440 
ANATOMY OF THE HOUSE. 
i'orm. —Broad and flattened at the extremities; cordiform in 
the middle. 
Attachment. —Posteriorly, to the styloid process of the occipi¬ 
tal bone; anteriorly, to the side of the jaw, midway between the 
angle and the symphysis. 
Relation. —Externally, with the jaw and pterygoidei; inter¬ 
nally, with the larynx, os hyoides, and submaxillary gland : inte¬ 
riorly, with the submaxillary vessels and the skin. 
Direction. —Oblique: from behind, forwards and downwards; 
from before, upwards and backwards. 
Structure. —It consists of two fleshy bellies united by an inter¬ 
mediate tendon, which passes and plays through a sort of pulley 
formed by the tendon of the hyoideus. 
Action.— Not very apparent; implicated, seemingly, with that 
of the hyoideus. 
MYLO-HYOJDEUS. 
Situation. —Spreading along the side of the jaw. 
Figure. —Broad, thin, half-penniform. 
Attachment. —Outwardly, to the roots of the alveolar processes 
and the side of the jaw, extending forwards to the symphysis: 
inwardly, to the body of the os hyoides. 
Relation. —Outwardly, with the jaw; inwardly, with the sub¬ 
lingual gland, genio-hyoideus, and gustatory and ninth pair of 
nerves. 
Direction. —Oblique: from above downwards, inclining out¬ 
wards. 
Structure. —Fleshy : united to its fellow (of the opposite side) 
through the medium of a tendinous line, which extends from the 
end of the spur process of the os hyoides to the symphysis of the 
jaw. 
Action. —To draw the os hyoides forwards and upwards; and, 
thereby, raise the tongue within the mouth. 
GENIO-HYOIDEUS. 
Situation. —Above the preceding muscle. 
Figure. —Half-penniform: extremities, narrow; middle part, 
broad. 
Attachment. —Anteriorly, to the jaw, near the symphysis; pos¬ 
teriorly, to the spur process of the os hyoides. 
Relation. —lnferiorly and externally, with the mylo-hyoideus; 
superiorly, with the genio-hyo-glossus; internally, with its fellow. 
Direction. —Oblique : from before, backwards; and from with¬ 
out, inwards. 
Structure. —Tendinous at the extremities: intermediate part, 
fleshy. 
