ARTicle | InjeCTIon TeCHnIque |
into the skin of the forehead and brows, and interdigitates with the fibres of the procerus, corrugators, and orbicularis oculi. The frontalis is the only powerful levator muscle of the upper third of the face. It produces the pull-up strength and elevates brows. When it contracts, it produces transverse forehead lines. The platysma is a superficial broad sheet muscle
arising from the pectoral fascia, which ascends superomedially across the mandible to insert into the skin and subcutaneous tissue of the lower face. Some of its fibres insert into the mandible, while some interlace with the fibres of the opposite side and blend with other muscles around the corner of the mouth. Some fibres can be traced to the lower margin of the orbicularis oculi muscle. even though the platysma and frontalis are similar in shape, their functions are completely opposite. The frontalis is considered as the potent levator, while the platysma is the powerful depressor that pulls down the corner of the mouth, producing jowls, double chin, and wrinkling on the neck. The orbicularis oculi muscle is a thin, broad muscle
circling the eye. It adheres to the skin and spreads over the temple and downwardly on the cheek. It is classified as the depressor muscle which pulls down to cause crow’s feet, under-eye bags, and sagging in the midface. The orbicularis oris is a circular muscle surrounding
Figure 1 Anatomy of the facial muscles (courtesy of Benedetto21 ) being treated as multi-area injections, rather than one
treatment per session. The fact that treating one muscle may affect the surrounding muscles, patient evaluation within the framework of facial enhancement will lead to a treatment plan that incorporates the creation of harmony and balance, rather than wrinkle removal in isolation4, 8
.
The facial muscles of expression The facial muscles of expression are striated muscles lying just underneath the skin to control facial expression. They generally originate on the bone, insert into the under-surface of the skin and interdigitate with the others, like an elastic sheet stretched over the facial bones. When these mimetic muscles contract, they pull and move the skin, causing wrinkling that is generally perpendicular to the direction of muscle contraction9 These muscles vary widely in their shape and size, lie
. 24 ❚
in different planes, and differ in their functions (Figure 1). Anatomically, their shapes vary from small, elongated to broad, flat sheet, to triangular, or even circular. Functionally, the facial muscles are classified into the levators to pull up or elevate a certain part of the face, and the depressors to pull down. Interestingly, their functions are not determined by their shape. The frontalis is a broad, sheet-like, quadrilateral muscle, which originates from the galea aponeurotica to insert
October 2011 |
prime-journal.com
the orifice of the mouth. It forms complex insertion with other mid- and lower-facial musculature. As ageing progresses, it ultimately contributes to the formation of outwardly radiating perioral lines. The procerus is a small muscle with a pyramid shape,
most patients
who receive treatment to the lower face
usually experience treatment in other areas of the face.
arising from fascia covering the nasal bone, inserting superficially into the skin between the brows, and interlacing with the fibres of the frontalis. The corrugator supercilii is a small, narrow, deeply situated muscle arising from the nasal process of the frontal bone, extending laterally and upwardly, inserting into the skin above the mid-brow, and blending with the fibres of orbicularis oculi and frontalis. These two muscles work together as depressors to pull the head of the brows medially and downwardly to produce frown lines and nasal creases. The zygomaticus major and minor are
small muscle strands to lift up the corner of the mouth to produce a smiling expression. The other facial muscles,
namely levator labii superioris, levator labii superioris alaeque nasi, levator anguli oris, depressor anguli oris, depressor labii inferioris, and mentalis, are also small deeper muscles; their names indicate their functions.
Intramuscular injection technique In the conventional injection technique, toxin is injected intramuscularly or subcutaneously. There does not seem to be any agreement in the literature on how to determine which dilutions should be used when reconstituting a 100 unit vial of onabotulinumtoxinA. Furthermore, there does not seem to be even one particular injection technique or pattern that provides results better than
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