Suprahyoid muscles

Suprahyoid Muscles

Diagram of the suprahyoid muscles

The suprahyoid muscles are a group of muscles located above the hyoid bone in the neck. These muscles play a crucial role in the movement of the hyoid bone and the larynx, which are essential for swallowing and speech.

Anatomy

The suprahyoid muscles consist of four main muscles:

• Digastric muscle: This muscle has two bellies, the anterior and posterior, connected by an intermediate tendon. The anterior belly originates from the digastric fossa of the mandible, while the posterior belly originates from the mastoid notch of the temporal bone.

• Mylohyoid muscle: This muscle forms the floor of the mouth. It originates from the mylohyoid line of the mandible and inserts into the body of the hyoid bone.

• Geniohyoid muscle: Located above the mylohyoid muscle, it originates from the inferior mental spine of the mandible and inserts into the body of the hyoid bone.

• Stylohyoid muscle: This muscle originates from the styloid process of the temporal bone and inserts into the body of the hyoid bone. It is responsible for elevating the hyoid bone during swallowing.

Function

The primary function of the suprahyoid muscles is to elevate the hyoid bone and the larynx during swallowing and speech. They also assist in depressing the mandible, which opens the mouth. These actions are crucial for the proper functioning of the oral cavity and the pharynx.

Innervation

The innervation of the suprahyoid muscles varies:

• The anterior belly of the digastric muscle and the mylohyoid muscle are innervated by the mylohyoid nerve, a branch of the inferior alveolar nerve from the mandibular nerve (CN V3).

• The posterior belly of the digastric muscle and the stylohyoid muscle are innervated by the facial nerve (CN VII).

• The geniohyoid muscle is innervated by fibers from the hypoglossal nerve (CN XII) that travel with the first cervical nerve (C1).

Clinical Significance

Dysfunction of the suprahyoid muscles can lead to difficulties in swallowing (dysphagia) and speech. Conditions such as myasthenia gravis or nerve damage can affect these muscles, leading to clinical symptoms that require medical attention.

Related pages

• Infrahyoid muscles
• Hyoid bone
• Swallowing
• Speech