Purpose The purpose of this study was to map saphenous nerve injuries after gracilis tendon harvest, with the aim of contributing knowledge that makes it possible to prevent these injuries. Methods Twenty-two cadaver limbs were used. Three were dissected to examine fascial structures between the saphenous nerve and the gracilis tendon. In 19 limbs, the gracilis tendon was harvested according to standard operative routine. The saphenous nerve was subsequently exposed by dissection and injuries were recorded. Results A well-defined sub-sartorial fascial layer separated the saphenous nerve from the gracilis tendon. Incisional injuries involving either a medial cutaneous crural branch or the infrapatellar branch were found in 14 of the 19 cases. Non-incisional injuries affecting the sartorial branch of the saphenous nerve (to conform to most surgical literature, we use the term 'sartorial branch' to denote the continuation of the saphenous nerve after departure of the infrapatellar branch) were found in six cases located 5-8 cm proximal and posterior to the gracilis tendon insertion on tibia. The fascia separating the saphenous nerve from the gracilis tendon had been perforated in relation to all non-incisional injuries. Conclusions Small subcutaneous branches of the saphenous nerve are at risk of injury from the incision, while the sartorial branch is at risk outside the incision area. Descriptions of the location of non-incisional injuries have not been published before and are of clinical relevance, as they can contribute to the prevention of saphenous nerve injuries during gracilis tendon harvest.