Where does flap collide?

In neurology a flap, or flapping tremor (asterixis), is a brief, involuntary loss of posture seen when the arms are held out and the wrists extended: the hands drop and recover in an irregular flapping motion caused by momentary lapses in muscle contraction, classically a sign of metabolic brain disturbance such as liver or kidney failure. Smythe's 1957 Hepatic-type "flapping tremor" occurring in patients without hepatic disease documented the sign and noted it can arise without liver disease. The referent is a negative-myoclonus clinical sign of the limbs, observed at the bedside, and it has nothing to do with a wing surface or a graft of skin but the look of flapping.[1]

Unit

Not applicable (a clinical sign)

Recovery means

The sign typically resolves as the underlying metabolic disturbance is corrected

Measured by

Elicited by sustained wrist extension and seen (or recorded electromyographically) as lapses in postural muscle activity

In reconstructive surgery a flap is a block of living tissue, skin and often fat, muscle, or bone, that is moved from one site to another while keeping its own blood supply, which lets it survive over a wound and distinguishes it from a free graft that must take up new vessels. Bardach and Kurnatowski's 1962 Blood supply of a Filatov's skin flap examines the vascular basis of a classic tubed pedicle flap. The referent is a vascularised unit of transferred tissue, classified by its blood supply and composition, and it is a different construct from a wing's high-lift panel or a flapping hand, joined only by the word.[2]

Unit

Not applicable (a transferred block of vascularised tissue)

Recovery means

Flap survival depends on its blood supply; failure shows as congestion or necrosis of the transferred tissue

Measured by

Judged by perfusion and survival of the tissue, and classified by blood supply (random versus axial) and content