The sternothyroid muscle is a thin, strap-like muscle located in the neck. It originates at the sternum (breastbone) and the manubrium (upper part of the sternum), and extends downward and forward to insert into the thyroid cartilage, a large cartilage in the front of the neck that forms the laryngeal prominence (Adam's apple). The sternothyroid muscle is part of a group of muscles called the infrahyoid muscles, which are located below the hyoid bone and play a role in moving the hyoid bone and the mandible during swallowing and speaking.

The sternothyroid muscle has several important functions in the head and neck. It helps to lift the hyoid bone and the mandible during swallowing, and is also involved in the production of speech sounds. It also helps to support the floor of the mouth and the tongue, and can assist in keeping the airway open during respiration.

The sternothyroid muscle is innervated by the ansa cervicalis, a nerve bundle that arises from the cervical spinal nerves. It is a voluntary muscle, meaning that it can be controlled voluntarily by the person.

In some cases, the sternothyroid muscle may be surgically modified or altered to address certain medical conditions, such as problems with swallowing or speaking. It may also be used as a donor muscle for reconstructive surgery in the head and neck region.