Hypothesis 3rd and 4th-degree perineal tears extend into or through the anal sphincter complex and may be associated with pelvic floor dysfunction. To date, there is scant knowledge of pelvic floor muscle (PFM) function after severe perineal tears. This study aimed to test the association between measurement with surface electromyography (sEMG) of the PFM and transperineal ultrasound of levator hiatus (LH) dime...