Lecture 4 - Muscles Of The Forearm Flashcards

1
Q

How many muscles are there in the forearm?

A
  • 18 total muscles
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2
Q

What do the muscles in the forearm do?

A
  • they cross the wrist, allowing all the fine motor skills that we perform with our hand
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3
Q

What type of muscles are in the anterior compartment of the forearm?

A
  • flexors
  • Pronators
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4
Q

What type of muscles are in the posterior compartment of the forearm?

A
  • extensors
  • supinator
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5
Q

How many layers are in the anterior compartment of the forearm muscles? And how many muscles in each ?

A
  • made up of 4 layers:
  • first (superficial) layer - 4 muscles
  • second layer - 1 muscle
  • third layer - 2 muscles
  • very deep layer - 1 muscle
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6
Q

What 4 muscles are in the anterior compartment of the first (superficial) layer of the forearm?

A
  • Pronator teres
  • flexor carpi radialis
  • palmaris longus
  • flexor carpi ulnaris
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7
Q

What is the origin/insertion/Innervation/main action of the Pronator teres?

A
  • O: Medial epicondyle of the humerus
  • I: Mid-shaft of lateral radius
  • Inn: Median nerve
  • MA: Radioulnar (forearm) pronation
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8
Q

What is the origin/insertion/Innervation/main action of the flexor carpi radialis ?

A
  • O: Medial epicondyle of humerus
  • I: Base of metacarpals 2 & 3
  • Inn: Median nerve
  • MA: Wrist flexion & abduction
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9
Q

What is the origin/insertion/Innervation/main action of the palmaris longus?

A
  • 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
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10
Q

What is the origin/insertion/Innervation/main action of the flexor carpi ulnaris?

A
  • O: Medial epicondyle of humerus
  • I: Base of 5th metacarpal via pisiform
  • Inn: Ulnar nerve
  • MA: Wrist flexion & adduction
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11
Q

What muscle is in the second layer of the anterior compartment of the forearm?

A
  • flexor digitorum superficialis
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12
Q

What is the origin of the flexor digitorum superficialis?

A
  • medial epicondyle of the humerus to the mid-shaft of the radius
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13
Q

what is the insertion/Innervation of the flexor digitorum superficialis?

A
  • I: Palmar surfaces of middle phalanx on digits 2-5
  • Inn: Median nerve
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14
Q

What is the main action of the flexor digitorum superficialis ?

A
  • Flexion at proximal interphalangeal & metacarpophalangeal joints
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15
Q

What 2 muscles are in the third layer of the anterior compartment of the forearm?

A
  • flexor digitorum profundus
  • flexor pollicis longus
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16
Q

What is the origin of the flexor digitorum profundus?

A
  • O: Anterior ulna & medial half of interosseous membrane
17
Q

What is the insertion/Innervation of the flexor digitorum profundus?

A
  • I: Bases of the distal phalanges
  • Inn: Lateral half median nerve & Medial half ulnar nerve
18
Q

What is the main action of the flexor digitorum profundus?

A
  • Flexion of distal & proximal interphalangeal joints & metacarpophalangeal joints
19
Q

What is the origin/insertion/Innervation/main action of the flexor pollicis longus?

A
  • 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)
20
Q

Which muscle is in the very deep layer of the anterior compartment of the forearm?

A
  • Pronator quadratus
21
Q

What is the origin/insertion/Innervation/main action of the Pronator quadratus?

A
  • O: Lower/distal 1/4 anterior ulna
  • I: Lower/distal 1/4 anterior radius
  • Inn: Median nerve
  • MA: Radio-ulnar (forearm) pronation
22
Q

How many layers are in the posterior compartment of the forearm? How many muscles in each?

A
  • made up of 2 layers:
  • superficial layer - 5 muscles
  • deep layer - 5 muscles
23
Q

What 5 muscles are in the superficial layer of posterior compartment of the forearm?

A
  • extensor carpi radialis longus
  • extensor carpi radialis brevis
  • extensor digitorum
  • extensor digiti minimi
  • extensor carpi ulnaris
24
Q

What is the origin/insertion/Innervation/main action of the extensor carpi radialis longus?

A
  • O: Lateral epicondyle & lateral supracondylar ridge of the humerus
  • I: Dorsal surface of base of metacarpal 2
  • Inn: Radial nerve
  • MA: Wrist extension & abduction
25
Q

What is the origin/insertion/Innervation/main action of the extensor carpi radialis brevis?

A
  • O: Lateral epicondyle of humerus
  • I: Dorsal surface of base of metacarpal 2 & 3
  • Inn: Radial nerve
  • MA: Wrist extension & abduction
26
Q

What is the origin/insertion/Innervation/main action of the extensor digitorum?

A
  • O: Lateral epicondyle of humerus
  • I: Dorsal aspect of base of distal phalanges of digits 2-5; Via the extensor hoods
  • Inn: Radial nerve
  • MA: Extension of the distal and proximal IP joint & the MCP joint & Wrist extension
27
Q

What is the origin/insertion/Innervation/main action of the extensor digiti minimi?

A
  • O: Lateral epicondyle of humerus
  • I: Extensor hood of digit 5
  • Inn: radial nerve
  • MA: Extension of digit 5
28
Q

What is the origin/insertion/Innervation/main action of the extensor carpi ulnaris?

A
  • O: Lateral epicondyle of humerus & posterior border of ulna
  • I: Medial side of base of 5th metacarpal
  • Inn: radial nerve
  • MA: Wrist extension & adduction
29
Q

What 5 muscles are in the deep layer of posterior compartment of the forearm?

A
  • supinator
  • extensor indices
  • abductor pollicis longus
  • extensor pollicis longus
  • extensor pollicis brevis
30
Q

What is the origin/insertion/Innervation/main action of the supinator?

A
  • O: Lateral epicondyle of the humerus & the proximal end of the ulna
  • I: Posterior proximal radius
  • Inn: radial nerve
  • MA: Radio-ulnar (forearm) supination
31
Q

What is the origin/insertion/Innervation/main action of the extensor indices?

A
  • O: Posterior surface of ulna (distal to extensor pollicis longus) & adjacent interosseous membrane
  • I: Extensor hood of digit 2
  • Inn: radial nerve
  • MA: Extension of digit 2
32
Q

What is the origin/insertion/Innervation/main action of the abductor pollicis longus?

A
  • O: Posterior surfaces of ulna & radius & intervening interosseous membrane
  • I: Lateral side of base of 1st metacarpal
  • Inn: radial nerve
  • MA: Thumb abduction at CMC joint
33
Q

What is the origin/insertion/Innervation/main action of the extensor pollicis brevis?

A
  • O: Posterior surface of radius & adjacent interosseous membrane
  • I: Dorsal surface of base of the proximal phalanx of the thumb
  • Inn: radial nerve
  • MA: Thumb extension CMC & MCP joints
34
Q

What is the origin/insertion/Innervation/main action of the brachioradialis ?

A
  • O: Lateral supracondylar ridge of the humerus
  • I: Styloid process of the radius
  • Inn: Radial nerve
  • MA: Elbow flexion in semi-pronation
35
Q

What tendons make up the anatomical snuff box?

A
  • extensor pollicis longus
  • extensor pollicis brevis
  • abductor pollicis longus
36
Q

What are superficial landmarks of the thumb, index, middle, & ring fingers?

A
  • Thumb = Pronator teres
  • Index = flexor carpi radialis
  • Middle = palmaris longus
  • Ring = flexor carpi ulnaris