Osteology (1) Flashcards
Anatomical Position
- standing erect - facing observer - upper extremities at side - palms anterior - thumbs lateral - feet flat
Reclining position
Prone: laying face down Supine: laying face up
Regional Name
Cranial: skull
Anatomic Planes (3)
- Sagittal / Median - Axial / Transverse / Horizontal - Coronal / Frontal
Sagittal
- median - divides L/R - mid-Sagittal: equal L/R
Transverse
- axial / horizontal - divides superior/ inferior
Coronal
- frontal - divides anterior/ posterior
Directional Terms - superior vs. inferior - anterior vs. posterior - superficial vs. deep - medial vs. lateral
- cranial vs. caudal - ventral vs. dorsal - towards the body vs. away from the body - towards body midline vs. away from body midline
Fetal skull starts to develop at (week ?)
-week 4
Molding
Overlapping of adjacent bones of fetal skull during passage through the birth canal
Fontanelle
“soft spot” that allows for molding to occur
What type of tissue constitutes fontanelles and what does it allow for?
-connective tissue -molding
What do fontanelle overlie?
Venous and CSF draining routes
How many fontanelles are there?
6 — 4 paired, 2 unpaired
Unpaired fontanelles
- frontal / anterior: unpaired, diamond shape, located in coronal suture - occipital / posterior: unpaired, located in lambdoidal suture
Paired fontanelles
- sphenoidal / anterolateral: paired, located on either side of the skull - mastoid: posterolateral: paired, located between the temporal, parietal, and occipital bone
What does a sunken fontanelle indicate?
- dehydration, failure to thrive, poor venous blood volume or low intracranial pressure
What does a raised fontanelle indicate?
Increased intracranial pressure due to poor drainage of venous blood or cerebral edema
Process
A projection or outgrowth of a tissue from a larger area
Protuberance
A rounded elevation on the surface of the bone
Condyle
Projection of bone located at articulation points
Fossa
Shallow depression on surface of the bone *may receive articulation from another bone to form a joint (mandibular fossa)
Groove (sulcus)
Shallow indentation that transmits blood vessels and nerves
Aperture
Large opening in the skull
Foramen
Circular or oval-shaped opening in skull bones
Fissure
Narrow, cleft like opening between adjacent parts of the bone or bones that form a passageway for neurovascular structures
Anterior Skull Landmarks (4)
- superciliary arches : prominent aspect of frontal bone, underlie eyebrows - glabella: smooth, slightly depressed area between superciliary arches. **point of fusion of frontal suture (present in infant skull)** - nasion: intersection between frontal and nasal bone (bridge of nose) - mental protuberance: triangular bony elevation formed by two halves of mandible (prominence of chin)
Lateral Skull Landmarks (7)
- temporal fossa: shallow depression, contains pterion - infratemporal fossa: irreg. space inferior and deep to zygomatic arch and ramus of mandible, located posterior to maxilla, contains important neurovascular structure - external acoustic meatus: external opening into auditory canal - mastoid process of temporal bone: site of muscle attachment - styloid process of temporal bone: site of muscle attachment - zygomatic arch: (cheek bone) formed by zygomatic process of temporal bone and temporal process of zygomatic bone - pterion: H shaped formation of sutures that unite frontal, sphenoid, temporal and parietal
What happens if there is trauma to the pterion?
- vulnerable to fracture from blunt force trauma - overlies middle meningeal artery on internal surface —— can lead to epidural hematoma
Posterior Skull Landmarks (1)
- external occipital protruberance: prominence of bone at center of occiptal lobe; overlies the confluence of sinuses
Internal Cranial Fossae (3)
- anterior cranial fossa - middle cranial fossa - posterior cranial fossa
Anterior Cranial Fossa (formed by)
- shallow and most elevated - formed by: ~ frontal bone ~ ethmoid bone ~ body of sphenoid ~ lesser wing of sphenoid
Anterior Cranial Fossa (bony features - 3)
- frontal crest: median bony extensions that contains foramen cecum ( “see some” - 3rd eye) ~ not all skulls but some transmits veins -crista galli: thick ridge of bone that projects superiorly and serves to anchor falx cerebri ~ tent & galli = rooster - cribriform plate: perforated by many foramina to allow passage of olfactory nerve into nasal cavity
Middle Cranial Fossa (formed by:)
- seperated from ACF by sphenioid crest - bounded posteriorly by superior border of petrous part of temporal bone - formed by: ~ greater wing of sphenoid bone ~ body of sphenoid ~ part of temporal bone ~ part of partial bone
Posterior Cranial Fossa (contains and formed by:)
- largest and deepest - contains cerebellum, pons, and medulla oblingata - formed by: ~ occipital bone (majority) ~ part of paritetal ~ part of temporal
cranial suture are what type of joints?
fibrous joints
cranial sutures (3)
- coronal: unites frontal and parietal bone - sagittal: unites the two parietal bones - lambdoid: unites the parietal and occipital
what are pneumatized bones?
bones that contain air spaces in the from of air cells or large sinuses in order to decrease the weight of the bone
T/F: volume of air spaces increases with age
true
pneumatized bones (7)
- frontal - ethmoid - sphenoid - maxilla (paired) - temporal (paired)
paranasal sinuses (description and function)
- air filled chambers w/i bone - extensions of the respiratory part of the nasal cavity into pneumatized bones - increases with age - function: ~ lighten skull weight ~ provide mucus epithelium
paranasal sinuses (4)
- frontal sinus - ethmoid sinus - maxillary sinus - sphenoid sinus
why can infections spred from nasal cavity into different sinuses?
- direct connection
what sinus is most commonly affected?
maxillary sinus
how many sinuses are in close proximity to the orbits?
3
- temporal fossa
- infratemporal fossa
- external acoustic meatus
- mastoid process of the temporal bone
- styloid process of temporal bone
- zygomatic arch
- pterion
- frontal
- sphenoid
- temporal
- ethmoid
- maxilla
