How Did Odysseus Get The Scar On His Leg?

Odysseus has seen his fair share of battles. Throughout his journey to get back home, he has faced one difficult encounter after another. One would not be surprised to see that Odysseus received his scars from these battles. But there is one scar he has received not from a battle.
In Book 19 of the Odyssey, when Odysseus arrives to Ithaca disguised as a beggar, an old nurse, Eurycleia, is assigned the duty of bathing the guest. She innocently comments on how much he resembles her king, whom she raised from early childhood. Stunned, she identifies a scar, over his knee, left by a boar's tusk, and realizes that she is, indeed, bathing, her master. Odysseus immediately and sternly swears her to silence, forbidding her even to tell Penelope his identity.
This is the scar that Odysseus got when he went boar hunting with his grandfather Autolycus. Odysseus was the first to raise his spear and try to drive it into the brute, but the boar was too quick for him, and charged him sideways, ripping him above the knee with a gash that tore deep though it did not reach the bone. As for the boar, Odysseus hit him on the right shoulder, and the point of the spear went right through him, so that he fell groaning in the dust and died.