Superficial Reflexes

Definition and nerves involved

Corneal reflex

Involuntary blinking in response to corneal stimulation

Afferent: Trigeminal nerve (CN 5)

Efferent: Facial nerve (CN 7)

Abdominal reflex

Contraction of superficial abdominal muscles when stroking abdomen lightly

T7-T12

Asymmetry: usually signifies a UMN lesion on the absent side

Cremasteric Reflex

Contraction of the cremaster muscle after stroking the same side of superior/inner thigh

L1-L2

Absent with SCI and corticospinal lesions

Plantar reflex/Babinski

the plantarflexion of the toes is elicited when stroking of the lateral sole of the foot from calcaneus to base of 5th metatarsal

S1-S2, tibial nerve

+Positive Babinski= Dorsiflexion of the great toe and fanning of the four small toes, commonly see in corticospinal/UMN lesion

Anal reflex

Reflexive contraction of the external anal sphincter upon stroking the skin around the anus

Afferent: pudendal nerve

Efferent: S2-S4

Bulbocavernosus reflex

Anal sphincter contraction in response to squeezing glans penis or tugging on an indwelling foley catheter

Mediated by S2-S4

First reflex to return after SCI as an indicator that the body is out of spinal shock