DEPARTMENT OF BIOMEDICAL ENGINEERING

FACULTY OF ENGINEERING

UNIVERSITY OF MALAYA

NAME : NUR RASYIDAH BT HASAN BASRI

MATRIC NUMBER : KED 120013

NAME PROGRAMME : BIOMEDICAL ENGINEERING (PROSTHETIC & ORTHOTICS)

GROUP NUMBER : GROUP 2

Component of below elbow prosthesis

o Terminal device (hand) – voluntary opening (VO) or voluntary closing (VC)

Use to replace human hand that can be custom made or bought commercially. There

are passive and active prosthetic hands. Passive for cosmetic and active for functional

prosthesis.

PVC cosmetic glove – cosmetically use, more resistance to tearing but easy to

strain.

VC mechanical hand – mimic the ‘3 jaw chuck grip’ and prosthetic help in hand

grip.

Hook – powered by body power, less cosmetic but most functional TD. Lighter, stronger

and easy to use than mechanical hand.

Hosmer type split – hook

Child split hook

Bilateral split hook

Canted jaws for left sided operation

Locking pliers - custom made devices made for specific tasks such as holding a

plier or operating machinery. Normally can be interchangeable.

o Wrist unit - used to attach the TD to the rest of the prosthesis. 2 main types of wrist that

allow removal or replacement of the TD: the quick disconnect wrist and the screw fitting

wrist.

Quick disconnect wrist - easily remove and replace their TD, allowing different

TD’s to be used for different tasks. Allow rotation of the TD and hold the rotated

position of the TD either by friction or preferably a lock.

Flexion wrist Locking wrist

Screw fitting wrist - threaded section on the TD screwing into a threaded socket

on the prosthesis. This allows interchangeability of the TD, but not accurate

rotational control.

o Socket The Strathclyde Supra Olecranon Socket

Allow the prosthesis to be worn as long as necessary from day one

Maximise stump flexion.

Utilises the area above the olecranon on the triceps tendon as the main

suspension area.

.Medial and lateral “wings” extend over the epicondyles to the parallel

section of the humerus above.

The primary purpose of these extensions is to keep the posterior

section of the socket in place and not to provide suspension.

The area above the epicondyles does not have a good tolerance to

pressure.

The anterior of the socket is the only area that varies depending on

stump length.

Strathyclyde Extended Cup socket

Suspension that comes from pressure superior to the epicon- dyles is

not normally very effective on a patient with a congenital trans-radial

absence, as their epicondyles are not normally fully developed.

Provides the main amount of suspension when the patient extends their

elbow.

The brim socket relies on a skin friction ring around the proximal trim

line which helps prevent loss of suspension during flexion

o Elbow Joint

Free swinging hinge

2 main method to control elbow lock:

Hand operated elbow lock - by using a body powered cable in a similar manner

to operating a TD.

Ratchet lock - a cosmetic prosthesis, but these are generally not suitable for

functional prostheses.

Suspension of below elbow prosthesis

o Self-suspending socket

Muenster Technique – proper fit to stump for full elbow extension.

Limited to elbow or wrist disarticulation and transradial amputation.

Commonly utilized by externally powered, myoelectrically control prosthesi

o Harnessed-based system

Most common suspension system used.

There is strap around axilla on the sound side.

Provide counterforce for suspension and control-cable forces.

Anterior strap at prosthetic side attached direct to the socket.

Posterior strap at prosthetic side attaches to control cable.