Flashcards in Week 5 Deck (91)
Where does the Oculomotor nerve originate from?
Medial side of cerebral peduncle.
What 2 cranial nerves pass between cerebral arteries and the superior cerebellar arteries?
Oculomotor and Trochlear.
What does the occlumotor nerve supply?
Medial rectus muscle, inferior rectus muscle, inferior oblique muscle, superior rectus and levator palpebrae superioris muscle.
Where does the trochlear nerve originate from?
Emerges dorsally (posteriorly) from brainstem.
What cranial nerve cannot be seen on an mri scan and why?
Has few axons- trochlear nerve.
Where does the Abducens nerve emerge from?
Just below the pons.
What muscle does the trochlear nerve supply?
Superior oblique muscle.
What muscle des the abducens nerve supply and what does this muscle do?
Lateral rectus muscle- abducts the eye.
Where does the trigeminal ganglion sit in the cranial cavity?
Sits in depression of the middle cranial fossa (the foramen ovale is at its lateral side).
What does the trigeminal ganglion contain?
Cell bodies of sensory neurons.
What is meckels cave?
Invagination of dura matter that contains cerebral spinal fluid. This is where the trigeminal ganglion is found.
What does the facial nerve supply?
Taste to the anterior 2/3 of the tongue, parasympathetic supply to structures of the face including the submandibular and sublingual glands.
Where does the vestibulocochlear and the facial nerve emerge from?
They are closely related to the temporal bone- they emerge from just inferior to the pons lateral to where the 6th cranial begins.
Where is the lateral geniculate nucleus located?
The lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a relay center in the thalamus for the visual pathway. It receives a major sensory input from the retina.
What does the vestibulocochlear nerve do?
It is two nerves bound together. It carries sensation of balance from the vestibule and carries impulses from cochlea that makes up hearing.
What does the glossopharyngeal nerve do?
It carries sensory nerves for the whole pharynx and carries taste from posterior 1/3 of the tongue.
What nerves pass through the jugular foramen and where do they originate?
9th 10th and 11th cranial nerves. They originate from the lateral portion of the medulla.
What does the vagus nerve supply?
The vagus nerve supplies motor parasympathetic fibers to all the organs (except the adrenal glands), from the neck down to the second segment of the transverse colon. The vagus also controls a few skeletal muscles, including: Cricothyroid muscle. Supplies the muscles of the pharynx and larynx.
What nerve stays in the carotid sheath throughout the whole of the neck?
What two muscles does the accessory nerve supply?
Trapezius and Sternocleidomastoid muscle.
What are the two parts of the accessory nerve called?
Spinal (spinal accessory) and cranial portion (follows vagus nerve and performs similar functions).
What does the hypoglossal nerve do?
Controls intrinsic and extrinsic nerves of the tongue.
Where is the hypoglossal channel?
Through the occipital bone immediately above the foramen magnum.
What is the two layers of compact bone called in the outside of the cranial base?
Inner and outer tables.
What is a clinical problem that can affect the red bone marrow between the inner and outer tables of the skull?
What bones are in the anterior cranial fossa?
Frontal, sphenoid and ethmoid bone.
What lobe lies in the anterior cranial fossa?
Where is the crista galle?
Lies anteriorly in the anterior cranial fossa- it is a bony projection in the midline.
What starts at the foramen cecum?
Superior saggital sinus.
What bone forms the boundary between the anterior and middle cranial fossa?
The lesser wing of the sphenoid bone.
What cranial fossa is the greater wing of the sphenoid bone in?
Middle cranial fossa.
Where does the pituitary gland sit in?
Sits in the middle cranial fossa in the hypopyseal fossa.
What is the boundary between the middle and posterior cranial fossa?
Superior border of the petrous temporal bone and the dorsum sellae.
What cranial fossa are the cerebellum and brainstem found?
Posterior cranial fossa.
What is the clivus (bone)?
The clivus (Latin for "slope") is a bony part of the cranium at the skull base, a shallow depression behind the dorsum sellæ that slopes obliquely backward. It forms a gradual sloping process at the anterior most portion of the basilar occipital bone at its junction with the sphenoid bone.
What bone is the spheno-occipital synchondrosis located on?
Where are the grooves for the transverse sinus?
At the back of the posterior cranial fossa.
Where does the first cranial nerve exit the skull?
Through holes in the cribiform plate.
