UPPER LIMB PROSTHETIC

What are Upper Limb Prosthetics?


According to research in 2005, 540,000 people suffer from loss of upper limb. Out of these; 40,000 were those who suffered from amputation above the wrist. The most common cause of amputation is cancer, disease, or trauma. The upper limb areas consist of the following areas of the body:

•Shoulder

•The transhumeral

•Elbow

•Wrist

•Transcarpal

•Metacarpal

•Transphalangeal


The most common type of amputation is the Trans-radial, or a partial amputation of the arm below the elbow, at some point along the radial bone. An upper prosthesis is beneficial in restoring normal functions of the amputated body part.


Prescription of Prosthesis


The Prosthetist prescribes an upper limb prosthetic depending upon several factors such as:

•Level of amputation

•The geometry of the residual limb

•Sensation

•Motion range

•Strength

•Cognition

•Hobbies/activities of the amputee


The patient and rehabilitation team decides the type of prosthetic for the patient. Cooperation between the patient and the rehab team helps in making the right choice.


Types of Upper Limb Prosthetics


Upper limb prosthetics are generally of two categories:

1. Above the elbow -This type is also called Transhumeral. Examples of this type of prosthetic include the lower and upper arm and a prosthetic elbow

2. Below the elbow - This type is also called Transradial. An example of this type of prosthetic is a prosthetic forearm.


Mechanism of Working for Upper Limb Prosthetic


Control System


The control of this type of prosthetic is via a body source or by an external source or by a hybrid system. Prosthetics controlled by body movement transfer this energy to a terminal device. The generation of myoelectric signals affects the contraction of muscles. These help to provide mechanical and proportional control of the prosthetic.


Prosthetic powered by an external source does not need activation. It also requires less movement for activation. It is more costly as compared to other types of prosthetics. These also require high maintenance.


Terminal Device


A terminal device is the most commonly used type of upper limb prosthetic. It utilizes the mechanism of hooks and hands that require external power. This type of prosthetic is mostly for cosmetic purposes.


They usually do not operate much as compared to the control system prosthetics. However, the terminal device costly and does not need constant maintenance. Therefore, this makes it a more practical form of prosthetic.


Conclusion


There are currently several ongoing research studies for upper limb prosthetics. Many of these now allow the patient to develop sensations, but they are not commonplace just yet. The limited need for such advanced prosthetics is because they tend to be much higher in cost than other prosthetics.