A medical delivery device is provided for delivering a medicinal substance into a user's body. A foldable hub has a left wing and a right wing, where the hub is attached at one end to a tube, and at an opposite end to a needle. At least one first rib is disposed on the left wing and at least one second rib is disposed on the right wing. When the wings are folded back away from the needle and pinched together, the first and second ribs prevent twisting and/or sliding of the wings relative to each other during an insertion of the needle into a user's skin, thereby preventing a breakage of the needle due to undesirable movement of the wings.