What cranial nerves pass through the superior orbital fissure?
3rd 4th and 6th cranial nerves and the opthalmic division of the trigeminal nerve.
What does the opthalmic divisIon of the trigeminal nerve supply?
Sensory supply to the forehead, structures of the forehead and the front half of the scalp. The opthalmic veins also pass through here to go to the middle cranial fossa.
What passes through the foramen rotundum?
Maxillary division of the trigeminal nerve.
What passes through the foramen ovale?
Mandibular division of the trigeminal nerve. TINY BRANCHES COME OFF EHRE TO SUPPLY THE SURROUNDING MENINGES.
Where is the middle meningeal artery located?
Runs between dura and bone of the vault of the skull and comes into the cranial cavity through the foramen spinosum. it runs in groove postal-lateral to the foramen ovale.
What passes through the sphenoidal emissary foramen?
Carries a little vein from veins behind the upper jaw (pterygoid vein plexus) to the cavernous sinus.
*If at all present, the sphenoidal emissary foramen gives passage to a small vein (vein of Vesalius) that connects the pterygoid plexus with the cavernous sinus. The importance of this passage lies in the fact that an infected thrombus from an extracranial source may reach the cavernous sinus.
What passes through the foramen lacerum?
The artery of pterygoid canal, the nerve of pterygoid canal and some venous drainage pass through the foramen lacerum. ... Furthermore, one of the terminal branches of the ascending pharyngeal artery (itself a branch of the external carotid artery) passes through the foramen lacerum.
What nerves pass into the internal aucustic meatus?
Cranial nerves 7 and 8 pass into the temporal bone through the internal aucustic meatus.
What is an aucustic neuroma and why is it difficult to operate on?
Benign tumour of Schwann cells on cranial nerve 8- it is difficult to operate on due to being in close proximity to cranial nerve 7. The pressure on the nerve from the tumor may cause hearing loss and imbalance.
What cranial nerves pass through the jugular foramen to exit the skull?
Where does the hypoglossal nerve exit the skull?
Hypoglossal canal (condylar canal is near here which carries a little vein- emissary vein).
Where does the spinal root of the accessory nerve exit the skull?
The nerve travels along the inner wall of the skull towards the jugular foramen. Leaving the skull, the nerve travels through the jugular foramen with the glossopharyngeal and vagus nerves. The spinal accessory nerve is notable for being the only cranial nerve to both enter and exit the skull.
What do the occipital condyles articulate with?
The atlas of the vertebral column.
What is the spheno-occipital synchondrosis?
The spheno-occipital synchondrosis (SOS) is a cartilaginous growth center between the occipital and sphenoid bones. It is composed of hyaline cartilage, which is abundant during the growth phase of the cranial base and then ossifies during skeletal maturation. ALLOWS BASE OF SKULL TO GROW IN LENGTH.
What is the pterygoid hannulus?
The pterygoid hamulus is a bony projection at the lower extremity of the medial pterygoid plate of the sphenoid bone. Around it glides the tendon of the tensor veli palatini- SPREADS OUT IN PALATE TO FORM THE PALATAL APONEUROSIS. As well, it is the superior origin of the pterygomandibular raphe. SITE USED IN DENTURE MANUFACTURING.
WHERE DOES IN INTERNAL CAROTID ARTERY ENTER THE BASE OF THE SKULL?
Through the carotid canal. The artery bends medially within this canal to the middle cranial fossa.
Where does the sigmoid sinus meet the internal jugular vein?
Where in the skull does the facial nerve exit the skull?
It emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue. The nerves typically travels from the pons through the facial canal in the temporal bone and exits the skull at the stylomastoid foramen.
The facial nerve then passes through the parotid gland, which it does not innervate, to form the parotid plexus, which splits into five branches (temporal, zygomatic, buccal, marginal mandibular, and cervical) innervating the muscles of facial expression.
What age does the mastoid process form and what may happen to it during a forceps delivery?
Age 2. Instruments from a forcep delivery might cause facial paralysis in the baby due to being closer to the outside. Compression of the mastoid process which damages this nerve.
What is the Falx cerebri?
The falx cerebri, also known as the cerebral falx, is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres of the human brain.
Where does the Falx cerebri connect to?
What connective tissue is the Falc Cerebri made up of?
Dense irregular connective tissue.
What is the horizontal fold of dura matter that covers the cerebellum called?
