- Platysma is also a plant taxon synonym with Podochilus, an orchid genus.
The platysma is a superficial muscle
that overlaps the sternocleidomastoid
It is a broad sheet arising from the fascia
covering the upper parts of the pectoralis major
; its fibers cross the clavicle
, and proceed obliquely upward and medially along the side of the neck.
The anterior fibers interlace, below and behind the symphysis menti
, with the fibers of the muscle of the opposite side; the posterior fibers cross the mandible
, some being inserted into the bone below the oblique line, others into the skin and subcutaneous
tissue of the lower part of the face. Many of these fibers blend with the muscles about the angle and lower part of the mouth.
Sometimes fibers can be traced to the zygomaticus
, or to the margin of the orbicularis oculi
. Beneath the platysma, the external jugular
vein descends from the angle of the mandible to the clavicle.
Variations occur in the extension over the face and over the clavicle and shoulder; it may be absent or interdigitate with the muscle of the opposite side in front of the neck; attachment to clavicle, mastoid process or occipital bone occurs. A more or less independent fasciculus
, the occipitalis
minor, may extend from the fascia over the trapezius
to fascia over the insertion of the sternocleidomastoideus
The platysma is supplied by the Facial nerve (CN VII).Anatomy & Physiology, 8th Edition, McGraw-Hill Co.,... Read More