| Platysma muscle | |
|---|---|
 The platysma is visible, with skin removed. | |
 The muscles of the face, platysma visible at bottom right. | |
| Details | |
| Origin | Subcutaneous tissue of infraclavicular and supraclavicular regions |
| Insertion | Base of mandible; skin of cheek and lower lip; angle of mouth; orbicularis oris |
| Artery | Branches of thesubmental artery andsuprascapular artery |
| Nerve | Cervical branch of thefacial nerve |
| Actions | Draws the corners of themouthinferiorly and widens it (as in expressions of sadness and fright). Also draws theskin of thenecksuperiorly whenteeth are clenched |
| Antagonist | Masseter muscle,temporalis muscle |
| Identifiers | |
| Latin | platysma |
| TA98 | A04.2.01.001 |
| TA2 | 2147 |
| FMA | 45738 |
| Anatomical terms of muscle | |
Theplatysma muscle orplatysma is asuperficialmuscle of thehumanneck that overlaps thesternocleidomastoid. It covers the anterior surface of the neck superficially. When it contracts, it produces a slight wrinkling of the neck, and a "bowstring" effect on either side of the neck.
First recorded in the period 1685–1695, the word comes viaNeo-Latin fromGreekplátysma, a plate, literally, something wide and flat, equivalent toplatý(nein), to widen, + -sma, a variant of theresultative suffix-ma.[1] The botanistWilliam T. Stearn argues thatplatýs, "in Greek compound words, usually signifiesbroad, rarelyflat," which describes the platysma's broad sheet of muscle.[2]
The platysma muscle is a broad sheet of muscle arising from thefascia covering the upper parts of thepectoralis major muscle anddeltoid muscle. Its fibers cross theclavicle, and proceed obliquely upward and medially along the side of the neck. This leaves the inferior part of the neck in the midline deficient of significant muscle cover.[3]
Fibres at the front of the muscle from the left and right sides intermingle together below and behind themandibular symphysis, the junction where the two lateral halves of themandible are fused at an early period of life (although not a true symphysis). Fibres at the back of the muscle cross the mandible, some being inserted into the bone below the oblique line, others into the skin andsubcutaneous 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.[3]
Sometimes fibers can be traced to thezygomaticus major muscle, or to the margin of theorbicularis oris muscle. Beneath the platysma, theexternal jugular vein descends from theangle of the mandible to theclavicle.[4]
The platysma muscle is supplied by thecervical branch of thefacial nerve.[3]
The platysma muscle is supplied by branches of thesubmental artery andsuprascapular artery.
The platysma muscle lies just deep to the subcutaneous fascia andfat.[3][5] It covers many structures found deeper in the neck, such as theexternal carotid artery, theexternal jugular vein,[6] theparotid gland,[6] thelesser occipital nerve,[6] thegreat auricular nerve,[6] and themarginal mandibular branch of thefacial nerve.[7]
Variations occur in the extension over the face and over the clavicle and shoulder. The platysma muscle 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 independentfasciculus, theoccipitalis minor muscle, may extend from the fascia over thetrapezius muscle to fascia over the insertion of thesternocleidomastoid muscle.
When the entire platysma muscle is in action, it produces a slightwrinkling of the surface of the skin of theneck in an oblique direction (at an angle to the midline). It creates a distinctive "bowstring" effect on either side of the neck, where fibres move away from the midline.[5]
The anterior portion of the platysma muscle, the thickest part of the muscle, depresses the lower jaw. It also draws down the lower lip and angle of the mouth in afrown. However, the platysma muscle plays only a minor role in depressing the lower lip, which is primarily performed by thedepressor anguli oris muscle and thedepressor labii inferioris muscle.
In a similar fashion to other muscles, the platysma muscle is vulnerable to tears,strains andmuscle atrophy, among many other possible conditions.
The platysma muscle is vulnerable to neck injuries that maypenetrate it, as it is both superficial and thin.[8] Penetrating trauma in the neck injuries can be defined as any that completely penetrate the platysma muscle, making it an important landmark.[8]Computed tomography angiography may be used to visualisearteries andveins, such as for complex injuries fromgunshot wounds orstab wounds, and is useful to image any damage to the muscle.[8][9] This minimises the number ofexploratory surgeries that need to be performed, thus improving the handling of the condition.[9]
When neck surgery is performed, the platysma muscle usually needs to be cut through to access deeper structures.[3][7] Fibres need to be sutured together accurately to prevent abnormalscar retraction, which may look unsightly.[3]
Wrinkly skin of the neck caused by decrease in muscle tone leading to thinning and shortening of muscle is the secondary complication of facial nerve palsy and can be associated with the normal aging process. Neck bands in the area above the platysma muscle become most noticeable with age.[5] These may be aggravated byweightlifting orfacelift procedures. This may be known as platysmadyskinesia or "turkey neck".
Conservative management may be used. Alternatively, interventions includebotulinum toxin injection andplatysmaplasty. Platysmaplasty is a surgery in this area, that can be open or closed; in the latter a specialised instrument called a plastymotome is used that allows the surgery to be done without incisions.[10] It takes approximately 2 weeks for the symptoms to be reduced.[11]
Adipose tissue is found above the platysma muscle, soliposuction of the neck may be performed fairly easily without the need to pierce it.[12] It is also important to not damage the platysma muscle to preventbleeding.[12]
This article incorporates text in thepublic domain frompage 387 of the 20th edition ofGray's Anatomy(1918)
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