Health Sciences · Robert W. Jackson Arthroscopy
An upper limb prosthesis consisting of a beige leather triceps cuff with a shoulder harness of the same material. Two metal hinges form a framework for the cuff and join it to a solid forearm socket of a glossy pale yellow material such as resin or fibreglass. At the wrist of the forearm is a metal socket attachment that holds a metal asymmetric split hook terminal device. Grip force is controlled by a sturdy metal spring. Two small spring-loaded metal knobs near the socket retain and release the terminal device so that it can be replaced with another.
A white cord runs from a strap on the harness, along the metal frame and hinge, to a leaver on the terminal device. This permits the terminal device to be controlled by movements of the shoulder and back.
Accession Number: 2025.JAC.303
Alternative Name:
Primary Materials: Leather, Metal, Resin
Markings:
(Arm folded 90 °) height = 30, Width = 13, Length = 46.
This is a body-controlled upper limb prosthesis, a prosthetic arm with a prosthetic hand or terminal device that is actuated by movements of the shoulder and back by means of a cord and pulley. It is a long-established and efficient technology. It is mechanically simple, requires no external power source, and can be exposed to the elements. Experience users can use specialized terminal devices, line the split hook terminal device on this example, with remarkable dexterity. This example is adapted to a user who is missing a hand.
A limitation is the trade-off between grip force and fine control. A terminal device with more grip force can handle a greater range of tasks. Less grip force offers finer dexterity. In modern devices, users can adjust grip force by exchanging rubber bands on the terminal device. This is a voluntary closing terminal device, meaning that it is held closed by spring force, with the user’s input opening it.
This artifact is intact and in very condition. There is light wear to the surface of the forearm. Some of the fasteners are oxidizing. A red, powdery substance is coming off the interface between the metal buckles and the leather that they attach them.
Associated Instruments:
Manufacturer:
Date of Manufacture: Mid-to-late 20th c.
The Robert W. Jackson Arthroscopy Collection was acquired by the University of Toronto from Dr. Jackson’s family on November 12th, 2020.
Peter Kyberd (2022). Making Hands : A History of Prosthetic Arms. London, England ; Elsevier.
David W. Dorrance (1912). Artificial Hand. US Patent No. US1042413
The body-powered split hook prosthesis was patented by American David W. Dorrance (1856-1933) in 1912.