Clinical Case Study Muscular System In Chapters 7 and 8, you were introduced to Kayla Tanner, a 45-year-old mother of four who had suffered a dislocated right hip in the bus accident on Route 91. Six weeks after the injury, Mrs. Tanner reported that she was still unable to walk or run without hip pain, and had weakness in her hip, knee, and ankle. Mrs. Tanner walked with a limp that her doctors attributed to weaknesses in flexion at the knee, inversion of the foot, and plantar flexion. Electromyography (which measures muscle electrical activity) and nerve conduction studies (which measure the speed of nerve impulses) revealed that Mrs. Tanner's sciatic nerve had been damaged as a result of her injuries-most likely as a result of the nerve being compressed when the hip was dislocated. This large nerve innervates a large number of lower limb muscles. Since her surgery, Mrs. Tanner has been undergoing intense physical therapy and has shown significant improvement.

1. During her initial visit with the physical therapist, Mrs. Tanner presented with significant “foot drop” (the inability to dorsiflex the foot when taking a step). Mrs. Tanner was asked to perform a variety of movements with her right lower extremity. The therapist focused her attention on the prime movers and synergists of the hip, knee, and ankle. What are “prime movers” and “synergists”? 2. In order 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? 3. Mrs. Tanner’s physical therapist performed a variety of assessments in order to establish a baseline from which her recovery could be measured. For each of the descriptions below, name the muscle (or muscles) that the therapist was assessing. a. With Mrs. Tanner in the seated position, the therapist positioned Mrs. Tanner’s legs shoulder-width apart, then asked Mrs. Tanner to bring her feet together while the therapist applied resistance to the right leg. b. The therapist applied resistance to the top of Mrs. Tanner’s foot and asked her to pull her forefoot up toward her shin. c. With Mrs. Tanner in the prone position (on her stomach), the therapist applied resistance to the leg while Mrs. Tanner was instructed to bring her heel up toward her buttocks (flex her knee). 4. Using descriptions similar to those listed in the question above, explain how you would assess the function of the following muscles. a. Extensor hallucis longus b.Fibularis (peroneus) longus c. Gastrocnemius