Radiographic Skull Flashcards
What are the 8 bones in the skull?
1 frontal 2 parietal 2 temporal 1 sphenoid 1 ethmoid 1 occipital
What’s a suture?
Joins the bones of the cranium
What are the junctions of the brain?
Bregma
Lambda
Pterion
Asterion
What’s joined by the bregma junction?
Coronal and sagittal sutures
What’s joined by the lambda junction?
Lambdoidal and sagittal sutures
What’s joined by the pterion?
Parietal bone, temporal bone and sphenoid bone
What’s joined by the asterion?
Occipital bone, parietal bone, and temporal bone
What’s a fontanel and which age group are they found in?
- Soft spot in the skull of an infant
- Found in infants
- The bones in a newborn infant are not fully developed
Where are the 7 fontanels located?
- 2 in the sagittal plane
- Anterior fontanel at bregma
- Posterior fontanel at lambda
- 2 at pterion (called sphenoidal fontanel)
- 2 at asterion (mastoid fontanel)
What are the 3 cranial fossae?
Anterior
Middle
Posterior
What’s in the anterior cranial fossa?
- Frontal bone
- Ethmoid bone
- Lesser wing of sphenoid bone
- Frontal lobes of brain
What’s in the middle cranial fossa?
- Body of sphenoid and temporal bones
- Pituitary gland
- Hypothalamus
- Temporal lobes
What’s in the posterior cranial fossa?
- Occipital bone
- Temporal bone
- Cerebellum
- Brainstem
What’s formed by the frontal bone?
- Forehead
- Roofs of the orbit
- Most of the anterior part of cranial floor
- Contains frontal sinuses
What’s the parietal eminence?
Smooth rounded surface that forms the widest part of the cranium
What are the 4 parietal borders and their articulations?
Superior = Parietal bone (forms sagittal suture)
Inferior = Sphenoid and temporal bones
(forms squamous suture)
Anterior = Frontal bone
(coronal suture)
Posterior = Occipital bone (lambdoidal suture)
What is the zygomatic arch and where is it found?
Cheek bones
Found as a zygomatic process that runs anterior on the bone
What’s on the inferior portion of the temporal bone?
- Mandiublar fossa that will articulate with the mandible to form the temporomandibular joint (TMJ)
Where is the mastoid portion of the temporal lobe located?
Posterior and inferior to the External Auditory Meatus (EAM)
What is the mastoid portion of the temporal lobe?
- Contains mastoid process, which contains several air cells
- Site of muscle attachment
What is the purpose of the Internal Audtiory Meatus (IAM)
Opening through which the facial and vestibulocochlear nerves pass
What is the petrous portion of the temporal bones
Triangular part that houses the middle and inner ear
Contains carotid foramen
What is the occipital bone?
- Forms posterior part and most of base of cranium
What is the purpose of the foramen magnum?
Allow the brainstem to travel through
Where are the occipital condyles and what are their purpose?
- Either side of the foramen magnum
- To allow head movement
What is the purpose of the external occipital protuberance?
Attachment site of the nuchal ligament
What are the 4 occipital articulations?
- Parietal bones at lambdoidal suture
- Temporal bones
- Sphenoid
- C1 Atlas forms Atlanta-occipital joints
Which bone articulates with all other cranial bones?
Sphenoid bone
What is the purpose of the sphenoid sinus?
Drains into the nasal cavity
What is the function of the sella turcica, and where is it located?
Located on the superior body of the sphenoid
Houses the pituitary gland
Define lesser wing of the sphenoid
- Projects laterally from the upper anterior part of the body
- Forms part of the orbit
Define greater wing of the sphenoid
- Extends laterally from the body and form the anterolateral floor of the cranium
Where is the optic foramina found and what is its function?
Found between the greater and lesser wing
Allow optic nerve and ophthalmic arteries to pass
Where is the ethmoid bone found?
- Midline in the anterior part of the cranial floor
- Medial to the orbits
- Anterior to sphenoid
- Posterior to the nasal bones
Which 4 structures does the ethmoid bone form
- Part of the anterior wall of the cranial floor
- Superior portion of the nasal septum
- Medial wall of the orbits
- Superior side wall of the nasal cavity
What is the cribriform plate?
ethmoid bone
- Superior part of the ethmoid
- Contains the olfactory foramina through which the olfactory nerve passes
What is the crista galli?
ethmoid bone
Process on the superior aspect that serves as an attachment site for membranes
What are the lateral masses?
ethmoid bone
Compose most of the wall between the nasal cavity and orbits
What is the perpendicular plate?
ethmoid bone
Forms septum of nose
What is the function of the superior and medial nasal concha?
(ethmoid bone)
Increase mucus membrane surface area in the nasal cavities
What is the function of the ethmoid sinuses?
Provide lubrication (mucus) to the inner nose
What is the zygomatic arch?
- Formed by zygomatic process of temporal bone and temporal process of the zygomatic bone (side of cheekbone)
