Objective: Examine embalmed human cadavers for diastasis rectus abdominis by measuring inter-recti distance (IRD) at 3 locations: supraumbilical, umbilical, and infraumbilical. Factors examined that can influence IRD included gender, waist girth, subcutaneous fat, waist-hip ratio (WHR), abdominal scarring, and age.
Study Design: Basic science.
Background: Diastasis rectus abdominis is an abnormal separation of the rectus abdominis muscles at the linea alba. The criteria for and factors that predispose an individual to diastasis rectus abdominis remain unclear in the literature.
Methods and Measures: Thirty-four embalmed cadavers (16 women and 18 men) between 47 and 99 years of age were included. Morphological measures—waist and hip girth—were taken, followed by dissection of the rectus sheath/rectus abdominis muscles. Digital calipers were used to measure IRD at the umbilicus and 4.5 cm above and below the umbilicus; the depth of subcutaneous fat was recorded. Regression analysis was used to determine whether gender, waist girth, subcutaneous fat, WHR, abdominal scarring, or age influenced maximal IRD.
Results: Upon optimizing the mathematical model, a 102-cm threshold was identified and included in the regression as “waist index” (R2 = 0.539). This threshold indicates that at more than 102 cm, waist girth has a greater contribution to IRD. Factors increasing IRD were waist girth (P = .0016) and scarring (P = .0222) in the supraumbilical region, waist index (P = .0100) and scarring (P = .0131) at the umbilicus, and WHR (P = .0169) and gender (P = .0000) in the infraumbilical region. Age did not increase IRD.
Conclusions: Waist girth more than 102 cm, female gender, abdominal scarring, and increased WHR are predictors of increased IRD in cadavers.