cranial fossa Flashcards
what does the anterior cranial fossa form?
the roof of the orbit, contributes to the nasal cavities and has foramina related to the special senses of vision and smell
what lobes of the brain are found in the anterior cranial fossa?
the frontal lobes
what is the attachment site for the dura mater?
the crest Galli - a bony ridge formed by the frontal bone
the cribriform plate is part of which bone?
the ethmoid bone
in life what lies on the superior surface of the cribiform plate?
the olfactory bulbs
what bone that contributes to the anterior cranial fossa contains the optic canals?
the sphenoid bone
what is the function of the optic canals?
allow optic nerves (Cn2) and ophthalmic arteries to pass between the orbit and inside the skull
explain the contribution of the sphenoid bone to the middle cranial fossa
the sphenoid bone contributes to the floor of hte middle cranial fossa and forms the floor of the orbital fissures, foramen rotundum, foramen ovale and foramen spinosum
where does the trigeminal nerve divide into its 3 divisions?
it forms a large ganglion that sits on the floor of the middle cranial fossa and here it divides into its three divisions
explain the course of the ophthalmic division of the trigeminal nerve (V1)
it is a sensory nerve that passes through the superior orbital fissure to reach the orbit
what nerves accompany the ophthalmic division of the trigemianl nerve as it passes through the superior orbital tissue to reach the orbit?
oculomotor (CN3), trochlear (CN4) and abducens (CN6)
explain the course of the maxillary division of the trigeminal nerve (V2)
it carries sensory nerves which pass through the foramen rotundum to pass towards the maxilla
explain the course of the mandibular division of the trigeminal nerve (V3)
it carries motor and sensory fibres through the foramen ovale to the infratemporal fossa
apart from the mandibular division of the trigeminal nerve what else passes through the foramen ovale?
the otic ganglion, the accessory meningeal artery, the lesser petrosal nerve and emissary veins
what does the foramen spinosum carry?
the middle meningeal artery
where does the middle meningeal artery arise from and what does it supply?
is a branch of the maxillary artery
supplies blood to the dura
what foramen allows the internal carotid artery to enter the middle cranial fossa?
the foramen lacerum
what lobes of the brain lie in the middle cranial fossa?
the temporal lobes
how does the internal carotid artery enter the skull?
via the carotid canal
explain the course of the internal carotid artery
it enters the skull via the carotid canal then turns away from the canal and enters the top of the foramen lacerum it does not pass all the way through the foramen lacterum and small blood vessels transverse the length of the foramen lacterum
the artery then lies either side of the body of the sphenoid bone where it will enter the cavernous venous sinus before contributing to the circle of willis
which bones make up the posterior cranial fossae?
the temporal bone (contributes to the floors of both the middle and posterior cranial fossae)
the occipital bone (forms most of the floor of the posterior fossa)
which structures pass through the jugular foramen?
the internal jugular vein
the glossopharyngeal nerve
the vagus nerve
the accessory nerve
which structures pass though the foramen magnum?
the spinal cord and its meninges (leaving the skull)
the vertebral arteries and part of the accessory nerve (entering the skull)
what structure passes through the hypoglossal canal?
the hypoglossal nerve (exiting the skull)
what structure passes through the hypoglossal canal?
the hypoglossal nerve (exiting the skull)
what part of the brain lies in the posterior cranial fossa?
the cerebellum
what sits in the petrous bit of the temporal bone?
the internal acoustic meatus
what passes through the internal acoustic meatus?
the facial nerve and vestibular cochlear nerve (exiting the cranial cavity and entering the temporal bone)