Inguinal canal: boundaries, contents and applied anatomy
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Inguinal canal: oblique intermuscular passage in the lower anterior abdominal wall, above the medial half of the inguinal ligament.
Transmits the spermatic cord (male) or round ligament of the uterus (female).
Extent and Inguinal Rings
Extends from the deep inguinal ring (oval opening in fascia transversalis) to the superficial inguinal ring (triangular gap in external oblique aponeurosis).
About 4 cm long, directed downward, forward and medially.
Deep ring lies 1.25 cm above the midinguinal point.
Fascia transversalis is prolonged from its margins into the canal as a sleeve, the internal spermatic fascia, around the traversing structures.
Superficial ring lies above and lateral to the pubic crest, which forms its base; its margins (crura) meet laterally at an obtuse apex, united by intercrural fibres.
Superficial ring is 2.5 cm long, 1.2 cm broad at the base.
Surface marking: two parallel lines, 1 cm apart and 4 cm long, just above the medial half of the inguinal ligament.
Centre of the superficial ring lies 1 cm above and lateral to the pubic tubercle.