E1E Flashcards

posterior compartment of the forearm

1
Q

extensor retinaculum

A
  1. thickening of deep fascia of forearm that stretches across back of wrist  holds long extensor tendons in position and prevents them from bowstringing as they cross wrist joint
  2. converts grooves on posterior aspects of distal ends of radius and ulna into 6 separate compartments (tunnels) for long extensor tendons (surrounded by synovial sheaths)
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2
Q

superficial muscle of the posterior compartment of the forearm

A
brachioradialis 
extensor carpi radialis longus
extensor carpi radialis brevis
extensor digitorum
extensor digiti minimi
extensor carpi ulnaris
anconeus
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3
Q

brachioradialis origin

A

upper part of lateral supracondylar ridge of humerus

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4
Q

brachioradialis insertion

A

lateral side of distal end of radius, just superior to styloid process

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5
Q

brachioradialis innervation

A

radial nerve

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6
Q

brachioradialis action

A

flexion of forearm at elbow joint and assists with supination of forearm

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7
Q

extensor carpi radialis longus origin

A

lower part of lateral supracondylar ridge of humerus

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8
Q

extensor carpi radialis longus insertion

A

tendon passes under extensor retinaculum and inserts into base of 2nd metacarpal

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9
Q

extensor carpi radialis longus innervation

A

radial nerve

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10
Q

extensor carpi radialis longus action

A

extension and abduction of hand at wrist joint

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11
Q

extensor carpi radialis brevis origin

A

ommon extensor tendon (attached to lateral epicondyle of humerus)

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12
Q

extensor carpi radialis brevis insertion

A

tendon passes under extensor retinaculum and inserts into base of 3rd metacarpal

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13
Q

extensor carpi radialis brevis innervation

A

deep branch of radial nerve

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14
Q

extensor carpi radialis brevis action

A

extension and abduction of hand at wrist joint

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15
Q

extensor digitorum origin

A

common extensor tendon (attached to lateral epicondyle of humerus)

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16
Q

extensor digitorum insertion

A
  1. muscle belly gives rise to 4 tendons (for medial 4 digits)
  2. tendons pass under extensor retinaculum and fan out over dorsum of hand, where adjacent tendons are interconnected
  3. near proximal interphalangeal joint, each tendon divides into 3 bands
  4. central band inserts into base of middle phalanx and 2 lateral bands converge to insert into base of distal phalanx
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17
Q

extensor digitorum innervation

A

deep branch of radial nerve

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18
Q

extensor digitorum action

A

extension of distal, middle and proximal phalanges of medial 4 digits
extension of hand at wrist joint

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19
Q
extensor expansion
(extensor hood, dorsal digital expansion)
A
  1. each tendon of extensor digitorum is held in a central position over dorsum of corresponding metacarpophalangeal (MCP) joint by a flat fibrous sheet called extensor expansion
  2. extensor expansion wraps around dorsum and sides of metacarpal head and proximal phalanx and forms movable hood that moves distally when MCP joint is flexed and proximally when MCP joint is extended
  3. tendons of interosseous and lumbrical muscles of hand insert into extensor expansions
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20
Q

extensor digiti minimi origin

A

common extensor tendon (attached to lateral epicondyle of humerus)

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21
Q

extensor digiti minimi insertion

A

tendon passes under extensor retinaculum and joins tendon of extensor digitorum for little finger

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22
Q

extensor digiti minimi innervation

A

deep branch of radial nerve

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23
Q

extensor digiti minimi action

A

extension of distal, middle and proximal phalanges of little finger and assists with extension of hand at wrist joint

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24
Q

extensor carpi ulnaris origin

A

humeral head: common extensor tendon (attached to lateral epicondyle of humerus)
ulnar head: posterior border of shaft of ulna

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25
Q

extensor carpi ulnaris insertion

A

tendon passes under extensor retinaculum and inserts into base of 5th metacarpal

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26
Q

extensor carpi ulnaris innervation

A

deep branch of radial nerve

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27
Q

extensor carpi ulnaris action

A

extension and adduction of hand at wrist joint

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28
Q

anconeus origin

A

lateral epicondyle of humerus

29
Q

anconeus insertion

A

lateral surface of olecranon and posterior surface of shaft of ulna

30
Q

anconeus innervation

A

radial nerve

31
Q

anconeus action

A

assists triceps brachii with extension of forearm at elbow joint and may abduct ulna during pronation of forearm

32
Q

deep muscles of the posterior compartment

A
supinator
abductor pollicis longus
extensor pollicis brevis
extensor pollicis longus
extensor indicis
33
Q

supinator origin

A

lateral epicondyle of humerus, radial collateral and annular ligaments of elbow joint, supinator crest and fossa of ulna

34
Q

supinator insertion

A

fibers wrap around radius  insert into anterior, lateral and posterior surfaces of upper ⅓ of radius (from radial tuberosity to insertion of pronator teres)

