Podcast
Questions and Answers
What is the primary muscle involved in thumb extension?
What is the primary muscle involved in thumb extension?
What is the range of motion for thumb extension at the metacarpophalangeal joint?
What is the range of motion for thumb extension at the metacarpophalangeal joint?
Which muscle is responsible for extending the interphalangeal joints of the thumb?
Which muscle is responsible for extending the interphalangeal joints of the thumb?
What nerve supplies both the extensor pollicis longus and brevis?
What nerve supplies both the extensor pollicis longus and brevis?
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What is the action of the extensor pollicis brevis?
What is the action of the extensor pollicis brevis?
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What consequence can occur due to weakness in the extensor pollicis longus?
What consequence can occur due to weakness in the extensor pollicis longus?
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Which of the following muscles is primarily involved in thumb abduction?
Which of the following muscles is primarily involved in thumb abduction?
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What happens to the proximal phalanx of the thumb if there is weakness in the extensor pollicis brevis?
What happens to the proximal phalanx of the thumb if there is weakness in the extensor pollicis brevis?
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What is the primary action of the abductor pollicis brevis?
What is the primary action of the abductor pollicis brevis?
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Which joint allows for the thumb's extension ranged between 0 to 40-50 degrees?
Which joint allows for the thumb's extension ranged between 0 to 40-50 degrees?
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Where does the opponens pollicis muscle originate?
Where does the opponens pollicis muscle originate?
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Which nerve supplies the adductor pollicis muscle?
Which nerve supplies the adductor pollicis muscle?
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What is the insertion point of the abductor pollicis longus?
What is the insertion point of the abductor pollicis longus?
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Which primary muscle is responsible for the thumb adduction motion?
Which primary muscle is responsible for the thumb adduction motion?
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What action does the opponens digiti mini perform?
What action does the opponens digiti mini perform?
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What is the origin of the adductor pollicis's oblique head?
What is the origin of the adductor pollicis's oblique head?
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Study Notes
Thumb Extension, Abduction, Adduction, and Opposition
- Muscles Involved in Thumb Extension: Extensor pollicis longus, Extensor pollicis brevis
- Range of Motion for Thumb Extension: 60° – 70° to 0° (metacarpophalangeal), 90° – 0° (interphalangeal)
- Muscles Involved in Thumb Abduction: Abductor pollicis longus, Abductor pollicis brevis
- Range of Motion for Thumb Abduction: 0° to 40°–50° (metacarpophalangeal)
- Muscles Involved in Thumb Adduction: Adductor pollicis
- Range of Motion for Thumb Adduction: 40°–50° to 0°
- Muscles Involved in Thumb Opposition: Opponens pollicis, Opponens digiti minimi
- Range of Motion for Thumb Opposition: Opposes (medially rotates and flexes) carpometacarpal and metacarpophalangeal joints of the thumb.
Primary Muscles: Detailed Anatomy, Origin, Insertion, Nerve Supply, and Action
Extensor Pollicis Longus
- Origin: Middle third of posterior ulna
- Insertion: Base of distal phalanx of thumb
- Nerve Supply: Radial nerve
- Action: Extends interphalangeal and metacarpophalangeal joints of thumb
Extensor Pollicis Brevis
- Origin: Posterior surfaces of radius and interosseous membrane
- Insertion: Base of proximal phalanx of thumb
- Nerve Supply: Radial nerve
- Action: Extends proximal phalanx of thumb at the carpometacarpal joint
Abductor Pollicis Longus
- Origin: Upper posterior surface of ulna and middle third of posterior surface of radius
- Insertion: Over tendons of radial extensors, brachioradialis to the base of 1st metacarpal and trapezium
- Nerve Supply: Radial nerve
- Action: Abducts and extends thumb at carpometacarpal joint
Abductor Pollicis Brevis
- Origin: Tubercle of scaphoid and flexor retinaculum
- Insertion: Radial sesamoid of proximal phalanx of thumb and tendon of extensor pollicis longus
- Nerve Supply: Median nerve
- Action: Abducts thumb at the metacarpophalangeal and carpometacarpal joints
Adductor Pollicis
- Origin: Oblique head: base of 2nd and 3rd metacarpals, trapezoid, and capitate; Transverse head: palmar border and shaft of 3rd metacarpal
- Insertion: Ulnar side of base of proximal phalanx of thumb and tendon of extensor pollicis longus
- Nerve Supply: Ulnar nerve
- Action: Adducts carpometacarpal joint of thumb
Opponens Pollicis
- Origin: Flexor retinaculum and tubercle of trapezium
- Insertion: Whole of radial border of 1st metacarpal
- Nerve Supply: Median nerve
- Action: Opposes (medially rotates and flexes) carpometacarpal and metacarpophalangeal joints of thumb
Opponens Digiti Minimi
- Origin: Flexor retinaculum and hook of hamate
- Insertion: Ulnar border of shaft of 5th metacarpal
- Nerve Supply: Ulnar nerve
- Action: Opposes (flexes and laterally rotates) carpometacarpal and metacarpophalangeal joints of little finger
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Description
Explore the critical functions and anatomy of the muscles involved in thumb extension, abduction, adduction, and opposition. This quiz includes details on the range of motion and specific muscles' origins, insertions, and actions. Perfect for students of anatomy and physiotherapy.
