Reference no: EM133198680
To conduct this assessment:
1. The patient sits with their arm completely relaxed on their thigh.
2. The clinician will locate the biceps brachii tendon by palpating within the antecubital fossa.
3. The clinician places their thumb over the tendon and strikes their thumb with the pointed end of the reflex hammer.
4. The vigor (strength) of the contraction is then assessed using the scale in the table below.
The vigor of contraction is graded on the following scale:
Score
|
Contraction Vigor
|
Possible indication
|
0
|
No evidence of contraction
|
Disorder or damage in sensory neurons or lower motor neurons (limb injury)
Diseased or damaged neuromuscular junctions or muscles
|
1+
|
Diminished contraction, but still present (hyporeflexic response)
|
Disorder or damage in sensory neurons or lower motor neurons (limb injury)
Hypoparathyroidism
|
2+
|
Normal
|
|
3+
|
Brisk or Super-normal contraction (hyperreflexic response)
|
Disorder or damage in upper motor neurons in the CNS (stroke or cord injury)
Hyperparathyroidism
|
4+
|
Clonus: Repetitive shortening of the muscle after a single stimulation
|
Lesions to upper motor neurons (stroke, cord injury, Multiple sclerosis)
Liver failure or serotonin syndrome
|
Interpret the results of the biceps brachii tendon reflex test for the Patients below:
1. Sarah shows no evidence of contraction after dislocating her shoulder. What is her score & what might this indicate?
2. Jerome demonstrates clonus when testing his reflexes at his yearly exam. What is his score & what might this indicate?
3. Using your notes or textbook, define stretch reflex and explain the protective purpose of this reflex.
B. Patellar tendon reflex test:
This test is used to assess the stretch reflex, determining the function of the reflex arcs for spinal nerves L2, L3, L4 & the femoral nerve. Specifically, this test activates the stretch receptors in the quadriceps femoris muscles which send signals through these nerves stimulating a reflex contraction in the muscles. This contraction is seen when the lower leg kicks forward. The strength of the contraction is assessed to determine possible damage to sensory or motor neurons within the pathways. (See the table on the previous page).
To conduct this assessment:
1. The patient is seated on the lab table with legs hanging freely,
2. The clinician finds the patellar tendon by palpating just below the patella.
3. The clinician strikes the patellar tendon with the pointed end of the reflex hammer.
4. The vigor (strength) of the contraction is then assessed using the scale in the table on page 1.
Interpret the results of the patellar tendon reflex test for the Patients below:
When reviewing a patient's record, you see their score for their patellar tendon reflex is 3+.
Based on this score, what was the contraction vigor for this patient's tendon reflex?
The patient's record states that they have hypoparathyroidism. Does this make sense with the results? Explain.
Watch This!
Click on the link below to watch a video describing what happens during the patellar tendon reflex.
YouTube Video: 2-Minute Neuroscience: Knee-jerk Reflex
2. Describe what happens during the patellar tendon reflex to explain why tapping on the tendon causes the leg to kick forward.