From the Research
The geniohyoid muscle is innervated by C1 nerve fibers. This is based on the most recent and highest quality evidence available, which describes the anatomical relationship between the hypoglossal nerve and the geniohyoid muscle 1. The C1 fibers travel with the hypoglossal nerve (cranial nerve XII) and branch off to supply the geniohyoid muscle. The other muscles mentioned have different innervation patterns:
- the genioglossus is innervated by the hypoglossal nerve proper (CN XII) 2,
- while both the mylohyoid and anterior belly of the digastric are innervated by the mylohyoid nerve, which is a branch of the mandibular division of the trigeminal nerve (CN V3). Understanding these innervation patterns is important for clinical assessment of cervical spine injuries and neurological disorders affecting the upper cervical region. Key points to consider include:
- The hypoglossal nerve is a purely motor nerve responsible for the innervation of all the intrinsic tongue muscles and some extrinsic tongue muscles, including the genioglossus, but also has a relationship with C1 fibers for the geniohyoid muscle 2.
- The geniohyoid muscle's innervation by C1 fibers is consistent across studies, highlighting the importance of considering this anatomical detail in clinical assessments 1.