The Wrist Complex: Anatomy and Functions

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Questions and Answers

What is the primary function of the distal radioulnar joint?

Wrist flexion and extension

Forearm pronosupination (correct)

Wrist radial and ulnar deviation

Forearm flexion and extension

What type of joint is the radiocarpal joint?

Pivot joint

Ball-and-socket joint

Ellipsoid joint (correct)

Condyloid joint

Which of the following is NOT a function of the wrist complex?

Control of multi-articular muscles of the hand

Fine adjustment of the grip

Wrist rotation

Elbow flexion (correct)

What is the convex rule in wrist osteokinematics?

Roll and glide occur in opposite directions Signup and view all the answers

During wrist flexion, what happens to the carpal bones?

They roll anterior and glide posterior Signup and view all the answers

Which joint has three or more articulation surfaces?

Intercarpal joint Signup and view all the answers

What is the direction of gliding during radial deviation?

Ulnar Signup and view all the answers

What provides static stability to the wrist?

Capsule attaching to the radius, ulna, and proximal row of carpal bones Signup and view all the answers

During wrist extension, what happens to the carpal bones?

They roll posterior and glide anterior Signup and view all the answers

What is the arthrokinematic component of pronation?

Palmar rolling and gliding Signup and view all the answers

What is the function of the triangular fibrocartilage complex (TFCC) in the wrist joint?

It facilitates the complex movements at the wrist joint and stabilizes the radiocarpal and ulnocarpal joints. Signup and view all the answers

What type of ligament is the scapholunate ligament?

Passive ligament Signup and view all the answers

What is the location of the triangular fibrocartilage complex (TFCC) in the wrist region?

On the medial aspect of the wrist region between the lunate, triquetrum, and ulnar head Signup and view all the answers

What is the result of injuries to the scapholunate ligament?

Pain, weakness, and limited range of motion Signup and view all the answers

What type of ligaments are the palmar and dorsal ligaments in the wrist?

Passive ligaments Signup and view all the answers

What is the function of the palmar and dorsal musculature in the wrist?

Dynamic support of the wrist joint Signup and view all the answers

What connects the scaphoid bone to the lunate bone in the wrist?

Scapholunate ligament Signup and view all the answers

What is the role of the triangular fibrocartilage complex (TFCC) in the radiocarpal joint?

It stabilizes the radiocarpal joint Signup and view all the answers

What is the result of repetitive stress on the scapholunate ligament?

Injury to the scapholunate ligament Signup and view all the answers

What is the purpose of the intercarpal ligaments in the wrist?

To connect the carpal bones together Signup and view all the answers

Study Notes

Wrist Complex Functions

Controls multi-articular muscles of the hand
Provides fine adjustment of grip
Has 2 degrees of freedom: radial/ulnar deviation and flexion/extension

Wrist Complex Structure

Consists of distal radio-ulnar joint, radiocarpal joint, and midcarpal articulation

Distal Radioulnar Joint

Pivot joint
Radius (concave) moves according to the concave rule
Function: forearm pronosupination
Arthrokinematic components:
- Pronation: palmar rolling and gliding
- Supination: dorsal rolling and gliding

Radiocarpal Joint

Ellipsoid joint
Proximally: radius and radioulnar disk (distal radius is concave)
Distally: 3 bones in the proximal carpal row: scaphoid, lunate, and triquetrum

Midcarpal/Intercarpal Joint

Compound joint with three or more articulation surfaces
Consists of two single functional units:
- Proximal row: scaphoid-lunate-triquetrum (mobile)
- Distal row: trapezium-trapezoid-capitate-hamate (immobile)

Wrist Osteokinematics

Open kinematic chain
Flexion/extension:
- Roll anterior and glide posterior
- Radiocarpal (red arrows)
- Midcarpal/intercarpal (white arrows)
Radial/ulnar deviation:
- Radiocarpal (red arrows)
- Midcarpal/intercarpal (white arrows)
- Roll and glide occur in opposite directions

Wrist Arthrokinematics

Convex rule
Radiocarpal and midcarpal/intercarpal joints

Wrist Stability

Static:
- Capsule attaches to radius, ulna, and proximal row of carpal bones
- Ligaments:
  - Radiocarpal: palmar, dorsal, radial, and ulnar collateral ligaments
  - Intercarpal: palmar and dorsal
- Triangular fibrocartilage complex (TFCC)
Dynamic:
- Palmar and dorsal musculature of the wrist
Passive ligaments limit osteokinematics

Triangular Fibrocartilage Complex (TFCC)

Load-bearing structure located on the medial aspect of the wrist region
Functions as a major stabilizer of radiocarpal and ulnocarpal joints
Facilitates complex movements at the wrist joint
Passive ligament limits osteokinematics

Scapholunate Ligament

Connects scaphoid bone to lunate bone
Helps stabilize the two bones, maintaining alignment of carpal bones
Injuries can occur due to falls, sudden impacts, or repetitive stress
Can lead to instability of the wrist joint, resulting in pain, weakness, and limited range of motion

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Description

This quiz covers the functions and anatomy of the wrist complex, including the distal radioulnar joint, radiocarpal joint, and midcarpal articulation. It also explores the movements and functions of the wrist, such as radial/ulnar deviation and flexion/extension.