What is the brain covered by?
Covered by cerebral spinal fluid (lies in subarachnoid space).
What is the large venous channel that is inside the Falx Cerebri?
Superior saggital sinus.
What is a sinus in the brain?
It is a venous channel covered by dura folds- lined by endothelium.
What veins drain the upper part of the cerebral hemispheres?
Superior cerebral veins.
What might happen to the superior cerebral veins in an older patient if they knock their head?
Tissues are in less good condition in an older patient so if they have a fall or bump their head these veins can become detached and blood spills between the dura and the subarachnoid space- called a subdural haemorrhage.
What veins drain the mid part of the forebrain?
Great cerebral vein.
What vein is a continuation of the great cerebral vein?
What two veins join up to make the superior saggital sinus?
Inferior saggital sinus and great cerebral vein.
What is the pathway of the straight sinus?
The straight sinus runs backwards to the external occipital protuberance and turns left to from the left transverse sinus (runs into attachment of the tentorium on left side)- it then has an S shaped course and this is the left signmoid sinus.
What is the connection of two sinuses called?
"Confluence of sinus".
What are the veins called that are draining from the orbit to the cranial cavity?
How can a blood clot form in the cavernous sinus from the veins in the orbit?
Veins inside the orbit have an anastomoses with the facial veins and bacteria within the face can flow back through these orbital veins into the cranial cavity. The ophthalmic veins form a large channel that is close to the pituitary called the cavernous sinus. The blood flow is slow within this sinus (as it has lots of little passageways) and bacteria can multiply here and cause a clot.
What are the symptoms of a cavernous sinus blockage?
Temperature and swollen eyes.
What is the venous connection behind the upper jaw called?
Sphenoidal emissary vein.
How can a blood clot form in the cavernous sinus from a dental absess on the posterior teeth?
The infection from the absess can travel in the sphenoidal emissary vein (from the area behind the upper jaw) to the cavernous sinus to cause a clot due to the slow blood flow within this sinus.
What is the pathway of veins of the superior saggital sinus?
The superior saggital sinus turns to the right and runs along the inside of the attachment of the tentorium to side wall (runs inside the dura matter). When it gets to the front of where the cerebellum is sitting it turns a corner and runs in a deep groove in an S shape (gets more blood from the posterior cerebral hemisphere and the cerebellum here) and this is now called the right transverse sinus. It then changes direction to form the right sigmoid sinus.
What sits underneath the optic chiasm?
The pituitary gland.
What structures make up the brainstem?
Midbrain and pons and medulla.
What arch is the stylopharyngess muscle from?
3rd pharyngeal arch.
How do you test CN1 clinically?
Ask them if they have had an change in their sense of smell recently.
How do you test CN2 clinically?
-Any double vision? any restrictions of eye movement if they are following their eyes on your pen- might be a lesion on the occlumotor nerve.
-Inspect size and alignment of pupils.
-Shine a bright light into the eyes to assess papillary reflexes.
-"Swinging light test" - may reveal a relative afferent papillary defect.
-Assess ability to focus by making them focus on a pen.
-Doing a sight test:
1. move closer 3m
2.if unable- move closer again 1m
3.if still unable- assess ability to count fingers
4.if still unable-assess ability to detect a moving hand
5.if still unable assess light perception.
What does nystagmus mean?
Nystagmus is a condition whereby a person suffers with involuntary, uncontrollable eye movements. The condition can often make someone's eyes look like they are shaking, moving quickly either from side to side, up and down, or in a circular motion.
How do you test CN5 clinically?
-Clench jaws and feel masseter and temporalis.
-Use a bit of cotton wool and make patient close their eyes and touch their face with it- they say now when it is touching their face (MAKE SURE TO DO BOTH SIDES). Ask them if it felt any different on both sides of the face.
How do you test CN5 clinically?
-Clench forehead and puff out cheeks. Purse lips and smile.
-Any change in taste?
-Hearing sounds louder than usual?
How do you test CN8 clinically?
Cover one ear and whisper a number and move 1m away and do it again.
How do you test the glossopharyngeal and vagus nerve clinically?
Patient says "ahhh". Assess the soft palate for symmetry and uvular movement.
How do you clinically test the accessory nerve?
Patient shrugs shoulders and can turn head against your hand when they turn to the left or right.
How do you test the hypoglossal nerve clinically?
Stick out tongue (will go towards affected side).