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Questions and Answers
What type of joint is the proximal radioulnar joint?
What type of joint is the proximal radioulnar joint?
Which ligament forms an osteo-ligamentous ring at the proximal radioulnar joint?
Which ligament forms an osteo-ligamentous ring at the proximal radioulnar joint?
What structures articulate at the distal radioulnar joint?
What structures articulate at the distal radioulnar joint?
Which structure separates the distal radioulnar joint from the wrist joint?
Which structure separates the distal radioulnar joint from the wrist joint?
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Which nerves are responsible for the innervation of the proximal radioulnar joint?
Which nerves are responsible for the innervation of the proximal radioulnar joint?
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What is the primary action that occurs when the distal end of the radius moves medially over the ulna?
What is the primary action that occurs when the distal end of the radius moves medially over the ulna?
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Which ligament is responsible for holding the forearm bones together during pronation and supination?
Which ligament is responsible for holding the forearm bones together during pronation and supination?
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Which muscle is most effective at supination when the forearm is in a flexed position?
Which muscle is most effective at supination when the forearm is in a flexed position?
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During which motion do the tendon of the biceps brachii and the supinator muscle become unwrapped from the proximal end of the radius?
During which motion do the tendon of the biceps brachii and the supinator muscle become unwrapped from the proximal end of the radius?
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Which of the following structures additionally stabilizes the distal radio-ulnar joint?
Which of the following structures additionally stabilizes the distal radio-ulnar joint?
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What type of joint is formed between the metacarpal 1 and trapezium in the thumb?
What type of joint is formed between the metacarpal 1 and trapezium in the thumb?
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How many phalanges are present in the thumb?
How many phalanges are present in the thumb?
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What type of movement is primarily allowed by the carpometacarpal joints of digits 2-5?
What type of movement is primarily allowed by the carpometacarpal joints of digits 2-5?
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What articulates with the base of each proximal phalanx?
What articulates with the base of each proximal phalanx?
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Which of the following statements about the distal phalanx is correct?
Which of the following statements about the distal phalanx is correct?
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Which bone is considered the largest of the carpal bones?
Which bone is considered the largest of the carpal bones?
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How many phalanges does the thumb have?
How many phalanges does the thumb have?
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Which carpal bone is boat-shaped?
Which carpal bone is boat-shaped?
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What shape is the lunate bone?
What shape is the lunate bone?
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Which carpal bone articulates with the metacarpal bone of the thumb?
Which carpal bone articulates with the metacarpal bone of the thumb?
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Which of the following is NOT a phalange?
Which of the following is NOT a phalange?
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How many carpal bones make up the wrist?
How many carpal bones make up the wrist?
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Which carpal bone is known for having a prominent hook on its palmar surface?
Which carpal bone is known for having a prominent hook on its palmar surface?
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Which of the following bones is located in the distal row of carpal bones?
Which of the following bones is located in the distal row of carpal bones?
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Which of the following groups includes the bones of the metacarpus?
Which of the following groups includes the bones of the metacarpus?
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What is the primary function of the ulna in the forearm?
What is the primary function of the ulna in the forearm?
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Which joint movements are essential for the process of supination?
Which joint movements are essential for the process of supination?
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What occurs at the elbow during supination?
What occurs at the elbow during supination?
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How does the radius move relative to the ulna during pronation?
How does the radius move relative to the ulna during pronation?
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Which structure does the radial head glide against at the proximal radio-ulnar joint?
Which structure does the radial head glide against at the proximal radio-ulnar joint?
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What describes the motion of the ulnar notch of the radius during supination?
What describes the motion of the ulnar notch of the radius during supination?
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What role does the anular ligament play in forearm movement?
What role does the anular ligament play in forearm movement?
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What is the consequence of the radius's lateral positioning in the forearm?
What is the consequence of the radius's lateral positioning in the forearm?
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What type of joints are the metacarpophalangeal (MCP) joints classified as?
What type of joints are the metacarpophalangeal (MCP) joints classified as?
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Which of the following movements is NOT a function of the metacarpophalangeal (MCP) joints?
Which of the following movements is NOT a function of the metacarpophalangeal (MCP) joints?
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What ligaments reinforce the interphalangeal (IP) joints?
What ligaments reinforce the interphalangeal (IP) joints?
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The metacarpophalangeal (MCP) joints allow for which of the following movements?
The metacarpophalangeal (MCP) joints allow for which of the following movements?
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Distal interphalangeal (DIP) joints primarily enable which type of motion?
Distal interphalangeal (DIP) joints primarily enable which type of motion?
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What is the primary role of the deep transverse metacarpal ligaments?
What is the primary role of the deep transverse metacarpal ligaments?
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Which descriptions correctly characterize the interphalangeal joints?
Which descriptions correctly characterize the interphalangeal joints?
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How do the movements at the MCP joints differ from those at the IP joints?
How do the movements at the MCP joints differ from those at the IP joints?
