It is reported that calf vein thrombosis affects 10 % of patients with a previous tennis leg lesion [1].

The thrombosis is mainly due to lack of calf muscular contracture and rest during healing but the possibility of direct trauma to the veins should be kept in mind [2, 3].

Intramuscular veins of each head of the gastrocnemius consist of two veins running close to a central artery and within a central septa. Veins appear anechoic in the transverse plane and are normally compressible with the probe.

The diagnosis is usually simple but it is necessary to allow accurate treatment and prevent complications such as post-thrombotic syndrome or pulmonary embolism. Muscular vein thrombosis may be suspected on B-mode when muscular veins are filled by a non-compressible echoic material [4, 5].

At color Doppler, there is no spontaneous flow within the veins.

Indirect signs include lack of vein compressibility in the transverse plane and increased diameter just proximal to the thrombus. It appears echoic at the acute phase and tend to become hypoechoic at the chronic phase. It is also soft initially and becomes slightly harder later [6, 7].