Neuroanatomy: Spinal Cord Anatomy and Ascending + Descending Pathways Flashcards
Which are the two areas of enlargement in the spinal cord?
Cervical (upper limb) and lumbar (lower limb).
What are the named segments of the nerve fibres as they leave the spinal cord?
Dorsal/ventral rootlets
Posterior/anterior roots
Mixed spinal nerve
Posterior/anterior rami
Which rami carries motor information?
Anterior (move forward)
Which rami carries sensory information?
Posterior (kiss my arse)
Why is the posterior root larger than the anterior root?
Enlarged by dorsal root ganglion.
What is the name and level of the termination of the spinal cord?
Conus Medullaris (L1)
What structure continues down the cord, anchoring to the dorsum of the coccyx?
Filum terminale
What name is given to the spinal levels below the termination at L1?
Cauda Equina
Which structure suspends the spinal cord in the canal?
Denticulate ligament
What layers of meninges form the tentacular ligament?
Pial and Arachnoid tissue (attaching it to the dura)
In the grey matter of the spinal cord, which horns are the biggest?
Posterior - extend right to edge.
Which horn can also be found between spinal segments T1 to L2?
Lateral horn (pre-ganglionic sympathetic neurones)
What is the blood supply to the spinal cord?
Longitudinal arteries: 1 anterior, 2 posterior. originating at vertebral arteries.
Segmental arteries: derived from vertebral, intercostal and lumbar arteries.
Radicular arteries: travel along the dorsal and ventral routes.
In the spine, unlike in the cranial cavity, there is space between dura and bone - what is this space called?
Epidural Space
What is found in the epidural space?
Adipose tissue, anterior and posterior venous plexi.
Where is the somatosensory cortex located?
Post-central gyrus.
Somatosensory information from which area DOES NOT travel within the spinal cord?
Face and scalp
In which tract does fine touch and proprioception travel?
Posterior (Dorsal) Column Medial Lemniscal Pathway
What are the 2 components of the dorsal column?
Fasciculus Gracilis & Fasciculus Cuneatus
What does the fasciculus gracilis (medial) carry?
Sensation from the legs
What dies the fasciculus cuneatus (lateral) carry?
Sensation from the arms
What is the course of the PCML pathway?
Cervical and lumbar cords decussate in medulla
2nd order neurones to the thalamus
3rd order neurones to somatosensory cortex
What information is carried in the Spinothalamic tract?
Pain, temperature & deep pressure
What is the course of the spinothalamic tract?
Tracts decussate at whatever level they enter
2nd order neurones towards thalamus.
3rd order neurones from thalamus to somatosensory cortex.
Where is the motor cortex located?
The pre-central gyrus
What motor tract carries information about fine, precise movement?
Corticospinal Tract
What is the course of the corticospinal tract?
Begins in the cortex and descends to midbrain.
85% fibres cross at the medulla forming the lateral corticospinal tract.
15% continue down forming the ventral corticospinal tract.
The 15% decussate at the appropriate level in the spinal cord.
What may the corticospinal tract also be referred to as?
Pyramidal tract
Which tract is responsible for orientating head and eye movement to audio and visual stimuli?
Tectospinal tract
Which tract forms a diffuse network of nuclei and interconnections, responsible for many motor functions e.g. voluntary movement, respiration?
Reticulospinal tract
Which tract is responsible for excitatory input to antigravity (extensor) muscles?
Vestibulospinal tract
What is unusual about the vestibulospinal tract?
It is ipsilateral and does not cross the tract.
