Neuro anatomy Flashcards
What is the function of the thalamus?
Bodies info relay station
All info (except smell) is processed here before being sent to the cerebral cortex
What is the internal capsule?
Two way tract for transmission of information to and from the cerebral cortex
Where does sensory info from below T6 synapse first?
Fasiculus gracillis
Where does sensory info from above T6 synapse first?
Faciculus Cuneatus
What nerve is damaged if corneal reflex/blink is absent
Opthalmic
What foramina does the opthalmic nerve pass through?
Superior orbital fissure
Gag reflex is which nerve and which foramen does it pass through?
Glossopharyngeal (CN IX)- jugular foramen
What is Bell’s palsy?
A palsy of the facial nerve (CN VII) causes unilateral facial weakness
Tx- pred
What does the facial nerve pass through
Internal Acoustic Meatus
Damage to what portion of the thalamus would affect facial sensation?
Ventral posteromedial nucleus
Describe Alzheimer’s
Caused by cortical plaque deposition due to abnormal aggregation of tau protein
Signs/symptoms- misplacing items, difficulty remembering new things but can recall earlier memories
Ix- atrophy of brain sulci on CT
Where does the maxillary nerve pass through the sphenoid bone?
foramen rotundum
What can B12 deficiency cause?
Damage of the dorsal columns and corticospinal tracts so affect light touch, vibration and proprioception
What nerve innervates the carotid body and sinus?
Glossopharyngeal
Describe the flow of CSF through the ventricles
Two lateral ventricles drain into 3rd ventricle via interventricular foramina
Then to 4th ventricle via:
Foramen of Magendie into cisterna magna (between cerebellum and medulla) -> subarachnoid space
Laterally via foramina of Luschka into cerebellopontine angle cistern (between pons and cerebellum)
State how rootlets become rami
At each segment of the spinal cord dorsal and ventral rootlets arise
Then become anterior and posterior roots
Then join to become a mixed spinal nerve
Then divide into anterior and posterior rami
What do posterior rami supply
The posterior body wall
What do anterior rami supply
Anterolateral body wall
What innervation do anterior roots always carry?
Motor innervation
What innervation do posterior roots always carry?
Sensory innervation
What innervation do spinal nerves carry?
Mixed modalities
- general sensory to all structures
-somatic motor to skeletal muscles
-sympathetic nerve supply to skin -smooth muscles of arterioles
Where does sympathetic supply exit?
T1-L2 only thoracolumbar through anterior root onto sympathetic chain then rides on arteries to head and neck.
What are the two major ateries of blood supply to the brain?
Internal Carotid and vertebral arteries
Which foramina does the vertebral artery pass?
Foramen Magnum
What provides blood to the dura mater?
Middle meningeal artery
In a third nerve palsy where is the lesion?
Posterior communicating artery aneurysm located in the circle of willis
What is a non-epileptic attack disorder?
A seizure not caused by abnormal brain electrical activity but psychological stress.
Key features- pelvic thrusting, head movements, closed eyes, post-ictal weeping
What does the anterior spinothalamic tract carry?
Crude touch and pressure
What does the lateral spinothalamic tract carry?
Carries sensation of pain and temp
What is the function of the cerebellum?
Coordinating movement and balance
Where does the cerebellum get its input from?
Motor cortex, brainstem, somatosensory system
What does the basal ganglia help do?
Facilitate wanted and inhibit unwanted movements
Which vessel is damaged in an extradural haematoma?
Middle meningeal artery
Which vessel is damaged in a subdural haemorrhage?
Anterior/middle cerebral arteries
Where does a extradural haemorrhage occur?
Between the dura and the skull
Where does a subdural haematoma occur?
Between dura mater and arachnoid mater
Where does a subarachnoid haemorrhage occur?
Between arachnoid and pia mater
What does a subdural haematoma look like on CT?
Cresent shaped hyperdense lesion
What muscles make up the erector spinae
Illiocostalis+longissiumus+spinalis
What would happen following occlusion of the basilar artery?
Bilateral loss of corticospinal tracts.
What is the role of the medial longitudinal fasciculus?
Myelinated fibre tract in the brainstem which acts as the central connection for the oculomotor nerve, trochlear nerve, and abducens nerve. Carries info about the direction the eyes should move.
How does internuclear ophthalmoplegia present?
Ipsilateral impairment of the adducting eye and nystagmus in the abducting eye on contralateral gaze
What are the vertebral arteries a branch of?
Subclavian arteries
What is the middle cerebral artery a branch of?
Internal carotid
What supplies the skin over the angle of the mandible and part of the external ear?
Great auricular nerve C2,3
Flexion of the fingers is which myotome?
C8
Extension of the fingers is which myotome?
C7
Ab/adduction of the fingers is which myotome?
T1
Flexion of the wrist is which myotome?
C6,7
Extension of the wrist is which myotome?
C7,8
Flexion of the hip joint is which myotome?
L2,3
Extension of the hip joint is which myotome?
L5,S1
What nerves arise from the pons?
CN 5,6,7,8
Function of the rubrospinal tract?
Excites flexor muscles and inhibits extensor muscles, primarily of upper body
Which mechanoreceptors sense stabbing pain?
Alpha delta- thick myelinated
Which mechanoreceptors sense slow, throbbing pain?
C-fibres- unmyelinated
Where is a lumbar puncture taken from?
Between L3 and L4 within the subarachnoid space
Where does the dural sac terminate?
S2
What is Wernicke’s area supplied by?
Inferior division of the left MCA
What does morphine bind to?
µ receptors (Mu) in CNS
What do schwann cells do?
Myelination in peripheral nervous system
How does neurogenic shock arise?
Cervical/high thoracic injuries above T6. Symp outflow from T1-L2 so disrupts this leading to unopposed parasymp tone = hypotension and bradycardia
What nerve is involved in plantar flexion and foot eversion?
Superficial peroneal nerve
What is babinski sign positive in?
Corticospinal tract lesion
How does the internal carotid form?
Brachiocephalic trunk -> right common carotid -> right internal carotid
What is the blood supply to the brain?
Internal carotid and vertebral arteries
What do the R+L vertebral arteries branch from?
Subclavian arteries
Roots of the axillary nerve
C5,C6
Roots of the median nerve
C5-T1
Roots of the ulnar nerve
C8-T1
Roots of the femoral nerve
L2-L4
Cauda equina nerve roots?
L1-L5
Decreased sensation in 1st webspace?
Deep peroneal nerve
Eversion of foot?
Common Peroneal
Dorsiflexion of ankle?
Deep fibular/peroneal nerve
Loss of sensation to sole of foot?
Tibial
