20 Questions
What is the primary function of the distal radioulnar joint?
Forearm pronosupination
What type of joint is the radiocarpal joint?
Ellipsoid joint
Which of the following is NOT a function of the wrist complex?
Elbow flexion
What is the convex rule in wrist osteokinematics?
Roll and glide occur in opposite directions
During wrist flexion, what happens to the carpal bones?
They roll anterior and glide posterior
Which joint has three or more articulation surfaces?
Intercarpal joint
What is the direction of gliding during radial deviation?
Ulnar
What provides static stability to the wrist?
Capsule attaching to the radius, ulna, and proximal row of carpal bones
During wrist extension, what happens to the carpal bones?
They roll posterior and glide anterior
What is the arthrokinematic component of pronation?
Palmar rolling and gliding
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.
What type of ligament is the scapholunate ligament?
Passive ligament
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
What is the result of injuries to the scapholunate ligament?
Pain, weakness, and limited range of motion
What type of ligaments are the palmar and dorsal ligaments in the wrist?
Passive ligaments
What is the function of the palmar and dorsal musculature in the wrist?
Dynamic support of the wrist joint
What connects the scaphoid bone to the lunate bone in the wrist?
Scapholunate ligament
What is the role of the triangular fibrocartilage complex (TFCC) in the radiocarpal joint?
It stabilizes the radiocarpal joint
What is the result of repetitive stress on the scapholunate ligament?
Injury to the scapholunate ligament
What is the purpose of the intercarpal ligaments in the wrist?
To connect the carpal bones together
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
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.
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