Reflex testing
AIM- CLINICAL EXAMINATION OF REFLEXES
PRINCIPLE-
Reflex is defined as an involuntary response to a stimulus, it depends on the integrity of the reflex
arc, which consist of
Receptor
Afferent nerve
Center
Efferent nerve
Effector organ
Types of reflexes-
1. Monosynaptic reflexes/muscle stretch reflexes/ myotactic reflexes/deep tendon reflexes
When the tendon of a lightly stretched muscle is struck a single sharp blow by the patellar
hammer, causes sudden stretching of the muscle, which results in muscle contraction.
Knee jerk
Ankle jerk
Biceps jerk
Triceps jerk
Supinator jerk
Jaw jerk
2. Polysynaptic reflexes-
a. Superficial reflexes- stimulation of skin or mucus membrane results in contraction of
underlying muscle.
1. Reflexes mediated by spinal nerves e.g.
Abdominal reflex
Planter reflex
2.Reflexes mediated by cranial nerves e.g.
Conjunctival reflex
Corneal reflex
Pupillary reflex
Light reflex- Direct, Indirect
Accommodation reflex
b. Visceral reflex e.g. Swallowing, defecation, micturition
APPARATUS- clinical examination table, patellar hammer, cotton wisp, torch and card board(6”X6”)
PROCEDURE-
Deep reflex-
1. Knee jerk-
Make the subject to sit comfortably with his/her legs dangling freely.
Ask the subject to relax
Palpate the patellar tendon and strike with the patellar hammer.
Observe for the contraction of quadriceps and extension of knee joint.
Elicit the knee jerk on other side and compare.
2. Ankle jerk-
Make the subject to sit comfortably with his/her legs dangling freely.
Ask the subject to relax
Dorsiflex the foot with one hand to stretch the Achilles tendon.
Strike the tendon on the posterior surface.
Observe for contraction of calf muscle and planter flexion at the ankle joint.
Elicit the ankle jerk on the other side and compare.
3. Biceps jerk-
Make the subject to sit comfortably
Ask the subject to relax
Expose the arm
Flex the elbow to right angle and rest his/her forearm in semi pronated position on your left
hand.
Place your left thumb on the biceps tendon and strike it with the patellar hammer.
Observe the contraction of the biceps and flexion of the forearm.
Elicit the biceps jerk on the other side and compare.
4. Triceps jerk-
Make the subject to sit comfortably
Ask the subject to relax
Expose the arm
Flex the elbow to right angle and rest his/her forearm in semi pronated position on your left
hand.
Strike the triceps tendon with the broader end of the patellar hammer.
Observe contraction of the triceps and extension of the forearm
Elicit the triceps jerk on the other side and compare.
5. Supinator jerk
Make the subject to sit comfortably
Ask the subject to relax
Expose the arm
Flex the elbow to right angle and rest his/her forearm in semi pronated position on your left
hand.
Strike the brachioradialis tendon at the styloid process with the narrow end of the patellar
hammer.
Observe contraction of the brachioradiallis and flexion at the elbow supination of the
forearm.
Elicit the supinator jerk on the other side and compare.
6. Jaw jerk –
Make the subject to sit comfortable
Ask the subject to relax and open his/her mouth partially.
Place the index finger firmly on the chin
Strike the index finger with other hand as in percussion.
Observe the closure of the mouth.
Superficial reflexes
1.Abdominal reflex-
Make the subject to lie comfortably.
Expose the abdomen
Ask the subject to relax
Stroke the skin of the abdomen lightly and briskly with the metallic end of the patellar
hammer from the outer aspect towards the midline, below the coastal margin, at the level of
umbilicus and in iliac fossa
Observe a ripple of contraction of the underlying abdominal muscle.
2.Planter reflex-
Make the subject to lie comfortably.
Ask the subject to relax
Scratch the outer edge of the sole of the foot by the metallic end of the patellar hammer
from the heel towards the little toe and then medially across the metatarsals.
Observe planter flexion of the toes. (flexor planter response)
Elicit the planter reflex on the other side and compare.
Babinski’s sign- extensor planter response characterized by –
Dorsiflexion of the great toe.
Abduction or fanning of other toes and dorsiflexion of the ankle.
3.Conjuctival reflex-
Make the subject to sit comfortably
Ask the subject to fix his/her gaze at a distant object or the ceiling.
Bring the cotton wisp from the side of the subject and touch the bulbar part of conjunctiva.
Observe the subject blinks his/her eyes.
Elicit the conjunctival reflex on the other side and compare.
4.Corneal reflex-
Make the subject to sit comfortably
Ask the subject to fix his/her gaze at a distant object or the ceiling.
Bring the cotton wisp from the side of the subject and touch the lateral edge of the cornea
at its conjunctival margins.
Observe the subject blinks his/her eyes.
Elicit the conjunctival reflex on the other side and compare.
5.Pupillary reflex-
Light reflex-direct
Make the subject to sit comfortably
Ask the subject to fix his/her gaze at a distant object or the ceiling.
Shine the bright light in one eye with the torch.
Observe immediate constriction of pupil in the same eye.
Elicit the light reflex on the other side and compare.
Indirect-
Make the subject to sit comfortably.
Ask the subject to fix his/her gaze at a distant object
Hold the cardboard on the forehead and bridge of the nose.
Shine a bright light in one eye with the torch
Observe immediate constriction of pupil of both the eyes
Elicit the light reflex on the other side and compare.
Observations:
S.NO Reflexes Findings Remarks
.
Right Left
1. Deep Reflexes
Knee jerk
Ankle jerk
Biceps jerk
Triceps jerk
Supinator jerk
Jaw jerk
2. Superficial reflexes
Abdominal reflex
Planter reflex
Conjunctival reflex
Corneal reflex
Pupillary reflexes
Light reflex
a. Direct
b. Indirect
