Lec 6

Question 1

Damage to what area causes foot drop?

How does foot drop effect gait?

Answer 1

Damage to dorsiflexors (L5 roots) = foot hang down (can’t dorsiflex)

When walking - high steppage gait
1. Must flex knee more
2. no dorsiflexion in swing phase of walking
3. foot lands on toe first rather than heel

Question 2

Damage to what areas is considered lower motor neuron lesions (damage to where)

Answer 2

Motor nuclei in anterior horn of grey matter (motor nuclei are in here)

Ventral nerve roots damage (motor neurons exit there)

Damage to spinal nerves or peripheral nerve after spinal exit.

Question 3

Describe polio and how it affects nervous system.

What is post polio.

Answer 3

Viral infection - attacks cell bodies in anterior horn (mostly motor neurons)

Mostly affects legs and intercostals leading to difficulty breathing (iron lung was created)

Can recover mostly. Unless damage is done to spinal cord and brainstem result in permanent paralysis.

Post polio - symptoms of polio later in life for ppl that had it

Question 4

Describe how direct spinal cord damage could be considered lower motor neuron lesion

What are three things that can cause damage

Answer 4

If damage affect the monosynaptic reflex arc

1. disk herniation
2. break/other lesion
3. tumour

These things will be considered upper motor neuron damage if the effect the upper motor neurons

Question 5

Where is the primary motor cortex in relation to the central sulcus

From the midline to the outer distal edge of the brain, what part controls what part of the body? (think homunculus)

Answer 5

Just anteriorly/rostral

From deep centre: toes, feet, knee

top middle to outside: hip, trunk, shoulder, arm, elbow, wrist, hand, fingers

From half way down brain to side: neck, brow, eye, face, lips, jaw, tongue, pharynx, larynx

Question 6

what are the two cortico-spinal tracts and what they do?

Answer 6

Lateral - controls distal muscles of hands and feet (distal muscles). Terminates at the cervical and lumbo-sacral enlargements.

• control muscles on contralateral side (sometimes called “pyramidal tract”

Anterior -

Question 7

What is a decussation

Answer 7

where nerve fibres cross over from one side of CNS to other