Spinal Cord Compression is a clinical condition where the spinal cord is mechanically pressed or constricted. It is a neurologic and musculoskeletal emergency concept because sustained pressure can impair cord function. It is commonly discussed in orthopedics, neurosurgery, emergency medicine, oncology, and rehabilitation settings. It is typically evaluated using focused neurologic exam and spine imaging, most often MRI.

Spinal Deformity is an abnormal curvature and/or alignment of the spine in the coronal, sagittal, and/or axial plane. It is a clinical concept and a group of conditions rather than a single diagnosis. It is commonly discussed in orthopedics, spine surgery, physical medicine and rehabilitation, pediatrics, and neurology. It is used in practice to describe posture, balance, pain patterns, functional limits, and neurologic risk related to spinal alignment.

Facet Arthropathy refers to degenerative or inflammatory changes affecting the spine’s facet (zygapophyseal) joints. It is a clinical condition and an imaging descriptor often associated with spinal osteoarthritis. It is commonly discussed when evaluating neck or low back pain and stiffness. It is frequently referenced in radiology reports and musculoskeletal assessments in orthopedic and spine care.

Degenerative Disc Disease is a clinical concept used to describe age- and stress-related changes of the intervertebral discs. It is categorized as a condition and a descriptive diagnosis rather than a single, uniform disease entity. It is most commonly used in spine care to explain back or neck symptoms and to frame imaging findings. It appears frequently in orthopedic, neurosurgical, physiatry, and primary-care documentation and care planning.

Calcific Tendinitis is a condition where calcium deposits form within a tendon. It most often affects the rotator cuff tendons of the shoulder. It is commonly evaluated in orthopedic, sports medicine, and musculoskeletal clinics. It can cause pain and limited motion, especially during inflammatory phases.

Heel Spur is a bony outgrowth (an **enthesophyte**) that forms at the heel bone (the **calcaneus**). It is a **condition and imaging finding**, rather than a single disease by itself. Heel Spur is most often discussed when evaluating **heel pain**, especially pain near the plantar fascia or Achilles tendon insertions. In practice, it is commonly identified on **plain radiographs** and interpreted alongside the history and physical exam.

A Bone Spur is a bony outgrowth that forms along the edge of a bone or near a joint. A Bone Spur is a clinical concept and imaging finding rather than a single disease. Clinicians commonly discuss a Bone Spur in the context of osteoarthritis, tendon/ligament attachment stress, and mechanical impingement. In practice, a Bone Spur is described in radiology reports, orthopedic exams, and surgical planning discussions.

Avascular Necrosis is the death of bone tissue due to reduced or absent blood supply. It is a medical condition (also called osteonecrosis) that affects joints and weight-bearing bones. It is commonly discussed in orthopedics, radiology, rheumatology, and primary care when evaluating joint pain and collapse risk. It is frequently identified using imaging, especially MRI, and staged to guide management decisions.

Osteonecrosis is bone tissue death caused by reduced blood supply. It is a **condition** (a disease process), not a procedure or device. It is most often discussed in orthopedics when evaluating joint pain and risk of bone collapse. It commonly involves the femoral head (hip) but can affect other bones and joints.

Stress Shielding is a biomechanical concept describing reduced mechanical loading of bone when an implant or device carries most of the load. It is not a disease or procedure; it is a load-transfer phenomenon relevant to musculoskeletal biology. It is most commonly discussed in arthroplasty, fracture fixation, and spinal instrumentation. Clinically, it matters because bone adapts to load, and reduced load can contribute to bone loss around implants.