Plastic. Use this economy disarticulated model of the human half skeleton to explain the intricacies of the human skeletal system and reinforce topics such as form and function. Bones from 1 side of the body are included, along with a 3-piece skull with removable skullcap and mandible. The sternum is cast in 1 piece and includes ribs from 1 side of the body. Separate bones of the hand and foot are articulated on wire for easy identification. The hyoid bone and loose bones of 1 upper extremity, 1 lower extremity, and the vertebral column (with intervertebral discs) are included. Skeleton Storage Case (item #249890A) is available separately.