35
Q

supinator innervation

A

deep branch of radial nerve

36
Q

supinator action

A

supination of forearm

37
Q

abductor pollicis longus origin

A

posterior surfaces of shafts of ulna and radius and interosseous membrane

38
Q

abductor pollicis longus insertion

A

tendon passes under extensor retinaculum and inserts into base of 1st metacarpal

39
Q

abductor pollicis longus innervation

A

deep branch of radial nerve

40
Q

abductor pollicis longus action

A

abduction and extension of thumb at carpometacarpal joint and assists with abduction of hand at wrist joint

41
Q

extensor pollicis brevis origin

A

posterior surface of shaft of radius and interosseous membrane

42
Q

extensor pollicis brevis insertion

A

tendon passes under extensor retinaculum and inserts into base of proximal phalanx of thumb

43
Q

extensor pollicis brevis innervation

A

deep branch of radial nerve

44
Q

extensor pollicis brevis action

A

extension of proximal phalanx of thumb and 1st metacarpal

45
Q

extensor pollicis longus origin

A

posterior surface of shaft of ulna and interosseous membrane

46
Q

extensor pollicis longus insertion

A

tendon passes under extensor retinaculum (medial to dorsal tubercle of radius, which uses as a pulley) and inserts into base of distal phalanx of thumb

47
Q

extensor pollicis longus innervation

A

deep branch of radial nerve

48
Q

extensor pollicis longus action

A

extension of distal and proximal phalanges of thumb and 1st metacarpal

49
Q

extensor indicis origin

A

posterior surface of shaft of ulna and interosseous membrane

50
Q

extensor indicis insertion

A

tendon passes under extensor retinaculum and joins tendon of extensor digitorum for index finger

51
Q

extensor indicis innervation

A

deep branch of radial nerve

52
Q

extensor indicis action

A

extension of distal, middle and proximal phalanges of index finger and assists with extension of hand at wrist joint

53
Q

compartments under extensor retinaculum

A

1st - 6th, M-L
1st to 4th tunnels are related to distal end of radius, 5th tunnel is at the level of distal radioulnar joint and 6th tunnel is related to distal end of ulna

54
Q

1st compartment under extensor retinaculum

A

tendons of abductor pollicis longus and extensor pollicis brevis

55
Q

2nd compartment under extensor retinaculum

A

tendons of extensor carpi radialis longus and extensor carpi radialis brevis

56
Q

3rd compartment under extensor retinaculum

A

tendon of extensor pollicis longus

57
Q

4th compartment under extensor retinaculum

A

tendons of extensor digitorum and extensor indicis

58
Q

5th compartment under extensor retinaculum

A

tendon of extensor digiti minimi

59
Q

6th compartment under extensor retinaculum

A

tendon of extensor carpi ulnaris

60
Q

anatomical snuff box tendons

A

anterior: abductor pollicis longus and extensor pollicis brevis
posterior: extensor pollicis longus

61
Q

anatomical snuff box bones

A

styloid process of radius, scaphoid, trapezium and base of 1st metacarpal are found on its floor (from proximal to distal)

62
Q

anatomical snuff box vasculature

A

radial artery

origin of cephalic vein from dorsal venous arch of hand

63
Q

anatomical snuff box nerve

A

superficial radial nerve

64
Q

radial nerve

A

divides into superficial and deep terminal branches anterior to lateral epicondyle of humerus
before dividing into its terminal branches, radial nerve supplies three heads of triceps brachii, anconeus, brachioradialis and extensor carpi radialis longus and it also gives off cutaneous branches to arm and forearm

65
Q

superficial branch of radial nerve

A

descends in forearm deep to brachioradialis muscle and lateral to radial artery
in distal forearm, it separates from artery and passes posteriorly, under tendon of brachioradialis, to reach posterior surface of wrist
divides into branches that supply skin of lateral part of dorsum of hand and dorsal aspects of lateral 2½ (or 3½) digits (digital branches do not extend far beyond proximal phalanges)

66
Q

deep branch of radial nerve

A

pierces supinator and winds around lateral aspect of radius within supinator to reach posterior compartment of forearm
after it emerges from supinator, it is sometimes referred to as posterior interosseous nerve then descends between superficial and deep muscles of posterior compartment of forearm and terminates on posterior aspect of wrist
it also gives off articular branches to distal radioulnar and wrist joints

67
Q

blood supply of posterior compartment of arm

A

anterior and posterior interosseous arteries

68
Q

posterior interosseous artery

A

originates in anterior compartment of forearm from common interosseous artery
passes posteriorly, between ulna and radius, and above superior border of interosseous membrane, to reach posterior compartment
accompanies posterior interosseous nerve in posterior compartment
gives off interosseous recurrent artery and participates in arterial anastomosis around elbow joint

69
Q

anterior interosseous artery

A

pierces interosseous membrane and anastomoses with posterior interosseous artery