Download Anatomic and Biomechanical principles related to splinting

Anatomic location
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Arm: area from shoulder to elbow (humerus)
Antecubital fossa: depression at the bend of
the elbow
Forearm: area from elbow to wrist
Carpal: wrist or carpal bones
Fingers: thumb, index, middle, ring, little
Numbering fingers: I, II, III, IV, V (thumb)
Palmar = volar: ant aspect of hand and forarm
Radial : thumb side / Ulnar: little finger side
Muscles and function nerve
supply
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Study table 4-4 on page 59
Arches of the hand
1. longitudinal arch
2. Distal transverse arch
3. Proximal transverse arch
 Functional significance
 Never splint the hand flat .. Creates
deformity
 Specially with tendon and nerve injury
Creases of the hand
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Three main palmar
creases: distal, proximal
and thenar creases
The distal palmar crease
extends from the fifth
MCP joint to a point
midway between the
second and third MCP
joints. This is important for
allowing motion of the
MCP’s for a wrist
immobilization splint
Creases of the hand
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Important for landmarks when making splint
pattern and molding
Figure 4-11
When splinting to immobilize a join, the crease
should be included in the splint
When mobilizing a joint?
What happens with:
› Edema
› Paralysis
› disuse
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Correct Biomechanics of Splint Design
Splints are simply machines and levers that
work together.
Optimal client outcomes rely on
biomechanics
Weak muscles are supported, and the pull
of stronger muscles is counteracted.
Reduces risk of skin irritation due to pressure
Ultimately may lead to patient comfort,
compliance, and function
three point pressure
 Mechanical advantage (F1*D1 = F2*D2)
 Torque
 Pressure and stress
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› 1. degree
› 2. duration
› 3. repetition
› 4. direction
The skin is the least tolerating tissue to
stress
 Skin becomes ischemic as load increases
 Even low stress can cause capillary
damage and lead to ischemia
 Splints may do that, this is why it is
advised to distribute pressure over a
larger area of skin
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It could lead to inflammation and skin
breakdown
 You have to remember that some
diseases (lymph and vascular
involvement) leads to an altered sense
of tolerance
 Small and sharp edges lead to stress
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You have to remember that there are
three directions of stress:
1. Compression
2. Tension
3. Shear
Pressure = Total Force/ Area of force
application
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