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168 ANATOMY.

aponeurosis and the pericranium there is a small amount of loose
connective tissue, which permits easy movement and readily admits of
dissection
Posteriorly, this aponeurosis is attached to the occipitalis muscle, a
portion of the superior semicircular line, and the occipital protuberance.
Anteriorly, it terminates in the frontalis muscle. Laterally, it presents
no distinct marginal termination, but is gradually blended into the
superficial temporal fascia, and affords attachment to the superior and
anterior aural muscles. Its outer surface is closely attached to the
skin by numerous bands of connective tissue.
Aotio7i.—By the contraction of the frontalis muscle the eyebrows are
elevated or arched, as in expressing surprise, delight, or doubt. This
elevation of the eyebrows causes the skin to wrinkle over the surface
of the forehead.
By the contraction of the occipitalis muscle the scalp is drawn back-
ward, and by an alternating action of the two muscles the scalp may
be moved forward and backward. Most people have not the power of
moving the scalp in both directions, the motion being limited to an
anterior direction only.
The Pt/ramidales Nasi are two in number. Their form, as their
name indicates, is pyramidal, and they are formed by the continuation
of the fasciculi from the frontalis muscle. They extend downward on
either side of the nose, widening as they descend, and, becoming ten-
dinous, join the tendinous insertion of the compressor nasi.
Relations.—By its upper surface with the skin, and below with the
nasal bones.
The Orbicularis Palpebrarum is a thin sphincteric or elliptical muscle
having a bony attachment. It is closely adherent to the integument
covering the eyelids and surrounding the orbits. It is divided into
three portions—orbital, jxilpebral, and concentric.
The Orbital or Peripheral Portion arises fi'om the internal angular
process of the frontal bone, the nasal ])rocess of the superior maxilla, and
the lachrymal groove. Its fasciculi diverge as they extend, the superior
passing ujnvai'd and outward over the superior orbital arch toward the
temple, while the inferior pass downward and outward, inosculating with
the superior fibres at the outer portion of the orbit. The orbital por-
tion of tlie orbicularis palpebrarum is the strongest, while its fibres are
of deeper color than the other two portions. Internally, its fibres are
attached to the tarsal ligament, while next to the nose it has a bony
attachment such as described above. Its superior border is partially
held in position by descending fibres from the frontalis and by the
corrugator supercilii muscles. Its lower and outer margins are free.
The Palpebral Portion arises from the superior and inferior margins
of the tarsal ligament, passes outward over the eyelids, and is inserted
into the outer and lesser tarsal ligaments. This portion is much thinner
and its fibres are paler than the preceding.
The Concentric Ciliary or Inner Portion is somewhat stronger than
that covering the eyelids, and is confined to the margins of the vela.
The inner edges are free.
Relations.—By its upper surface with the integnment ; by its under