A wedge shaped pad of fibrous connective tissue that lies beween the corium of the frog and the end of the deep digital flexor tendon. Laterally and medially it is bordered by the ungular (co-lateral) cartilages and to the back (palmar/plantar aspect) it lies directly underneath the corium and epidermis of the bulbs. It contains a high proportion of collagenous and elastic fibres, along with fat cells, islets of cartilage and relatively few blood vessels.