Temporomandibular Disorder or TMD is a condition that affects many dental patients. New evidence suggests that it may be associated with undiagnosed hypothyroidism. Hypothyroidism symptoms included muscle weakness, stiffness, and aches. This can affect the muscles of the head and neck, affecting their ability to properly support the joint. In fact the forward head posture of some TMD patients may also put pressure on the thyroid gland. There is also a higher occurrence of the thyroid conditions of Hashimoto’s Disease and Wilson’s disease with severe TMD patients. When the subject of joint pain comes up it might be a good time to discuss the symptoms of hypothyroidism. They include the following: muscle weakness, dry skin, constipation, puffy face, hoarseness, impaired memory, carpal tunnel syndrome, fatigue, weight gain, thinning hair, slowed heart rate, joint pain/stiffness, brittle fingernails, cold sensitivity, heavy/irregular menstrual periods, depression, elevated cholesterol, muscle aches/tenderness/stiffness, and infertility. It can be very beneficial to the patient to review these conditions and symptoms to see if a trip to their medical doctor is in order in cases of TMD.