Podcast
Questions and Answers
What percentage of forces run through the radial side of the radiocarpal joint?
What percentage of forces run through the radial side of the radiocarpal joint?
What is the main axis of rotation for wrist motion?
What is the main axis of rotation for wrist motion?
During wrist extension, which movement occurs at the lunate on the radius?
During wrist extension, which movement occurs at the lunate on the radius?
Which movement occurs during ulnar deviation at the wrist?
Which movement occurs during ulnar deviation at the wrist?
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Which joint area has limited arthrokinematics according to the discussion?
Which joint area has limited arthrokinematics according to the discussion?
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What is the total number of carpal bones present in the wrist?
What is the total number of carpal bones present in the wrist?
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Which joints are involved in the wrist's ability to flex and extend?
Which joints are involved in the wrist's ability to flex and extend?
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What anatomical feature divides the extensor carpi radialis brevis tendon from the extensor pollicis longus tendon?
What anatomical feature divides the extensor carpi radialis brevis tendon from the extensor pollicis longus tendon?
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Which wrist motion is referred to as radial deviation?
Which wrist motion is referred to as radial deviation?
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What anatomical characteristic of the ulna is noted in discussions of wrist mechanics?
What anatomical characteristic of the ulna is noted in discussions of wrist mechanics?
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What anatomical feature allows for more ulnar deviation compared to radial deviation in the wrist?
What anatomical feature allows for more ulnar deviation compared to radial deviation in the wrist?
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Which carpal bone is most commonly dislocated due to its lack of muscular attachments?
Which carpal bone is most commonly dislocated due to its lack of muscular attachments?
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What is the primary function of the articular cartilage surrounding the scaphoid bone?
What is the primary function of the articular cartilage surrounding the scaphoid bone?
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Which bone serves as a key articulation point in the wrist, connecting to seven different bones?
Which bone serves as a key articulation point in the wrist, connecting to seven different bones?
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Which carpal bone is located on the palmar side and serves as an attachment site for muscles?
Which carpal bone is located on the palmar side and serves as an attachment site for muscles?
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Study Notes
Wrist Anatomy
- The wrist, also known as the carpus, is made up of 8 carpal bones.
- There are 3 joints that make up the wrist: the distal radioulnar joint, radiocarpal joint, and midcarpal joint.
- The radial bone is larger distally than the ulna.
- The ulnar styloid process and the styloid process of the radius are easily palpated.
- The tubercle of the radius is important because it divides the extensor carpi radialis brevis tendon from the extensor pollicis longus tendon.
- Ulnar tilt, which is an angulation at the distal radioulnar joint, facilitates ulnar deviation and limits radial deviation.
- The radius is tilted slightly toward the palmar side of the hand, known as palmar tilt, contributing to greater wrist flexion than extension.
Carpal Bones
- Scaphoid: Named for its boat-like shape, it articulates with the radius, capitate, trapezium, trapezoid, and lunate.
- Lunate: Moon-shaped bone; the most commonly dislocated carpal bone due to its lack of muscular attachments.
- Triquetrum: Triangular bone located in the most ulnar position.
- Pisiform: Located on the palmar surface of the hand and articulates with the triquetrum.
- Hamate: Medial bone in the distal row. It has a hook on the palmar side.
- Capitate: Central pillar of the wrist; the largest carpal bone, articulates with 7 other bones, including the hamate, lunate, scaphoid, trapezoid, and 3 metacarpals.
- Trapezoid: Sits between the trapezium and capitate.
- Trapezium: Asymmetrically shaped bone located under the thumb.
Wrist Joints
- Radiocarpal Joint: About 80% of forces applied to the hand are transmitted through the radius and only 20% through the ulna.
- Midcarpal Joint: Divided into the medial and lateral compartments. Arthrokinematics primarily occur here, with limited movements in the lateral compartment.
Wrist Motions
- Flexion/Extension: Occur through the medial/lateral axis and the capitate is the center of motion.
- Ulnar/Radial Deviation: Occur through the anterior/posterior axis and involve the capitate.
- Axial Rotation: Not a primary motion of the wrist, but can occur to a limited extent.
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Arthrokinematics:
- During wrist extension, the lunate rolls dorsally and slides palmarly while the capitate rolls dorsally and slides palmarly.
- During wrist flexion, the lunate rolls palmarly and slides dorsally while the capitate rolls palmarly and slides dorsally.
- The radiocarpal joint and midcarpal joint contribute equally to wrist motion.
- During ulnar deviation, the luminate and scaphoid roll towards the ulnar side with a palmar slide, and the same movement occurs at the proximal radioulnar joint.
- During radial deviation, the luminate and scaphoid roll towards the radial side with an ulnar slide.
- The scaphoid bumping against the styloid process of the ulna limits radial deviation, with 85% of radial deviation occurring at the midcarpal joint.
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Description
Test your knowledge on wrist anatomy and the carpal bones in this quiz. Learn about the different joints, bones, and their functions. Perfect for students studying human anatomy or medical professionals looking to refresh their knowledge.
