Editing Skin excisions general (section)

== Skin tension lines: ==

* Types of tension lines:
** Biodynamic excisional skin tension (BEST) lines were derived using tensiometer data to show optimal orientation of a skin excision to minimise tension across its closure
** Cleavage lines (including Langer lines) were derived from experiments on cadavers determining the shape of wounds
** Wrinkle lines are based on observational data of wrinkles in elderly people. They do not always align with tension lines, especially on chin, dorsum of nose, and the area lateral to the eyes.
** Relaxed skin tension lines are produced by positioning the body so that the skin is relaxed, then gently pinching the skin to reveal a crease. These differ from Langer lines, since they are tested on living people. On the face, they often go at right angles to Langer lines.
* The best guide to orientating excisions is found using relaxed skin tension lines, BEST lines, and lines following the direction of stretch marks. 
* Scars parallel to Langer's lines and relaxed skin tension lines look better
* Note that some types of lesions will naturally grow with their long axes aligned with skin tension lines - for example, ovoid seborrheic keratoses are generally aligned.
* Long axis of ellipses should be oriented along skin tension lines, with a ratio of 3-4:1 of length to width.
* If lines meet at 30 degrees or less, should be able to avoid dog ears