The mylohyoid muscle divides the lower part of the oral cavity into 2 spaces: the sublingual space, which is located superior to the muscle, and the submandibular space, inferior to the muscle but superior to the hyoid bone. Although the submandibular and sublingual spaces are small, a wide range of pathologic processes may involve these spaces. They include cystic lesions, inflammatory conditions with various causes, rare vascular lesions, and benign and malignant neoplasms. This article outlines the radiologic anatomy of the region, describes the various pathologic processes that may affect it, and discusses the use of imaging in their evaluation.