Br. J. Surg. Vol. 65 (1978) 351

Popliteal vein entrapment J O H N C O N N E L L *

SUMMARY A case of popliteal vein entrapment by an abnormal ‘third’ head of the gastrocnemius muscle is reported. Complete relief of disabling symptoms was obtained by dividing the abnormal muscle band.

CONSTRICTION of the popliteal artery in the popliteal fossa due to a muscular congenital anomaly is a rare condition. Since its original description by Hamming in 1959, fewer than 20 cases have been reported. Con- striction of the popliteal vein from the same cause is much rarer, and only 2 cases have previously been reported (Rich and Hughes, 1967; Edmondson and Crowe, 1972).

This is a report of a further case of popliteal vein entrapment, due to an anomalous insertion of the medial head of the gastrocnemius muscle. Unlike the first 2 cases reported, the popliteal artery was un- affected and the patient free of ischaemic symptoms.

Case report A 43-year-old woman was referred in November 1976 with a long history of aching pain and tiredness in the left leg. For 10 months she complained of chronic swelling of the foot and ankle, a condition always worse at the end of a day or after prolonged standing. In 1964, when her symptoms first com- menced, she had been told that she had a popliteal vein throm- bosis, but venography was not done at that time. She had no other medical history of importance.

On examination she had obvious swelling of the left foot and ankle, with easily elicited pitting. The oedema suggested venous swelling rather than lymphatic obstruction. No varicose veins were visible or palpable. The arterial pulses were normal and the nutrition to the foot was satisfactory.

a b Fig. 1. Lateral (a) and anteroposterior (6) ascending venograms showing compression of the popliteal vein laterally.

Fig. 2. Diagrammatic view of the operative findings.

A left lower limb venogram was carried out and revealed no intrinsic abnormality in the veins below the knee. However, the popliteal vein was displaced posteriorly and laterally and was considerably narrowed (Fig. 1). No other abnormality was noted.

In January 1977 the left popliteal fossa was explored through a curved vertical incision. After the medial popliteal nerve had been exposed and mobilized laterally, it was found that the medial head of the gastrocnemius muscle had a double origin. Most of the muscle arose from the medial side of the posterior surface of the femur, but it was joined, about 4 cm below its origin, by a large muscle slip which arose from the lateral side of the femur. The origin of this latter muscle belly was the femur just above the origin of the plantaris.

The popliteal vein was exposed high in the popliteal fossa and followed downwards. At the level of the anomalous muscle belly the vein was found to be acutely compressed both posteriorly and laterally (Fig. 2). The abnormal muscle band was divided carefully and separated from the underlying vein. Once the adventitia of the vein was loosened a little, the vessel immediately expanded to a normal size.

Before the muscle was divided it had been noted that the popliteal artery was not compressed and that it pulsated normally below.

The patient soon recovered from her operation and quickly returned to full activities. She has had no return of swelling or pain in the leg since. A postoperative venogram was suggested but, in view of her well-being, the patient refused it, which was not considered an unreasonable decision.

References EDMONDSON H. T. and CROWE J. A. jun. (1972) Popliteal arterial

and venous entrapment. Am. J. Surg. 38, 657-659. HAMMING J . J. (1959) Intermittent claudication at an early age

due to anomalous course of the popliteal artery. Angiolugy 10, 369.

RICH N. M. and HUGHES c. w. (1967) Popliteal artery and vein entrapment. Am. J. Surg. 113, 696-698.

Paper accepted 23.1 1.1977.

* St Vincent’s Hospital, Melbourne. Correspondence to : 24 Collins Street, Melbourne 3000 Australia.