The Middle Cranial Fossa Flashcards
What are the different modalities of the cranial nerves
Somatic sensory (sensory info from the body wall to the brain)
Somatic motor ( from cns to skeletal muscle)
Parasympathetic motor
Special sensory
Mixed
Visceral sensory
Explain what is meant by somatic sensory and motor nerve s
Sensory - from skin etc to CNS, mental nerve
Motor – to skeletal muscle form CNS, spinal accessory
Explain what is meant by the parasympathetic nerves and special sensory
Parasymp motor - rest and digest, glands get secretomotor innervation
Special sensory - from sense organ, optic nerve
Explain what a mixed nerve is nd what a visceral sensory nerve I
Mixed - mix of a few modalities, trigeminal
Visceral sensory - from carotid body, Glossopharyngeal
What are the cranial nerves
Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Facial Vestibulocochlear Glossopharyngeal Vagus Spinal accessory Hypoglossal
What are the modalities of the cranial nerves
Some say marry money my brother says big brains matter more
Explain some features of the olfactory nerve
Special sensory
Smell
Olfactory receptors in the crubiform plate
Olfactory tract and bulb
Explain some feature of the optic nerve
Special sensory
Sight
Passes through optic canal thro the formina
Optic nerves meet at chiasms and cross over
What are the two main structures of the eye
Pupil - hole the centre where light passes through
Iris coloured part
associciated circular smooth muscle sphincter pupillae
And radial is dilator pupillae
What causes the pupil to constrict
Parasympathetics
Oculomotor nerve reached to eye
What causes the pupil to dilate
Sympathetics
Reach the orbit following arteries
How do u clinically test the optic nerve
Flashing light in eyes See pupillary light reflex Both eyes hold constrict Sensory is from optic nerve Moto pr is from oculomotor
Describe some features of the oculomotor nerve
Mixed
Somatic motor - muscles of eye in orbit extra ocular
Parasympathetic - sphincter pupillae muscle
What does the trochlear nerve suppl
One extra ocular muscle = superior oblique muscle
Very delicate
Only cranial nerve that emerges form midbrain
Called trochlear as Ct tubing where muscle is called trochlea
What does the abducens nerve supply
Somatic motor
Of one extra ocular eyes the lateral rectus muscle which helps abduct the eye
Leaves the brain from the junction between the pons and medulla
What does the trigeminal nerve innervate
Mixed
Somatic motor - root shoes rate joins with sensory part of Vc at foramen ovale
Sensory - Va sensory to upper face, Vb sensory to mid face
Vc - mixed as has sensory to lower face and motor for muscles of mastication
What are all the foraminae that the cranial nerves exit out of
Olfactory- crubiform Optic - optic canal Oculomotor - superior orbital fissure Trochlear - superior orbital fissure Trigeminal - Va and Vb (foramen rotundum) Vc (foramen ovale) Abducens - superior orbital fissure Facial - internal acoustic meatus Vestibulocochlear - internal acoustic meatus Glossopharyngeal - jugular foramen Vagus - hypoglossal canal Spinal accessory - spine Hypoglossal - hypoglossal canal
What nerves pass thought the lateral walls of the cavernous sinus
Oculomotor, trochlear and the Opthalmic and maxillary divisions of the trigeminal nerve
What things pass through the actual cavernous sinus
Internal carotid artery
Abducens
(Submerged in venous blood)
What are the subdivisions of the cranial fossa
Anterior - frontal, ethmoid, sphenoid
Middle - sphenoid and temporal
Posterior - temporal and occipital
