KIN 100 - Muscles of the Posterior Arm (lecture 12) Flashcards
What are the muscles of the superficial layer of the posterior forearm (6)
- Brachioradialis
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris
What are the muscles of the deep layer of the posterior forearm (2)
- Supinator
- Extensor Indicis
What are the muscle of the Outcropping muscles of the posterior forearm (3)
- Abductor pollicis longus
- Extensor pollicis longus
- Extensor pollicis brevis
What is the common extensor origin
later epicondyle of the humerus
Brachioradialis
proximal attachment: Later supraepicondylar ridge of humerus
Distal attachment: Distal radius (does not cross wrist)
Innervation: Radial nerve
Actions: elbow flexion in a semi-prone position
Extensor carpi radialis longus
Proximal attachment: lateral supraepicondylar ridge of humerus
Distal attachment: Base of 2nd metacarpal
Innervation: Radial nerve
Actions: wrist extension, wrist abduction (radial deviation)
Extensor carpi radialis brevis
Proximal attachment: common extensor origin
Distal attachment: Base of 3rd metacarpal
Innervation: deep branch of radial nerve
Action: wrist extension and wrist abduction (radial deviation)
Extensor digitorum
Proximal attachment: Common extensor origin
Distal attachment: Distal phalanges of digit II, III, IV, and V via extensor expansions
Innervation: deep branch of radial nerve
Actions: wrist extension and extension of all joints of digits II to V
How are Extensor Expansions formed, what digits does it affect
flatten out to form extensor expansions on the dorsal aspect of the metacarpals and phalanges of digits II - V
- divided into a median bad and two lateral bands
What can extensor expansions also be referred to as
dorsal expansion or “hood”
Where does the median band of the extensor expansion inster onto
the middle phalanx
Where does the lateral bands of the extensor expansion interts onto
the distal phalanx
Extensor digiti minimi
Proximal attachment: Common extensor origin
Distal attachment: Distal phalanx of digit V via extensor expansion
Innervation: Deep branch of radial nerve
Actions: WRIST EXTENSION and extension of all joints for digit V
Extensor Carpi ulnaris
Proximal attachment: Common extensor origin
Distal attachment: Base of 5th metacarpal
Innervation: Deep branch of radial nerve
Actions: Wrist extension and wrist adduction (ulnar deviation)
Supinator
Proximal attachment: Common extensor origin and SUPINATOR CREST OF ULNA
Distal attachment: Proximal third of radius
Innervation: Deep branch of radial nerve
Action: Forearm supination
