Unit 8

Neonatal Reflexes and testing reflexes

TOPICS COVERED

Neonatal reflexes

Disorders

UNIT CONTENT

Neonatal reflexes

If these reflexes are not functioning normally, it could indicate a problem in the spinal cord
Failure for these reflexes to “disappear” in a timely manner may suggest slow development of cortical control of movement

Doll’s Eye reflex: When a baby’s head is manually turned, the eyes will stay fixed, instead of moving with the head. This reflex will disappear at about 1 month.

Galant reflex: While stroking a baby's back to one side, the spine and trunk will arch toward that side.

Moro Reflex: Also called the startle reflex. If the baby’s head is not supported the arms will thrust outward and then seem to embrace themselves as the fingers curl. This reflex disappears at about 2 months of age.

Sucking reflex: This reflex occurs when something is placed in the baby's mouth. It ensures that the baby will nurse on a breast or bottle. This reflex is gradually replaced by voluntary sucking around 2 months of age.

Babinski reflex: When the baby’s foot is stroked from heel toward the toes the big toe should lift up, while the others fan out. Absence of reflex may suggest immaturity of the spinal cord. The Babinski reflex may be present up to 1 year. After that the stroking should elicit a downward curling of the toes.

Babkin reflex: When both of baby's palms are pressed, her eyes will close, mouth will open and her head will turn to one side. The Babkin reflex will disappear around 3-4 months.

Rooting reflex: When the baby’s cheek is stroked, it will turn towards the source of the stimulation, usually looking for food. This reflex can be self-induced as the baby fails its arms. This reflex is generally disappears by about 4 months.

Stepping reflex: If a baby’s feet are placed on a flat surface while the upper body is supported, the baby will “walk by placing one foot in front of the other. This isn't really walking and will disappear by about 4 months of age.

Asymmetrical Tonic Neck reflex: Also called the fencing reflex, because of the position the baby assumes. When the baby turns its head to one side the arms and legs will extend on that side. The opposite arm and leg will flex – thus the “fencing” position. This reflex will disappear about the 4 month.

Symmetrical Tonic Neck reflex: When a baby’s head is flexed forward both arms flex and the legs extend. Conversely, when the head is extended backwards, the arms extend and the legs flex. This reflex is will disappear about the 4 month.

Asymmetrical tonic neck reflex

Asymmetrical tonic neck reflex and you

Perez reflex: If a baby’s spine is firmly stroked from tail to head, the baby will cry out and head will rise. The Perez reflex should disappear by 4-6 months

Palmar Grasp reflex: When the palm is touched the fingers will curl around and cling to a finger or object. This is the reflex that allows the baby to “hold hands until it disappears at about 6 months.

Swimming reflex: If babies are placed in water, they will move their arms and legs while holding their breath. This reflex will disappear around the 6 month

Withdrawal reflex: A pin prick to the sole of baby's foot will result in knee and foot flexion.

1st Required QUIZ

UNIT 8

Please take in : www.uh.edu/webct

You will have 8 minutes to complete the Required Quiz

Testing Reflexes

The Knee Jerk
The Ankle Jerk
The Biceps Jerk
The Triceps Jerk
The Supinator Jerk
The Plantar Reflex

Intact reflexes require

· intact sensory afferent nerves (coming to the spinal cord)

· intact synapse within the spinal cord

· intact efferent motor nerves coming from the spinal column

· Adequately functioning muscle.

Reflexes can also be modified by conditions higher in the cord than the relevant synapse including the brain itself. The purpose of testing reflexes is to check the integrity of the system as a whole. An absent reflex indicates a problem somewhere in the reflex arc but it does not tell you where. Individual elements can often be tested separately by checking muscle power and sensation.

General principles of reflex testing

· Explain to the patient what you are going to do. ("I’m just going to tap you on the arms with this - show patellar hammer")

· Help them to relax ("Just let me hold your legs")

· In the case of tendon reflexes stretch the tendon as much as you can before you tap it with the patellar hammer.

· Apply stimulus

· Observe response

· Interpret response

The purpose of this session is to give you expertise in testing the main tendon reflexes.

