Muscles of the Posterior Forearm Flashcards
Muscles of the posterior forearm are considered the __________________ group.
Extensor-Supinator
What are the 2 layers of the muscles of the posterior forearm?
1) Superficial Layer
2) Deep Layer
A less clinically relevant structure that the extensor tendons at the wrist pass under.
Extensor Retinaculum
What are the 6 muscles in the superficial layer of the posterior forearm?
1) Brachioradialis
2) Extensor Carpi Radialis Longus (ECRL)
3) Extensor Carpi Radialis Brevis (ECRB)
4) Extensor Digitorum (ED)
5) Extensor Digiti Minimi
6) Extensor Carpi Ulnaris (ECU)
Proximal Attachment: lateral supracondylar ridge of humerus (proximal part)
Distal Attachment: lateral, distal radius
Brachioradialis
What is the action of brachioradialis?
Elbow Flexion
Brachioradialis is the strongest elbow flexor when the forearm is in a _______ position.
Neutral
Brachioradialis is part of the __________________ group because it is innervated by the ______ nerve, which is the same as the other muscles in that group.
Extensor-Supinator
Radial
Proximal Attachment: lateral supracondylar ridge of humerus (distal part)
Distal Attachment: base of 2nd MC
Extensor Carpi Radialis Longus (ECRL)
What are the 2 actions of extensor carpi radialis longus?
1) Wrist Extension
2) Radial Deviation (with FCR/ECRB)
A common proximal tendinous attachment that connects to the lateral epicondyle of the humerus.
Common Extensor Tendon (CET)
Associated with inflammation of the common extensor tendon and also referred to as lateral epicondylitis.
Tennis Elbow
Proximal Attachment: lateral epicondyle of humerus via CET
Distal Attachment: base of 3rd MC
Extensor Carpi Radialis Brevis (ECRB)
What are the 2 actions of extensor carpi radialis brevis?
1) Wrist Extension
2) Radial Deviation (with FCR/ECRL)
Which 3 muscles make up the WAD of 3?
1) Brachioradialis
2) Extensor Carpi Radialis Longus (ECRL)
3) Extensor Carpi Radialis Brevis (ECRB)
Proximal Attachment: lateral epicondyle of humerus via CET
Distal Attachment: distal phalanges of medial 4 digits
Extensor Digitorum (ED)
What are the 2 actions of extensor digitorum?
1) 2nd-5th Digit Extension (MCP & IP joints)
2) Wrist Extension
Proximal Attachment: lateral epicondyle of humerus via CET
Distal Attachment: extensor expansion of 5th digit MCP
Extensor Digiti Minimi
What is the action of extensor digiti minimi?
5th Digit Extension
Connective tissue that forms a hood at the 2nd-5th MCPs to support local structures.
Extensor Expansion
Proximal Attachment: lateral epicondyle of humerus via CET
Distal Attachment: base of 5th MC
Extensor Carpi Ulnaris (ECU)
What are the 2 actions of extensor carpi ulnaris?
1) Wrist Extension
2) Ulnar Deviation (with FCU)
What are the 5 muscles of the deep layer of the posterior forearm?
1) Supinator
2) Extensor Incidis
3) Abductor Pollicis Longus
4) Extensor Pollicis Brevis
5) Extensor Pollicis Longus
Proximal Attachment: lateral epicondyle of humerus, LCL and annular ligament (superficial layer) and supinator fossa/crest of ulna (deep layer)
Distal Attachment: anterior, lateral and posterior parts of proximal radius
Supinator
What is the action of supinator?
Forearm Supination
Proximal Attachment: posterior mid-distal ulnar surface and interosseous membrane
Distal Attachment: extensor expansion of 2nd digit at MCP
Extensor Incidis
What is the action of extensor incidis?
2nd Digit Extension
Proximal Attachment: posterior mid-distal surface of ulna, radius and interosseous membrane
Distal Attachment: base of 1st MC
Abductor Pollicis Longus
What is the action of abductor pollicis longus?
1st Digit Abduction (CMC joint)
Proximal Attachment: posterior mid-distal radial surface and interosseous membrane
Distal Attachment: base of proximal phalanx of thumb
Extensor Pollicis Brevis
What is the action of extensor pollicis brevis?
1st Digit Extension (CMC & MCP joints)
Proximal Attachment: posterior mid-distal ulnar surface and interosseous membrane (superior to extensor incidis)
Distal Attachment: base of distal phalanx of thumb
Extensor Pollicis Longus
What is the action of extensor pollicis longus?
1st Digit Extension (MCP & IP joints)
Extensor pollicis longus uses ________ tubercle as a pulley.
Lister’s
A hollow on the posterior lateral aspect of the hand at the base of the thumb. The radial artery passes through this area.
Anatomical Snuffbox
What is the anterior border of the anatomical snuffbox?
Abductor Pollicis Longus
Extensor Pollicis Brevis
What is the posterior border of the anatomical snuffbox?
Extensor Pollicis Longus
What carpal bone makes up the floor of the anatomical snuffbox?
Scaphoid
