The nurse explains that, if muscles are not regularly stretched and contracted, the muscles will become:

Correct Answer: C

Rationale: Muscles require regular movement to maintain their length and elasticity. Without stretching and contraction, they adapt to a shortened position due to immobility, losing their ability to elongate fully over time. This results in reduced elasticity, making them prone to stiffness and contractures. Longer and flexed muscles would imply active stretching, which doesn't occur without intervention. Fibrosis and spasticity suggest scarring or neurological overactivity, more common in specific conditions like cerebral palsy, not general immobility. Shorter and painful could occur, but pain isn't a universal outcome of disuse shortening and loss of elasticity are the primary physiological changes. This explanation underscores the need for exercise to preserve muscle function, aligning with the natural response of tissues to prolonged inactivity.

Correct Answer: B

Rationale: An abductor wedge keeps the legs apart post-hip replacement to prevent dislocation by maintaining proper alignment. Assessing peripheral circulation is critical, as pressure from the wedge could compress blood vessels or nerves, leading to numbness, swelling, or impaired flow, which needs prompt correction. Muscle spasms might occur but aren't the primary concern with the wedge's positioning. Compression fractures relate to spinal issues, not hip surgery. Wedge size matters for comfort but is secondary to circulation, which directly impacts tissue health. Monitoring circulation ensures the device supports recovery without causing vascular compromise, a key risk in this context.

Correct Answer: A

Rationale: Intense pain, fever (102°F), and swelling at a fracture site in traction point to osteomyelitis, a bone infection possibly from pin sites or open injury, common in such setups. The acute inflammatory signs fit this diagnosis, requiring urgent antibiotics or surgery. Fat embolism causes respiratory distress and petechiae, not localized swelling and fever. Traction misalignment might cause pain but not systemic fever or such swelling. Nonunion is a chronic failure to heal, not an acute febrile state. Osteomyelitis matches the sudden, severe presentation, demanding immediate attention to prevent bone damage or sepsis.

Correct Answer: B

Rationale: The prime mover, also called the agonist, is the muscle primarily responsible for generating a specific movement. For example, in knee extension, the quadriceps act as the prime mover. Deep refers to muscle location, not function. Antagonist opposes the prime mover, while synergists assist it, neither being the main force. The prime mover's role as the dominant muscle in producing movement is a core principle in kinesiology, making it the correct answer. This term encapsulates the muscle that drives the action, distinguishing it from supporting or opposing muscles, and its significance is evident in every coordinated motion, from lifting to walking.

Correct Answer: C

Rationale: Circular fascicle arrangements, like those in the orbicularis oris or sphincters, are designed to control the opening or closing of orifices (e.g., mouth, anus) under voluntary or involuntary contraction. Their ring-like structure constricts or relaxes to regulate passage. Pennate fascicles (feather-like) maximize force, not orifice control. Triangular (e.g., pectoralis major) spread force broadly, not circularly. Parallel fascicles (e.g., sartorius) produce linear movement, not sphincter action. Circular arrangement is the correct answer, as it uniquely enables the constriction needed for orifice regulation, a critical function in muscles governing entry or exit points in the body.