Joint Instability means a joint moves more than expected or feels unable to stay “centered” during motion or load. It is a clinical concept and condition used to describe abnormal joint laxity, recurrent “giving way,” or subluxation/dislocation risk. It is commonly discussed in sports medicine, trauma, rheumatology, and orthopedic clinics. It is assessed with history, physical examination maneuvers, and selected imaging.

Tendon Repair is a procedure intended to restore continuity and function of an injured tendon. It is most commonly used after tendon laceration, rupture, or avulsion from bone. It can be performed in multiple anatomic regions, including the hand, shoulder, elbow, hip, knee, ankle, and foot. In practice, it is used by orthopedic, hand, sports medicine, and plastic surgery teams, often alongside structured rehabilitation.

Ligament Reconstruction is a surgical procedure that replaces a damaged ligament with a graft. It is a procedure used to restore joint stability when a ligament can no longer function adequately. It is commonly used in sports medicine and orthopedic trauma care. It is most often discussed around the knee, ankle, shoulder, elbow, and thumb.

Myopathy is a broad term for diseases that primarily affect skeletal muscle. It is a **condition/concept** used to describe muscle weakness, abnormal muscle function, or muscle injury. Clinicians use it across orthopedics, neurology, rheumatology, rehabilitation, and primary care. It helps frame evaluation when symptoms suggest the muscle (rather than nerve, joint, or tendon) is the main problem.

Myalgia means pain originating in muscle tissue or perceived as muscle pain. It is a clinical concept and symptom descriptor rather than a single diagnosis. Myalgia is commonly used in orthopedic, primary-care, sports medicine, rheumatology, and neurology settings. Clinicians use the term to organize a broad differential and guide focused evaluation.

Muscle Cramps are sudden, involuntary, and often painful muscle contractions. They are a clinical concept and symptom, not a single diagnosis. They are commonly discussed in orthopedic, sports-medicine, and general medical evaluations of limb pain and function. They can reflect benign physiologic triggers or signal an underlying neuromuscular or systemic condition.

Muscle Spasm is a sudden, involuntary contraction of skeletal muscle that can cause tightness, pain, or restricted motion. It is a clinical concept and exam finding rather than a single diagnosis. It is commonly discussed in orthopedics, sports medicine, emergency care, neurology, and rehabilitation. In practice, it often signals underlying irritation, injury, or altered neuromuscular control around the musculoskeletal system.

A Muscle Tear is a disruption of skeletal muscle fibers, ranging from microscopic damage to complete rupture. It is a **condition** that commonly follows overload, rapid stretching, or direct trauma. In orthopedic, sports medicine, and emergency settings, it is used as a working diagnosis for acute pain and loss of function. Clinicians use the term to communicate severity, guide imaging choices, and frame rehabilitation and return-to-activity planning.

Dermatomyositis is an autoimmune inflammatory condition that affects skin and skeletal muscle. It is categorized as an inflammatory myopathy with characteristic cutaneous findings. It is commonly discussed in rheumatology, dermatology, neurology, and musculoskeletal/orthopedic care because it can cause proximal weakness, pain, and functional limitation. In clinical practice, it often appears during evaluation of weakness, elevated muscle enzymes, rash, and systemic complications.

Polymyositis is an inflammatory disease that primarily affects skeletal muscle. It is a **medical condition** within the broader group of idiopathic inflammatory myopathies. It commonly presents as gradually progressive weakness in proximal muscles such as the hips and shoulders. In practice, it is discussed in orthopedic, neurology, rheumatology, and rehabilitation settings when evaluating unexplained muscle weakness and functional decline.