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skeleton of the hand

carpals in the wrist, metacarpals in the hand proper, phalanges in the fingers

1

numbering of metacarpals and phalanges

1 to 5, beginning with the thumb and ending with little finger

2

palmar aspect of hand features central concavity that separates two eminences

lateral, more prominent thenar eminence at the base of the thumb
medial, smaller, hypothenar eminence proximal to the base of the 5th finger

3

fascia of palm

continuous with antebrachial fascia and fascia of dorsum of hand
thin over thenar and hypothenar eminences, but thivk centrally where it forms fibrous palmar aponeurosis and in the fingers where it forms the digital sheaths

4

palmar aponeurosis

strong, well defined part of deep fascia of palm
covers soft tissues and overlies long flexor tendons
poximal end or apex: continuous with the flexor retinaculum and the palmaris longus tendon
distal to apex: forms four longitudinal digital bands that radiate from the apex and attach distally to the bases of the proximal phalanges, where they become continuous with the fibrous digital sheaths

5

fibrous digital sheaths

ligamentous tubes that enclose flexor tendons and synovial sheaths that surround them as they pass along the palmar aspect of their respective digit

6

medial fibrous septum

extends deeply from medial border of palmar aponeurosis to the 5th metacarpal

7

hypothenar compartment

medial to septum
contains hypothenar muscles

8

lateral fibrous septum

extends deeply from the lateral border of the palmar aponeurosis to the 3rd metacarpal

9

thenar compartment

lateral to lateral fibrous septum
contains thenar muscles

10

central compartment

between hypothenar and thenar compartments
contains flexor tendons and their sheaths, lumbrical muscles, superficial arterial arch and digital vessels and nerves

11

adductor compartment

deepest muscular plane of the palm
contains adductor pollicis

12

two potential spaces

between flexor tends and fascia covering deep palmar muscles
thenar space and midpalmar space
bounded by fibrous septa passing from edges of palmar aponeurosis to metacarpals
between two spaces is lateral fibrous septum, attached to 3rd metacarpal
midpalmar space continuous with anterior compartment of forearm via carpal tunnel

13

five compartments of intrinsic muscles of hand

thenar compartment
hypothenar compartment
adductor compartment
central compartment
interosseous compartments

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muscles in thenar compartment

thenar muscles
abductor pollicis brevis, flexor pollicis brevis, opponens pollicis

15

muscles in hypothenar compartment

hypothenar muscles
abductor digiti minimi
flexor digiti minimi brevis
opponens digiti minimi

16

muscle in adductor compartment

adductor pollicis

17

central compartment contents

lumbricals: short muscles of hand
with long flexor tendons

18

interosseous compartments

contain interossei in separate ones between the metacarpals

19

thenar muscles chiefly responsible for

opposition of thumb

20

freedom of movement of thumb results from

1st metacarpal being independent

21

abduction of thumb

APL and abductor pollicis brevis

22

adduction of thumb

adductor pollicis and 1st dorsal interosseous

23

extension of thumb

EPL, EPB and APL

24

flexion of thumb

FPL and flexor pollicis brevis

25

opposition of thumb

opponens pollicis

26

opposition occurs at

carpometacarpal joint of thumb
begins with thumb in extended position and initially involves abduction and medial rotation of1st metacarpal: opponens pollicis and then flexion at metacarpophalangeal joint
reinforcing action of AD and FPL increases pressure

27

palmarisbrevis in hypothenar einence

small muscle in subcutaneous issue
wrinkles the skin, deepeing the hollow of the palm, thereby aiding the palmar grip
covers and protects the ulnar nerve and artery
attached proximally to the medial border of the palmar aponeurosis and to the skin on the medial border of the hand

28

short muscles of hand

four slender lubrical muscles
four dorsal interosseous: DAB
three palmar interosseous: on palmar surfaces of 2nd 4th and 5th metacarpals: PAD

