A Subtrochanteric bursa is a small, fluid-filled sac near the upper femur (thigh bone) just below the hip. It helps soft tissues glide over bone with less friction during walking and hip motion. Clinicians consider it when evaluating certain patterns of lateral or deep hip pain. It is most often discussed in the context of bursitis (inflammation of a bursa) and related hip overuse conditions.

Subspine impingement syndrome is a cause of hip pain related to bony contact at the front of the hip joint. It involves the region just below the anterior inferior iliac spine (AIIS), a bony landmark on the pelvis. It is often discussed alongside femoroacetabular impingement (FAI) because symptoms and exam findings can overlap. The term is commonly used in orthopedics, sports medicine, and hip-preservation care to describe a specific pain generator in active hips.

Subspine impingement is hip pain and motion restriction caused by contact between the upper thigh bone and bone beneath the pelvis. It involves the area under the anterior inferior iliac spine (AIIS), sometimes called the “subspine” region. It is commonly discussed alongside femoroacetabular impingement (FAI) and labral problems. Clinicians use the term to describe a specific, front-of-hip pinching pattern during hip flexion.

Subchondral sclerosis is a term used in orthopedics and radiology to describe increased bone density just beneath a joint’s cartilage surface. It is most commonly reported on X-rays and other imaging when evaluating arthritis and other joint problems. It is a *finding*, not a diagnosis by itself. It is frequently discussed in the hip, knee, and spine, where weight-bearing forces are high.

A Subchondral fracture is a crack or break in the layer of bone just beneath joint cartilage. It most often involves weight-bearing joints such as the hip, knee, and ankle. Clinicians use the term to describe a specific pattern of bone injury that can cause joint pain and limited function. It is commonly discussed in orthopedic clinics and on MRI reports when evaluating unexplained joint pain.

Subchondral edema is swelling-like signal change in the bone just under joint cartilage. It is most often described on MRI as a type of “bone marrow edema pattern.” It can appear in the hip, knee, ankle, and other weight-bearing joints. Clinicians use it as a clue to explain pain and to look for an underlying cause.

A Subchondral cyst is a small cavity or “pocket” within bone just beneath a joint surface. It is most often described on X-ray, CT, or MRI when evaluating joint pain or arthritis. In everyday terms, it is a bone change that can appear near worn joint cartilage. It is commonly discussed in the hip, knee, and other weight-bearing joints.

Subchondral cyst formation is the development of small fluid-filled or tissue-filled cavities in bone just beneath joint cartilage. It is most commonly discussed as an imaging finding in arthritis and other joint conditions. Clinicians use the term in X-ray, CT, or MRI reports to describe changes near weight-bearing surfaces such as the hip. It helps communicate the pattern and severity of joint-related bone remodeling.

Subchondral bone is the layer of bone that sits directly under joint cartilage. It helps support and absorb forces across a joint when you stand, walk, or run. Clinicians discuss it often in osteoarthritis, stress injuries, and cartilage damage. It is commonly evaluated on X-ray, MRI, and CT when joint pain is being investigated.

Stress shielding is a biomechanical effect where bone loses density because it carries less load than it normally would. It most often comes up around orthopedic implants, such as hip replacements, plates, rods, and spinal hardware. In simple terms, when an implant “takes over” too much of the work, nearby bone may weaken over time. Clinicians monitor it because bone strength matters for long-term implant support.