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of the sphenoid bone, along the outer margin of the eus-
tachian . be.
It fills up the greater part of the pterygoid fossa ; and pas-
sing downwards and backwards, is inserted tendinous and
fleshy into the internal face of the angle of the lower jaw.
When the muscles of the opposite sides act, they close
the jaw.
Digastrieus.*
It is situated immediately under, and a little upon the in-
side of the lower jaw, and outside of the fauces, extend-
ing from the mastoid process to the chin, nearly along the
angle made by the neck and chin, or face. The name of
this muscle expresses its general shape, as it has two fleshy
bellies, and of course a middle tendon. Yet some of its
anterior belly does not arise from the tendon of the posterior,
but from the fascia, which binds it to the os-hyoides.
These two fleshy bellies do not run in the same line, but
form an angle, just where the tendon runs into the anterior
belly ; so that this tendon seems rather to belong to the pos-
terior, which is the thickest and longest.
This muscle arises from the sulcus made by the inside of
the mastoid process, and a ridge upon the temporal bone,
where it is united with the os occipitis. The extent of this
origin is about an inch. It is fleshy upon its outer part, viz.
that from the mastoid process ; and tendinous on the inside
from the ridge. From its origin it passes forwards down-
wards and a little inwards much in the direction of the pos-
terior edge of the mammillary process, and forms a round
tendon first in its centre and upper surface.
This tendon passes on in the same direction ; and when
got near the os-hyoides, it commonly perforates the anterior
Hunter, page 24—32.