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opponens policis origin

flexor retinaculum and tubercles of scaphoid and trapezium

30

opponens pollicis insertion

lateral side of 1st metacarpal

31

opponnens pollicis innervation

recurrent branch of median nerve
C8, T1

32

opponens pollicis action

to oppose thumb, it draws 1st metacarpal medially to center of palm and rotates it medially

33

abductor pollicis brevis origin

flexor retinaculum and tubercles of scaphoid and trapezium

34

abductor pollicis brevis insertion

lateral side of base of proximal phalanx of thumb

35

abductor pollicis brevis innervation

recurrent branch of media nerve
C8, T1

36

abductor pollicis brevis action

abducts thumb, helps oppose it

37

flexor pollicis brevis origin

flexor retinaculum and tubercles of scaphoid and trapezium

38

flexor policis brevis insertion

lateral side of base of proximal phalanx of thumb

39

flexor pollicis brevis innervation

superficial head: recurrent branch of median nerve
C8, T1
deep head: deep branch of ulnar nerve
C8, T1

40

flexor pollicis brevis action

flexes thumb

41

adductor policis origin

oblique head: bases of 2nd and 3rd metacarpals, capitate, adjacent carpals
transverse head: anterior surface of shaft of 3rd metacarpal

42

adductor pollicis insertion

medial side of base of proximal phalanx of thumb

43

adductor pollicis innervation

deep branch of ulnar nerve
C8, T1

44

adductor pollicis action

adducts thumb toward lateral border of palm

45

abductor digiti minimi origin

pisiform

46

abductor digiti minim insertion

medial side of base of proximal phalanx of 5th finger

47

abductor digiti minimi innervation

deep branch of ulnar nerve c8, T1

48

abductor digiti minimi action

abducts 5th finger, assists in flexion of its proximal phalanx

49

flexor digiti minimi brevis origin

hook of hamate and flexor retinaculum

50

flexor digiti minimi brevis insertion

medial side of base of proximal phalanx of 5th finger

51

flexor digiti minimi brevis innervation

deep branch of ulnar nerve
C8, T1

52

flexor digiti minimi brevis action

flexes proximal phalanx of 5th finger

53

opponens digiti minimi origin

hook of hamate and flexor retinaculum

54

opponens digiti minimi insertion

medial border of 5th metacarpal

55

opponens digiti minimi innervation

deep branch of ulnar nerve
C8, T1

56

opponens digiti minimi action

draws 5th metacarpal anterior and rotates it, bringing 5th finger into opposition with thumb

57

lumbricals origin

1 and 2: lateral two tendons of flexor digitorum profundus (as unipennate muscles)
3 and 4: medial three tendons of flexor digitorum profundus (as bipennate muscles)

58

lumbricals insertion

lateral sides of extensor expansions of 2nd-5th fingers

59

lumbricals innervation

1 and 2: median nerve (C8, T1)
3 and 4: deep branch of ulnar nerve (C8, T1)

60

lumbricals action

flex metacarpophalangeal joints
extend interphalangeal joints of 2nd to 5th fingers

61

dorsal interossei 1-4 origin

adjacent sides of two metacarpals (as bipennate muscles)

62

dorsal interossei insertion

bases of proximal phalanges
extensor expansions of 2nd to 4th fingers

63

dorsal interossei innervation

deep branch of ulnar nerve: C8, T1

64

dorsal interossei action

abduct 2nd to 4th fingers from axial line
act with lumbricals in flexing metacarpophalangeal joints and etending interphalangeal joints

65

palmar interossei 1-3 origin

palmar surfaces of 2nd, 4th and 5th metacarpals (as unipennate muscles)

66

palmar interossei insertion

bases of proximal phalanges; extensor expansions of 2nd, 4th and 5th fingers

67

palmar interossei innervation

deep branch of ulnar nerve C8, T1

68

palmar interossei action

adduct 2nd, 4th and 5th fingers toward axial line
assist lumbricals in flexing metacarpophalangeal joints and extending interphalangeal joints