The invention relates to a splint for a joint connecting two parts of a human body or of an animal, such as the ankle, knee or elbow for example, comprising at least one rigid shell (1,2), globally concave, for positioning around the joint in order to support said joint. The splint comprises, on the internal face thereof, in other words the concave face, a chamber (3,4) made from a flexible plastic material which may be placed under pressure by any suitable means, and positioned on the internal face of the shell (1,2) to provide a supportive cushion between said shell (1, 2) and the joint and covering at least a part of the internal face of the shell (1,2). The splint comprises means (6) for holding said shell (1,2) in position about the joint, characterized in that the shell (1,2) is made from a single element comprising at least one flexible zone (7, 8;12, 13) made from a styrene ethylene butylene styrene block copolymer (SEBS), chemically bonded to the rigid part of the shell (1,2) to avoid any injury to the oedematic tissue which appears after a sprain or strain of said joint.