Wrist And Hand Biomechanics

Question 1

What are the different types of joints involved in the wrist and hand ?

Answer 1

• ellipsoidal joint
• plane joints
• saddle joint

Question 2

What are the name of the articulations present in the wrist and hand ?

Answer 2

• radiocarpal joint
• mid-carpal joints
• inter-carpal joints

Question 3

What are the components of the radio carpal joint

Answer 3

Proximal components :

• radius
• articular discs (triangular fibrocartilage)

Distal components :

• scaphoid
• lunate
• triquetrum

Question 4

Describe the mid carpal joint

Answer 4

Articulation between the proximal and the distal row of carpal bones

Question 5

Describe the inter-carpal joints

Answer 5

13 separate inter carpal articulations

Question 6

Which bones are mostly implicated in wrist movement ?

Answer 6

First row of carpal bones

Question 7

Where can you find mechanoreceptors in the wrist ?

Answer 7

Dorsal ligaments contributes to wrist proprioception

Question 8

What composes the triangular fibrocartilage complex ?

Answer 8

• articular disc
• distal radio-ulnar joint capsule ligaments
• palmar ulno-carpal ligament (ulno triquetral + ulnolunate )
• ulnar collateral ligament
• fascial sheath that encloses the tendon of the extensor carpi ulnaris

Question 9

What are the main functions of the articular disc located in the triangular fibrocartilage complex of the wrist ?

Answer 9

• stability of the distal radio ulnar joint
• permits radia rotation on fixed ulna
• transfer about 20% of the compression forces of the hand to the forearm

Question 10

What type of joint are the mid-carpal and radiocarpal joints ?

Answer 10

Elipsoidal joints

Question 11

What is the convention to apply the concave/convex rule to wrist motions taking place in the sagittal plane and frontal plane ?

Answer 11

The convention is to use the central column composed by the alignement of distal radius, lunate, capitate and 3rd metacarpal bone.

Question 12

Which arthrokinematics rule do you apply for wrist motions happening in the sagittal plane (OKC) ?

Answer 12

Convex on Concave so the glide is opposite to the movement direction

Question 13

What is the arthrokinematics rule applied to movements of the wrist in the frontal plane ?

Answer 13

Convex on concave so the glide is opposite to the movement direction

Question 14

What structures limit the ulnar deviation ?

Answer 14

• contact of the triquetrum against the triangular fibrocartilage complex
• soft tissues

Question 15

What limits the radial deviation ?

Answer 15

• styloid process of the radius

Question 16

What are the usual ROM of wrist flexion and extension

Answer 16

• wrist flexion : 80°-90°

- wrist extension : 70°

Question 17

What are the usual ROM of the wrist ulnar and radial deviation ?

Answer 17

• ulnar deviation : 35°-45°

- radial deviation : 20°

Question 18

What are the usual ROM of forearm pronation and supination ?

Answer 18

• pronation : 80°-90°

- supination : 75°-80°

Question 19

What are the usual ROM of elbow flexion and extension ?

Answer 19

• flexion : 145°

- extension : 0°

Question 20

Name the agonists of wrist flexion

Answer 20

1) flexor carpi radialis
Origin : common flexor tendon from medial epicondyle of the humerus
Insertion : bases of second and third metacarpals

2) flexor carpi ulnaris
Origin : common flexor tendon from medial epicondyle of the humerus (humeral head) and posterior surface of proximal 2/3rd of ulna
Insertion : pisiform, hook of the hamate and base of fifth metacarpal

3) palmaris longus
Origin : common flexor tendon from medial epicondyle of the humerus
Insertion : flexor retinaculum and palmar aponeurosis

Question 21

Name the agonists of wrist extension

Answer 21

1) extensor carpi radialis longus
Origin : lateral supracondylar ridge of humerus
Insertion : base of second metacarpal

2) extensor carpi radialis brevis
Origin : common extensor tendon from the lateral epicondyle of the humerus
Insertion : base of third metacarpal

3) extensor carpi ulnaris
Origin : common extensor tendon from the lateral epicondyle of the humerus
Insertion : base of fifth metacarpal

Question 22

Name the agonists of wrist ulnar deviation

Answer 22

• extensor carpi ulnaris

- flexor carpi ulnaris

Question 23

Name the agonists for wrist radial deviation

Answer 23

• extensor carpi radialis longus
• extensor carpi radialis brevis
• extensor pollicis longus
• extensor pollicis brevis
• flexor carpi radialis
• abductor pollicis longus

Question 24

What arthorokinematics rule apply to CMC, MP and IP joints ?

Answer 24

Concave on convex rule so the slide takes place in the same direction as the movement

Question 25

What are the ROM of finger joints ?

Answer 25

- flexion DIP : 90° - flexion PIP : 100° - flexion MCP : 90° - extension MCP : 45° - extension DIP : non present on slide - abduction / adduction : non present on slide

Question 26

What are the different thumb movements

Answer 26

Opposition/Reposition Flexion/Extension Abduction/Adduction

Question 27

Define the features of a saddle joint

Answer 27

Each articular surface is convex in one dimension and concave in the other dimension

Question 28

Link the thumb movements to their respective planes and axis of action

Answer 28

Abduction and adduction take place in the sagittal plane along the frontal axis Flexion and extension take place in the frontal plane along the sagittal axis

Question 29

Describe the arthrokinematics of thumb abduction/ adduction

Answer 29

Convex aspect of the articular surface of metacarpal bone moves on concave surface of the trapezium so the glide is opposite to the movement : - abduction : palmar roll and dorsal glide - adduction : dorsal roll and palmar glide

Question 30

Describe the arthrokinematics of thum flexion/extension

Answer 30

Concave aspect of the articular surface of metacarpal roll on convex aspect of trapezium so the glide goes in the same direction as the movement - Flexion : medial roll and slide - Extension : lateral roll and slide

Question 31

Describe the phases of thumb opposition

Answer 31

Phase 1 : thumb abducts | Phase 2 : thumb flexes and medially rotates

Question 32

Name the ligaments of the carpometacarpal joint of the thumb

Answer 32

- anterior oblique - posterior oblique - radial collateral - ulnar collateral - intermetacarpal

Question 33

Name the agonists of fingers extension

Answer 33

- extensor digitorum | - lombricals

Question 34

Name the agonists for fingers flexion

Answer 34

- flexor digitorum superficialis - flexor digitorum profondus - flexor digiti minimi brevis - lombricals

Question 35

Name the agonists of thumb flexion

Answer 35

- flexor pollicis longus | - flexor pollicis brevis

Question 36

Name the agonists of thumb extension

Answer 36

- extensor pollicis longus | - extensor pollicis brevis

Question 37

Name the agonists for thumb opposition

Answer 37

- opponents pollicis