Muscles Involved in Muscle Strain Under the Tongue While Eating
The primary muscles involved in a muscle strain under the tongue while eating include both intrinsic tongue muscles (superior longitudinal, inferior longitudinal, transverse, and vertical muscles) and extrinsic tongue muscles (particularly the genioglossus, styloglossus, and hyoglossus).
Intrinsic Tongue Muscles
The intrinsic muscles of the tongue are entirely contained within the tongue structure and are responsible for changing the shape of the tongue during eating:
Superior Longitudinal Muscle (SLm) - Runs beneath the dorsal mucosa of the tongue and is divided into bundles by other muscles passing through it to the dorsum; contributes to tongue elevation and shortening during eating 1, 2
Inferior Longitudinal Muscle (ILm) - Ascends from the root of the tongue and joins with other muscles; plays a major role during food ingestion with significantly enhanced activity 2, 3
Transverse Muscle - Passes laterally from the lingual septum; forms part of the three-dimensional latticework of tongue muscles that enables complex movements during eating 2
Vertical Muscle - Sandwiched between the genioglossus and hyoglossus; works with the transverse muscle during drinking and food manipulation 2, 3
Extrinsic Tongue Muscles
The extrinsic muscles originate outside the tongue and insert into it, controlling tongue position:
Genioglossus - Forms the bulk of the muscle mass at the base of the tongue; extends internally to the dorsum and plays a major role during ingestion 1, 3, 4
Styloglossus - Has external, middle, and internal bundles that course through the tongue in different patterns; particularly active during chewing with significantly greater integrated EMG activity 2, 3
Hyoglossus - Has anterior and posterior parts that extend externally to the inferior longitudinal muscle and converge to the root of the tongue, respectively 2
Palatoglossus - Courses externally with the styloglossus and contributes to tongue movement during eating 2
Functional Relationships During Eating
During eating, these muscles work in coordinated patterns:
The majority of activity in both intrinsic and extrinsic tongue muscles occurs during jaw opening and the occlusal phases of chewing 3
The genioglossus and vertical/transverse muscles show simultaneous activation during drinking 3
During food ingestion, the genioglossus and inferior longitudinal muscles show greatly enhanced activity compared to their activity during chewing 3
The superior and inferior longitudinal muscles and styloglossus typically show two phases of activity during chewing - first starting at jaw opening and second at late jaw closing phases 3
Clinical Relevance of Tongue Muscle Strain
When experiencing a muscle strain under the tongue while eating:
The intrinsic muscles (particularly the longitudinal muscles) are likely involved as they show higher activity levels during eating tasks 3
The genioglossus muscle is critical for establishing anterior-posterior tongue location while intrinsic muscles play a greater role in force generation 5
Tongue retractor muscles (styloglossus and hyoglossus) discharge in synergy with suprahyoid muscles during swallowing 6
Muscle strain may particularly affect the vertical and transverse muscles which are active during 35-48% of the chewing cycle 3
Biomechanical Considerations
The intrinsic and extrinsic muscles of the tongue are not independent groups but form an interconnected three-dimensional latticework 2
Each muscle contains numerous bundles or lamellae as functional units that can act separately or cooperate across muscles 2
During protrusion tasks (which may occur during eating), both genioglossus and intrinsic muscles are simultaneously active, with intrinsic muscles showing significantly higher activity levels when force is required 5
The complex arrangement of these muscles enables the tongue's versatility in food manipulation but also makes it susceptible to strain during prolonged or forceful eating 2, 5