Questions and Answers
What type of joint is the wrist joint?
Synovial joint
Describe the bones involved in the wrist joint. Which are convex and which are concave?
The radius has a concave articular surface and the scaphoid, lunate, and triquetrum have convex articular surfaces.
What type of movement cannot be performed at the wrist because of the ellipsoidal shape of the joint?
Rotation
What movements can be done at the wrist joint?
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Why doesn't the ulna partake in the wrist joint?
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Which of the 4 proximal carpal bones does the radius not articulate with?
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Which carpal bone lies lateral to the distal end of the radius?
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Which carpal bone lies medial to the distal end of the radius?
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Which bone lies distal to the articular disc?
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Differentiate between the triquetrum, trapezoid, and trapezium bones of the hand.
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What are the weak points of the fibrous capsule of the wrist joint?
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What are the two ligaments at these weak points?
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What are the strong special ligaments that reinforce the capsule laterally and medially?
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Where do the radial and ulnar collateral ligaments originate from?
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Name the four ligaments of the radiocarpal joint.
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What bones articulate together at the radiocarpal joint?
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What are the joints in the wrist and fingers?
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Where does the ulnar collateral ligament originate and attach?
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Where does the radial collateral ligament originate and attach?
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What are the flexor muscles in the forearm?
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Which of the flexor muscles are radial deviators (abductors)?
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Which of the flexor muscles are ulnar deviators (adductors)?
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What are the extensor muscles in the forearm?
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Which of the extensor muscles are radial deviators (abductors)?
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Which of the extensor muscles are ulnar deviators (adductors)?
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What type of joint is the midcarpal joint?
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Where is the midcarpal joint located?
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What movements are permitted at the midcarpal joint?
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Compare movement in the midcarpal joint to movement at the radiocarpal joint.
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What type of joint are intercarpal joints?
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Where are the intercarpal joints located?
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What type of joint are intermetacarpal joints?
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Where are the intermetacarpal joints located?
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Study Notes
Joints of the Wrist, Hand, and Fingers
- Wrist (radiocarpal) joint is a synovial, biaxial, ellipsoidal joint.
- The concave socket is formed by the radius and the articular disc, while the convex surface is formed by the scaphoid, lunate, and triquetrum.
- Rotation is not permitted at the wrist; however, flexion, extension, abduction, and adduction are allowed.
- The ulna does not participate in the wrist joint due to the presence of the articular disc.
- The radius does not articulate with the pisiform carpal bone.
- Scaphoid lies laterally to the radius, lunate medially, and triquetrum is distal to the articular disc.
Triquetrum, Trapezoid, and Trapezium
- Triquetrum is a proximal carpal bone; the pisiform sits atop it.
- Trapezoid is the smallest bone in the distal row of carpal bones.
- Trapezium, also in the distal row, articulates with the thumb.
Capsule of the Wrist Joint
- The fibrous capsule is weak anteriorly and posteriorly.
- Anteriorly, it features the thin palmar radiocarpal ligament; posteriorly, the thin dorsal radiocarpal ligament.
- Strong lateral and medial ligaments include the radial and ulnar collateral ligaments.
- These collateral ligaments originate from the styloid processes of the radius and ulna, attaching to the scaphoid and triquetrum respectively.
Ligaments of the Radiocarpal Joint
- Anterior: palmar radiocarpal ligament (thin, weak).
- Posterior: dorsal radiocarpal ligament (thin, weak).
- Laterally: radial collateral ligament (thick, strong).
- Medially: ulnar collateral ligament (thick, strong).
- At the wrist joint, the distal radius and articular disc articulate with the scaphoid, lunate, and triquetrum.
- Joints in the wrist and fingers include radiocarpal joint, midcarpal joint, intercarpal joints, and carpometacarpal joint (including the thumb).
- Ulnar collateral ligament connects ulna's styloid process to the triquetrum; radial collateral ligament connects radius's styloid process to the scaphoid.
Flexor and Extensor Muscles of the Forearm
- Flexor muscles include: flexor carpi radialis (FCR), abductor pollicis longus (APL), palmaris longus (PL), finger flexors (FDS, FDP), and flexor carpi ulnaris (FCU).
- Radial deviators (abductors) are FCR and APL; ulnar deviator (adductor) is FCU.
- Extensor muscles include: extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), finger extensors, and extensor carpi ulnaris (ECU).
- Radial deviator (abductor) is ECRL; ulnar deviator (adductor) is ECU.
Midcarpal Joint
- The midcarpal joint is a synovial, uniaxial hinge joint.
- It is located between the proximal and distal rows of carpal bones.
- Movements permitted are limited to flexion and extension.
- Compared to the radiocarpal joint, the midcarpal joint allows a greater range of flexion than extension; much of the wrist flexion appears to occur here.
Intercarpal Joints
- Intercarpal joints are synovial, multiaxial plane/gliding joints.
- They are located between individual carpal bones.
Intermetacarpal Joints
- Intermetacarpal joints are also synovial joints.
- They are situated between the metacarpal bones and facilitate complex hand movements.
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Description
Explore the intricacies of the wrist, hand, and finger joints with these flashcards. Delve into the types of joints, the bones involved, and the movements possible at the wrist. Perfect for anyone looking to strengthen their understanding of human anatomy.
