Podcast
Questions and Answers
Which muscle assists in the extension of the elbow?
Which muscle assists in the extension of the elbow?
What is the action of the brachioradialis muscle?
What is the action of the brachioradialis muscle?
Which of the following muscles is responsible for extending the metacarpophalangeal (MP) and interphalangeal (IP) joints of the medial four fingers?
Which of the following muscles is responsible for extending the metacarpophalangeal (MP) and interphalangeal (IP) joints of the medial four fingers?
Which muscle originates from the lateral supracondylar ridge?
Which muscle originates from the lateral supracondylar ridge?
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What action is primarily performed by the extensor carpi radialis longus?
What action is primarily performed by the extensor carpi radialis longus?
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Where does the extensor carpi ulnaris insert?
Where does the extensor carpi ulnaris insert?
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Which muscle is classified as the short muscle in the posterior compartment of the forearm?
Which muscle is classified as the short muscle in the posterior compartment of the forearm?
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Which muscle does NOT run along the lateral border of the forearm?
Which muscle does NOT run along the lateral border of the forearm?
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What condition is characterized by pain and tenderness on the outside of the elbow due to overuse?
What condition is characterized by pain and tenderness on the outside of the elbow due to overuse?
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Which muscle is responsible for supinating the extended arm?
Which muscle is responsible for supinating the extended arm?
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Which muscle extends the joints of the little finger?
Which muscle extends the joints of the little finger?
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What is the primary function of the abductor pollicis longus?
What is the primary function of the abductor pollicis longus?
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From which structure does the posterior interosseous nerve arise?
From which structure does the posterior interosseous nerve arise?
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Which muscle inserts into the base of the distal phalanx of the thumb?
Which muscle inserts into the base of the distal phalanx of the thumb?
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Which muscle primarily extends the proximal phalanx of the thumb?
Which muscle primarily extends the proximal phalanx of the thumb?
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Which of the following muscles is NOT supplied by the posterior interosseous nerve?
Which of the following muscles is NOT supplied by the posterior interosseous nerve?
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Study Notes
Forearm Muscles
- The posterior compartment of the forearm contains muscles responsible for wrist and digit extension, and supination of the hand.
- There are 12 muscles in this compartment, organized into superficial and deep groups.
Superficial Group
- This group comprises 7 muscles:
- Anconeus: A short, triangular muscle on the back of the elbow. Originates from the lateral epicondyle of the humerus and inserts into the posterolateral surface of the olecranon. Its action is assisting in extension of the elbow.
- Brachioradialis: Runs along the lateral border of the forearm. Its origin is from lateral supracondylar ridge. It inserts into the base of the styloid process of radius. Its action is flexing the elbow in mid-prone position.
- Extensor carpi radialis longus: Originates from the lateral supracondylar ridge, inserts into the second metacarpal bone, and its action is extending and abducting the hand at the wrist.
- Extensor carpi radialis brevis: Originates from the common extensor origin, inserts into the base of the third metacarpal bone, and its action is extending and abducting the hand at the wrist joint.
- Extensor digitorum: Originates from the common extensor origin and inserts through extensor expansion. It extends the metacarpophalangeal (MP) and interphalangeal (IP) joints of the medial four fingers.
- Extensor digiti minimi: Originates from the common extensor origin. Its tendon joins the extensor expansion of the little finger and extends all joints of the little finger.
- Extensor carpi ulnaris: Originates from the common extensor origin, inserts into the fifth metacarpal, and extends and adducts the hand at the wrist.
Deep Group
- This group has 5 muscles; one is short and four are long.
- Supinator: Is a short muscle, and originates by two heads. It inserts into the lateral surface of the radius. Its action is supinating the extended arm.
- Abductor pollicis longus: Originates from the posterior surface of radius and ulna, inserts into the first metacarpal, and abducts and extends the thumb at the carpometacarpal joint.
- Extensor pollicis brevis: Originates from the posterior surface of radius, inserts into the base of the proximal phalanx of the thumb, and extends the proximal phalanx of the thumb.
- Extensor pollicis longus: Originates from the posterior surface of ulna, inserts into the base of the distal phalanx, and extends the distal phalanx of the thumb.
- Extensor indicis: Originates from the posterior surface of ulna, inserts into the extensor expansion of the index finger, and extends the joints of the index finger.
Nerve Supply
- Anconeus, brachioradialis, and extensor carpi radialis longus are supplied by the radial nerve.
- The remaining muscles are supplied by the posterior interosseous nerve, a branch of the radial nerve.
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Description
Test your knowledge on the muscles of the posterior compartment of the forearm. This quiz covers both superficial and deep muscle groups, including their origins, insertions, and actions. Challenge yourself to recall important details about each muscle's function and anatomy!
