Superficial and deep muscles of posterior forearm Flashcards
What are the 5 deep muscles of the posterior forearm?
supinator
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
extensor indicis proprius
What nerve supplies all of the muscles in the posterior forearm?
Radial nerve
Where is brachioradialis, and what are its origin and attachment sites?
7, brachioradialis originates from lateral supracondylar ridge of humerus and attaches to distal, lateral surface of radius just before radial styloid process
What is the action of the brachioradialis?
Elbow flexion
Where is extensor carpi radialis longus, and what are its origin and attachment sites?
1, it originates from lateral supracondylar ridge of humerus and becomes a tendon to attach to base of 2nd metacarpal
What are the 2 actions of extensor carpi radialis longus?
Wrist abduction
Wrist extension
Where is extensor carpi radialis brevis, and what are its origin and attachment sites?
2, originates from lateral epicondyle of humerus and becomes a tendon to attach to base of 3rd metacarpal
What are the 2 actions of extensor carpi radialis brevis?
Wrist abduction
Wrist extension
Where is extensor digitorum communis, and what are the origin and attachment sites?
10, originates from lateral epicondyle of humerus than splits into 4 tendons in distal forearm, each tendon attaches to extensor hood of a finger
Extensor hood surrounds distal metacarpal head and proximal phalange
What are the 2 actions of extensor digitorum communis?
Extension of metacarpophalangeal joints
Extension of interphalangeal joints
(Main extensor of fingers)
Where is extensor digiti minimi, and what are the origin and attachment sites?
9, originates from lateral epicondyle of humerus and joins with extensor digitorum tendon to attach to extensor hood of little finger
What are the 2 actions of extensor digiti minimi?
Extension of little finger (main action)
Wrist extension (weak action)
Where is extensor carpi ulnaris, and what are the origin and attachment sites?
8, originates from lateral epicondyle of humerus and attaches to base of 5th metacarpal
What are the 2 actions of extensor carpi ulnaris?
Wrist extension
Wrist adduction
Where is anconeus, and what are the origin and attachment sites?
11, originates from lateral epicondyle of humerus and attaches to posterolateral surface of olecranon process
What are the 2 actions of anconeus?
Elbow extension
Ulnar abduction during pronation of forearm
Where is supinator, and what are its origin and attachment sites?
6, One head originates from lateral epicondyle of humerus and other head originates from ulna posterior surface
Attaches to posterior radial surface
What muscle makes up the floor of the cubital fossa?
Supinator
What is the action of supinator?
Forearm supination
Where is abductor pollicis longus, and what are the origin and attachment sites?
3, originates from interosseus membrane and posterior surfaces of radius and ulna, attaches to lateral side of 1st metacarpal base
Contributes to lateral border of anatomical snuffbox
What is the action of abductor pollicis longus?
Thumb abduction
Where is extensor pollicis brevis, and what are its origin and attachment sites?
4, originates from radial posterior surface and attaches to base of thumb proximal phalange
Immediately distal to abductor pollicis longus
Forms lateral border of anatomical snuffbox
What are the 2 actions of extensor pollicis brevis?
Extension of thumb metacarpophalangeal joint
Extension of thumb carpometacarpal joint
Where is extensor pollicis longus, and what are its origin and attachment sites?
originates from posterior ulnar surface and attaches to distal phalange of thumb
Forms medial border of anatomical snuffbox
What is the action of extensor pollicis longus?
Extends all joints of the thumb: carpometacarpal, metacarpophalangeal and interphalangeal
Where is extensor indicis proprius, and what are the origin and attachment sites?
12, originates from posterior ulnar surface and attaches to extensor hood of index finger
Immediately distal to extensor pollicis longus
What is the action of extensor indicis proprius?
Extension of index finger
Independent of other fingers during extension as this tendon only attaches to index finger
What structures make up the borders and floor of anatomical snuffbox/radial fossa?
Lateral border is extensor pollicis brevis, contribution from abductor pollicis longus
Medial border is extensor pollicis longus
Floor is trapezium and scaphoid bones
What are the superficial muscles of the posterior forearm?
Brachioradialis
Extensor digitorum communis
Extensor digitorum minimi
Extensor carpi ulnaris
Extensor carpi radialis brevis
Extensor carpi radialis longus
Anconeus
