American Nurses Credentialing Center (ANCC) Practice Exam

The technique of sharply dorsiflexing the foot and maintaining this position is crucial for evaluating ankle clonus because it directly assesses for the presence of involuntary muscle contractions that can occur in response to this maneuver. When the foot is dorsiflexed, an absence of clonus would typically result in no further movement; however, if ankle clonus is present, there will be rhythmic contractions and relaxations of the calf muscles, causing a recognizable oscillatory movement of the foot. This assessment is particularly relevant in patients with hyperactive reflexes, as clonus is often a manifestation of an upper motor neuron lesion or heightened excitability in the neural pathways involved in reflex action. By sustaining the dorsiflexed position, the practitioner can effectively observe for the involuntary contractions that characterize clonus, thereby making a critical evaluation of the patient's neuromuscular status. Other options do not specifically elicit or assess for clonus. For instance, applying a tuning fork, striking the Achilles tendon, or stroking the sole may yield reflex responses or assess other reflexes, but they do not provide the focused evaluation needed for ankle clonus.