Lecture 4 - Muscles Of The Forearm Flashcards
(36 cards)
How many muscles are there in the forearm?
- 18 total muscles
What do the muscles in the forearm do?
- they cross the wrist, allowing all the fine motor skills that we perform with our hand
What type of muscles are in the anterior compartment of the forearm?
- flexors
- Pronators
What type of muscles are in the posterior compartment of the forearm?
- extensors
- supinator
How many layers are in the anterior compartment of the forearm muscles? And how many muscles in each ?
- made up of 4 layers:
- first (superficial) layer - 4 muscles
- second layer - 1 muscle
- third layer - 2 muscles
- very deep layer - 1 muscle
What 4 muscles are in the anterior compartment of the first (superficial) layer of the forearm?
- Pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
What is the origin/insertion/Innervation/main action of the Pronator teres?
- O: Medial epicondyle of the humerus
- I: Mid-shaft of lateral radius
- Inn: Median nerve
- MA: Radioulnar (forearm) pronation
What is the origin/insertion/Innervation/main action of the flexor carpi radialis ?
- O: Medial epicondyle of humerus
- I: Base of metacarpals 2 & 3
- Inn: Median nerve
- MA: Wrist flexion & abduction
What is the origin/insertion/Innervation/main action of the palmaris longus?
- O: Medial epicondyle of humerus
- I: Palmar aponeurosis of hand; Connects skin to the underlying structures of the hand
- Inn: Median nerve
- MA: Wrist flexion
What is the origin/insertion/Innervation/main action of the flexor carpi ulnaris?
- O: Medial epicondyle of humerus
- I: Base of 5th metacarpal via pisiform
- Inn: Ulnar nerve
- MA: Wrist flexion & adduction
What muscle is in the second layer of the anterior compartment of the forearm?
- flexor digitorum superficialis
What is the origin of the flexor digitorum superficialis?
- medial epicondyle of the humerus to the mid-shaft of the radius
what is the insertion/Innervation of the flexor digitorum superficialis?
- I: Palmar surfaces of middle phalanx on digits 2-5
- Inn: Median nerve
What is the main action of the flexor digitorum superficialis ?
- Flexion at proximal interphalangeal & metacarpophalangeal joints
What 2 muscles are in the third layer of the anterior compartment of the forearm?
- flexor digitorum profundus
- flexor pollicis longus
What is the origin of the flexor digitorum profundus?
- O: Anterior ulna & medial half of interosseous membrane
What is the insertion/Innervation of the flexor digitorum profundus?
- I: Bases of the distal phalanges
- Inn: Lateral half median nerve & Medial half ulnar nerve
What is the main action of the flexor digitorum profundus?
- Flexion of distal & proximal interphalangeal joints & metacarpophalangeal joints
What is the origin/insertion/Innervation/main action of the flexor pollicis longus?
- O: Anterior radius & lateral half of the interosseous membrane
- I: Palmar surface of distal phalanx of the thumb
- Inn: Median nerve
- MA: Thumb flexion (at the interphalangeal joint as well as the metacarpophalangeal joint)
Which muscle is in the very deep layer of the anterior compartment of the forearm?
- Pronator quadratus
What is the origin/insertion/Innervation/main action of the Pronator quadratus?
- O: Lower/distal 1/4 anterior ulna
- I: Lower/distal 1/4 anterior radius
- Inn: Median nerve
- MA: Radio-ulnar (forearm) pronation
How many layers are in the posterior compartment of the forearm? How many muscles in each?
- made up of 2 layers:
- superficial layer - 5 muscles
- deep layer - 5 muscles
What 5 muscles are in the superficial layer of posterior compartment of the forearm?
- extensor carpi radialis longus
- extensor carpi radialis brevis
- extensor digitorum
- extensor digiti minimi
- extensor carpi ulnaris
What is the origin/insertion/Innervation/main action of the extensor carpi radialis longus?
- O: Lateral epicondyle & lateral supracondylar ridge of the humerus
- I: Dorsal surface of base of metacarpal 2
- Inn: Radial nerve
- MA: Wrist extension & abduction
