Questions and Answers
What is the styloid process associated with the bony landmarks of the radius?
What are the bony landmarks of the ulna?
What comprises the bony landmarks of carpal bones?
Proximal row: Scaphoid, Lunate, Triquetrum, Pisiform; Distal row: Trapezium, Trapezoid, Capitate, Hamate
What is the radiocarpal joint composed of?
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What classification does the radiocarpal joint belong to?
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Define circumduction.
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What are midcarpal joints?
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What do carpometacarpal (CMC) joints connect?
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What is meant by wrist flexion and palmar flexion?
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What does hyperextension refer to?
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How many degrees of flexion and extension are approximately present in the wrist?
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What do radial and ulnar deviation occur around?
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What is the function of the dorsal radiocarpal ligament?
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Where does the radial collateral ligament attach?
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What is the function of the ulnar collateral ligament?
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What does the palmar radiocarpal ligament limit?
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What is the joint capsule?
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What is the role of the articular disk?
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What is palmar fascia also known as?
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Where is the flexor carpi ulnaris muscle located?
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What does the flexor carpi radialis muscle do?
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Describe the palmaris longus muscle.
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Where is the extensor carpi radialis longus muscle located?
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What does the extensor carpi radialis brevis muscle arise from?
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Study Notes
Anatomy of the Wrist Joint
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Boney Landmarks: Radius
- Key structure includes the styloid process.
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Boney Landmarks: Ulna
- Notable features are the styloid process and the head.
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Boney Landmarks: Carpal Bones
- Proximal row consists of: Scaphoid, Lunate, Triquetrum, Pisiform.
- Distal row consists of: Trapezium, Trapezoid, Capitate, Hamate.
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Radiocarpal Joint
- Formed by the distal end of the radius and the radioulnar disk superiorly, articulating with scaphoid, lunate, and triquetrum inferiorly.
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Classification of Radiocarpal Joint
- Condyloid joint: The concave distal radius and articular disk articulate with convex scaphoid, lunate, and triquetrum.
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Circumduction
- Movement involves all four motions: flexion, extension, radial deviation, and ulnar deviation.
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Midcarpal and Intercarpal Joints
- Located between rows of carpal bones, they allow wrist motion. Classified as plane joints due to their irregular shape.
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Carpometacarpal (CMC) Joints
- Formed between the distal row of carpal bones and the proximal metacarpals.
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Joint Motions
- Wrist flexion and palmar flexion are equivalent; similarly, extension, hyperextension, and dorsiflexion are synonyms.
- Neutral position is midway between flexion and extension, aligning the hand with the forearm.
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Hyperextension
- Defined as movement that exceeds the neutral position.
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Flexion and Extension Degrees
- Approximately 90 degrees of flexion and 70 degrees of extension is possible.
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Radial and Ulnar Deviation
- Occurs in the frontal plane around the sagittal axis; radial deviation roughly 25 degrees and ulnar deviation about 35 degrees.
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Dorsal Radiocarpal Ligament
- Attaches from the distal radius to the posterior surfaces of scaphoid, lunate, and triquetrum. Limits wrist flexion.
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Radial Collateral Ligament
- Connects the styloid process of the radius with the scaphoid and trapezium.
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Ulnar Collateral Ligament
- Extends from the styloid process of the ulna to the pisiform and triquetrum, providing medial support.
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Palmar Radiocarpal Ligament
- A robust ligament limiting wrist extension, linking the anterior surfaces of the distal radius and ulna to the proximal flexion.
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Joint Capsule
- Encloses the radiocarpal joint, reinforced by collateral ligaments and palmar/dorsal radiocarpal ligaments.
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Articular Disk
- Positioned on the distal ulna, articulates with triquetrum and lunate. Functions as a shock absorber and filler between bones.
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Palmar Fascia
- A thick, triangular fascia in the palm, also called palmar aponeurosis; covers flexor tendons and protects palm structures.
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Flexor Carpi Ulnaris Muscle
- A superficial muscle situated along the ulnar side of the forearm.
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Flexor Carpi Radialis Muscle
- Superficial, runs from the medial epicondyle to the second and third metacarpals; a prime mover for wrist flexion and radial deviation.
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Palmaris Longus Muscle
- Superficial muscle that runs from the medial epicondyle to the palmar fascia, particularly active during wrist flexion.
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Extensor Carpi Radialis Longus Muscle
- Located at the wrist's posterior side, primarily superficial in position.
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Extensor Carpi Radialis Brevis Muscle
- Positioned alongside the extensor carpi radialis longus, arises from the common extensor tendon at the lateral epicondyle.
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Description
Explore the essential bony landmarks and features of the wrist joint with this informative flashcard quiz. Learn about the radius, ulna, and carpal bones, including the important radiocarpal joint. Perfect for anatomy students looking to reinforce their understanding of wrist anatomy.