Jaw Jerk Reflex

Authors

Affiliations

Nate Yomogida, B.S., SPT

Doctor of Physical Therapy

B.S. in Kinesiology

Chloë Kerstein, B.S., SPT

Doctor of Physical Therapy

B.A. in Neuroscience

A reflex test that assesses both the sensory and motor aspects of the CN V Trigeminal nerve mandibular branch.

Technique

With mouth slightly open, one index finger on chin, tap w reflex hammer

Grading / Interpretation

Normal: Slight closure (upward jerking of mandible by masseter muscles) or no reflex

Abnormal:

• UMN Lesion: Extremely pronounced reflex (clearly visible)

Tip

If you can obviously see it, it is abnormal!