Table 5: Classification of perineal injuries.
Classified by
severity of wound and tissue damage |
1st
degree tear, involves perineal
skin layer only. |
2nd
degree tear, involves posterior vaginal wall,
subcutaneous fat, perineal skin layer, superficial
muscles (bulbocavernosus and transverse perinei) and deep muscle (pubococcugeus). |
Episiotomy
involves the same structures as for 2nd degree tears. |
3rd
degree tears, involve the same structures as for
2nd degree tears and in addition, the anal sphincter. 3rd
degree tears are
classified by injuries to the external anal sphincter (EAS), internal anal
sphincter (IAS) and anal epithelium. 3a < 50% of external anal sphincter (EAS) thickness
torn. 3b > 50% of EAS thickness torn. 3c Internal anal sphincter (IAS) torn. |
A 4th
Degree tear, involves the anal sphincter
complex (EAS and IAS) and anal epithelium. |