Osteology (3) Flashcards
what are the two bridging bones of the cranium?
sphenoid & ethmoid
which bone is the largest contribution to the floor of the cranium?
sphenoid
what do bridging bones unite?
neurocranium and viscerocranium
Sphenoid (internal features 4)
- A clinoid process: part of lesser wing - attachment site for diaphragma sellae - P clinoid process: attachment site for diaphragma sellae - sella turcica “Turkish saddle/hypophyseal fossa”: overlies sphenoid sinus and houses the pituitary gland (meningeal covering) - sphenoid sinus: air-filled space within the body
Medial & Lateral Pterygoid Processes
- attachment site for mastication muscles
the superior orbital fissure transmits (5)
- oculomotor n. CIII 2. trochlear n. IV 4. abducens n. VI 5. opthalmic n. CV1 6. superior opthalmic v.
foramina of sphenoid bone: the superior orbital fissure - location and what does it transmit? (5)
located between greater and lesser wing
- transmits nerves and one vein transmits
1. oculomotor n. CIII
2. trochlear n. IV
3. abducens n. VI
4. ophthalmic n. CV1
5. superior ophthalmic v.
foramina of sphenoid bone (6)
- superior orbital fissure - inferior orbital fissure - foramen rotundum - foramen ovale - foramen spinosum - foramen lacerum
foramina of sphenoid bone: the inferior orbital fissure- location and what does it transmit? (2)
located between greater wing of the sphenoid and orbital plate of maxilla transmits: 1. zygomatic and infraorbital nn. (branches of CN V2) 2. inferior ophthalmic v.
foramina of sphenoid bone: foramen rotundum - location and transmits (1)
most medial foramen on either side of the sphenoid transmits the maxillary n. (CN V2)
foramina of sphenoid bone: foramen ovale - shape and transmits (1)
ovoid in shape transmits the mandibular nerve (CN V3)
foramina of sphenoid bone: foramen ovale - shape and transmits (1)
ovoid in shape transmits the mandibular nerve (CN V3)
foramina of sphenoid bone: foramen spinosum - entrance
entrance for medial meningeal artery into the skull
foramina of sphenoid bone: foramen lacerum - covered by, formed by, transmits what (1)?
- partially covered by cartiage - formed between the sphenoid, temporal, and occipital bone - transmits the nerves to the pterygoid canal
what artery courses along the cranial bones in the location of the pterion?
middle meningeal artery
trauma in the pterion can fracture the cranium and result in what?
epidural hematoma
sphenoid articulations (14)
frontal occipital ethmoid vomer parietal (2) temporal (2) palatine (2) zygomatic (2) maxillae (2)
ethmoid - forms (3)
- anteromedial floor of the cranium
- roof of nasal cavity & makes up part of the nasal septum
- part of the medial orbital wall
ethmoidal air cells:
a network of air pockets w/i the bone that makes up the ethmoid sinus
ehtmoid - anterior view (3)
- orbital plate - perpendicular plate: forms part of the nasal spetum and makes up the medial wall of the nasal cavity - superior and middle conchae: lie in the lateral wall of the nasal cavity
ethmoid - superior and medial view (3)
- crista galli: located in anterior cranial fossa – anchor for falxi cerebri - cribiform plate: barrier between the nasal cavity and anterior cranial fossa – contains small foramina for the passage of the olfactory bulb into the nasal cavity - perpendicular plate: makes up 1/3 of nasal septum that forms the medial wall of the nasal cavity
what does the lateral wall of the ethmoid bone contain? (2)
- superior nasal concha 2. middle nasal concha
ethmoid articualtions (13)
- nasal (2) - maxillae (2) - lacrimal (2) - palatine (2) - inferior nasal conchae (2) - vomer - frontal - sphenoid
inferior nasal conchae
- hollow bone that lies in the lateral wall of the nasal cavity - independent bone that arises from the maxilla - purpose: warm and humidy air - covered w/ mucus membrane that producesmucus in certain situations
inferior nasal conchae articulations ( 4)
- maxilla - palatine - lacrimal - ethmoid
Vomer - shape, forms, and articulates (4)
- thin, flat and unpaired midline facial bone - almost trapezoidal shape - forms posterior part of the nasal septum and separates posterior nasal cavity into right and left halves articualtions: - palatine - maxilla - ehtmoid - sphenoid
palatine
- paired - located in p. nasal cavity between maxilla and pterygoid plates of the sphenoid bone - L shaped bone that form the hard palate of the bone - consists of a vertical and horizontal process
horizontal processes
join the midline w/ a suture to form the roof of the mouth and articulates with the maxillary bones
where do verticsl processes extend?
they extend superiorly into the orbit to form a small part of the orbit floor
what does the maxilla form?
the upper jaw
where do the two maxillae fuse?
intermaxillary suture
from the anterior view what features of maxilla are visible (3)
- frontal process: upward projection of maxila between lacrimal and nasal bone - orbital plate: anterior part of maxilla that contributes to the floor of the orbit - infra orbital foramen: exit for infraorbital n. and a.
maxillary sinus
- hollow space w/i maxillary bone - loacted above superior teeth and below the cheeckbone - largest of paranasal sinuses - located immediately inferior to the orbit
orbital surface of maxilla is seperated by, contains, and is the weakest where?
- separated from the sphenoid bone by the inferior orbital fissure - contains the infraorbital groove/sulcus that becomes the infraorbital canal and terminates on the facial surface as the infraorbital foramen - weakest along the infraorbital canal
maxilla articulations
- opposite maxilla - lateral wall of nasal cavity - ethmoid
nasal articualtions (4)
frontal maxillae ethmoid opposite nasal
lacrimal (p or up, size, location, makes up what?)
paired smallest bone of the skull located between frontal process of maxilla and orbital plate of ethmoid makes up part of the medail orbital wall
posteror lacrimal crest
bony projection of the lacrimal bone that creates posterior boundary of the lacrimal fossa
lacrimal fossa
depression formed by lacrimal grooves of the lacrimal and maxillary bones that houses the lacrimal sac
lacrimal articualtions (3)
maxilla ethmoid frontal
the zygomatic bone is also called the?
malar bone
the zygomatic contributes to what?
the lateral wall and floor of the orbit
zygomatic foramina (2)
- zygomaticofacial foramen: transmits zygomaticofacial n. (branch of zygomatic n. of V2) 2. zygomaticotemporal foramen: transmits the zygomaticotemporal n. (branch of zygomatic n. of V2)
zygomatic articulations (4)
temporal maxillary sphenoid frontal
mandible
single facial bone that forms lower jaw only freely movable bone and does not articulate w/ adjacent bones via suture
where does the mandible articulate?
temporomandibular joint(TMJ) only articulates w/ temporal bone
mandible external features (3)
- condylar process: bopny extrusion that forms lower bony compartment of the TMJ 2. mental foramen: opening that transmits the mental n. (branch of V3) – brings sensory to face 3. mental protruberance (eminence): landmark where two halves of mandible fused during development
superior and middle conchae of ethmoid bone are
narrow curled bones that warm and humidify air & protrude into the breathing passage
