Spinal Reflexes

Question 1

What spinal levels are the patellar reflex (quads) and Achilles tendon reflex (gastrocnemius and soleus) testing?

Answer 1

patellar - L3,4

Achilles - S1,2

Question 2

What occurs in the Babinski reflex test? What is a normal sign vs. abnormal? What does the presence of a Babinski sign indicate?

Answer 2

stroke sole of foot; normal - flexion of big toe; abnormal - extension of big toe; UMN damage

Question 3

What occurs during a Hoffman reflex? What kind of damage has occurred if the fingers flex in this test?

Answer 3

tap distal phalanx of third or fourth finger; UMN damage

Question 4

What does the doctor do during a glabellar reflex test? What is an abnormal sign?

Answer 4

tap forehead; when eyes closed, nodding? persists on repetition

Question 5

What are the 3 types of spinal reflexes?

Answer 5

stretch (myotatic)
autogenic inhibition (inverse myotatic)
flexor

Question 6

What is the stimulus for each spinal reflex?

Answer 6

S - rapid stretch of muscle (tendon tap)
AI - large force on tendon (pull on muscle when resisted)
F - sharp, painful stimulus (like a nail)

Question 7

What is the response of each spinal reflex?

Answer 7

S - stretched muscle contracts rapidly
AI - muscle tension decreases (clasped knife)
F - limb rapidly withdrawn from stimulus

Question 8

What sensory receptors are involved in each spinal reflex?

Answer 8

S - MS Ia and II
AI - Golgi t.o. Ib
F - cutaneous (skin) and pain receptors

Question 9

What synapses are involved in each spinal reflex?

Answer 9

S - MS Ia - monosynaptic
S - MS II - polysynaptic and monosynaptic weakly
AI - polysynaptic (via interneuron)
F - same as AI

Question 10

What is the effect on the muscle from each spinal reflex?

Answer 10

S - excite homonymous m.
AI - inhibit homonymous m.
F - excite flexor m.

Question 11

What other effects do each of the spinal reflexes have other than the primary one?

Answer 11

S - excite synergist and inhibit antagonist mm
AI - inhibit synergist mm and excite antagonist mm
F - inhibit extensors of same limb; excite extensors and inhibit flexors of opposite limb (crossed extensor reflex)

Question 12

What are the functions for each spinal reflex?

Answer 12

S - aid in maintaining posture, counter sudden loads
AI - protective, prevent damage to tendon
F - protective, withdraw from painful stimulus; cross extension supports posture when leg is lifted

Question 13

What spinal levels are the biceps, triceps, and intrinsic hand muscle stretch reflexes testing?

Answer 13

biceps - C5,6
triceps - C6, 7
hand mm - C7, 8