What is an Arm Prosthetic?

Upper-arm prostheses are prosthetics used to provide upper-arm amputees with functions similar to upper-arms.

Upper arm prosthesis

Upper-arm prostheses are prosthetics used to provide upper-arm amputees with functions similar to upper-arms.

Chinese name

Upper arm prosthesis

Suitable for

Upper arm

Suitable for upper arm

After the amputation of the upper arm, the function of the upper limb is severely lost due to the loss of the elbow joint. Although the assembled upper arm prosthesis has an active elbow joint, it is necessary to accurately realize the flexion and extension of the elbow and the opening and closing of the artificial hand. It is complicated, and the actual operation is difficult. Therefore, the compensation function of the upper arm prosthesis is far less than that of the forearm prosthesis, and its operation training is more important.

Upper-arm amputees can install cable-controlled upper-arm prostheses, electromyographic control or switch-controlled electric hands, hybrid upper-arm prostheses, and of course, decorative upper-arm prostheses. The decorative upper arm prosthesis is especially suitable for patients who only focus on lightness and beauty, but do not wear functional prostheses. The receiving cavity of the modern upper arm prosthesis is a full-contact receiving cavity made of synthetic resin vacuum forming. The receiving cavity of the short upper limb prosthesis of the upper arm requires a double structure receiving cavity composed of a full-contact inner receiving cavity and an outer arm cylinder. In order to ensure the stable suspension of the prosthesis, the prosthetic hand is controlled more accurately.

Upper arm prosthetic cable controlled upper arm prosthesis

Cable-controlled upper arm prostheses have the same hands and wrist joints as forearm prostheses. The forearm tube is mostly made of plastic. A locking elbow flexion mechanism, a mechanical elbow joint, is added to allow the patient to flex his elbow actively. The traction device is relatively complicated. Generally, it is controlled by a triple traction cable, that is, three different traction cables are used to control the movement of the hand, elbow flexion, and elbow lock through different movements of the shoulder.

Upper-arm prosthetic electromyography for upper-arm prosthesis

There are two degrees of freedom and three degrees of freedom for EMG control of the upper arm prosthesis. The prerequisite for assembly is that different EMG signals must be used to control the movement of the hand device and the elbow joint. Two degrees of freedom are active control of hand opening and closing, elbow flexion and extension, and three degrees of freedom are hand opening and closing, wrist flexion (or rotation), and elbow flexion and extension active control. Since the more degrees of freedom, the more difficult it is to control with significantly different EMG signals, and the more likely it is to malfunction, so most patients are fitted with two-degree-of-freedom EMG prostheses.

Upper arm prosthesis hybrid upper arm prosthesis

A hybrid upper arm prosthesis is a prosthesis that combines electromyographically controlled hand movements with cable-controlled elbow movements. Due to the large lever force required for elbow flexion, if electric elbow flexion is used, a large amount of power will be consumed, and using a shoulder strap to pull the traction rope to control elbow flexion can significantly extend the battery life.

No matter what kind of upper arm prosthesis is installed, it can be used to grasp and extract items, or to assist the healthy side to complete some daily activities. The upper arm prosthesis with electric hand is more practical than the cable-controlled prosthesis with manipulator, but it is more expensive. In addition, in addition to the electromyographic control of the upper arm prosthesis, the switch-controlled electric upper arm prosthesis is also an effective prosthesis, and the price is moderate.