Case 3 anatomy Flashcards
what does the lateral fissure do? another name?
Slyvian fissure - separates parietal and temporal lobes
what does the calcarine sulcus do?
divides the visual cortex into two - lies between the gyri of the primary visual cortex
what are the fibres called the connect the two hemispheres?
COMMISSURAL fibres
what do the superior and inferior longitudinal fasciculi connect?
- The superior longitudinal fasciculus connects the frontal lobe with the occipital lobe
- The inferior longitudinal fasciculus connects the occipital lobe with the temporal lobe
what is an example of commisural fibres (not corpus callosum) and what does it connect?
anterior commissure
connects the inferior and middle temporal gyri and olfactory regions of each side
describe the most imporant route of the projection fibres
- Corona radiata = fibre bundle that projects to and from the cortex
- Fibres in this bundle converge to form the internal capsule (separates the caudate nucleus and the thalamus from the putamen and the globus pallidus) which passes towards the midbrain
- In the midbrain the fibres of the internal capsule form the crus cerebri (anterior portion of the cerebral peduncle which contains the motor tracts, travelling from the thalamus to the pons and spine)
what does the internal capsule consist of?
anterior limb, posterior limb, genu and retrolenticular part
what does each part of the internal capsule contain?
- Anterior limb – contains connections between the thalamus and prefrontal cortex and frontopontine fibres that connect the frontal cortex to the pontine nuclei (nuclei of the pons involved in motor activity – located in the ventral pons)
- Posterior limb – contains corticobulbar (upper motor neurons of the cranial nerves – bulbar becomes goes to medulla (‘bulbar’)) and corticospinal fibres and also thalamocortical fibres that pass between the ventral posterior nucleus of the thalamus and the primary sensory cortex
- Retrolenticular part – contains fibres that pass from the lateral geniculate nucleus (of thalamus) to the visual cortex and from the medial geniculate nucleus (of thalamus) to the auditory cortex (retrolenticular part is the bit at end of the posterior limb)
how many layers in the cortex? what according to?
- Cerebral cortex consists of neuronal cell bodies, dendrites and axons
- There are 6 layers of cortex according to the arrangement of these components
- The arrangement of these layers differs in different regions of the brain
- Brodman’s numbering system
the primary somatosensory area receives fibres conveying information about what?
course touch and pressure, fine touch and proprioception, pain and temperature
how is the primary somatosensory cortex arranged?
somatotopically
- using sensory homunculus - head first, then arm, then leg (going laterally to medially)
- up the face, up the arm, down the leg
where is the primary auditory cortex?
superior temporal gyrus
where is the sensory cortex for smell?
spread over number of areas:
- uncus
- entorhinal area
- limen insula
how is the primary motor cortex arranged?
- somatotopically
- motor humunculus - same arrangement as sensory basically
what is the frontal eye field? what does it do?
part of the DLPFC
plays an important role in the control of visual attention and eye movements
what is the supplementary (secondary) motor area?
contributes to control of movement, important in planning complex movement (contralateral side)
in the midline just in front of primary motor cortex
premotor cortex is lateral to SMA
what is the auditory association area?
Wernicke’s area - interpretation and understanding of spoken words
which muscles are involved in speech and therefore are coordinated by broca’s area?
the muscles of respiration, larynx, pharynx, tongue, palate, lips and the jaw
what does the arcuate fasciculus form part of?
the superior longitudinal fasciculus
where are blind spots?
15* from central line
what happens to some fibres arising from the inferior colliculus?
• Some fibres arising from the inferior colliculus project directly to the motor nuclei in the brain stem or spinal cord – these fibres initiate auditory reflexes involving muscles of the head, neck and trunk
does the palatine bone contribute to the orbit? does the temporal?
yes - inferior wall - small and at the back
no
where does the optic canal lie?
in the lesser wing of sphenoid
what are the anterior and posterior ethmoidal foramina?
small foramina located on the medial wall of the orbit within the ethmoid bone – they communicate with the lateral wall of the nasal cavity
(they’re where ethmoidal bone meets frontal bone)
what does the lacrimal groove lead to?
nasolacrimal canal -> inferior meatus of nasal cavity
inferior orbital fissure - what between? what communicate with?
- slit-like opening located posteriorly between the maxilla and the greater wing of sphenoid
- it communicates with the pterygopalatine fossa
what do the infraorbital and supraorbital nerves pass through?
- Infraorbital nerve passes through the inferior orbital fissure
- Supraorbital nerve passes through the supraorbital notch
what lines the orbit?
the periorbita - which is periosteum
where does the fascial sheath extend from and to? what does it do?
- extends from optic nerve to the corneoscleral junction
- separates the eyeball from the surrounding periorbital fat
where and what are the medial and lateral check ligaments?
- The medial and lateral check ligaments are triangular expansions of the sheaths of the medial and lateral rectus muscles
- The medial check ligament is attached to the lacrimal bone – this limits abduction
- The lateral check ligament is attached to the zygomatic bone – this limits adduction
what forms the suspensory ligament?
check ligaments blend with the fascia of the inferior oblique and inferior rectus muscles forming a sling to suspend the eyeball
where is the inferior check ligament? what does it do?
- An inferior check ligament arises from the inferior rectus muscle
- The inferior check ligament retracts the inferior eyelid when the gaze is directed downwards
what is enopthalmos?
when eyeballs retracted into orbit
what is the muscle on the top eyelid?
superior tarsal muscle (assists levator palpebae superioris in elevating eyelid)
what is the superior eyelid called?
superior tarsus