The Knee Jerk

1. What it is.
A contraction of the quadriceps muscles when the patellar tendon is stretched.

2. What it tests.
A reflex arc involving the 2^nd 3^rd and 4^th lumbar segments.

3. The stimulus
A sharp tap over the patellar tendon using a patellar hammer. Picture

4. How to elicit it
Lie the patient flat and tell them to relax and that you will tap them just below the knee.

Place your arm under one knee and lift it from the bed while supporting your hand on the patient’s other knee. You can lift up both knees together if you like. Locate the patellar tendon between the tibial tubercle and the lower border of the patella Swing the patellar hammer so that it falls onto the patellar tendon At the same time watch for a contraction in the quadriceps muscle.

5. Grade and interpret the response

Observation	Grade	Interpretation
Not even twitch of the muscle	Reflex absent	Lesion of the afferent nerves, anterior horn cells or efferent nerves
Muscle twitches and knee jerks	Reflex normal
Muscle twitches and leg jerks off the bed	reflex increased	Upper motorneurone lesion anywhere above the spinal segments involved in the reflex. Tetanus Thyrotoxicosis Nervousness
Muscle twitches and knee jerks but is slow to relax and go back to normal	reflex myotonic	Myxoedema Hypothermia Myotonia

6. Confirm the finding

7. Test the other side

8. What can go wrong

· You find no reflex because the patient is not relaxed.

· You find no reflex because the striking the patient’s knee is painful. They have some other problem there.

· You poked at the tendon rather than striking it sharply. The tendon has to be stretched fairly quickly to elicit the reflex

· You have missed the tendon.

The Ankle Jerk

1. What it is.
A contraction of the calf muscles when the Achilles tendon is stretched.

2. What it tests.
A reflex arc involving the 1^st and 2^nd sacral segments.

3. The stimulus
A sharp tap over the Achilles tendon using a patellar hammer.

4. How to elicit it

Arrange the leg so that the knee is bent and lying outwards (Knee flexed and hip externally rotated)

Make sure the patient is fully covered between their legs.

Stretch the Achilles tendon by pushing up with your left hand on the ball of the foot (extend the ankle)

Swing the patellar hammer onto the tendon striking it sharply.

Measure the response by feeling the push against your left hand and observing the contraction of the calf muscles

5. Grade and interpret the response

This is the same as for the knee jerk

6. Confirm the finding

· Repeat the observation

7. What can go wrong

· You find no reflex because the patient is not relaxed.

· The reflex may appear to be absent in women because they find the position undignified even when properly covered. Use the alternative method described below.

· You find no reflex because the striking the patient’s ankle is painful. They have some other problem there.

· You poked at the tendon rather than striking it sharply. The tendon has to be stretched fairly quickly to elicit the reflex.

· You have missed the tendon.

12. An alternative method.

A quicker and easier method, that is just as effective, does not involve externally rotating the hip.

Keep the leg straight.

Stretch the Achilles tendon by pushing up with your left hand on the ball of the foot (extend the ankle). Make sure the patient relaxes their foot.

Swing the patellar hammer onto the fingers of your left hand striking them sharply.

Measure the response by feeling the push against your left hand. You may see the calf muscles contract though this is more difficult than with the first method.

The Biceps Jerk

1. What it is.
A contraction of the biceps muscle when the biceps tendon is stretched.

2. What it tests.
A reflex arc involving the 5^th and 6^th cervical segments.

3. The stimulus
A sharp tap over the biceps tendon using a patellar hammer.

4. How to elicit it

Bend the patient’s arm at the elbow so it is lying relaxed across the lower part of the chest

Find the long head of biceps tendon in the antecubital fossa and stretch it by pushing down on it with your thumb

Swing the patellar hammer down and strike your thumb sharply.

Make sure the patient is fully covered between their legs from the knees upwards.

Measure the response by observing the contraction of the biceps muscle.

5. Grade and interpret the response

This is the same as for the knee jerk

6. Confirm the finding

Repeat the observation

7. Test the other side.

This requires some manual dexterity. Check how the hammer is held picture

· 8. What can go wrong

o You find no reflex because the patient is not relaxed.

o You find no reflex because the striking the patient’s arm is painful. They have some other problem there.

o You poked at the tendon rather than striking it sharply. The tendon has to be stretched fairly quickly to elicit the reflex.

o You did not stretch the tendon enough to start with.

