Clinical Neuroanatomy Flashcards
Label the following diagram:
Label the following diagram:
Describe the normal visual pathway [5]
- The contralateral visual field projects onto the temporal or lateral portion of the retina. The ipsilateral visual field projects onto the nasal or medial portion of the retina
- The optic nerve carries all the information from the ipsilateral eye
- Nasal retinal fibres cross in the optic chiasm
- The optic tract contains fibres from the contralateral visual field
- The optic radiations are the projections from the lateral geniculate body to the primary visual cortex
Describe the lesion that would cause monocular vision loss [2]
- A lesion to the optic nerve of one eye will lead to loss of the complete visual field of that eye.
- The other eye can still perceive the entire visual field.
Describe the lesion that would cause bitemporal hemianopia [3]
- A lesion to the optic chiasm leads to loss of the nasal retinal fibers from both eyes.
- These nasal retinal fibers carry information about the temporal visual field.
- A lesion of the optic chiasm leads to the loss of the temporal visual field in both eyes.
Describe the lesion that would cause contralateral homonymous hemianopia [3]
- A lesion to the optic tract will affect the nasal (crossed) fibers from the contralateral eye and the temporal (uncrossed) fibers from the ipsilateral eye.
- These fibers carry information from the contralateral visual field.
- A lesion of the optic tract will lead to the loss of the contralateral visual field in both eyes.
Describe the lesion that would cause contralateral superior quadrantanopia [2]
A lesion to the Meyer loop will affect the fibers from the upper portion of the contralateral visual field from both eyes
Describe the lesion that would cause contralateral inferior quadrantanopia [2]
A partial lesion of the optic radiations before they are joined by fibers from Meyer’s loop will affect fibers from the lower portion of the contralateral visual field from both eyes
Describe the lesion that would cause contralateral homonymous hemianopia [2]
A lesion of the entire primary visual cortex on one side will lead to the loss of the contralateral visual field from both eyes
What areas of the nervous system are responsible for controlling speech? [5]
- Broca’s area
- Arcuate fasciculus
- Wernicke’s area
- Auditory cortex
- Corticobulbar tract & bulbar muscles
What is the function of Broca’s area? [1]
responsible for the initiation and control of speech
What is the arcuate fasciculus? [1]
bundle of axons that connects Broca’s area and Wernicke’s area in the brain
What is the function of Wernicke’s area? [1]
responsible for the comprehension of speech
Label the following diagram of the brainstem:
What is the epidural space and what does it hold? [3]
- true space between the dura and the vertebral periosteum
- filled with fat and venous plexus
What is the subarachnoid space filled with? [1]
CSF
Where does the dura mater extend to? [1]
extends to S2
Describe the features of the posterior root of spinal cord [3]
- what type of info does it carry?
- where are the cell bodies located?
- where does it enter the spinal cord?
- carries sensory information
- cell bodies are in the spinal ganglion
- enters the spinal cord in the posterolateral sulcus
Describe the features of the spinal ganglion [3]
- what does it contain?
- what type of neurons is it composed of?
- are there any synapses?
- contains the nerve cell bodies of primary sensory afferents
- composed of pseudounipolar neurons
- there are no synapses
What are the denticulate ligaments and what do they separate? [2]
- extensions of pia that anchor the spinal cord to the dura
- lateral denticulate ligaments separate the posterior and anterior roots
What is the function of the fasciculus gracilis? [5]
sensory tract from the ipsilateral lower limb:
- fine touch
- vibration
- proprioception
What is the function of the fasciculus cuneatus? [5]
sensory tract from the ipsilateral upper limb:
- fine touch
- vibration
- proprioception
What is the function of the spinocerebellar tract? [2]
proprioception from the limbs to the cerebellum
What is the function of the lateral corticospinal tract? [2]
motor to ipsilateral anterior horn (mostly limb musculature)
What is the function of the spinothalamic tract? [3]
pain and temperature from the contralateral side of the body
What is the function of the anterior corticospinal tract? [3]
motor to the ipsilateral and contralateral anterior horn (mostly axial musculature)
What is the function of the anterior white commissure? [3]
-
area of decussation:
- pain and temperature fibres cross
- anterior corticospinal tract fibres cross
Describe the dorsal column-medial lemniscal pathway (DCML), which is responsible for light touch, vibration and proprioception [6]
Describe the spinothalamic pathway, responsible for pain and temperature sensation [5]
Describe the motor corticospinal tract [6]
What are the different patterns of sensory loss and what are each caused by? [8]
Describe how a spinal reflex works [6]
- Ia fibre from muscle spindle senses stretching of the muscle
- Ia fibre synapses directly with α-motor neuron in anterior horn
- α-motor neurons to the extensor muscles are excited
OR
- Ia fibre synapses with inhibitory interneuron
- inhibitory interneuron inhibits the α-motor neuron of the antagonist muscle
- α-motor neuron of antagonist muscle is inhibited
