Temporomandibular pain, often known as temporomandibular disorder or temporomandibular dysfunction, is a term used to describe a group of disorders that affect the temporomandibular joints and the muscles that control jaw movement.

Lumbar spondylolisthesis is a condition where one vertebra in the lumbar (lower) spine slips forward over the vertebra below it. This displacement can occur due to various reasons, and it is classified based on the degree of slippage. The term "spondylolisthesis" is derived from the Greek words "spondylos," meaning spine, and "listhesis," meaning to slip or slide.

Pigmented villonodular synovitis (PNSV) is a joint disease characterized by inflammation of the synovial membrane, which is the lining of the joints. This inflammation can lead to the formation of synovial nodules or masses, which contain inflamed synovial tissue and the pigment hemosiderin, a breakdown product of hemoglobin.

Mixed Connective Tissue Disease (MCTD) is a rare autoimmune disorder characterized by a combination of clinical and laboratory features from various connective tissue diseases, including systemic lupus erythematosus (SLE), systemic sclerosis (scleroderma), and polymyositis/dermatomyositis. It was first described in the 1970s and is considered an overlap syndrome due to the overlap of symptoms from different autoimmune conditions.