Professional and Linguistic Assessments Board (PLAB) Practice Exam

What common sign would you look for in Hoffmann's sign?

1. Flexion of the thumb

2. Flicking of the middle finger's nail

3. Extension of the wrist

4. Adduction of the little finger

The correct answer is: Flicking of the middle finger's nail

Hoffmann's sign is a clinical test used to assess for possible lesions in the corticospinal tract, particularly in the cervical spine region. The sign is elicited by flicking the distal phalanx of the middle finger. If the reflex mechanism is intact, this flicking will provoke the flexion of the thumb and possibly the index finger. This response indicates that there may be an upper motor neuron lesion present. The correct answer being the flicking of the middle finger's nail aligns with the method used to elicit Hoffmann's sign. The resulting reflex action—flexion of the thumb and index finger—illustrates the functionality of the neural pathways being tested. The other options do not reflect the manifestation or elicitation of Hoffmann's sign. For instance, flexion of the thumb is a potential response but not the sign itself. Similarly, extension of the wrist and adduction of the little finger are not related to the test of Hoffmann's sign and do not provide information pertinent to diagnosing issues in the corticospinal tract.