Hand Movement and Function

Question 1

OPPONENS

Answer 1

• Little finger is the only finger w/ active rotation

- Other digits (2-4) have passive rotation only

Question 2

Physiological vs Accessory movements

Answer 2

• Movts that a person can perform themselves are “physiological”
• Many joints must be able to move passively to achieve full ROM
• These movts that are operator-directed are termed “accessory” movts + are necessary for full ROM
• E.g. gliding b/w the trapezium + 1st MC base or gliding (anterior to posterior) at the MCP + IP joints

Question 3

Functional interdependence between the wrist and hand

Answer 3

Position of function

• Wrist - extended 20-30°, 5-10° ulnar deviation
• MCP joints: flexed (70°)
• IP’s flexed

RESTING HAND

• Wrist - neutral (not flexed or extended)
• Slight MCP flexion
• Slight ulnar deviation

Question 4

Wrist position affects digital movements:

Answer 4

Neutral (or flexed) wrist:

• Extrinsic finger flexors are slack
• A concentric contraction of these flexors first takes up the slack in the tendon THEN begins to pull on the bony attachments

Extended wrist:

• Extrinsic finger flexors are first passively lengthened by the wrist extension so there is no slack in the tendon (i.e. tension is optimal)
• A concentric contraction of these flexors THEN translates immediately into finger flexion

Question 5

Active and passive insufficiency of extrinsic finger muscles

Answer 5

• Simultaneous full flexion of the wrist, MCP, PIP and DIP joints is not possible because 1) active insufficiency of the extrinsic finger flexors + 2) passive insufficiency of the extrinsic finger extensors
• Simultaneous full extension of the wrist, MCP, PIP and DIP joints is not possible because of 1) active insufficiency of the extrinsic finger extensors + 2) passive insufficiency of the extrinsic finger flexors

Question 6

Normal Digital Sweep

Answer 6

• MCP flexion - intrinsic musculature - lumbricals (reinforced by long finger flexors)
• Flexion of IP joints - extrinsic musculature (FDS + FDP)
• Widest arc of the movt of the tip of a digit through flexion (via lumbricals, FDP + FDS)

Question 7

Role of wrist joint complex:

in power grips

Answer 7

• Provide a stable base to grip

- Move through range to control the tool/object

Question 8

Role of wrist joint complex:

in precision grips

Answer 8

• Provide a stable base

- Optimise length tension r/s for long finger muscles

Question 9

Grip types: Power

Answer 9

Palmar
- Hand is used in addition to fingers
- Thumb Counter pressure
Hook
- FDS + FDP isomeric contraction

Question 10

Grip types: Precision grips

Answer 10

Pincer (terminal opp)

• tip of thumb to tip of index finger
• IP joints more flexed

Pad-to-Pad (subterminal opp)

• pad of thumb to pad of index finger
• IP joints more extended

Key (subterminolateral opp)
- pad of thumb to radial side of index finger

Finger Adduction
- radial side of one finger to ulnar side of neighbouring finger