The conjoint junction of the triceps surae: implications for gastrocnemius tendon lengthening

Forty embalmed cadaver lower limbs were dissected to identify the morphology of the conjoint junction of the tendons of gastrocnemius and soleus and the location of the gastrocnemius tendon relative to bony landmarks. Five patterns of conjoint junction morphology were found: transverse (25%), oblique passing distally and medially (45%), oblique passing distally and laterally (5%) and arcuate as an inverted U (17.5%) and a U-shape (7.5%). Left-right asymmetry of the junction was observed in 31.6% of 19 paired cadaver legs. On the medial side of the calf the gastrocnemius tendon could be located between 38 and 46% of the proportion of the distance between the upper border of the calcaneus and the fibular head. Corresponding values for the midline and lateral side of the calf were 45-58% and 48-51%. The location of the gastrocnemius tendon relative to bony landmarks may help to guide incision planning for open or endoscopic division of the tendon.