하악 (lower jaw) is the lower part of the jawbone in humans and many animals. It plays a crucial role in the structure of the face and is essential for functions such as chewing and speaking. The 하악 connects to the upper jaw, or 상악, through the temporomandibular joint, allowing for movement. The 하악 consists of two main parts: the body and the ramus. The body is the horizontal portion that holds the teeth, while the ramus is the vertical part that connects to the skull. Proper alignment and function of the 하악 are important for overall oral health and can affect bite and jaw pain.