1. Sanofi Project
Concept Ideation and
Development
Tuesday, April 3, 2012
Some Thoughts from Andrea

2. Common Causes of
Limitations in the Use of the Hands:
Age and Arthritis
 Loss of Strength and Dexterity in the Hands is Common,
beginning at Age 50 – 59, and increasing in severity with
more advanced age.
 With Age – Loss of strength in muscle tissue throughout
body, including the hands.
 Prevalence of severe hand disability in the general
population age 50 and older is 12%, with increased
occurrence over the age of 70 and in the female gender.
 Arthritis – The leading cause of disability in the United
States (Centers for Disease Control)

3. Age – Loss of Strength and
Dexterity
 In Hand Weakness due to
Age, the Lateral Pinch Grip
weakens less than other
pinch grips.
 Lateral Pinch Grip –
Example: Grip Used when
Grasping and Turning a Key.
 Design to accommodate the
Lateral Pinch Grip by
making a larger contact
area for the fingers.

4. Osteoarthritis (OA) – caused by wear and tear
leading to deterioration of cartilage in the joints
Commonly Affected by OA:
Finger Joints Less Commonly
•Distal Finger Joints
Affected by OA:
•Base of Thumb
 Middle Joints (Proximal
Interphalangeal Joints) (35%
of individuals with OA)
 Base of Fingers –
(Matacarpophalangeal
Joints) (15% of individuals
with OA)

5. Osteoarthritis
 Friction (due to cartilage deterioration) results in:
 Pain
 Stiffness
 Swelling
 Reduced Range of Motion
 Pieces of Bone may break off and float within the joint
and the joint lining (synovium) and cause further
inflammation.

6. Rheumatoid Arthritis (RA) Unknown
Cause - Autoimmune Disease
Commonly Affects Wrist and Fingers
 Unlike OA, Finger Joints closest
to the palm of the hand
• Cartilage Deterioration (Metacarpophalangeal Joints)
• Deformation of Joints are commonly affected.
 Phasic
o Severity Up and Down
 Pain
 Inflammation
 Swelling
 Stiffness
 Reduced Range of Motion

7. Examples of Accommodations for OA & RA
 Distal Finger Joints are used in most
Pinch and Precision Grips.
o A small pinch or other precision grip will often cause pain in the
distal finger joints with Osteoarthritis.
 Make grip larger or change type of grip.
 The Thumb is used in All Grip Types.
o A too wide grip will often cause pain in an arthritic joint at the
base of the thumb
 Maximum Grip Span for OA (Osteoarthritis) and RA (Rheumatoid
Arthritis) of moderate severity is not more than 2.5 to 3 inches.

8. Accommodation Examples - Continued:
 Rheumatoid Arthritis – Joint Deformation
o Joint Deformation affects the types of grips
that can be made.
 Example of Accommodation:
Instead of using a pinch grip, a person with
deformed finger joints may have to instead use
a lateral key pinch grip.

9. Lateral Key Pinch Grip
ie: Grip Used When Grasping and Turning a Key

10. Types of Hand Grasps
 There is no one standard classification of grasps.
 Names for specific grasps can vary.
 The following slides show examples of grasp
classifications.

11. Napier (1956)
Prehensile – Where an object is held by the hand
Power Grasp – Where an object is held in the palm of the hand
The forces of the thumb are opposed by the forces of the fingers
Muscular force is often high in the power grasp
Precision Grasp – Where an object is held between the
opposing fingers and thumb
Muscular force is usually more limited in the Precision grasp than in
the Power Grasp
Non-Prehensile – No seizing – The hand or finger applies pressure to an
object

12. The following Three Slides
10 hand grasps Classified by Karl Kroemer
(1986)
Coupling the Hand with the Handle

16. Prehensile Grasps
Ayoub, MacKenaie, Deivanayagam, Smith, Kroemer, Napier,
Ladsmeern
 Hand Grasp / Power Grasp
 Spherical Grasp – Spherical object in Hand
 ie: Door Knob, Baseball
 Cylindrical Grasp – Around circumference of a
cylindrical object
 ie: Hammer Handle
 Disc Grasp – Used on a disc shaped object
 ie: Lid of Jar
 Hook Grasp – Handle is hooked by digits 2 – 5
 ie: Carrying a Briefcase

17. Pinch Grasps (Smith, 1985)
 Pulp Pinch
Pad of thumb opposes pad of another finger
 Pulp Pinch = Compression
 Example: Pulp Pinch 2 = Thumb Opposes Index finger
 For Small Contact Areas and High Precision
 Example: Threading a Needle

18. Tip Pinch – Tip of thumb
opposes tip of another finger

19. Gripping Larger Contact Areas and
Applying Greater Force
 Lateral Pinch (Key Pinch) – Thumb
opposes the radial lateral aspect of the index finger in the
clenched fist.
 Lateral Pinches
 Aid Rotation
 Chuck Pinch – similar to pulp and tip pinches
except the thumb opposes both the index and middle finger
simultaneously.

20. Pinch or Precision Grasps
 Tools that Require Precision Movements
 Surgical Instruments, Pens or Pencils
 Small Force
 Grip that Facilitates Precise Motions
 Fingers and Wrist Play a Prominent Role

21. Power Grasps
 Tools that Require More Muscular Force due to
 Use
 Weight
 Size
 Function
 Need Larger Surfaces for the Hand to Contact to Form
More of a Power Grip

22. Ideas for a Better Grip
 Shape with Bulges and Indents for a better grip
 Avoid Cylindrical Grips
 Pinch Grips
 Provide Contact Surface Area that is as large as the entire
surface of the pad of the thumb or fingertips to increase
strength
 A Pinch Grip is Five Times More Stressful than a Power Grip
(National Institute for Safety and Health)
 Power Grips
 Contact Surface Area large enough to allow contact with the
entire palm of the hand

23. Better Grip Ideas continued:
 Eliminate Pressure Points - sharp edges and other
surface features that will cause local tissue pressures.
 Padding can be added at Pressure Points of the palm
and fingers
 Does the design work for left-handed people?
 Size and Shape Gripping Area to Allow Alternatives
to the Standard Grip.

24. Texture or Non-Slip Material
can be added to surfaces to minimize slippage.

25. Inspirational Forms - Orbs

26. Orbs

27. Orb Cluster

30. 3 Orbs – Large on End

32. 3 Orbs – Large in Middle

34. Orbs with Box #1

36. Orbs with Box #2

37. Stone #1

39. Stone #2