The diagnosis and treatment of temporomandibular joint disorders remains one of the most challenging areas of dentistry. The clinical problems are complex since TMJ dysfunction etiology is multifactorial. Although most occurrences are related to internal derangement, many joints are painful secondary to nondiscogenic causes, such as, referred pain from spondylosis of the upper cervical spine and other inflammatory and neoplastic bone lesions in the vicinity of the TMJ. This book describes the etiology and exacerbating factors for internal derangements of TMJ which help the clinicians in early diagnosis and further treatment of TMJ.