Comparative tensile properties of the equine vagina, penile sheath, and scrotum

This experimental study characterizes the elastic behavior of male and female equine genital tissues using uniaxial tensile testing, with strain measurements obtained via digital image correlation. Dog-bone-shaped tissue specimens were excised from mares and geldings (n=23 from female specimens and n=42 from male specimens) with all specimens aligned along the circumferential direction (CD) of the vagina, penis, and scrotum. The results include load-displacement data, stress-strain data, and tangent moduli for the penile sheath, vaginal canal, and scrotum, with strain measured in both the CD and the longitudinal direction (LD). Findings indicate that vaginal and scrotal tissues exhibit comparable mechanical properties (tangent moduli: 10.16 ± 1.30 MPa for the vagina and 4.81 ± 1.66 MPa for the scrotum), whereas the penile sheath (tangent modulus: 2.30 ± 1.43 MPa) differs significantly from the vaginal and scrotal tissues (p<0.01 and p<0.05, respectively). This mechanical evaluation of vaginal, penile, and scrotal tissues has implications for advancing surgical techniques, developing genital prostheses, and informing biomechanical models of the pelvic region.