7. The Tongue
This portion of the dissection will concentrate on the muscles of the tongue. These muscles
are divided into extrinsic (originating outside the tongue) and intrinsic (situated within the
tongue) muscles. First, we examine the attachments of the tongue's extrinsic muscles and
attempt to understand how they serve to move and shape the tongue during speech. Then,
we bisect the tongue and excise one half This will allow us to examine the tongue's intrinsic
muscles and how they serve to move and shape the tongue during speech.
The four major extrinsic muscles of the tongue are shown in figure 7.1:
The mylohyoid muscle, which is responsible for raising the body of the tongue in high
vowels and velar consonants.
The hyoglossus, which pulls it downwards (and slightly backwards).
The styloglossus, which pulls the tongue upwards and backwards.
The genioglossus, which forms the bulk of the inferior part of the tongue and pulls the
body of the tongue forwards.
Figure 7.1. The extrinsic muscles of the tongue.
We have already observed the mylohyoid muscle in Section 4. It forms the floor of the
mouth and controls the raising of the tongue. It is also an elevator of the hyoid bone, and hence
elevates the larynx. The hyoglossus is a broad, flat muscle running from the greater horn of
the hyoid to the posteroinferior lateral aspects of the tongue (on the sides of the lower back of
the tongue). It is a depressor (lowerer) of the tongue. The styloglossus extends from the styloid
process, a projection of the skull at about the level of the ear down into the lateral aspect of the
tongue, interdigitating with the inserting fibers of the hyoglossus. The genioglossus is attached
to a point on the mandible about halfway between the chin and the lower incisors (front teeth).
(Check by feeling with a forefinger down behind the lower front teeth in your own mouth, and
1
styloglossus
geniohyoid genioglossus
hyoglossus
stylohyoid