The Triceps Jerk

1. What it is.
A contraction of the triceps muscle when the triceps tendon is stretched.

2. What it tests.
A reflex arc involving the 6^th and 7^th cervical segments.

3. The stimulus
A sharp tap over the triceps tendon using a patellar hammer.

4. How to elicit it

Bend the patient’s arm at the elbow so it is lying relaxed across the mid part of the chest. This should be enough to give some initial stretch to the triceps tendon.

Gently support the arm by holding it against the chest

Identify the triceps tendon just above the elbow

Swing the patellar hammer down and across to strike the triceps tendon sharply. Don’t put your finger on the tendon.

When eliciting the patient’s right Triceps Jerk it is often easier to swing the hammer under your supporting left arm.

5. Grade and interpret the response

This is the same as for the knee jerk

6. Confirm the finding

Repeat the observation

7. Test the other side.

8. What can go wrong

· You find no reflex because the patient is not relaxed.

· You find no reflex because the striking the patient’s arm is painful. They have some other problem there.

· You poked at the tendon rather than striking it sharply. The tendon has to be stretched fairly quickly to elicit the reflex.

· You did not stretch the tendon enough to start with.

· You hit the muscle and not the tendon. Muscle contraction under these circumstances is a direct response and not dependent on an intact reflex arc.

The Supinator Jerk

1.What it is.
A contraction of the supinator muscle when the supinator tendon is stretched.

2. What it tests.
A reflex arc involving the 5^th and 6^th cervical segments.

3. The stimulus
A sharp tap over the supinator tendon using a patellar hammer.

4. How to elicit it

Bend the patient’s arm at the elbow so it is lying relaxed across the lower part of the chest.

Gently support the arm by holding it against the chest

Identify the supinator tendon just above the elbow

Swing the patellar hammer down and strike the supinator tendon sharply. Don’t put your finger on the tendon.

5. Grade and interpret the response

This is the same as for the knee jerk

6. Confirm the finding

Repeat the observation

7. Test the other side.

8. What can go wrong

· The commonest problem is failure to identify the supinator tendon properly.

· You find no reflex because the patient is not relaxed.

· You find no reflex because the striking the patient’s arm is painful. They have some other problem there.

· You poked at the tendon rather than striking it sharply. The tendon has to be stretched fairly quickly to elicit the reflex.

· You did not stretch the tendon enough to start with.

· You hit the muscle and not the tendon. Muscle contraction under these circumstances is a direct response and not dependent on an intact reflex arc.

The Plantar Reflex

1.What it is.
A movement of the great toe when the lateral part of the sole of the foot is scratched

2. What it tests.
The presence of an upper motorneurone lesion in the spinal cord or above.

3. The stimulus
A scratch over the lateral border of the sole of the foot

4. How to elicit it

Select an ‘orange stick’ or other blunt but pointed instrument.

Say "I am going to scratch the sole of your foot with this small stick"

Draw the stick firmly up the lateral border of the sole of the foot starting near the heel and stopping near the base of the little toe. (Some neurologists will continue scratching round in an arc across the metatarsal heads ending up at the base of the great toe).

Observe any movement of the great toe.

5. Grade and interpret the response

Under normal circumstances the toe will go down. In patients with upper motorneurone lesions it will go up and the toes will tend to fan out. This is called ‘an extensor plantar response’ or a ‘positive Babinski sign’. Sometimes the toe will go up and down – it is the initial movement that counts.

6. Confirm the finding

Only do this if you are really not sure what happened. Eliciting the plantar response is unpleasant.

7. Test the other side.

8. What can go wrong

· The toe did not move at all. The patient may have sensory loss over the sole of the foot or your stimulus was not strong enough.

· The patient jerks their foot away as soon as you start to scratch it. You did not warn them what you were going to do or the stimulus was too strong. For some people quite small stimulus is enough, just a scratch with the back of your thumbnail will do.

2nd Required QUIZ

UNIT 8

Please take in : www.uh.edu/webct

You will have 13 minutes to complete the Required Quiz