TH harnessing, componentry, & control pt. 1

hessing

what kind of pad can be added to a harness for axilla comfort?

double ring, BAHA, pads

ways to increase comfort in a TH harness

elastic

kind of material that a chest strap should be made of, to allow breathing

humerus doesn’t have bony lock

why is it typically better to use a lanyard than a pin lock system in TH patients?

lightweight prosthesis

why would you only need a sleeve for suspension?

lateral

to what side will everything in a TH prosthesis want to shift?

lateral suspensory strap

what is 1?

axilla loop

what is 2?

cross-point/NW ring

what is 3?

anterior suspensor strap

what is 4?

control attachment strap

what is 5?

elbow lock control strap

what is 6?

lateral suspensor strap

primary suspensor of TH figure-8 harness

proximal wall of socket, slightly anterior to acromion

position of lateral suspensor strap

anchors harness

function of axilla loop

distal 2/3 of the anterior portion

how much of the anterior suspensor strap should be elastic?

delto-pectoral groove

where should the anterior suspensor strap be positioned?

slightly medial to elbow lock cable

distal attachment point of anterior suspensor strap

distal 1/3 of scapula

position of control attachment strap

anterior suspensor strap

where does the elbow lock control strap originate?

sew non-stretching fabric coins (like dacron) onto it

how to create rigid points on elastic

chest strap

what is 1?

shoulder saddle

what is 2?

control attachment strap

what is 3?

lateral suspensor

what is 4?

elbow lock control strap

what is 5?

anterior suspensor

what is 6?

BAHA, NW ring

what can you use instead of a shoulder saddle in a similar-looking set-up with the chest strap?

TH

does sequential activation work best for TH or TR amputation levels?

4 1/2”

how much excursion to simultaneously flex elbow and open TD in a TH prosthesis?

2

how many cables are needed to operate a standard BP TH prosthesis?

fair-lead

which cable/housing system is used primarily in TH prostheses?

split

does the fair-lead cable system have split or joined housing?

cable can flex elbow (when unlocked) and the operate the TD

function of split housing

cyclically locks/unlocks elbow alternately

function of elbow lock control cable

TD activates

once the elbow is fully flexed in a fair-lead system, where does the leftover tension transfer to?

GH flexion, biscapular abduction

control methods for sequential function with dual control

flex

in sequential function system with dual control, you must (flex/extend) the elbow and (lock/unlock) it before using the TD

GH abduction, shoulder depression, GH extension

motion to lock/unlock elbow in fair-lead system

parallel

location of elbow turntable relative to the ground

1 1/2” distal, 1” anterior

bench alignment: location of elbow flexion attachment (lift tab) relatively to epicondyle

neutral

bench alignment: humeral turntable ext/int rotation

slightly medial to elbow lock cable

bench alignment: location of anterior suspensor attachment

1” proximal to cut end of bone, on posterior/lateral aspect

location of baseplate/retainer on socket

add 2nd baseplate/retainer to guide housing

what to do if residuum is short and the housing is moving behind the epicondyle

elbow flexion attachment

what is an EFA?

1/2” proximal to EFA, 1/2” distal clearance when TD is open and fully supinated

bench alignment: distal segment housing length

1/2” clearance between housing segments when in fully elbow flexion, 1/2” housing proximal to base plate and retainer

bench alignment: proximal segment of housing length

1/4” beyond proximal housing when TD is fully pronated and closed, elbow is extended, and elbow turntable is in neutral rotation

bench alignment: cable length

inverse

force and excursion have a (direct/inverse) relationship

more, less

if the EFA is closer to the epicondyle, it takes (more/less) force and (more/less) excursion to operate

more, less

if the EFA is farther from the epicondyle, it takes (more/less) excursion and (more/less) force to operate

force

if the patient has difficulty flexing the elbow, it is probably a (force/excursion) problem

excursion

if a patient has difficulty opening their TD at the mouth, it is probably a (force/excursion) problem

too proximal

how could the forearm lift tab cause a patient to have difficulty flexing their elbow?

too posterior

how could the cable’s location relative to the elbow center cause a patient to have difficulty flexing their elbow?

too heavy

how could the weight of the TD cause a patient to have difficulty flexing their elbow?

too long

how could the length of the forearm cause a patient to have difficulty flexing their elbow?

inefficient

how could the harness cause a patient to have difficulty flexing their elbow?

too distal or anterior

how could the forearm lift tab’s location cause a patient to have difficulty opening their TD at the mouth?

too lose

how could the control strap cause a patient to have difficulty opening their TD at the mouth?

too far toward prosthetic side

how could the NW ring cause a patient to have difficulty opening their TD at the mouth?

too high

how could the proximal base plate cause a patient to have difficulty opening their TD at the mouth?

not on distal 1/3 of scapula

how could the location of the control strap cause a patient to have difficulty opening their TD at the mouth?

too proximal, too short

how could the forearm lift tab position cause a patient to accidentally open the TD during elbow flexion?

not enough rubber bands

how could the TD resistance cause a patient to accidentally open the TD during elbow flexion?

too heavy

how could the weight of the TD cause a patient to accidentally open the TD during elbow flexion?

too long

how could the weight of the forearm cause a patient to accidentally open the TD during elbow flexion?