Spinal Reflexes

Question 1

What is a reflex?

Answer 1

Predictable stereotyped response to a specific stimulus (e.g., muscular contraction after stretch of the patella tendon)

• Spinal reflexes are mediated at the level of the spinal cord

Question 2

Whatis the monosynaptic reflex?

Answer 2

Monosynaptic reflex

• Afferent and efferent limb are directly connected (e.g., deep tendon reflex)

Question 3

What is the poly synaptic reflex?

Answer 3

Polysynaptic reflex

• Afferent and efferent limb are interconnected with one or more interneurons (abdominal reflex)

Question 4

What is the function and segm. Of the diaphragm?

Answer 4

Inspiration

C3,4,5

Question 5

What is the function and segm. Of the deltoid?

Answer 5

Shoulder abduction

C5

Question 6

What is the function and segm. Of the biceps brachii, brachioradialis, brachialis?

Answer 6

Elbow flexion, C5,C6

Question 7

What is the function and segm. Of the extensor carpi, radialis longus and brevis?

Answer 7

Wrist extension

C6,7

Question 8

What is the function and segm. Of the triceps brachii?

Answer 8

Elbow extension

C7-8

Question 9

What is the function and segm. Of the flexor digutorum superficualis and profundus?

Answer 9

Finger flexion

C8

Question 10

What is the function and segm. Of the interossei?

Answer 10

Finger ab- and adduction

C8, T1

Question 11

What is the function and segm. Of the adductor longus and brevis?

Answer 11

Thigh adduction

L2,3,4

Question 12

What is the function and segm. Of the quadriceps?

Answer 12

Knee extension.

L2-4

Question 13

What is the function and segm. Of the extensor hallucus longus?

Answer 13

Great toe Extension

L5, S1

Question 14

What is the function and segm. Of the gastrocnemius, soleus?

Answer 14

Ankle plantar flexion

S1,2

Question 15

What is the function and segm. Of the sphincter ani externus?

Answer 15

S2,3,4

Anal contraction

Question 16

What are the landmarks for reflex testing?

Answer 16

• C5, C6: Biceps, brachioradialis
• C7,C8:Triceps
• L2, L3, L4: Knee jerk
• L5, S1: Plantar Response
• T8–T12:AbdominalReflex
• S1: Ankle jerk

Question 17

Describe the scale for reflex testing

Answer 17

Normal responses vary widely, and healthy individuals can express weak reflexive responses

• Differences between sides often indicate disease

0- absent, areflexia

1+ may or may not be normal, diminished, hyporeflexia

2+ brisk, nirmal

3+ - may or may not be normal, hyperrefkexia, very brisk

4+-exxagerated, hyperreflexia+ clonus

Question 18

What is the plantar response?

Answer 18

When the lateral aspect of the sole is stroked from the heel to the ball of the foot with a semi-sharp object, a plantar response is evoked.

• Afferent limb: nociceptive fibers (A delta and C).
• Efferent limbs: alpha motor neurons (L5 and S1).

Question 19

What is to be pbserved in the plantar response?

Answer 19

Observe the movement of the toes:

Normal: Brisk flexion of all toes when the sole of the foot is stroked by a blunt instrument (flexor response). Seen in adults or a children older than 2-years old

Abnormal: Dorsiflexion of the great toe while the other toes fan out (extensor response) This is called the Babinski Reflex and indicates an upper motor neuron lesion