National Physical Therapy Examination (NPTE) Practice Exam

A patient with spastic cerebral palsy has a supinated foot on the right side. Which muscle is most likely hyperactive?

1. Tibialis posterior

2. Tibialis anterior

3. Quadriceps

4. Gastrocnemius

The correct answer is: Tibialis posterior

In the context of spastic cerebral palsy, a supinated foot is often associated with an overactivity of certain muscles that contribute to ankle and foot positioning. The tibialis posterior is primarily responsible for foot inversion and helps to maintain the arch of the foot. When hyperactive, it can lead to excessive supination, where the foot rolls outward when weight-bearing. When considering the typical presentation of spastic cerebral palsy, the condition is characterized by muscle tightness and imbalances. The tibialis posterior’s role in facilitating supination makes it the most likely muscle to be hyperactive in this patient, as it can lead to a fixed position of the foot that doesn't allow for natural movements. The other muscles listed do have roles in foot and ankle function, but they are either less directly involved in creating a supinated foot or are associated with different movements. For instance, the gastrocnemius, while contributing to plantarflexion, does not contribute to the supination position specifically. Understanding these relationships helps to pinpoint which muscle activity is altered in conditions like cerebral palsy.