Valvular mechanisms in the formation of synovial cysts

Ilio-psoas bursa enlargement

The clinical and radiological features of 14 patients with ilio-psoas bursal enlargement associated with articular disease of the hip are presented. The condition primarily affects patients over the range of 50 years with pre-existing hip disease, usually of long duration. A clinical diagnosis before investigation was never made in our series as the symptoms were non-specific and varied, consisting of pain (40%), a palpable groin mass (40%) and lower limb swelling (28%). The diagnosis can be made pre-operatively and the extent along the path of the ilio-psoas accurately delineated. The bursal contents, although predominantly fluid in nature, do include a varying proportion of solid components. Ultrasound is the simplest, quickest and most cost effective means of demonstrating the hip effusion, the bursa, its contents and extent. Although the compressive effects are well seen sonographically, computed tomography (CT) and magnetic resonance imaging (MRI) provide a better appreciation of the regional anatomy and hip joint disease.

Radiographic investigation of popliteal cysts

Forty-one patients with popliteal cysts were examined radiographically. All cysts consisted of a dilated gastrocnemio-semimembranosus bursa. A valve mechanism at the site of their communication with the joint was demonstrated by a specific radiographic technique in the majority of cases. The radiographic findings in popliteal cyst ruptures simulating deep venous thrombosis are described.