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Study Notes
Radioulnar, Wrist & Hand Joints
- Pivot type of synovial joint
- Head of radius articulates with radial notch of ulna
- Fibrous capsule and synovial membrane continuous with elbow joint
- Anular ligament forms osteo-ligamentous ring with radial notch of ulna
- Rotation of radius head
- Blood supply from anterior and posterior interosseous arteries
- Innervation from musculocutaneous, median, radial, and ulnar nerves
Proximal Radioulnar Joint
- Pivot type of synovial joint
- Head of radius articulates with radial notch of ulna
- Fibrous capsule and synovial membrane continuous with elbow joint
- Anular ligament forms osteo-ligamentous ring with radial notch of ulna
- Rotation of head of radius
- Blood supply from anterior and posterior interosseous arteries
- Innervation from musculocutaneous, median, radial, and ulnar nerves
Distal Radioulnar Joint
- Pivot type synovial joint
- Distal head of ulna articulates with ulnar notch of radius
- Fibrous articular disc separates distal radioulnar joint from wrist joint
- Fibrous capsule is attached to articular margins including fibrocartilage disc inferiorly
- Blood supply and innervation provided by anterior/posterior interosseous arteries and nerves
Pronation/Supination
- Ulna is the stabilizing bone of the forearm located medially
- Radius, positioned laterally, pivots around the ulna
- Rotation of radius at elbow allows rotation of the hand when elbow is flexed
- Movement is required at both proximal and distal radioulnar joints
Pronation/Supination - Details at Elbow
- Superior articular surface of the radial head spins on the capitulum
- At proximal radio-ulnar joint, radial head slides against radial notch of ulna and adjacent areas of the joint capsule and anular ligament
Pronation/Supination - Details at Distal Radio-ulnar Joint
- Ulnar notch of radius slides anteriorly over convex surface of ulna head
- Movement of the distal end of the radius medially over the ulna moves the hand from palm anterior (supinated) to palm posterior (pronated)
Muscles of Supination
- Two muscles supinate the hand (biceps brachii and supinator)
- Located in posterior compartment of forearm
- Most effective as a supinator when the forearm is flexed
- Tendon wraps around proximal end of radius, unwinding from the bone to produce supination
Muscles of Pronation
- Two muscles are located in anterior compartment (pronator teres and pronator quadratus)
- They pull the distal end of the radius over the ulna, creating pronation of the hand
- Pronation/supination movements of the forearm are held together by the anular ligament of the radius at the proximal radioulnar joint and the interosseous membrane along the lengths of the radius and ulna.
Hand
- Region of upper limb distal to the wrist
- Subdivided into wrist (carpus), metacarpus, and digits (thumb, index, middle, ring, and little fingers)
- Has an anterior surface (palm) and a dorsal surface (dorsum of hand)
Bones of Hand
- Composed of 8 carpal bones, five metacarpals (1-5), and phalanges (bones of the digits)
Proximal Carpal Bones
- Scaphoid (boat-shaped)
- Lunate (crescent-shaped)
- Triquetrum (three-sided bone)
- Pisiform (pea-shaped)
Distal Carpal Bones:
- Trapezium
- Trapezoid
- Capitate
- Hamate (has a hook)
Articulations of Carpal Bones
- Numerous articulating surfaces (joint surfaces) that connect to other carpals
- Distal row articulates with the metacarpals with limited movement
- Proximal surfaces of scaphoid and lunate articulate with the radius at the wrist joint
Carpal Tunnel Description and Function
- Formed by the carpal arch (medial side formed by pisiform and hamate; lateral side by scaphoid and trapezium)
- Flexor retinaculum spans between medial and lateral sides to form anterior wall of carpal tunnel
Clinical- Carpal Tunnel Syndrome
- Entrapment of the median nerve within the carpal tunnel (most common nerve compression syndrome)
- Cause is unknown (but overuse, swelling of tendons/tendon sheaths, cysts arising from carpal joints are possibilities)
- Symptoms include: numbness, tingling, wasting of thenar muscles, Tinel's sign
- Therapy: splinting, anti-inflammatories, surgery
Metacarpals
- Each of the five metacarpals relates to a specific digit
- Metacarpal contains base, shaft (body), and head
- The base of the metacarpals articulate with the carpal bones (carpometacarpal joints) and the heads of metacarpals articulate with each other and the proximal phalanges (metacarpophalangeal joints).
Thumb
- Saddle joint between metacarpal 1 and trapezium
- Allows notable thumb mobility
Phalanges
- Thumb has 2 phalanges (proximal and distal)
- Other digits have 3 phalanges (proximal, middle, and distal)
- Each phalanx has a base, shaft (body), and head
Metacarpophalangeal (MCP) Joints
- Condylar synovial joints between the distal heads of metacarpals and the proximal phalanges
- Movements include flexion, extension, abduction, adduction and circumduction
- Joint capsule is reinforced by ligaments (palmar, medial and lateral collateral ligaments). Deep transverse metacarpal ligaments connect palmar ligaments and restrict joint movements.
Interphalangeal (IP) Joints
- Uniaxial hinge joints between the phalanges
- Mainly flexion and extension
- Reinforced by medial and lateral collateral ligaments and palmar ligaments.
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Description
This quiz covers the anatomy and function of the radioulnar, wrist, and hand joints, including their types, articulations, and innervations. You will explore details about the proximal and distal radioulnar joints, such as the fibrous capsules, blood supply, and relevant ligaments. Test your knowledge of these critical anatomical structures.