EXAMINATION OF REFLEXE
EXAMINATION OF REFLEXES
AIM: Examine the reflexes of the subject
Requirements: Reflex [knee] hammer, examination couch, wisp of cotton, tongue depressor, torch etc
I. General examination
II. Higher functions
Ill. Reflexes: can be broadly classified as
(a) Superficial Reflexes
(b) Deep (Tendon) Reflexes
(c) Visceral reflexes
(a) Superficial Reflexes:
(b) Deep (Tendon) reflexes:
Radial Supinator jerk
(c) Visceral reflexes:
Reflexes of micturition
Reflexes of defecation
Reflexes of sexual function
(A) SUPERFICIAL REFLEXES: are elicited by stimulating the touch receptors in the skin or mucous which results in the contraction of a muscle or a group of muscles.
(1) Conjunctival reflex: Stand on one side of the subject and ask him to look at a far object on the opposite side.
A sterile piece of cotton is twisted into a wisp and bring it from the back of the subject avoiding his visual attention.
Touch the conjunctiva and see the response. Both eyes are separately tested.
Observation: Bilateral closure of the eyes. Reflex pathway
Receptors: Touch receptors of the conjunctiva
Afferent limb: Ophthalmic division of trigeminal nerve
Efferent limb: Facial nerve
Effector muscle: Orbicularis oculi
Centre - Pons (Nucleus of Trigeminal Nerve)
(2) Corneal reflex: Tested in the same manner as above, but the stimulus is applied to the cornea (limbus) and observe the bilateral closure of eyes. Here the receptors are touch receptors in cornea. Afferents limb, Efferent limb, centre and effector muscle are same as above.
(3) Pupillary reflex: are of two types.
1. Light reflex: Direct and indirect [consensual] light reflex
2. Accommodation reflex
Direct light reflex:
Procedure: Make the subject sit comfortably and ask him to look at a distant object. Allow sufficient time for him to get adapted to the light of the room as well as the distant object, so that a moderately dilated state of the pupil results. The subject should be instructed not to look on to the light orto the movements of the examiner’s hands.
One eye is covered with the palm of the hand so that the light shown into the tested eye is prevented from falling into it. Bring the source of light (torch) from the lower lateral field of the eye so that light directly falls into the eye. Observe the pupil. It will constrict. Each eye should be tested separately.