Pathomechanics of Gowers' sign: a video analysis of a spectrum of Gowers' maneuvers.

Abstract

Gowers' sign is a screening test for muscle weakness, typically seen in Duchenne muscular dystrophy but also seen in numerous other conditions. The mildest presentations and the variations of Gowers' sign are poorly described in the literature but are important to recognize to help with early diagnosis of a neuromuscular problem. We therefore (1) defined the characteristics of the mildest forms and the compensatory mechanism used, (2) categorized the spectrum of this sign as seen in various neuromuscular diseases, and (3) provide educational videos for clinicians. We videotaped 33 patients with Gowers' sign and three healthy children. Weakness was categorized as: mild = prolonged or rise using single-hand action; moderate = forming prone crawl position and using one or two hands on thigh; severe = more than two thigh maneuvers, rising with additional aid, or unable to rise. The earliest changes were exaggerated torso flexion, wide base, and equinus posturing, which reduce hip extension moment, keep forces anterior to the knee, and improve balance. Patients with moderate weakness have wide hip abduction, shifts in pelvic tilt, and lordosis, which reduce knee extension moment, improve hamstrings moment arm, and aide truncal extension. The classic Gowers' sign (severe) exaggerates all mechanisms. The classically described Gowers' sign is usually a late finding. However more subtle forms of Gowers' sign including mild hand pressure against the thigh and prone crawl position should be recognized by clinicians to initiate additional diagnostic tests.