The muscle passes laterad as a flat band 8 to 10 millimeters wide over
the caudal surface of the concha of the ear, and is inserted (Fig. 64,
_q_) on the lateral surface of the eminentia conchæ, caudad of the
antitragus.
_Relations._--Outer surface with the levator auris longus (_g_) and the
integument. Inner surface with the auricularis superior (_k_), the
abductor auris brevis (_l_), and the concha.
_Action._--Pulls the external ear caudad.
=M. abductor auris brevis= (Fig. 63, _l_).
_Origin_ by a tendon from the lambdoidal crest for one or two
centimeters laterad of the middle.
The muscle passes lateroventrad lying beneath the abductor longus (_m_)
as a flat band 6 to 8 millimeters wide which is inserted into the medial
surface of the most proximal portion of the concha, just distad of its
junction with the cartilaginous auditory meatus.
_Relations._--Outer surface with the abductor longus (_m_), a small
strand of the platysma and the concha. Inner surface with the temporal
muscle (_n_).
_Action._--Pulls the concha caudad.
=M. epicranius= (or occipitofrontalis) (Fig. 63, _h_ and _h′_).
_Origin_ on the sagittal crest or suture, just craniad of the origin of
the levator longus auris, to the inner surface of which this muscle is
closely united. From the origin the fibres pass craniad forming a band
(_h_) about 8 or 10 millimeters in width, the two muscles lying close to
one another and partly united in the middle line. About two centimeters
craniad of their origin the fibres of both muscles end in a tendinous
sheet, the =galea aponeurotica=, which covers the surface of the skull
in the region between the ears and eyes, and is formed by the inner
surface of the intermedius scutulorum (_a_) and other muscles of this
region. The galea aponeurotica passes craniad onto the surface of the
nose, where it gives origin again to a thin sheet of muscle-fibres
(_h′_) which are inserted into the integument near the cranial ends of
the nasal bones.
M. epicranius is thus formed of two muscular portions (_h_ and _h′_),
connected by a long tendinous sheet. The caudal portion is frequently
distinguished as the occipital muscle (=M. occipitalis=, _h_), the
cranial portion, on the nose, as the =frontal= muscle (=M. frontalis=,
_h′_).
_Relations._--Outer surface of the occipitalis (_h_) with the
intermedius scutulorum (_a_), the levator auris longus (_g_), and the
integument; inner surface with the auricularis superior (_h_), the
abductor auris longus, and the bone. Outer surface of the frontalis
(_h′_) with the integument; inner surface with the bones of the skull.
_Action._--Moves the integument of the dorsal surface of the head and of
the nose.
Ventrad of the external ear the following three differentiated portions
of the platysma may be distinguished.
=M. zygomaticus= (major) (Fig. 64, _d_).--A slender band connecting the
angle of the mouth with the scutiform cartilage of the ear.
Public-domain text, read in full here on John Shaqi.
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