Inguinal canal anatomy
Overview of the Inguinal Canal
-
Location and Size
- The inguinal canal is situated in the lower anterior abdominal wall, just above the inguinal ligament.
- It is approximately 4 to 6 cm long and runs inferiorly and medially, parallel and superior to the inguinal ligament.
-
Structure and Borders
- Anterior Wall: Formed by the aponeurosis of the external oblique muscle, reinforced laterally by the internal oblique muscle.
- Posterior Wall: Comprised of the transversalis fascia.
- Roof: Consists of the transversalis fascia, internal oblique, and transversus abdominis muscles.
- Floor: Formed by the inguinal ligament and thickened medially by the lacunar ligament.
-
Openings of the Canal
- Deep (Internal) Inguinal Ring: An oval defect in the transversalis fascia, located at the midpoint of the inguinal ligament.
- Superficial (External) Inguinal Ring: A ‘V’ shaped defect in the external oblique aponeurosis, located just superior to the pubic tubercle.
-
Contents
- In Males: Contains the spermatic cord, the genital branch of the genitofemoral nerve, and the ilioinguinal nerve.
- In Females: Contains the round ligament of the uterus, the genital branch of the genitofemoral nerve, and the ilioinguinal nerve.
-
Clinical Significance
- The inguinal canal is a potential weak spot in the abdominal wall, making it a common site for herniation.
- During increased intra-abdominal pressure, the muscles of the anterior and posterior wall contract to prevent herniation, effectively ‘clamping down’ on the canal.
Ligaments of the Inguinal Canal
-
Inguinal Ligament (Poupart’s Ligament)
-
- Structure: A band of connective tissue forming the floor of the inguinal canal.
- Location: Extends from the anterior superior iliac spine of the ilium to the pubic tubercle on the pubic bone.
- Formation: Created by the free inferior border of the aponeurosis of the external oblique muscle.
-
Extensions of the Inguinal Ligament
- Lacunar Ligament(Ligamentum Gibernati): A thickened part of the inguinal ligament that reinforces the medial part of the floor of the inguinal canal.
- Pectineal Ligament (Cooper’s Ligament): Extends from the lacunar ligament to the pectineal line on the superior ramus of the pubic bone. It forms the posterior border of the femoral ring.
- Reflected Ligament (Colle Ligament or Reflex Ligament): A thin band extending from the medial end of the inguinal ligament to the linea alba.
-
Functional Significance
- These ligaments provide support and protection for the structures passing through the canal, such as the spermatic cord in males and the round ligament of the uterus in females.
- They also play a critical role in preventing herniation of the abdominal contents into the inguinal canal, especially during periods of increased intra-abdominal pressure.
Inguinal Ligament (Poupart’s Ligament)
-
- Structure: A band of connective tissue forming the floor of the inguinal canal.
- Location: Extends from the anterior superior iliac spine of the ilium to the pubic tubercle on the pubic bone.
- Formation: Created by the free inferior border of the aponeurosis of the external oblique muscle.
Lacunar Ligament
A thickened part of the inguinal ligament that reinforces the medial part of the floor of the inguinal canal.
Pectineal Ligament (Cooper’s Ligament)
Extends from the lacunar ligament to the pectineal line on the superior ramus of the pubic bone. It forms the posterior border of the femoral ring.
Inguinal Canal Walls
Anterior Wall: Formed by the aponeurosis of the external oblique muscle, reinforced laterally by the internal oblique muscle and its crus laterale and fibrae intercrurales.
Posterior Wall: Comprised of the transversalis fascia, reinforced medially by the reflex ligament and laterally by the interfoveolar ligament.
Roof: Made up of the internal oblique and transversus abdominis muscles, which fuse with their fasciae just above the inguinal ligament.
Floor: Formed by the inguinal ligament, reinforced medially by the reflex ligament.
Overview of the Inguinal Canal
-
Location and Size
- The inguinal canal is situated in the lower anterior abdominal wall, just above the inguinal ligament.
- It is approximately 4 to 6 cm long and runs inferiorly and medially, parallel and superior to the inguinal ligament.
-
Structure and Borders
- Anterior Wall: Formed by the aponeurosis of the external oblique muscle, reinforced laterally by the internal oblique muscle.
- Posterior Wall: Comprised of the transversalis fascia.
- Roof: Consists of the transversalis fascia, internal oblique, and transversus abdominis muscles.
- Floor: Formed by the inguinal ligament and thickened medially by the lacunar ligament.
-
Openings of the Canal
- Deep (Internal) Inguinal Ring: An oval defect in the transversalis fascia, located at the midpoint of the inguinal ligament.
- Superficial (External) Inguinal Ring: A ‘V’ shaped defect in the external oblique aponeurosis, located just superior to the pubic tubercle.
-
Contents
- In Males: Contains the spermatic cord, the genital branch of the genitofemoral nerve, and the ilioinguinal nerve.
- In Females: Contains the round ligament of the uterus, the genital branch of the genitofemoral nerve, and the ilioinguinal nerve.
-
Clinical Significance
- The inguinal canal is a potential weak spot in the abdominal wall, making it a common site for herniation.
- During increased intra-abdominal pressure, the muscles of the anterior and posterior wall contract to prevent herniation, effectively ‘clamping down’ on the canal.
Ligaments of the Inguinal Canal
-
Inguinal Ligament (Poupart’s Ligament)
-
- Structure: A band of connective tissue forming the floor of the inguinal canal.
- Location: Extends from the anterior superior iliac spine of the ilium to the pubic tubercle on the pubic bone.
- Formation: Created by the free inferior border of the aponeurosis of the external oblique muscle.
-
Extensions of the Inguinal Ligament
- Lacunar Ligament(Ligamentum Gibernati): A thickened part of the inguinal ligament that reinforces the medial part of the floor of the inguinal canal.
- Pectineal Ligament (Cooper’s Ligament): Extends from the lacunar ligament to the pectineal line on the superior ramus of the pubic bone. It forms the posterior border of the femoral ring.
- Reflected Ligament (Colle Ligament or Reflex Ligament): A thin band extending from the medial end of the inguinal ligament to the linea alba.
-
Functional Significance
- These ligaments provide support and protection for the structures passing through the canal, such as the spermatic cord in males and the round ligament of the uterus in females.
- They also play a critical role in preventing herniation of the abdominal contents into the inguinal canal, especially during periods of increased intra-abdominal pressure.
Inguinal Ligament (Poupart’s Ligament)
-
- Structure: A band of connective tissue forming the floor of the inguinal canal.
- Location: Extends from the anterior superior iliac spine of the ilium to the pubic tubercle on the pubic bone.
- Formation: Created by the free inferior border of the aponeurosis of the external oblique muscle.
Lacunar Ligament
A thickened part of the inguinal ligament that reinforces the medial part of the floor of the inguinal canal.
Pectineal Ligament (Cooper’s Ligament)
Extends from the lacunar ligament to the pectineal line on the superior ramus of the pubic bone. It forms the posterior border of the femoral ring.
Inguinal Canal Walls
Anterior Wall: Formed by the aponeurosis of the external oblique muscle, reinforced laterally by the internal oblique muscle and its crus laterale and fibrae intercrurales.
Posterior Wall: Comprised of the transversalis fascia, reinforced medially by the reflex ligament and laterally by the interfoveolar ligament.
Roof: Made up of the internal oblique and transversus abdominis muscles, which fuse with their fasciae just above the inguinal ligament.
Floor: Formed by the inguinal ligament, reinforced medially by the reflex ligament.