Chondroglossus

Abstract: The tongue is a highly muscular organ, and the extrinsic muscles of the tongue overlap one another, which makes their configuration intricate. The aim was to clarify their spatial interrelationships. The extrinsic muscles of the tongue were gross anatomically investigated in 42 cadavers. The hyoglossus consisted of two parts arising from the hyoid body and the greater horn, respectively. They ascended to the tongue external to the genioglossus. The quadrilateral anterior part contained several parallel bundles, and the triangular posterior part comprised of three bundles converging to the insertion. The genioglossus consisted of many compartments. Although its fibers radiated from the mental spine to the tongue internal to the inferior longitudinal muscle, the lateral fibers of the inferior parts passed externally to it, and the most inferior part attached to the hyoid bone and the epiglottis. The chondroglossus arising from the lesser horn ascended internally to the lateral fibers of the inferior parts. The styloglossus arising from the styloid process coursed externally and internally to the hyoglossus and between its two parts. The external and internal bundles fused with the fibers of the palatoglossus and the superior pharyngeal constrictor, respectively. Three bundles were inserted into the apex with the inferior longitudinal muscle or joined the inferior parts of the genioglossus. The extrinsic muscles are subdivided into small groups of fibers depending on their spatial interrelationships, suggesting that they contain many functional units. Some units act separately, and others cooperate across the traditional boundaries of the muscles.

Abstract: Summary The chondroglossus muscle was macroscopically studied to clarify its fundamental morphology This muscle was present in all of the 100 tongue halves examined in Japanese cadavers In 14% of the specimens, however, the muscular fibers were sparse and vestigial Originating mainly from the medial side of the lesser cornu of the hyoid bone, the chondroglossus muscle passed upward to penetrate the inferior longitudinal muscle of the tongue, and immediately entered the genioglossus muscle Ascending inside the genioglossus muscle, it's bundles spread, taking a broom head or a fan-like shape Thereafter it reached the submucosal layer in the root of the tongue, changed the direction from upward to forward, and terminated diffusely, never going past the sulcus terminalis The origin, course, and spreading manner of the chondroglossus muscle were quite different from those of the hyoglossus muscle The nerve fiber supplying the chondroglossus muscle was a ramus from the first lateral branch of the hypoglossal nerve It should be considered a separate extrinsic lingual muscle independent of the hyoglossus muscle, although they have a phylogenetically close relationship

Abstract: The genioglossus is a paired tongue muscle that is in the group of extrinsic muscles of the tongue. The other extrinsic muscles of the tongue are the hyoglossus (chondroglossus), styloglossus and the palatoglossus. All of these extrinsic muscles are within proximity of one another, which is why the entirety of the extrinsic muscle group usually functions as a unit. Each muscle has its individual function, but there tends to be more than one extrinsic muscle functioning at the same time.Histologically the genioglossus muscle has significant type 2 fibers present in the anterior section of the genioglossus muscle, whereas the posterior portion of the muscles does not have a large portion of type 2 fibers present. The specific fibers present in the particular portion of the genioglossus muscle determine the function of the muscle. For example, the anterior portion of the genioglossus contains type 2 fibers, and this suggests that this portion of the genioglossus muscle participates in phasic action. The posterior portion while it does not contain many type 2 fibers has significant muscle strength compared to the anterior portion of the genioglossus; because of this, it there are sugggestions that the posterior portion of the genioglossus holds responsibility in the nasopharyngeal airway, as well as in the production of the sound of vowels.