Upper Extremity Prosthetics Flashcards
BE Harnessing Housing Installation
- length between retainer and cross bar assembly => housing will be neither stretched nor unduly slack at any forearm position
- proximal to crossbar => about 1/2’’
- distal to base plate => long enough to prevent the cable from rubbing on the socket in any position of the terminal device, but not to interfere with the operating stroke of the device
BE Harnessing Retainer Placement
Goal is to
- minimize angulation between retainer and hook or hand anatomy
- give adequate clearance for hook or hand connections
- the plate may be placed as far as the proximal third of the forearm
- VO- just lateral to the top
VC-just lateral to the bottom
What Orientation Should OB Electrode Cables Be Installed
GREY up
BLUE down
When using software
R: Red
E: Extensor
O: Open
Measurements to Take for Transradial Assessment
Stump
- circumferences at intervals beginning @cubital fossa
- length from med. epicondyle OR olecranon to distal end
- M/L diameters @condyles and proximal to condyles and maybe A-P
Other side
- length from same landmark=> thumb tip
- cosmetic measurements
- hand size
Also
-any needed for suspension (ie. axilla loop)
Forearm Lever Loop Attachment
- typically: housing is gripped on the lever loop about 1’’ from its attachment point
- lever loop is attached 1.25’’ distal to the elbow centre
- cable housing extend 0.5-1’’ proximal to lever loop
Measurements to Take for Transhumeral Assessment
Stump
- circumferences @intervals beginning at axilla
- length from acromion => distal end
- diameter for wings; infrascapular fossa => pectoral fossa
Contralateral
- length; acromion =>med epicondyle
- length of forearm; med epicondyle => thumb tip
- cosmetic measurements
- hand size
Also- any needed for suspension (harness)
BE Harnessing: Cable Assembly
-once the housing has been properly adjusted
-cut cable length so that the hanger does not contact the proximal cable housing when the VO hook is closed and fully pronated
(maximum cable length)
Weak Signals and interferences of EMG
Chart
Internal vs. External Batteries
Chart
Transradial Socket Design Styles
Muenster
- narrow A/P
- high anterior trimline
- might reduce flexion ROM
- good for short limb but poor for bilateral
Northwestern
- self suspending
- supraconydlar
- good for long stumps due to lower anterior trimline=>easier flexion
3/4 socket; Northwestern w/ olecranon cut out, less constriction, more air flow, ability to ‘feel’ with elbow
How to Calculate Forearm or Humeral length with a Bilateral Amputee
Forearm; height x 0.14
Upper arm; height x 0.19
Body vs. External Power
Comparison
Body vs. External Power
Comparison
Body Motions for Control of a Below-Elbow Harness
- to control the relative displacement between the proximal retainer or the cuff and the attachment strap of the harness
1) Arm Flexion
2) Shoulder Depression
3) Scapular Abduction
4) Scapular Abduction (sound side)
Fair Lead Cable Control
- used for transhumeral prosthesis
- consists of a cable held in place and guarded by separate lengths of housing
- provides elbow flexion and TD control
Battery Types
Nickel Cad
- old
- rarely used tech
- memory effects
- low capacity
NiMH
- newer
- less memory
- mid range expense and capacity
Lithium Ion
- newest
- small and high capacity
- no memory
Hooks Canted vs. Lyre
CANTED: objects more visible when grasping
- object is rolled into its grasp
- cannot pick up pins well
LYRE
- more applicable for bottle or cylindrical shapes
- object is pinched
- can pick up pins
Transhumeral Amputation Levels
LONG
- condyles remaining
- primary control is from humeral
MED
- distal to deltoid insertion
- primary control from humerus but assisted by shoulder girdle
SHORT
- proximal to deltoid insertion
- primary control from shoulder girdle but assisted by humerus
Bowden Control Cable System
- single purpose; to operated the TD
- consists of a continuous length of housing
- housing is fastened by retainer to forearm and cross-bar assembly to triceps pad
Partial Hand Device Designs
MILBRANT
- for missing digits 2-5
- finger bar provides opposition to the thumb
- heavy duty and high friction material
OPPOSITION POST
- also for missing digits 2-5
- smaller piece of material to provide opposition to thumb
- better suited for lighter tasks and fine detail
SPATULA
- light duty device used when there are no fingers present
- provides opposition to the palm
- wrist motion needed
Harness Components
- northwestern or BAHA rings
- hanger
- quick release buckle
- 4 bar buckle
- cable and housing
- ferrel
- cross bar
- triceps cuff/triceps plate
- retainer
- base plate and bumper
- tripe swivel/ball terminal
- ball receiver
Wrist Options
QUICK DISCONNECT
-easy to swap terminal devices, locking option, more function, heavier, more mechanical parts, more costly, longer build height required
FRICTION
- lighter and lower build height
- can be oval for cosmesis, adjustable resistance to pronation/supination
FLEXION/RADIO-ULNAR DEVIATION
- lockable at different angles
- weight and build height increase
- more mechanical parts
- can be used to get TD closer to midline
- good for bilateral
Functional Loss of Partial Hand Amputation
-THUMB
@IP = 20%
@MCP = 40%
- 2ND OR 3RD DIGIT
@DIP = 9%
@PIP = 16%
@MCP = 20% - 4TH OR 5TH DIGIT
@DIP = 5%
@PIP = 8%
@MCP = 10%
