The stylohyoid muscle is a long, slender muscle belonging to the suprahyoid muscle group. It extends from the styloid process of the temporal bone to the hyoid bone and contributes to hyoid bone movements during swallowing, speech, and respiration.

Anatomy

Morphology and Connection Points

The stylohyoid muscle, a long and slender muscle, is located in the upper part of the neck, anterosuperior to the posterior belly of the digastric muscle. It extends from the styloid process of the temporal bone to the junction of the body and greater horn of the hyoid bone. Along its course, it is pierced by the intermediate tendon of the digastric muscle. As part of the suprahyoid muscle group, the stylohyoid muscle is closely associated with the structures that control the position of the hyoid bone. Its topographic proximity to the digastric and omohyoid muscles is particularly important for the muscle's functional integrity.

Embryological Origin and Classification

The stylohyoid muscle originates embryologically from the second pharyngeal arch. Muscles developing from this structure receive their motor innervation from the facial nerve (cranial nerve VII). Therefore, the stylohyoid muscle is included in this classification and is classified among the suprahyoid muscles controlled by the facial nerve. This embryological origin provides important information regarding the muscle's functional role and clinical neural relationships.

Nerve Innervation and Vascular Supply

The stylohyoid muscle receives its nerve supply via the stylohyoid branch of the facial nerve. This nerve branch travels along the muscle to synapse for motor function. The muscle's arterial supply comes primarily from branches of the facial artery, posterior auricular artery, and occipital artery. These vessels meet the muscle's metabolic needs and maintain its function.

Function and Clinical Relationships

The primary function of the stylohyoid muscle is to pull the hyoid bone upward and posteriorly. This movement facilitates elevation of the larynx during swallowing, supporting the passage of food into the pharynx. It also assists in movements of the floor of the mouth and the base of the tongue. Working in conjunction with the digastric muscle, it plays a role in the coordination of mandibular movements and indirectly contributes to basic functions such as chewing and swallowing. The stylohyoid muscle is considered an important reference point in head and neck anatomy. Particularly in neck surgery and radiologic imaging, the course of the stylohyoid muscle is critical for localizing surrounding vascular and nerve structures. Clinically, functional deficiencies of this muscle should be considered in swallowing disorders such as dysphagia. Anatomical variations may include the muscle being completely absent, having a double layer, coursing medially to the carotid artery, or supplying fibers to other surrounding muscles. These variations should be considered in surgical approaches.