Sciatic nerve is the largest peripheral nerve in the body. It runs from the lower back through the buttock and down the back of the leg. It carries both movement (motor) and feeling (sensory) signals. It is commonly discussed when evaluating radiating leg pain, numbness, or weakness.

Scans MRI hip refers to magnetic resonance imaging (MRI) focused on the hip joint and nearby soft tissues. It is a noninvasive imaging test that uses a strong magnetic field and radio waves to create detailed pictures. It is commonly used in orthopedics, sports medicine, and physical therapy evaluations of hip pain and reduced function. It helps clinicians assess bones, cartilage, labrum, muscles, tendons, bursae, and bone marrow without ionizing radiation.

Sartorius is a long, strap-like muscle that runs across the front of the thigh. It helps move both the hip and the knee during walking, climbing, and changing direction. Clinicians commonly reference Sartorius in hip and groin pain evaluations and in knee exams. It is also used as an anatomic landmark and, in select cases, as a surgical muscle flap.

Sacroiliac joint dysfunction is a term used when the sacroiliac (SI) joint is thought to be a meaningful source of pain or impaired movement. The SI joint sits where the spine meets the pelvis, connecting the sacrum to the ilium on each side. It is commonly discussed in evaluations of low back pain, buttock pain, and some forms of hip-region pain. Clinicians use the term to organize diagnosis and guide non-surgical and, in selected cases, procedural care.

The SI joint is the sacroiliac joint, where the sacrum meets the ilium on each side of the pelvis. It helps transfer forces between the spine and the legs during standing, walking, and lifting. In clinical care, the term SI joint is commonly used when discussing certain patterns of low back, buttock, or pelvic pain.

The Sacroiliac joint is the joint between the sacrum (base of the spine) and the ilium (part of the pelvis). It helps transfer forces between the upper body and the legs during standing and walking. Clinicians discuss it most often when evaluating low back, buttock, or posterior hip pain. It is also relevant in imaging, injections, and selected surgical procedures.

Sacrum is a triangular bone at the base of the spine and the back of the pelvis. It connects the lumbar spine to the pelvic bones through the sacroiliac (SI) joints. Sacrum is a common focus in orthopedics, sports medicine, physical therapy, and pain medicine when evaluating low back, buttock, and pelvic pain. It is also used as an anatomical landmark for imaging, injections, and certain pelvic or spine procedures.

Sacral slope is a measurement of how the top of the sacrum tilts when viewed from the side. It helps describe pelvic position and overall posture in the sagittal (side-view) plane. It is most commonly measured on lateral (side-view) spine or pelvis imaging. Clinicians use it to understand hip–pelvis–spine alignment and how it may relate to symptoms or surgical planning.

A Sacral ala fracture is a break in the “wing” (ala) portion of the sacrum, a bone at the base of the spine. It is a type of pelvic fracture that can cause buttock, low back, or groin-area pain. Clinicians commonly discuss it when evaluating unexplained pelvic pain after a fall, overuse, or bone fragility. The term is used in orthopedic care, sports medicine, emergency medicine, radiology, and physical therapy.

Robotic-assisted THA is a form of total hip arthroplasty that uses computer planning and a robotic system to help guide implant positioning. It is still a surgeon-performed hip replacement, with robotic tools used for planning and execution support. It is commonly used in hospitals and surgical centers that perform elective joint replacement. It is typically considered for arthritis-related hip pain and loss of function when non-surgical care is no longer sufficient.