Skull & Facial Bones Flashcards
Name the cranial & facial bones, including which are paired and which are singular.
8 cranial bones: (4 singular) - frontal - sphenoid - ethmoid (can be considered both a cranial and facial bone) - occipital
(2 paired)
- parietal
- temporal
14 facial bones:
(2 singular)
- vomer
- mandible
(6 paired)
- maxillae
- zygomatic
- lacrimal
- nasal
- inferior nasal conchae
- ethmoid
Name the 4 major sutures of the skull:
Coronal:
between frontal and parietal bones
Sagittal:
between parietal bones
Lamboidal:
between occiput and parietal bones
Temporal / squamous:
Between temporal, occipital and parietal bones
How many cranial bones are pneumatized and which ones are they?
5 are pneumatized (contain sinuses): Frontal Temporal (x 2) Sphenoid Ethmoid
Define the Pterion and Asterion
Pterion:
(temple)
between sphenoid, temporal, frontal & parietal bones
Asterion
(star shaped)
between parietal, temporal and occipital bones
Define Lambda and Bregma
Lambda:
junction of sagittal and lamboidal sutures (between parietal & occipital bones)
Bregma:
junction of coronal and sagittal sutures (between frontal & parietal bones)
Name the 6 features of the frontal bone & describe:
Supraorbital margin: ridge around top of orbital sockets
Supraorbital foramen / notch: on supraorbital ridge, for passage of supraorbital nerve & vessels
Supraciliary arches: deep to eyebrows and superior to supraorbital margin. Extends laterally from glabella.
Glabella: meeting point between supraciliary arches superior to root of nose. Most anterior projection of forehead.
Zygomatic process: where frontal bone joints with zygomatic at lateral edge of supraorbital margin
Frontal sinuses
Name the 3 features of the zygomatic bone and describe:
Frontal process: meeting point with frontal bone, at lateral edge of supraorbital margin
Temporal process: meeting point with temporal bone laterally
Zygomatic arch: contributes to zygomatic arch with temporal bone (= cheekbone)
Name the 6 features of the maxillae bones and describe:
Maxillae bones form upper jaw & most of piriform aperture
Zygomatic process: where zygomatic & maxillae bones meet
Frontal process: where maxillae & frontal bones meet (at superior piriform aperture)
Infra-orbital foramen - inferior to each orbit, for passage of infra-orbital nerves and vessels
Intermaxillary suture - unites the 2 maxillae bones in midline of the face. runs between teeth inferiorly and piriform aperture superiorly.
Alveolar Processes - tooth sockets (alveoli)
Maxillary sinuses
Name the 8 features of the mandible & describe
Body: horizontal aspect
Rami: vertical aspects (right and left)
Mental protruberance -prominence of chin
Mandibular condyle - posterior projection on rami, forms TMJ with articular fossa of temporal bone
Coronoid process - anterior projection on rami
Mental foramina - inferior to 2nd premolar teeth, for passage of mental nerves & vessels
Mandibular symphisis - osseous union where 2 halves of the infantile mandible fuse
Alveolar processes - support mandibular (bottom) teeth
Which 6 bones make up the bony orbit?
Frontal (superior) Zygomatic (lateral) Maxilla (infero-medial) Lacrimal (medial) Ethmoid (medial) Sphenoid (posterior)
Name the 4 boundaries of the bony orbit
Superior - frontal
Inferior - maxillae
Lateral - zygomatic (superficial) & sphenoid (deep)
Medial - Lacrimal (superficial) & ethmoid (deep)
What is the pifirorm aperture?
An anterior opening in the facial bones (nasal cavity).
Vomer & nasal septum divide aperture into 2 bilateral chambers.
Formed by: Nasal bones (superior) Maxillae bones (lateral and inferior) Ethmoid bone (interior - middle nasal conchae) Inferior nasal conchae (interior & inferior) Vomer bone (interior & inferior)
What are the 6 features of the temporal bone?
Temporal fossa (crosses to parietal, frontal & sphenoid bones) - bounded by superior & inferior temporal lines superiorly, & temporal arch inferiorly)
Zygomatic process -m eeting point with zygomatic bone laterally
Mastoid process - large round process behind ear on postero-lateral aspect of bone
Styloid process -slender process posterior to mastoid process on postero-lateral aspect of bone
Styloid mastoiod foramen - between mastoid & styloid processes
External acoustic meatus opening
What are the 6 features of the occipital bone?
EOP / Inion
3 x lines running laterally from EOP:
Highest nuchal line
Superior nuchal line
Inferior nuchal line
External occipital crest - descends from EOP toward foramen magnum
Foramen magnum - large circular opening in basal part of occipital bone, for passage of spinal cord & meninges, vertebral arteries, posterior & anterior spinal arteries, and CN XI spinal accessory nerve
What are the 4 main areas of the sphenoid?
Body
Greater wings
Lesser wings
Pterygoid processes
Describe the 5 features of the body of the sphenoid
Sella Turcica (Turkish Saddle) - a saddle like bony formation on superior surface, surrounded by anterior & posterior clinoid processes. Receives pituitary gland
Tuberculum sellae - horn of saddle anteriorly
Dorsum sellae - back of saddle posteriorly (bounded by posterior clinoid processes
Hypophysial fossa (seat of saddle) - fossa covering sella turcica, receives pituitary gland
Clinoid processes: 2 x anterior, 2 x posterior, bordering sella turcica
Describe the location of greater sphenoid, and the 2 passages in the bone including the structures they convey
Makes up the floor of the middle cranial fossa, extends to lateral wall of skull, and forms posterolateral wall of bony orbit.
Foramen ovale - large passage for CN V (V3 mandibular)
Foramen rotundum - small passage for CN V (V2 maxillae)
Describe the location of the lesser wing of sphenoid, and its main feature
Divides anterior & middle cranial fossa
Superior Orbital Fissure - for passage CN III (oculomotor), CN IV (trochlear), CN V (V1 opthalmic), CN VI (abducens)
Which nerves pass through the sphenoid bone, and through which passages?
CN III oculomotor - SOF
CN IV trochlear -SOF
CN V1 (trigeminal - opthalmic) - SOF
CN V2 (trigemenal - maxillae) - foramen rotundum
CN V3 (trigeminal - mandibular) - foramen ovale
VN VI abducens -SOF
Describe the location & contents of the jugular foramen and carotid canal
Jugular foramen - large opening between occipital & temporal bones. Passage for IJV & several cranial nerves
Carotid canal - anterior to jugular foramen, passage for internal carotid artery
Describe the ethmoid bone including its 5 features:
- located anterior to sphenoid bone. Considered both a cranial and facial bone. Makes up the interior medial border of the bony orbit, and the interior lateral aspect of the nasal cavity
Crista gallae - anterior and superior projection
2 orbital plates (vertical)
Cribiform plate - flat and horizontal, passage of olfactory nerves
Ethmoidal air cells
Superior & middle nasal conchae
