SN5 SHORT NOTE 5M ★ High-yield

Describe the inguinal ligament with its extensions and the structures passing behind it.

Anatomy · 1st Professional — Pre-Clinical

Definition

The inguinal (Poupart) ligament is the thickened, rolled-under lower border of the aponeurosis of the external oblique muscle, extending from the anterior superior iliac spine to the pubic tubercle.

It is the boundary between the abdomen and the thigh, and the key landmark of the groin

Extensions and Related Ligaments

Ligament	Description	Significance
Lacunar (Gimbernat)	Fibres passing backward and laterally to the pecten pubis	Medial boundary of the femoral ring; sharp and unyielding
Pectineal (Cooper)	Continuation along the pecten pubis	Posterior boundary of the femoral ring; used for anchoring in hernia repair
Reflected part	Fibres passing upward and medially	Behind the superficial inguinal ring

Structures Passing Behind It

Muscles — iliopsoas, pectineus
Vessels — femoral artery and vein
Nerves — femoral nerve, lateral cutaneous nerve of thigh, femoral branch of genitofemoral, nerve to pectineus
Lymphatics and the femoral canal
The space is divided by the iliopectineal arch into a lateral muscular and a medial vascular compartment

Important Surface Points

Point	Definition	Significance
Mid-inguinal point	Midway between the ASIS and the pubic symphysis	Femoral artery lies here
Midpoint of the inguinal ligament	Midway between the ASIS and the pubic tubercle	Deep inguinal ring lies about 1.25 cm above it
Pubic tubercle	Medial attachment of the ligament	The reference point for hernia diagnosis

The Inguinal Canal — Brief Account

Wall	Formed by
Anterior	External oblique aponeurosis; internal oblique laterally
Posterior	Fascia transversalis; conjoint tendon medially
Roof	Arching fibres of internal oblique and transversus
Floor	Inguinal ligament, with the lacunar ligament medially

Contents — spermatic cord (or round ligament of the uterus) and the ilioinguinal nerve
The deep ring is a defect in the fascia transversalis; the superficial ring in the external oblique aponeurosis
Mechanisms preventing herniation — obliquity of the canal, the shutter action of the arching fibres, and the sphincteric action of the internal oblique at the deep ring

Applied Aspects

Indirect inguinal hernia passes through the deep ring, lateral to the inferior epigastric artery, along the canal; congenital, commoner in the young
Direct inguinal hernia pushes through the posterior wall in Hesselbach's triangle, medial to the inferior epigastric artery; acquired, in older men with weak abdominal muscles
Hesselbach's triangle — bounded by the inferior epigastric artery laterally, the rectus abdominis medially, and the inguinal ligament below
The pubic tubercle distinguishes inguinal from femoral hernia — inguinal above and medial, femoral below and lateral
Ilioinguinal nerve injury during herniorrhaphy causes numbness of the scrotum or labium and the medial thigh, and chronic groin pain

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