228 THE VISCERA. 
each, which converge near the base of the tongue so as to form 
a V with the apex directed caudad. 
MUSCLES OF THE TONGUE (Fig. 96).—M. genioglossus 
(/) passes from the symphysis of the lower jaw into the tongue 
and lies beneath (dorsad of) the geniohyoid (4g). 
Origin from the medial surface of the mandible near the 
symphysis and dorsad of the origin of the geniohyoid. 
Insertion. —The fibres pass dorsad, diverging in a fan-like 
manner and forming a flat vertical plate closely applied to the 
muscle of the opposite side. This plate extends along the 
caudal three-fourths of the tongue, i.e. as far as it is attached. 
The cranial fibres arch craniad to the tip of the tongue, the 
caudal fibres arch caudad to the root of the tongue. Dorsad 
the muscle is confounded with the muscle of the opposite side. 
Action.—Draws the root of the tongue forward and the tip 
backward. 
M. hyoglossus (4).—From the body of the hyoid bone to 
the tongue. 
Origin.—(1) From the ventral surface of the body of the 
hyoid laterad of the geniohyoid (g), and (2) by a second head 
from the ceratohyal. 
Jnsertion.—Both heads penetrate into the tongue between 
the styloglossus (¢) and the genioglossus (/). The fibres 
intermingle with those of the styloglossus (¢) and thus help to 
form the lateral parts of the tongue. They finally end in the 
integument on the dorsum of the tongue at the sides. 
Action.~— Retracts the tongue and depresses it. 
M. styloglossus (¢).—From the stylohyal bone to the 
tongue. 
Origin from the mastoid process of the temporal bone, from 
the stylomandibular ligament (2) (which connects the border 
of the external auditory meatus with the angular process of the 
mandible) and from the proximal cartilaginous portion of the 
cranial cornu of the hyoid bone. The fibres pass mediad, 
diverging between those of the digastric and hyoglossus (4) 
into the lateral part of the tongue. 
Insertion.—The fibres pass toward the tip of the tongue, 
where the mass finally ends in a point, the superficial ones 
