Achilles tendon

In the myth of Achilles his mother held him by his ankle and dipped the rest of him into the magical river Styx to make him immortal, but the bit that she held on to did not get dipped, so it remained his vulnerable spot, or 'Achilles heel'.

Tissue banks frequently 'harvest' this tendon from human donors and it is freeze-dried and stored for transplant (eg to the knee), where it can be used for a variety of purposes to strengthen areas in the recipient patient where their own natural body tissues have failed. Such a graft of human tissue from another person is called an allograft.