Inguinal hernia may be classified according to integrity of the posterior wall and the deep inguinal ring into 4 groups. Inguinal hernia may be classified according to presence or absence of a peritoneal sac, size of the internal ring and integrity of the posterior wall of the canal into 5 groups.

• Inguinal hernia may be classified into several subtypes based on:^[1]
  • Nyhus classification
  • Gilbert classification
  • Casten classification
  • Mc Vay classification

• Inguinal hernia may be classified according to the integrity of the posterior wall, and the deep inguinal ring, into 4 groups:^[2]

• Normal inguinal ring, peritoneal sac is in the inguinal canal.

• Enlarged deep inguinal ring with the posterior wall intact, sac not in the scrotum

• Posterior wall (inguinal floor) defects:
  • Type 3a:
    • Direct hernia with a posterior floor defect only
  • Type 3b:
    • Indirect hernia with enlargement of deep inguinal ring and posterior floor defect
  • Type 3c:
    • Femoral hernia
  • Type 4:
    • Recurrent hernia
• Inguinal hernia may be classified according to the presence or absence of a peritoneal sac, size of the internal ring and integrity of the posterior wall of the canal, Gilbert classification, into 5 groups:^[3]
  • Type 1:
    • Hernias with a peritoneal sac passing through an intact internal ring, unable to admit 1 finger breadth (ie,<1 cm.) and the posterior wall is intact.
  • Type 2:
    • Hernias with a peritoneal sac coming through a 1-finger breadth internal ring (ie, ≤2 cm.) and the posterior wall is intact.
  • Type 3:
    • Hernias have a peritoneal sac that is able to accommodate a 2-finger breadth or wider internal ring (ie, >2 cm).
  • Type 4:
    • Hernias have posterior wall with either complete breakdown or multiple defects. There is intact inguinal ring with no peritoneal sac.
  • Type 5:
    • Hernias are pubic tubercle recurrence or primary diverticular hernias.

NOTE: Types 1, 2 and 3 are indirect hernias; types 4 and 5 are direct.

• Inguinal hernia may be classified according to Casten method into 3 stages:
  • Stage 1: an indirect hernia with a normal internal ring
  • Stage 2: an indirect hernia with an enlarged or distorted internal ring
  • Stage 3: all direct or femoral hernias

• Inguinal hernia may be classified according to McVay method into 4 classes:
  • Class 1: small indirect hernia
  • Class 2: medium indirect hernia
  • Class 3: large indirect hernia or direct hernia
  • Class 4: femoral hernia