Page 256 - Clinical Anatomy

ECA4 7/18/06 6:47 PM Page 241

Three important zones 241

usually passes laterally to the femoral canal and is out of harm’s way; more
rarely, it passes behind Gimbernat’s ligament and it is then in surgical
danger.

The lymph nodes of the groin and the
lymphatic drainage of the lower limb

The lymph nodes of the groin are arranged in a superficial and a deep
group. The superficial nodes lie in two chains, a longitudinal chain along the
great saphenous vein, receiving the bulk of the superficial lymph drainage
of the lower limb, and a horizontal chain, just distal to the inguinal ligament.
These horizontal nodes receive lymphatics from the skin and superficial
tissues of:
1◊◊the lower trunk and back, below the level of the umbilicus;
2◊◊the buttock;
3◊◊the perineum, scrotum and penis (or lower vagina and vulva) and the
anus below its mucocutaneous junction.
In addition, some lymphatics drain via the round ligament to these
nodes from the fundus of the uterus.
(All these sites, as well as the whole leg, must be examined carefully
when a patient presents with an inguinal lymphadenopathy.)
The two groups of superficial nodes drain through the saphenous
opening in the fascia lata into the deep nodes lying medial to the femoral
vein, which also receive the lymph drainage from the tissues of the lower
limb beneath the deep fascia. In addition, a small area of skin over the heel
and lateral side of the foot drains by lymphatics along the small saphenous
vein to nodes in the popliteal fossa and then, along the femoral vessels,
directly to the deep nodes at the groin.
The deep groin nodes drain to the external iliac nodes by lymphatics
which travel partly in front of the femoral artery and vein and partly
through the femoral canal.

Clinical features

1◊◊Minor sepsis and abrasions of the leg are so common that it is usual to
find that the inguinal nodes are palpable in perfectly healthy people.
2◊◊Secondary involvement of the inguinal nodes by malignant deposits
may be dealt with by block dissection of the groin. This involves removal of the
superficial and deep fascial roof of the femoral triangle, the saphenous vein
and its tributaries and the fatty and lymphatic contents of the triangle,
leaving only the femoral artery, vein and nerve. The inguinal ligament is
detached so that, in addition, an extraperitoneal removal of the external
iliac nodes can be carried out.
3◊◊In making a differential diagnosis of a lump in the femoral triangle,
think of each anatomical structure and of the pathological conditions to
which it may give rise, thus:
•◊◊skin and soft tissues—lipoma, sebaceous cyst, sarcoma;