Neuroanatomy Flashcards
Oculomotor nerve CN lll - derived from the Oculomotor nucleus in the midbrain.
It emerges anterior to the midbrain between which structures
Deep to PCA and superficial to SCA
Which nerve innervates the superior tarsal muscle
Sympathetic fibres - hitch-hikes on superior branch of CN III
The trochlear nerve CN IV is the smallest cranial nerve with the longest intra-cranial course - it emerges from the posterior aspect of the midbrain.
The nerve fibres cross over and innervate which muscle on the contralateral side?
Superior oblique
What are the clinical features of CN IV palsy?
Vertical diplopia - exacerbated when looking downwards and inwards
Head tilt away from affected side
The trigeminal nerve has 3 terminal branches - they exit the cranium via which foramen?
V1 - superior orbital fissure
V2 - foramen rotundum
V3 - foramen ovale
Name the terminal branches of V1
Frontal
Lacrimal
Nasociliary
The Lacrimal gland is innervated by which nerve fibres?
Post-ganglionic fibres from pterygopalatine ganglion (from facial nerve) - travel with V2 then lacrimal branch V1
Name the structures passing through the cavernous sinus
Oculomotor Trochlear Ophthalmic nerve V1 Maxillary nerve V2 Abducens ICA
- The facial nerve exits through which foramen in the temporal bone?
- CN V exits the cranium via which foramen?
- Internal acoustic meatus in petrous part of temporal bone
- Stylomastoid foramen via facial canal
Name the intra-cranial branches of the facial nerve and the structures they innervate
Greater petrosal nerve - parasynpathetic fibres to mucous glands and lacrimal gland
Nerve to srapedius - stapedius muscle
Chorda tympani - taste to anterior 2/3 tongue
Name the extra-cranial branches of the facial nerve and the structures they innervate
Posterior auricular nerve - muscles around the ear
Branch to posterior belly digastric
Branch to stylohyoid
Temporal branch - frontalis, obicularis oculi, corrugator supercilii
Zygomatic - obicularis oculi
Buccal - buccinator, obicularis oris, zygomaticus
Marginal mandibular - mentalis
Cervical - platysma
Causa equina is a bundle of nerve roots situated inferior to the spinal cord where it terminates at the conus medullaris (L1)
Cauda equina is formed by lower motor neurones innervating which anatomical structures?
Motor and sensory to lower limb (L1-S5)
Anal sphincter
Parasympathetic innervation to bladder
Causa equina is a bundle of nerve roots situated inferior to the spinal cord where it terminates at the conus medullaris (L1)
Cauda equina is formed by lower motor neurones innervating which anatomical structures?
Motor and sensory to lower limb (L1-S5)
Anal sphincter
Parasympathetic innervation to bladder
Cauda equina syndrome (CES) is a surgical emergency
- Clinical features
- Causes
- Investigation
1.1. Reduced lower limb sensation (bilateral) Saddle anaesthesia Lower limb weakness with hyporeflexia Bladder or bowel dysfunction - urinary retention, reduced ability to void Severe back pain Impotence
1.2. Disc herniation Trauma Neoplasm Infection - discitis or Potts disease Chronic spinal Inflammation Iatrogenic
1.3. Whole spine MRI
The descending tracts of the CNS can be divided into pyramidal and extra-pyramidal pathways.
The pyramidal tracts originate in the cerebral cortex - name their further subdivisions.
Corticospinal - supplies muscles of the body
Corticobulbar - supplies muscles of the head and neck
Describe the course of the corticospinal tract
Originates in cerebral cortex - recieves inputs from primary motor cortex, premotor cortex, supplementary motor area
Decend through internal capsule
Crus cerebri of midbrain, pons, medulla
Fibres within lateral corticospinal tract decussate in medulla
Anterior corticospinal tract remains ipsilateral
Terminate in ventral horn
Describe the course of the Corticobulbar tracts
Arise in the lateral aspect of the primary motor cortex
Converge in the internal capsule
Neurons terminate on the motor nuclei of cranial nerves
Synapse with LMNs
Regarding the dorsal-column medial lemniscus (DCML) pathway
1.1. Which sensory information do the carry
Describe the pathway for
- 1st order neurons
- 2nd order neurons
- 3rd order neurons
- Light touch, proprioception and vibration
- Sensory information from peripheral nerves to medulla oblongata via
- Upper limb (T6 and above) fasciculus cuneatus (lateral part dorsal column) to nucleus cuneatus
- Lower limb (T6 and below) fasciculus gracilis to nucleus gracilis
- Sensory information from peripheral nerves to medulla oblongata via
- Decussate in medulla - to the contralateral medial lemniscus to reach the thalamus (ventral posterolateral nucleus)
- Thalamus to ipsilateral primary sensory cortex
The spinothalamic tract is divided into anterior and lateral spinothalamic tract
Which sensory information is transmited respectively
Anterior spinothalamic tract - crude touch and pressure
Lateral spinothalamic tract - pain and temperature
Regarding the spinothalamic tracts - describe the pathway for
- 1st order neurons
- 2nd order neurons
- 3rd order neurons
- Sensory receptor in peripheral nerve - to SC and travels 1-2 levels to synapse in the substantia gelatinosa
- Decussate within the SC - travel to thalamus via 2 distinct tracts
Anterior and lateral spinothalamic tracts
1.3. Thalamus (ventral posterolateral nucleus) to ipsilateral primary sensory cortex through the internal capsule
The spinocerebellar tracts collectively transmit unconscious proprioceptive information
Name these tracts
Posterior spinocerebellar tract - proprioceptive information from LLs
Cuneocerebllar tract - ULs
Anterior spinocerebellar tract - LLs
Rostral spinocerebellar tract - ULs
ALL to ipsilateral cerebellum
The spinocerebellar tracts collectively transmit unconscious proprioceptive information
Name these tracts
Posterior spinocerebellar tract - proprioceptive information from LLs
Cuneocerebllar tract - ULs
Anterior spinocerebellar tract - LLs
Rostral spinocerebellar tract - ULs
ALL to ipsilateral cerebellum
