Upper arm prostheses

                – for upper arm (or transhumeral) amputation

An amputation between the shoulder and elbow is called a transhumeral (across the humerus) amputation.  Generally patients will have full range of movement at the shoulder. The elbow, wrist and hand will be replaced with prosthetic components.

The prosthetic socket is commonly made from fibreglass, although leather is sometimes used.  The socket typically extends around the front and back of the shoulder to provide stability to the prosthesis, and sometimes it will extend over the top of the shoulder as well.  The socket is held on with a harness that extends under the armpit on the other side.  For very long residual limbs (more than roughly half the original length from shoulder to elbow) or an elbow disarticulation (where the arm is removed through the elbow joint), it is possible to use the IceROSS system (Icelandic Roll-On Silicone Socket).  This features a silicone rubber liner that is rolled onto the residual limb and has a small pin on the end that engages in a lock at the end of the socket.

An elbow joint will be fitted that allows the arm to bend. This can be controlled by a control cable attached to the harness (operated by moving your shoulders backwards or forwards to pull or release the cable), or manually by simply moving the forearm with your other hand.  Elbows are normally fitted with a locking mechanism so that you do not have to hold it in a flexed position.

There are two basic types of upper-limb prosthesis:

• Dress limbs

• Functional (work) limbs

You might decide to have one of each to suit different activities.  A dress limb looks cosmetically appealing but provides little functional use.  They can be used for simple tasks such as holding something down (such as a piece of paper when writing), for stabilising an object against your body or other hand, and they give you symmetry and the ability to make gestures.

A functional or work limb may look a little more unusual but can give a great deal of functional improvement.  They can be fitted with a range of alternative hand units (called terminal devices), including hooks, grippers and specific tools such as hammers, steering wheel attachments and cutlery.  Some devices can be operated via a control cable that attaches to a strap around your shoulder; by moving your shoulders backwards and forwards, you pull or release the cable and the device opens or closes.  We can also manufacture specialised prosthetic arms for performing a specific task, such as cycling, kayaking, holding a camera and such like.  Ask your prosthetist for advice if you have a particular request.

While some functional hand units are mechanically activated, others are operated electronically.  These myoelectric (Greek: myo, muscle) use sensors in the socket to detect movement in certain muscle.  This contraction of the muscle generates a signal that turns on a small motor in the hand, moving the fingers, wrist or elbow.  These prostheses are very expensive and are not suitable for everyone but can offer a great deal of function and control.  The latest hand units include several pre-programmed modes that allow you to perform specific tasks such as turning a key in a lock, carrying a bag or typing.

For further information or if you would like to make an appointment with a member of our clinical prosthetic team, please call APOS on 091 796983.