Head And Neck Part 2 Flashcards
What are sutures bones?
Normal island-like bones within the lambdoid suture
-mistaken in X-rays for skull fractures
What is the Pterion?
Junction of
1. Frontal
2. Parietal
3. Temporal
4. Sphenoid bones
What is deep to the Pterion?
Middle meningeal artery
How does an epidural hematoma happen?
Lateral head trauma causes
-A ruptured middle meningeal artery
How does a Epidural Hematoma present on CT imaging?
Convex or lens shape due to the
-Dura mater separating from cranium forming a cavity containing blood
What do the two layers of the dura mater spilt into?
Spilt to form dual venous sinuses containing venous blood
What is deep to the dura mater?
Arachnoid mater
-subarachnoid space (with cerebrospinal fluid)
Pia mater (adheres directly to the brain)
What goes into the sulcus of the cerebral cortex and what crosses the sulcus of the cerebral cortex?
Into: Pia mater
Crosses: Arachnoid mater
What does the subarachnoid space contain?
Cerebrospinal fluid (CSF)
Cerebral arteries
Cerebral veins
What is the bridging vein between?
Dura mater and arachnoid mater
What is the middle meningeal artery between?
- Cranial bone
- Dura mater
*not in subarachnoid space
What do the cerebral veins drain to?
Dural venous sinuses
-via bridging veins
What do the bridging veins piece through?
- Arachnoid mater
- Meningeal (inner) layer of the dura mater
How does a subdural hematoma happen?
Bridging vein rupture between Dura and Arachnoid mater
-by head trauma or rapid deceleration causing intra-cranial shearing forces
How does a Subdural hematoma present on a CT?
Not strictly lens-shaped
-mixture of concave and convex
How does a Subarachnoid hematoma happen?
rupture of cerebral arteries
-Caused by ruptured aneurysm
*worse headache of their life
How does a Subarachnoid hematoma present on CT?
Blood will fill the subarachnoid space
-Highlighting the brain and brain stem contours
- Star shaped or asterisk
What is the purpose of an Emissary vein?
Provide communications between dural venous sinuses and the scalp
-Route for potential spread of infection from scalp into cranial cavity
Where does cerebrospinal fluid drain from?
Subarachnoid space into the dural venous sinuses BY THE
-Arachnoid granulations
What are the arachnoid granulations within?
- Superior Sagittal sinus
- Lateral lacuna
How does a Communicating Hydrocephalus happen?
Scarring of the Arachnoid Granulation due to a patient surviving
-A subarachnoid hemorrhage
-Will block resorption of CSF into dural venous
What happens to the brain when a Communicating Hydrocephalus occurs?
The CSF will accumulate in cavities within the ventricles of the brain
How does a Communicating Hydrocephalus present on CT imaging?
There will be an enlargement of the ventricles
-CSF filled spaces within the brain and brain stem
What are the infolding of the dura mater?
- Tentorium Cerebelli
- Falx Cerebri
What is the tentorium cerebelli between?
Cerebrum and cerebellum
What is the falx cerebri between?
Between cerebral hemispheres
Where does the straight sinus run between?
- Falx Cerebri
- Tentorium Cerebelli
What does the straight sinus connect?
Inferior sagittal sinus with confluence of sinuses
Where does the confluence of sinuses receive venous blood from?
- Superior sagittal sinus
- Straight Sinus
Where does the transverse sinus run along?
The lateral edge of Tentorium Cerebelli
What does the sigmoid sinus drain blood from?
Drains venous sinus system TO
-Internal Jugular vein at Jugular Foramen
What does the Sphenoid Crest separate?
Anterior and Middle Cranial Fossae
What does the Petrous Ridge of Temporal Bone separate?
Middle and Posterior Cranial Fossae
What does the Falx Cerebri attach to?
Crista Galli
What does the Tentorium Cerebelli attach to?
- Anterior Clinoid Process
- Posterior Clinoid process
- Petrous ridge of temporal bone
- Groove for Transverse Sinus
Where is the olfactory foramina (CN I-Olfactory) located?
