Prominence of the calcaneus: late results of bone resection.

VOL. 74-B, No. 2, MARCH 1992 tendon. Squeezing the calf was seen to deform the fleshy soleus causing the overlying gastrocnemius tendon to bow away from the tibia resulting in plantar flexion (Fig. 1). There was no longitudinal movement of the soleus while the gastrocnemius muscle bellies moved about 1 cm proximally, confirming our ultrasound findings. When the soleus tendon was divided the proximal movement of the gastrocnemius, due to direct pressure on the tapering bellies, produced only a small amount of plantar flexion. Division of the gastrocnemius tendon alone did not prevent full p!antar flexion on calf compression. Conclusion. The result of the Simmonds-Thompson test principally reflects the integrity of the soleus musculotendinous unit. Plantar flexion is caused by posterior bowing of the calf tendons and, to a less extent, by proximal displacement of the bellies of the gastrocnemius.