Ch. 11 Skull Flashcards
Frontal bone is divided into these two parts
- squamous / vertical portion
- orbital / horizontal portion
Smooth raised prominence between the eyebrows above the bridge of the nose
Glabella
Slight depression above each eyebrow
Supraorbital groove (SOG)
Directly below each eyebrow
Superciliary arch
This is the superior rim of each orbit
Supraorbital margin (SOM)
Small foramen in the SOM which allow an artery and a nerve to pass through
Supraorbital notch
Large prominences of the squamous portion of the frontal bone
Frontal tuberosity (eminence)
The orbital or horizontal portion of the frontal bone can be best viewed how
Inferior aspect
Forms the superior part of the orbit
Orbital plate
What lies below the orbital plate
Facial bones
What is above the orbital plate
Anterior part of the floor of the brain case
Each orbital plate is separated by this
Ethmoidal notch
Make up the lateral walls and the roof to the cranium
Parietal bones
Make the widest portion of the skull
Parietal tubercles (eminences)
Inferoposterior portion of the calvarium
Occipital bone
External surface of the occipital bone which is rounded
Squamous portion
The squamous portion of the occipital bone is superior to this
Occipital protuberance
Prominent skull landmark on the occipital bone
Occipital protuberance (inion)
Inferior to the inion
Foramen magnum
Two part articulation between the skull and the cervical spine
Occipito-atlantal joint
What are the 3 primary parts of the temporal bone
- squamous
- mastoid
- petrous
Complex structures that house the delicate organs of hearing and balance
Temporal bones
Extends anteriorly from the squamous portion of the temporal bone
Zygomatic process (arch)
Thin part, forms the wall of the skull, very vulnerable to fracture
Squamous portion of temporal bone
Posterior to the EAM, has a prominent mastoid tip which is palpable
Mastoid portion of temporal bone
Thickest most dense bone in the cranium
Petrous portion of temporal bone
Level of the petrous pyramids are at the level of this
TEA - top of ear attachment
Forms the anchor for all 8 cranial bones
Sphenoid bone
Central depression of the body of the sphenoid bone
Sella turcica
The sella turcica partially surrounds and protects this
Pituitary gland (hypophysis cerebri)
Back of the saddle
Dorsum sellae
This area forms the base of support for the pond portion of the brain and the basilar artery
Clivus
Lesser wings end medically and forms this which extend into the middle of each orbit
Anterior clinoid process
Between the lesser wings and the anterior bodies are groove like canals which begin this
Optic groove
Optic groove extends to the optic canal and ends at this
Optic foramen
Optic foramen are seen on what view of the orbits
PA obliques
Extend from the sides of the body and form a portion of the floor of the cranium
Greater wings
The 3 pairs of foramen located on the greater wings from front to back are what
- foramen rotundum
- foramen ovale
- foramen spinosum
Lies mostly beneath the floor of the cranium
Ethmoid bone
The ethmoid bone sits in this of the frontal bone
Ethmoidal notch
Small horizontal portion of bone, contains many small openings for olfactory nerves
Cribriform plate
Small projection from the cribriform plate similar to a roosters comb
Crista galli
Projecting downward in the midline of the ethmoid, helps form the nasal septum
Perpendicular plate
Suspended from the under surface of the cribriform plate
2 lateral labyrinths (masses)
The lateral labyrinths contain this to help form the medial orbital walls and the lateral walls of the nasal cavity
Ethmoid air cells (sinuses)
Projections of bone which extend from each labyrinth, scroll shaped
Superior and middle nasal conchae or turbinates
Separates frontal from two parietals
Coronal suture
Articulations or joints of the cranium
Sutures
Separates two parietal from midline
Sagittal suture
Separates two parietals from occipital bone
Lambdoidal suture
Inferior junction of each parietal bone with their respective temporal bone
Squamosal suture
Anterior end of the sagittal suture
Bregma
Posterior end of the sagittal suture
Lambda
The points at the junctions between the sphenoid, temporal, and parietals
Pterions
Posterior to the ear where the squamosal and lambdoidal sutures meet
Asterions
Channels sound waves to the EAM
Auricle (pinna)
Tubelike opening that ends at the tympanic membrane (eardrum)
external auditory meatus (EAM)
Actually tubelike portion of EAM
Acoustic canal
Contains air, located between the eardrum and the inner ear
Middle ear
The middle ear contains 3 small bones called
Auditory ossicles
Transmit sound vibrations from eardrum to the oval window of the internal ear
Auditory ossicles
Slightly anterior of the others and the most lateral auditory ossicle
Malleus (hammer)
Located in the middle of the malleus and stapes, looks like an anvil or tooth
Incus
Most medial of the 3 auditory ossicles, connects to the oval window of the cochlea
Stapes
Superior portion of the tympanic cavity
Epitympanic attic (recess)
Large cavity opposite the eardrum
Tympanic cavity proper
The tympanic cavity proper communicates with the nasopharynx by this
Eustachian tube
Small tube about 4 cm long, equalizes pressure between the middle ear and outside pressure, ear infections often happen by way of this tube
Eustachian tube
Attached to the drumcrest or spur which separates the EAM from the epitympanic recess
Tympanic membrane
The second communication to the middle ear occurs posteriorly to what
Mastoid air cells
Opening between the mastoid air cells (mastoid portion of temporal) and the epitympanic recess
Aditus
Large chamber connecting the air cells, allows infection to cross from the middle ear to the mastoid area which in turn can cause an infection to the brain
Antrum
Infection to the brain
Encephalitis
Small bone separating the mastoid air cells from the brain
Tegmen tympani
Contains both sensory apparatus for hearing and equilibrium
Internal ear
Enclosed the ducts and sacs of the membranous labyrinth
Osseous bony labyrinth
Houses a long tubelike duct of the membranous labyrinth, most anterior, has a round window at the base of it, related to the sense of hearing
Cochlea
Central portion of the osseous labyrinth which contains the oval window
Vestibule
Located posterior to the other inner ear structures and located at right angles to one another, relate to the sense of direction or equilibrium
Semicircular canals (superior, posterior and lateral)