Transhumeral Harnessing and Cabling

Question 1

The transhumeral cable system is referred to as a “Fair-Lead” system. The Cable housing:

Answer 1

Is split into two parts, creating the potential for elbow flexion.

Question 2

When the elbow is locked, power is transmitted down to the terminal device, resulting in its activation; ___ cable excursion is required for fully flex the elbow from its fully extended position and to completely open the terminal device, an additional ___ of excursion is needed.

Answer 2

2.5” and 2”

Question 3

The force required to flex the elbow is between 2-7 lbs. and varies according to the placement of the forearm lift tab. As the tab is moved distally (further away from the elbow center),

Answer 3

The less force is required to flex the elbow; however, more body motion (cable excursion) is needed to flex the elbow through its full ROM.

Question 4

The elbow locking cables operates by locking the elbow on the first pull then unlocking it on the second pull of the cable. The elbow lock cable requires 5/8” to 3/4” of excursion and roughly 2 lbs of force for proper operation.

Answer 4

True

Question 5

A cross-back strap may be used in a figure of eight transhumeral harness to maintain a more optimal positioning of the control attachment strap when the patient performs humeral abduction. The cross-back strap helps keep the control attachment strap in position distal to the scapula and doesn’t effect excursion.

Answer 5

False