In the Cribriform plate of the ethmoid bone
Where is the optic canal (CN II-Optic and ophthalmic artery) located?
In the lesser wing of the sphenoid bone
Where is the foramen spinosum (middle meningeal artery) located?
In the Greater Wing of Sphenoid Bone
What does the Superior Orbital Fissure contain?
CN III- Oculomotor nerve
CN IV- Trochlear
CN V1- Trigeminal (ophthalmic)
CN VI- Abducens
Where is the superior orbital fissure located?
Between Lesser and Greater Wings of Sphenoid Bone
What does the Foramen Rotundum contain?
CN V2 (maxillary)
Where is the Foramen Rotundum located?
In the Greater Wing of Sphenoid Bone
What does the Foramen Ovale contain?
CN V3 (mandibular)
Where is the Foramen Ovale located?
In the Greater Wing of Sphenoid Bone
What does the Foramen Magnum contain?
The spinal cord
Where is the Foramen Magnum located?
The occipital bone
Where do the sinuses drain to?
The internal jugular vein VIA
-The Groove for Sigmoid Sinus
*Can be followed to Jugular Foramen
What does the Jugular Foramen contain?
CN IX- glossopharyngeal nerve
CN X- Vagus Nerve
CN XI- Accessory nerve
Where is the Jugular foramen located?
Between Petrous Temporal bone and Occipital Bone
What does the Internal Acoustic Meatus contain?
CN VII- Facial Nerve
CN VIII- Vestibulocochlear nerve
Where is the internal Acoustic Meatus located?
Petrous Temporal Bone
What does the Hypoglossal Canal contain?
CN XII- Hypoglossal
Where is the Hypoglossal canal located?
The occipital bone
What is the Sella Turcica composed of?
- Anterior Clinoid Process
- Hypophyseal Fossa
- Posterior Clinoid Process
- Dorsum Sellae
Where is the pituitary gland located?
The Hypophyseal Fossa
What is the Plica Semilunaris?
The remnant of 3rd eyelid or nictitating membrane
What is the Limbus?
The border between Cornea and Sclera
What does the optic nerve contain?
Axons of retinal ganglion cells
-Holds visual information
What is the Fovea?
The area of greatest visual acuity
-Center of visual field
Where is the Aqueous humor located?
Anterior to the lens on either side of the iris
What causes Glaucoma?
Impaired drainage of Aqueous humor
-There will be damaged to retina and optic nerve due to intraocular pressure
What muscle mediates blinking?
Palpebral part of Orbicularis Oculi muscle
-Motor innervation=CN VII (facial nerve)
What is the sensory innervation of the Cornea?
Ophthalmic Division of the Trigeminal Nerve
CN V1
What does the blink reflex test?
CN V1 (Ophalmic division of trigeminal nerve)
CN VII (Facial)
What bones of the orbit osteology are thin and fragile?
Ethmoid Bone
Maxilla
What does the Periorbita contain?
Fascia investing contents of the orbit
What surrounds CN II (optic nerve)
Subarachnoid space
If the optic disc is blurred what could that indicate?
Elevated Intracranial Pressure
-Papilloedema
Where is the lacrimal gland located?
Posterior to the Orbital Septum
What does the Supraorbital Nerve branch from?
Frontal Nerve
-branch of CN V1 (trigeminal nerve)
What is the nerve supply of the Levator Palpebrae Superioris muscle?
Oculomotor Nerve (CN III)
What muscles elevate the eyelid?
- Levator Palpebrae Superioris Muscle
- Superior Tarsus Muscle (sympathetic innervation)
What helps close the eyelid?
Palpebral Part of Orbicularis Oculi Muscle
-CN VII (facial nerve)
What are the palpebral glands?
- Tarsal glands (Meibomian glands)
- Ciliary glands
What is the purpose of the Tarsal glands (Meibomian glands)
- Secrete oils that prevents lacrimal fluid from overflowing eyelids