The platysma muscle is a superficial

muscle Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...

of the

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

neck that overlaps the sternocleidomastoid. 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.

Structure

The platysma muscle is a broad sheet of muscle arising from the

fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organ ...

covering the upper parts of the pectoralis major muscle and

deltoid muscle The deltoid muscle is the muscle forming the rounded contour of the human shoulder. It is also known as the 'common shoulder muscle', particularly in other animals such as the domestic cat. Anatomically, the deltoid muscle appears to be made up ...

. Its fibers cross the clavicle, 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. Fibres at the front of the muscle from the left and right sides intermingle together below and behind the

mandibular symphysis In human anatomy, the facial skeleton of the skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more p ...

, the junction where the two lateral halves of the

mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bon ...

are fused at an early period of life (although not a true symphysis). Fibres at the back of the muscle cross the

, 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 major muscle, or to the margin of the orbicularis oris muscle. Beneath the platysma, the external jugular vein descends from the angle of the mandible to the clavicle.

Nerve supply

The platysma muscle is supplied by the cervical branch of the

facial nerve The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of ta ...

Blood supply

The platysma muscle is supplied by branches of the submental artery and suprascapular artery.

Relations

The platysma muscle lies just deep to the subcutaneous fascia and fat. It covers many structures found deeper in the neck, such as the external carotid artery, the external jugular vein, the parotid gland, the lesser occipital nerve, the great auricular nerve, and the marginal mandibular branch of the

Variation

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 independent fasciculus, the occipitalis minor muscle, may extend from the fascia over the trapezius muscle to fascia over the insertion of the sternocleidomastoid muscle.

Function

Wrinkling

When the entire platysma muscle is in action, it produces a slight

wrinkling A wrinkle, also known as a rhytid, is a fold, ridge or crease in an otherwise smooth surface, such as on skin or fabric. Skin wrinkles typically appear as a result of ageing processes such as glycation, habitual sleeping positions, loss of bo ...

of the surface of the skin of the neck 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.

Jaw and lip movement

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 a frown. However, the platysma muscle plays only a minor role in depressing the lower lip, which is primarily performed by the depressor anguli oris muscle and the depressor labii inferioris muscle.

Clinical significance

In a similar fashion to other muscles, the platysma muscle is vulnerable to tears, strains and muscle atrophy, among many other possible conditions.

Injury

The platysma muscle is vulnerable to neck injuries that may penetrate it, as it is both superficial and thin.

Penetrating trauma Penetrating trauma is an open wound injury that occurs when an object pierces the skin and enters a tissue of the body, creating a deep but relatively narrow entry wound. In contrast, a blunt or ''non-penetrating'' trauma may have some deep d ...

in the neck injuries can be defined as any that completely penetrate the platysma muscle, making it an important landmark. CTA ( computed tomography angiography) may be used to visualise arteries and veins, such as for complex injuries from gunshot wounds or stab wounds, and is useful to image any damage to the muscle. This minimises the number of exploratory surgeries that need to be performed, thus improving the handling of the condition.

Neck surgery

When neck surgery is performed, the platysma muscle usually needs to be cut through to access deeper structures. Fibres need to be sutured together accurately to prevent abnormal

scar A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a n ...

retraction, which may look unsightly.

Plastic surgery

Wrinkly skin of 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. These may be aggravated by weightlifting or facelift procedures. This may be known as platysma dyskinesia or "turkey neck". Conservative management may be used. Alternatively, interventions include botulinum toxin injection and

platysmaplasty Platysmaplasty, commonly referred to as a neck lift, is a form of cosmetic plastic surgery involving tightening and removing skin from the human neck The neck is the part of the body on many vertebrates that connects the head with the torso. T ...

. 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. It takes approximately 2 weeks for the symptoms to be reduced.

Adipose tissue Adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular ...

is found above the platysma muscle, so liposuction of the neck may be performed fairly easily without the need to pierce it. It is also important to not damage the platysma muscle to prevent bleeding.

Images

File:Platysma.png, Platysma is visible at bottom, in neck

References

;Books * {{Authority control Muscles of the head and neck