Clinical Examination of Reflexes

 Reflex Definition

• It is an immediate involuntary motor or visceral response to an afferent sensory impulse

Reflex arc

• Anatomical nervous pathway for reflex action
• Includes five components

1. Receptor
2. Afferent nerve
3. Centre
4. Efferent nerve
5. Effector organ

Clinical Classification of Reflexes

1. Superficial reflexes

• Involves skin and mucous membrane

2. Deep tendon reflexes

• Involves tendons

Superficial reflexes

• Protective reflexes

Stroking or pinching of particular area of skin

▼

Contraction of certain muscles

1. Conjunctival reflex
2. Corneal reflex
3. Abdominal reflex
4. Scapular reflex
5. Plantar reflex
6. Anal reflex
7. Bulbocavernus reflex
8. Cremastric reflex

Conjunctival reflex

Approach the patient from the sides and lightly touch the lateral portion of the conjunctiva with a strand of damp cotton wool. Avoid touching the eyelids or eyelashes.

 

Observation		Afferent	Center	Efferent
Left	Right
Blinking of eye	Blinking of eye	5th CN	Pons	7th CN

 

Cornea Reflex

• Not done
• Cornea is an avascular structure
• Any damage to the cornea will cause permanent scar on it

Abdominal reflex

Gently stroke the four quadrants of the abdomen with a blunt object from lateral to medial direction

 

Observation		Root value
Left	Right
Ipsilateral contraction of abdominal muscle and movement of umbilicus towards the site of stroke	Ipsilateral contraction of abdominal muscle and movement of umbilicus towards the site of stroke	T6 to T12

Scapular reflex

Stroke the skin in the interscapular region

 

Observation		Root value
Left	Right
Contraction of scapular muscles and drawing in of scapula		C5 to T1

Plantar reflex

Hold the ankle and firmly stroke the sole with a moderately sharp object such as key, on the lateral aspect of the sole running from the heel to the ball of the foot, curving medially across the ball

 

Observation		Root value
Left	Right
Plantar flexion and adduction of toes (Flexor plantar response)	Plantar flexion and abduction of toes (Flexor plantar response)	L5,S1

 LMN lesions of lumbar and sacral segment - plantar response absent

Extensor plantar response – Babinski’s sign (abnormal plantar response) - Dorsiflexion of the great toe followed by spreading out (fanning) and extension (Dorsiflexion) of the other toes - UMN lesion

Stimulus should not be painful - painful stimulus evokes a withdrawal response which may mimic a Babinski’s response