform aperture (dashed outline on diagram)

anterior bony opening of nasal cavity formed by nasal bones, nasal notches of maxilla, and anterior nasal spine

nasal notch (shorter arrow on diagram)

lateral and inferior portion of maxillary contour

anterior nasal spine (longer arrow on diagram)

sharp anterior projection of maxilla at midline inferior border of piriform aperture

maxillary sinus

air-filled cavity in central part (body) of maxilla

petrous part of temporal bone is embryologically derived from

otic capsule

groove for lesser petrosal nerve leads to

foramen ovale

groove for greater petrosal nerve leads to

internal opening of carotid canal

portion

central point of superior border of external acoustic meatus

mandible

only movable bone in skull that consists of tooth-bearing body and vertical ramus

mandibular ramus divides superiorly into

coronoid and condylar processes, separated by mandibular notch

coronoid notch

gentle concave curve on anterior surface of mandibular ramus

coronoid notch is palpable featured used in

administering inferior alveolar nerve block

temporal crest

vertical ridge from coronoid process to behind 3rd molar

temporal crest is attachment site of

temporalis muscle

pterygoid fovea

roughened depression on anterior surface of mandibular neck

pterygoid fovea is insertion site of

inferior head of lateral pterygoid m.

masseteric tuberosity

roughened area at lateral aspect of mandibular angle

masseteric tuberosity is attachment site for

some lower fibers of masseter m.

pterygoid tuberosity

roughened area on medial aspect of mandibular angle

pterygoid tuberosity is insertion site for

medial pterygoid muscle

retromolar triangle

small, depressed area posterior to last mandibular molar; bound by bony ridges of alveolar bone

mylohyoid line serves as

attachment site for mylohyoid muscle and delineates sublingual from submandibular fossa

mandibular foramen

on inner surface of mandibular ramus

inferior alveolar nerve enters mandible via

mandibular foramen to innervate mandibular teeth

lingula

small, tongue-like projection of bone near anterior margin of mandibular foramen

lingula is ligamentous attachment site for

sphenomandibular ligament

mandibular sulcus

shallow groove sloping from condylar process toward mandibular foramen

mylohyoid groove

shallow furrow extending from margin of mandibular foramen; where mylohyoid nerve lies

retromylohyoid area

smooth surface on mandibular ramus between mylohyoid groove and back of mylohyoid line

digastric fossae serve as attachment sites for

anterior bellies of digastric muscle

mental spines

bony projections near posterior aspect of mandibular symphysis; site of muscle attachment, usually more than one