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Explain where the trigeminal nerve exits externally.
1. Supraorbital notch
2. Infraorbital foramen
3. Mental foramen
What are the structures of the:
1. anterior base of the skull
2. medial base of the skull
3. posterior base of the skull
1. cribiform plate with holes for the olfactory nerve
2. Carotid canal, foramen ovale
3. Magnum foramen, internal accousti meatus, jugular foramen
What are the different duramatter in the brain?
Falx Cerebri: divides the cerebral lobes
Tentorium Cerebelli: Divides the cerebrum from the pons- except for the tentorial notch w/ allows communication
What is the structure of duramatter.
1. meningeal layer (to tissue)
2. periosteal layer (to the skull)
The area in between the two is sinus where vein can travel.
Explain the flow of veins in the brain.
Down posterior through superior saggital sinus of the falx cerebri. then through the transverse sinus of the tentorium cerebelli. then to the internal jugular vein.
Explain branching of the internal carotid artery.
1. opthalmic (eye supply)
2. Middle cerebral (lateral side of brain)
3. Anterior cerebral (anterior medial portion of the brain)
Anastomoses with the vertebral artery.
Explain the peripheral pathway of the CNI- Olfactory nerve.
Receptors in the nose travel to the cell bodies in the olfactory bulb that sits on the cribiform plate of the ethmoid bone. Here axons continue to the brain.
Explain the peripheral pathway of the CNVIII- Vestibulocochlear nerve.
1. Cochlear (for hearing) in the spiral part of the middle ear goes to the spiral ganglion (cell bodies)
2. Vestibular (balance) in the vestibular appartus goes to the vestibular ganglion (cell bodies)
Axons from both of these converge to leave middle ear to the brain.
What is the difference between the optic nerve and the optic track? How does crossing work in the nerves of the optic nerve.
Optic Nerve: eye to chiasm
Optic Tract: chiasm to brain
Nasal portion nerves cross in chiasm while the lateral portions do not. Thus left field processed by right side of the brain and vice-versa.
What muscles are responsible for opening and closing the eye?
Opening- Levator palpebrae superioris
Closing- orbicularis oculi
What muscles responsible for adduction and abduction of the eye?
Adduction: Medial, Superior, Inferior rectus
Abduction: Lateral, superior, inferior obliques
What muscles responsible for extortion and intorsion of the eye?
Extorsion: Inferior oblique and rectus
Intorsion: Superior oblique and rectus
What muscles responsible for looking up and down?
Up- Superior oblique and inferior rectus
Down- Inferior oblique and superior rectus
What specific muscles of the eye are controlled by the abducent nerve (CNVI) and the trochlear nerve (CNIV)
Abducent- Lateral rectus
Trochlear- Superior oblique
Explain the peripheral pathway of the CNVII- oculomotor nerve.
Has voluntary movement and parasymphthetic constriction of the eye. As such- synapse in the ciliary ganglion behind the eye and the to the brain. REMEMBER THIS SYNAPSE before going to the brain.
What divides the anterior, medial, and posterior cranial fossa?
Sphenoid ridge- Anterior from medial
Petrous ridge- medial from posterior
Explain the structures in the cavernous sinus.
Against Medial wall sits the carotid siphon and the sphenoid fossa.
CN III, IV, VI corse through to exit out the superior orbital fissure (between the wings of the sphenoid).
Trigeminal splits to exit (opthalmic out the superior orbital fissure, maxillary out the foramen rotunda, and mandibular out the foramen ovale).
Explain the pathway of the accessory nerve (CNXI) and the branches.
Has a cranial and spinal root. Spinal root comes to join the cranial root in the skull and then they leave the skull. Cranial root becomes apart of the vagus nerve and the spinal root innervates the traps and sternocleidomastoid. PAIN GOES TO CERVICAL NOT CRANIAL ROOTS.
Explain the function of the hypoglossal nerve (CNXII)
Supplies muscle of the tongue. Especially the genioglossus muscle going from the tip of the mandible to the posterior portion of the tongue.
What are the functions of the trigeminal nerve (CNV)
Opthalmic- sensation to forehead and cornea
Maxillary- sensation to maxillary and upper teeth
Mandibular- sensation to madible and works chewing muscles
Explain the function of the pterygopalatine ganglion.
Behind maxiallary sinus. Postganglionic sympathics from greater petrosal nerve (facial) for parasympth. of nasal/lacramal/palatine glands. also branches of the trigeminal
Explain the specific branches of the mandibular nerve.
Has the lingual (sensation to tonuge) and the mental (sensation to mandible) components.
Explain the function of the submandibular ganglion.
Chorda typani (facial) post ganglionic parasympathtics to the submandibular gland and the submental gland.
Explain how taste occurs.
Anterior 2/3 is the facial nerve (CNVII) through lingual nerve.
Posterior 1/3 is the glossopharngeal nerve (CN IX)
Explain the pathway of the facial nerve (CNVII)
Enters the internal acoustic meatus to hit the geniculate ganglion. Main branch goes out the stylomastoid foramen to supply face muscles, while it sends a chorda tympani branch to join lingual to go to submandibular/mental glands and carry taste. A smaller branch leaves geniculate ganglion called the greater petrosal nerve to hit the pterygopalatine ganglion and supply other glands.
What is the role of the geniculate ganglion?
It is the sensory ganglion for taste from the facial nerve (through the lingual nerve).
What is the role of the otic ganglion?
glossopharngeal (CNIX) sends preganglionic parasymphatetics to the parotid gland.
What are the parasympathetic ganglions in the face?
Ciliary (III), Otic (IX), Pterygopalatine (VII), Submandibular (VII).
Explain the jugular foramen?
Where the jugular vein leaves as well as CN 9, 10, 11. (Vagus, glosspharngeal, accessory).
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