The tongue has several nerves, and one major nerve, the hypoglossal nerve (XII), branches extensively within it. Specifically, the hypoglossal nerve in adult humans gives off approximately 50–60 primary nerve branches along its whole length within the tongue.
Understanding the Hypoglossal Nerve's Branches
Here's a breakdown of how the hypoglossal nerve (XII) typically branches within the tongue, according to research:
- The hypoglossal nerve (XII) originates outside of the tongue and enters at its root.
- From the root to the tip (apex) of the tongue, it branches into specific nerve paths.
Typical Branching Order of the Hypoglossal Nerve (XII)
The hypoglossal nerve generally branches in the following order from the root to the apex of the tongue:
- GH: Geniohyoid muscle branches.
- SL: Styloglossus muscle branches.
- SG: Superior genioglossus muscle branches.
- HG: Hyoglossus muscle branches.
- l-IL: Lateral inferior longitudinal muscle branches.
- Horizontal GG: Horizontal genioglossus muscle branches.
- Oblique GG: Oblique genioglossus muscle branches.
- Posterior T/V: Posterior transverse/vertical muscle branches.
- m-IL: Medial inferior longitudinal muscle branches.
- Anterior T/V: Anterior transverse/vertical muscle branches.
These branches serve to control the complex movements of the tongue required for speaking, swallowing, and manipulating food within the mouth.
Key Points
- The hypoglossal nerve (XII) is the primary motor nerve of the tongue.
- It branches significantly, sending out around 50-60 primary nerve branches throughout the tongue’s muscles.
- These branches follow a specific pattern as they progress from the root to the apex.
Therefore, while there are many sensory nerves in the tongue, the major nerve, the hypoglossal nerve, has many branches, approximately 50-60 in the adult human.
