Geniohyoid Muscle Anatomy

The geniohyoid muscle has a cylindrical shape located in the anterior neck region above the digastric muscle and the mylohyoid muscle, it manifests as a narrow, elongated muscular structure situated in the anterior neck region. This muscle extends from the inferior genial spine (mental spine) of the mandible to the anterior surface of the body of the hyoid bone. Its position and orientation create a parallel arrangement with its contralateral counterpart, forming a vital component of the floor of the mouth.

Geniohyoid Muscle Anatomy

The geniohyoid muscle originates from the inferior mental spine (inferior genial tubercle) and inserts on the body of the hyoid bone.

The geniohyoid muscle receives its primary innervation from the first cervical nerve (C1) via the hypoglossal nerve (cranial nerve XII). This neural pathway demonstrates an interesting anatomical arrangement where C1 fibers travel briefly with the hypoglossal nerve before innervating the muscle. The muscle’s blood supply primarily derives from the lingual artery, with additional contributions from small branches of the sublingual artery.

See Also: The 12 Cranial Nerves Anatomy & Function

The geniohyoid muscle exhibits multiple crucial functions in basic physiological processes. During deglutition, it acts to elevate and advance the hyoid bone, facilitating the superior and anterior movement essential for proper swallowing mechanics. Additionally, it assists in depression of the mandible when the hyoid bone is fixed, contributing to mouth opening. In respiration, the muscle’s activity helps maintain upper airway patency, particularly during inspiration.

Embryological Development

During embryological development, the geniohyoid muscle originates from the first cervical myotome, distinguishing it from other suprahyoid muscles. This developmental origin explains its unique innervation pattern and functional characteristics. The muscle becomes distinct during the eighth week of gestation, coinciding with the formation of the hyoid apparatus.

Clinical Implications

Understanding the geniohyoid muscle’s anatomy becomes particularly relevant in various clinical scenarios. Dysfunction of this muscle may manifest in swallowing disorders, particularly affecting the oral and pharyngeal phases of deglutition. In cases of obstructive sleep apnea, the muscle’s role in maintaining airway patency makes it a focus of therapeutic interventions.

Surgical procedures in the anterior neck region must account for the muscle’s location and relationships to avoid iatrogenic injury. Furthermore, radiological evaluation of the suprahyoid region requires thorough knowledge of the geniohyoid’s normal appearance and variations.

Advanced Imaging Considerations

Modern imaging techniques, particularly dynamic MRI and ultrasound have enhanced our understanding of the geniohyoid muscle’s functional anatomy. These modalities allow real-time visualization of muscle activity during swallowing and other physiological processes, providing valuable diagnostic information in cases of dysphagia and other functional disorders.

References

1. Khan YS, Bordoni B. Anatomy, Head and Neck, Suprahyoid Muscle. [Updated 2023 Jun 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: Pubmed
2. Gray’s Anatomy: The Anatomical Basis of Clinical Practice
3. Clinically Oriented Anatomy – 8th Edition