The suprahyoid muscles are a group of four muscles located superior to the hyoid bone of the neck. They all act to elevate the hyoid bone – an action involved in swallowing. The arterial supply to these muscles is via branches of the facial artery, occipital artery, and lingual artery. In this article, we shall look at the anatomy of the suprahyoid muscles – their attachments, actions, and innervation.
The suprahyoid muscles are a group of muscles located in the neck which include the digastric, mylohyoid and geniohyoid muscles. All four muscles, which have mutually supporting actions, are necessary for the completion of the physiological process of swallowing.
The stylohyoid muscle, which is the most anteriorly located of the four suprahyoid muscles, arises from the styloid process of the temporal bone and attaches to the lateral aspect of the hyoid bone. It initiates a swallowing action by pulling the hyoid bone in a posterior and superior direction. The stylohyoid is innervated by the stylohyoid branch of the facial nerve (CN VII), which arises proximally to the parotid gland.
The digastric muscle, which is the most posteriorly located of the four suprahyoid muscles, has two bellies which are connected by an intermediate tendon, which is attached to the hyoid bone via a fibrous sling. It depresses the mandible and elevates the hyoid bone. The anterior belly is innervated by the inferior alveolar nerve, a branch of the mandibular nerve (which is derived from the trigeminal nerve, CN V). The posterior belly is innervated by the digastric branch of the facial nerve.
The mylohyoid is a broad, triangular shaped muscle which forms the floor of the oral cavity and supports the floor of the mouth. It originates from the mylohyoid line of the mandible and attaches onto the hyoid bone. It elevates the hyoid bone and the floor of the mouth, and is innervated by the inferior alveolar nerve, a branch of the mandibular nerve (which is derived from the trigeminal nerve).
The geniohyoid muscle is located either side of the midline of the neck, deep to the mylohyoid muscle. It arises from the inferior mental spine of the mandible and attaches to the hyoid bone, and depresses the mandible and elevates the hyoid bone. It is innervated by C1 nerve roots that run within the hypoglossal nerve.
The action of the suprahyoid muscles is necessary for the physiological process of swallowing to be completed. Each of the suprahyoid muscles performs a related but distinct action in the overall swallowing mechanism. More specifically, the stylohyoid muscle initiates a swallowing action by pulling the hyoid bone in a posterior and superior direction. The digastric muscle depresses the mandible and elevates the hyoid bone, the mylohyoid elevates the hyoid bone and the floor of the mouth, and the geniohyoid depresses the mandible and elevates the hyoid bone. All four muscles are supplied by branches of the facial artery, occipital artery, and lingual artery, while innervation to the four muscles is provided by the facial nerve, mandibular nerve, and hypoglossal nerve.
The suprahyoid muscles are part of a complex system of muscles located in the throat and neck. These muscles are responsible for controlling the movements of the hyoid bone, which is an important part of the movement involved in swallowing. They are supplied by branches of the facial artery, occipital artery, and lingual artery, while innervation is provided by the facial nerve, mandibular nerve, and hypoglossal nerve.
Understanding the anatomy of the suprahyoid muscles, their attachments, actions, and innervation, is important for healthcare professionals in order to understand and manage a variety of disorders related to the swallowing mechanism. Therefore, it is important to be aware of the anatomy of the suprahyoid muscles, their actions, and their innervation.
