Spinal Tracts (156-172)

Question 1

In what surgeries do the hypogastric plexuses become damaged?;

Answer 1

Anterior resection, TME, rectal surgeries

Question 2

What nerves contribute to the micrturition process?;

Answer 2

Parasympathetic (to void [detrusor muscle contracts and internal sphincter relaxes]) - S2, S3, S4 (Pelvic splanchnic nerves).

Sympathetic (to retain urine [detrusor muscle relaxes and internal sphincter contracts) - T10, T11, T12, L1, L2 (Superior hypogastric and pelvic plexuses)

Somatic (voluntary) - Pudenal nerve (S2-4)

Question 3

What is the aetiology of a relflx bladder and overflow incontinence in patients with spinal cord injuries?;

Answer 3

Reflex bladder- high spinal cord injury & therefore parasympathetic is working (able to void) however loss of voluntary control so is overactive.

Overflow incointinence- Low spinal cord injury (at or below S2-4) & therefore parasympathetic is not working - so cannot void bladder resulting in distended bladder & overflow.

Question 4

Name three arteries that supply the spinal cord?;

Answer 4

Single anterior spinal artery (anterior 2/3rd of cord) and the two posterior spinal arteries (posterior 1/3rd of cord)

Question 5

Name the ascending tracts in the spinal cord?;

Answer 5

[ascending tracts=sensation]
* Dorsal column-medial lemiscal pathway (fine touch, proprioception).
* Anterior spinothalamic tract (crude touch and presure).
* Lateral spinothalmic tract (pain and temperature).
* Spinocerebellar tracts (unconscious sensation/proprioception)

Question 6

Name the descending tracts in the spinal cords;

Answer 6

[descending tracts=motor]
Anterior & lateral Corticospinal tracts (musculature of body).
Anterior & lateral Corticobulbar (musculature of head and neck). Extrapyramidal tracts

Question 7

What functions are carried out by the spinothalamic tracts?;

Answer 7

Anterior spinothalamic- Crude touch and pressure.
Lateral spinothalamic- pain and temperature

Question 8

What functions are carried out by the corticospinal tracts?;

Answer 8

Musculature of body (voluntary motor)

Question 9

What functions are carried out by the corticobulbar tracts?;

Answer 9

Musculature of head and neck (voluntary motor)

Question 10

At what levels do the descending spinal cord tracts decussate?;

Answer 10

Anterior corticospinal tract remains ipsilateral while descending down spinal cord and then decussates at the ventral horn where it terminates (synapses with lower motor neurons).

Lateral corticospinal tract decussate immeadiately at medullary pyramids (top of spinal cord) and then decend down contralateral side. Terminates at the ventral horn (synapses with lower motor neurons)

Question 11

Name three key features of neurogenic shock;

Answer 11

Hypotenion, Braycardia, flushed (decresed systemic vascular resistence due to loss of sympathetic tone resulting in blood pooling in extremities). [Can differentiate from spinal shock as there is loss of sympathetic tone to heart in neurogenic shock]

Question 12

Name five red flag features for a patient with back pain;

Answer 12

Urinary retention, Bladder/bowel incontinence, Altered perianal sensation or tone (saddle anaesthesia), unrelenting night pain, progressive neurological weakness, Bilateral radicular pain,

Question 13

What are the salient differences bewteen cauda equina and conus medullaris syndrome;

Answer 13

Cauda equina (distal to spinal cord - collection of spinal nerve root [horses tail])- gradual, asymmetric (sensory loss, motor deficit), LMN signs e.g. hyporeflexia, hypotonia, plantar flexor. Sphincter involvement & erectile dysfunction less common/late feature.

Conus medullaris (most distal part of spinal cord [tip is at L1/2)- sudden, symmetric (sensory loss, motor deficit), UMN signs e.g. hyperreflexia, hypertonia. Sphincter involvement & erectile dysfunction common/early feature (bulbocaverous relfex absent).

Question 14

What is anterior cord syndrome? What would be the functional deficit?;

Answer 14

Bilateral loss of motor, crude touch, pressue, pain and temperature sensation below level of injury (corticospinal tracts, anterior and lateral spinalthalmic tracts affected). Intact fine touch and proprioception (Doral colmn-medial lemiscal pathway intact)

Question 15

What is posterior cord syndrome? What would be the functional deficit?;

Answer 15

Loss of fine touch and proprioception (Dorsal column-medial lemiscal pathway affected). Intact pain and temperature sensation (lateral spinothalamic intact)

Question 16

What is central canal syndrome ? What would be the functional deficit?;

Answer 16

Upper extremities affected more than lower extremities. Sensory and motor deficits

Question 17

What is Brown-Sequard syndrome? What would be the functional deficit?;

Answer 17

Neurological syndrome due to hemitransection of the spinal cord.

Contralateral loss of pain and temperature (Lateral spinothalamic tract crosses at spinal cord from peripheries).
Ipsilateral loss of motor, fine touch, proprioception (Dorsal column-medial lemiscal pathway and Lateral Corticospinal tracts don’t cross at ventral horn).