Which area is likely to show signs of muscle spasm in a client with lumbar disk herniation?

In a client with lumbar disk herniation, the area most likely to show signs of muscle spasm is the lower back. This is primarily due to the body's compensatory mechanisms in response to the pain and discomfort caused by the herniated disk. When a disk herniates, it often affects the nearby spinal nerves, leading to pain in the lower back and potentially radiating down the legs.

Muscle spasms can occur as a protective response to the underlying injury in an effort to stabilize the affected area and limit movement that may worsen the pain. Therefore, the lower back is the site where muscle spasms will be most evident, reflecting the body's attempt to guard against further injury and alleviate discomfort associated with the herniated disk.

The shoulder, upper arm, and knees are not typically affected directly by lumbar disk herniation, making them less likely sites for muscle spasm in this context. The focus of symptoms and resulting muscle spasms tends to remain localized around the lumbar region where the herniation and nerve involvement occur.