Babinski’s reflex is actually a primitive reflex and should therefore also be listed in this section.
The snout reflex
- Gently tap your finger between the patient’s nose and mouth.
- In response the patient will briefly pout their lips.
Finally, the so-called pseudobulbar reflexes which occur due to a lesion of the corticobulbar tract (the pyramidal tract above the brainstem motor neuron nuclei). This type of lesion can lead to pronounced jaw reflex or jaw clonus (refer to ‘The cranial nerves’). In addition, the following reflexes can be evoked:
The palmomental reflex
- Using the end of a cotton swab, briefly and firmly stroke the ball of the patient’s thumb.
- Look for homolateral contraction of the mentalis muscle.
The corneomandibular reflex
- When eliciting the corneal reflex the lower jaw moves to the contralateral side.
- Another sign that can indicate a lesion in the corticobulbar tracts is compulsive laughing or compulsive crying. This can occur in response to an event which is only mildly emotionally charged, and spontaneous episodes of laughter and / or crying can also occur.
