Ans. d (Fascia transversalis). (Ref. BD Chaurasia, Anatomy 2nd vol., 3rd ed., 61, 177)Surgical anatomy of Inguinal region:AreaAnatomySuperficial inguinal ring# It is a triangular aperture in the aponeurosis of the external oblique and lies 1.25 cm above the pubic tubercle.# The ring is bounded by a superomedial and an inferolateral crus joined by the criss-cross intercrural fibres.# Normally, the ring will not admit the tip of the little finger.Deep inguinal ring# It is a U-shaped condensation of the transversalis fascia and it lies 1.25 cm above the inguinal (Poupart's) ligament, midway between the symphysis pubis and the anterior superior iliac spine.# The transversalis fascia is the fascial envelope of the abdomen and the competency of the deep inguinal ring depends on the integrity of this fascia.Inguinal canal# In infants the superficial and deep inguinal rings are almost superimposed and the obliquity of the canal is slight.# In adults the inguinal canal, which is 3.75 cm long, is directed downwards and medially from the deep to the superficial inguinal ring.# In the male the inguinal canal transmits the spermatic cord, the ilio-inguinal nerve and the genital branch of the genitofemoral nerve.# In the female the round ligament replaces the spermatic cord.Boundaries of the canal# The anterior boundary comprises mainly the external oblique aponeurosis with the conjoined muscle laterally.# The posterior boundary is formed by the fascia transversalis and conjoined tendon (internal oblique and transversus abdominus medially). The inferior epigastric vessels lie posteriorly and medially to the deep inguinal ring.# The superior boundary is formed by the conjoined muscles (internal oblique and transversus) and the inferior boundary is the inguinal ligament.DEEP INGUINAL RING# It is an oval opening in fascia transversalis about half an inch above mid-inguinal point,# I It lies immediately lateral to inferior epigastric artery.# It transmits spermatic cord in male and round ligament in female.# Fascia transversalis is the inner surface of abdominal muscles lining.# Fascia separates peritoneum from extraperitoneal tissue.# An indirect hernia travels down the canal on the outer (lateral and anterior) side of the spermatic cord. A direct hernia comes out directly forwards through the posterior wall of the inguinal canal.# While the neck of the indirect hernia is lateral to the inferior epigastric vessels, the direct hernia usually emerges medial to this except in the saddle-bag or pantaloon type, which has both a lateral and a medial component.# An inguinal hernia can be differentiated from a femoral hernia by ascertaining the relation of the neck of the sac to the medial end of the inguinal ligament and the pubic tubercle,i.e.in the case of an inguinal hernia the neck is above and medial, while that of a femoral hernia is below and lateral.