Chapter 10, Problem 2CCS

45-Year-Old Female with Motor Nerve Damage

In Chapters 7 and 8, you met Kayla Tanner, who suffered a dislocated right hip in a car accident. Six weeks later, Mrs. Tanner was still unable to walk or run without hip pain, and had weakness in flexion at the knee, excessive foot inversion and plantar flexion, and significant “foot drop” (the inability to dorsiflex the foot).

Electromyography (measurement of muscle electrical activity) and nerve conduction studies (measurement of the speed of nerve impulses) revealed sciatic nerve damage, most likely a result of the nerve being compressed when the hip was dislocated. This large nerve innervates many lower limb muscles. Since her surgery, Mrs. Tanner has been undergoing intense physical therapy and has shown significant improvement.

2. To assess the function and strength of a specific muscle, a physical therapist will often apply resistance (push against the moving limb) to mimic the action of an antagonist muscle. What is an antagonist muscle, and why would the therapist mimic its action?