Deep Digital Flexor Tendon – The muscle of this tendon originates at the ulna. The deep digital flexor tendon passes over the back of the knee in the carpal canal and is held in position by a carpal check ligament. It then extends down the back of the cannon bone between the superficial digital flexor tendon and the suspensory ligament. In the middle of the cannon bone the deep digital flexor tendon is joined by the carpal check ligament, known as the inferior check ligament. The tendon then passes over the sesamoid bones, it can give support, while allowing for movement, i.e. the cartilage that connects the ribs to the sternum.