Groin lumps

Anatomy

The inguinal canal

A short passage that extends inferomedially, through the inferior part of the abdominal wall.  It is superior and parallel to the inguinal ligament.

  • the inguinal ligament is simply a specialised border of the the external oblique muscle (rolled in on itself) which provides the abdominal muscles with a site of attachment.

The two openings to the inguinal canal are

  • the deep (internal) ring- located just above the midpoint of the inguinal ligament, lateral to the epigastric vessels.  It is a slit-like opening in the transversalis fascia

The abdominal inguinal ring.

  • the superficial (external ring)- lies just superior to the pubic tubercle.  It is a triangle shaped opening formed by the divergence of the external oblique aponeurosis, which has two ‘crura’ which border the ring.  The medial crux attaches to the pubic crest near the symphysis and the lateral attaches to the pubic tubercle.

The inguinal canal itself is bordered by:

  • Anterior wall: aponeurosis of the external oblique
  • Posterior wall: transversalis fascia
  • Roof: transversalis fascia; internal oblique; and transverse abdominis
  • Floor: inguinal ligament and thickened medially by the lacunar ligament

When intra-abdominal pressure rises, the abdominal viscera can be pushed into the inguinal canal.  The muscles of the anterior and posterior wall contract to prevent herniation, flattening the canal.

The femoral triangle

This is a hollow region in the anterior thigh, through which the femoral bundle travels out of the abdomen to the leg.

Its borders/walls consist of

  • inguinal ligament (superiorly)
  • medial border of the sartorius muscle (laterally)
  • medial border of the adductor longus muscle (medially)
  • The roof of the femoral triangle is formed by the fascia lata (deep fascia of the thigh)
  • The base is formed by the pectineus, iliopsoas and adductor longus muscles.

It contains (from lateral to medial- NAVELY)

  • Femoral Nerve (innervates the anterior thigh and provides branches for the leg/foot)
  • Femoral Artery (majority of lower limb is supplied by this)
  • Femoral Vein (in the femoral canal, the great saphenous vein drains into the femoral vein)
  • Empty space
  • Deep Lymph nodes and vessels
  • Y-fronts (genitals)

Inguinal lymph nodes

Divided into the deep and superficial group.

  • Superficial nodes are arranged in a ‘T’ formation- the vertical group sit along the saphenous vein and the horizontal group are parallel to the inguinal ligament
    • These drain the superficial tissues of the lower limb (except lateral foot/heel and back of the lower leg); gluteal region; trunk below the umbilicus; the perineum including the distal third of the anal canal, vagina and urethra; external genitalia except the testes and the glans penis/clitoris; fundus and the body of the uterus
  • The deep nodes are arranged along the femoral vein and drain
    • the deep structures of the lower limb; the glans penis/clitoris

Superficial inguinal lymph nodes

Differential Diagnosis

  • Inguinal swellings
    • Inguinal hernia
    • Lymph nodes
    • Encysted hydrocele of the cord
    • Undescended testis
    • Lipoma of the spermatic cord
  • Femoral swellings
    • Femoral hernia
    • Lymph nodes
    • Saphena varix
    • Psoas abscess (Pott’s disease- TB)
    • Ectopic testis
    • Femoral artery aneurysm
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