The inferior longitudinal muscle runs as a narrow band along the undersurface of the tongue between the genioglossus and hyoglossus muscles, from the tongue root to the tip. It acts to shorten the tongue and turn the tip downward, counterbalancing the superior longitudinal muscle. Together the two longitudinal muscles allow the tongue to curl and wave its tip precisely during speech articulation.
| Origin | Tongue root, blending with hyoglossus and genioglossus fibers inferiorly |
|---|---|
| Insertion | Tongue tip |
| Nerve Supply | Hypoglossal nerve (CN XII) |
| Blood Supply | Lingual artery (deep lingual branch) |
| Actions | Shortens the tongue; Curls the tongue tip downward |
|---|
The inferior longitudinal muscle runs just above the sublingual mucosa and is relevant in floor-of-mouth surgery and during tongue base resection for cancer. Its preservation during tongue resection maintains some tongue mobility. In tongue release surgery for ankyloglossia (tongue-tie), the frenulum beneath which this muscle runs is divided, immediately improving tongue tip mobility. Understanding the complete intrinsic muscle anatomy is essential for accurate functional reconstruction after glossectomy.
Palpable on the underside of the tongue as a longitudinal ridge when the tongue is pressed upward against the hard palate.
Resection of tongue base carcinoma involving the inferior longitudinal and intrinsic muscles causes permanent deficit in tongue retraction and inferior curling, affecting swallowing, speech, and quality of life, managed with swallowing rehabilitation and, when necessary, tongue reconstruction with free flap.
