Muscles of the Plantar Foot Flashcards Preview

Lower Limb > Muscles of the Plantar Foot > Flashcards

Flashcards in Muscles of the Plantar Foot Deck (68):
1

Layer 1 (3)

- Abductor hallucis
- Abductor digiti minimi
- Flexor digitorum brevis

"ABs Flex"

2

Layer 2 (4)

- Flexor digitorum longus
- Flexor hallucis longus
- Quadratus plantae
- Lumbricals

"Flex Flex QP L"
Remember that it is longus and not brevis because the lumbricals are found in the longus tendons

3

Layer 3 (3)

- Adductor hallucis
- Flexor digiti minimi brevis
- Flexor hallucis brevis

"AD Flexes"

4

Layer 4 (2)

- Dorsal interosseous
- Plantar interosseous

5

Abductor hallucis

1st layer
- Large muscle which has an expanded portion wich forms a HOOD over the porta pedis (tom, dick, very nervous harry)
- This makes sense because the flexor retinacula creates the porta pedis on the medial side of the foot where the abductor hallucis would run to go to the hallux

6

Origin of abductor hallucis

- Medial process of calcaneal tuberosity (FFA)
- Flexor retinaculum
- Plantar aponeurosis
- Intermuscular septum between itself and flexor digitorum brevis (1st layer)

7

Insertion of abductor hallucis

- Medial side, plantar surface of the base of the proximal phalanx
- Medial sesamoid of the 1st MPJ (possibly)

8

Innervation of abductor hallucis

- Medial plantar nerve

9

Action of abductor hallucis

- Abducts the first digit

10

Flexor digitorum brevis

1st layer
o Lies deep to central part of plantar aponeurosis
o Lateral plantar nerves and vessels are found deep to it

11

Origin of flexor digitorum brevis

o Plantar aponeurosis
o Medial and lateral intermuscular septa
o Medial process of calcaneal tuberosity (FFA)

12

Insertion of flexor digitorum brevis

One tendon attaches to each of the 4 lateral digits:
- Each runs in the tendon sheath of flexor digitorum longus until it reaches the base of the proximal phalanx
- At this point, it divides into two slips
- Slips diverge from each other to surround the tendon of the flexor digitorum longus
- Reunite to lie deep to flexor digitorum longus
- Slips divide again to insert into the middle phalanges of the lateral 4 digits

13

Innervation of flexor digitorum brevis

Medial plantar nerve

14

Function of flexor digitorum brevis

o Flex the proximal interphalangeal joints of lateral 4 digits
o Flex the metatarsophalangeal joints

15

Variation of flexor digitorum brevis

o The tendon to the 5th digit may be absent

16

Abductor digiti minimi

1st layer
o Lies superficial along the lateral margin of the foot

17

Origin of abductor digiti minimi

o Lateral processes of calcanea tuberosity
o Medial processes of calcanea tuberosity
o Depression between these two processes
o Note: this is the A in MLAP, LLAP and LA

18

Insertion of abductor digiti minimi

o Runs through a groove on plantar surface of the 5th met
o Inserts into lateral side of the plantar surface of the
base of the proximal phalanx of the 5th digit (same as flexor digiti minimi brevis)

19

Function of abductor digiti minimi

- Abduct 5th digit
- Flex 5th digit

20

Variation in abductor digiti minimi

- May be an accessory insertion into base of 5th metatarsal
- If present, forms a separate muscle: abductor os metatarsal digiti minimi

21

Second layer

NOTE
- The lateral plantar aponeurosis lies between the 1st and 2nd layers of muscle

Muscles of the 2nd layer
- Flexor digitorum longus
- Flexor hallucis longus
- Quadratus plantae
- Lumbricals

22

Quadratus plantae

2nd layer
- AKA flexor accessorius
- Two heads of origin, which are separated by the long plantar ligament
- Medial head is larger

23

Origin of quadratus plantae

- Medial head: medial process of calcaneal tuberosity
- Lateral head: lateral process of calcaneal tuberosity

24

Insertion of quadratus plantae

- Tendon of flexor digitorum longus
- Note that fivers from both heads unite together to insert

25

Innervation of quadratus plantae

Trunk of lateral plantar nerve

26

Function of quadratus plantae

- Accesory flexor of lateral 4 digits
- Helps flexor digitorum longus by putting tension on its tendon and straightening the line of pull of the long flexor

27

Variation of quadratus plantae

- The entire muscle, or just the lateral head may be absent

28

Lumbricals

2nd layer
- 4 lumbricals, numbered medial to lateral

29

Origin of lumbricals

- Flexor digitorum longus tendon
- 1st lumbrical originates from the medial side of the most medial tendon only
- 2nd-4th lumbricals originate from the adjacent sides of flexor tendons

30

Course of lumbricals

- Al lumbricals continue distally with the flexor tendons
- This forms their lateral origin
- Lumbricals and flexor tendons cross the medial side of the metatarsophalangeal joint
- After crossing the joint, they continue along the medial side of digits 2-5
- They all course superficial to the deep transverse metatarsal ligament

31

insertion of lumbricals

Medial surface of extensor expansion (a little dorsal to the horizontal plane)
- 1st lumbrical inserts on extensor expansion of the 2nd digit
- 2nd lumbrical inserts on extensor expansion of the 3rd digit
- 3rd lumbrical inserts on extensor expansion of the 4th digit
- 4th lumbrical inserts on extensor expansion of the 5th digit

NOTE: the lumbrical tendons form part of teh WING of the extensor hood

32

Innervation of lumbricals

1st lumbrical
- Medial plantar nerve

2nd-4th lumbricals
- Deep branch of lateral plantar nerve

33

Function of lumbricals

- Flex the metatarsophalangeal joints
- Extend the interphalangeal joints

34

Variation in lumbricals

- One or more of the lumbricals may be absent
- 3rd or 4th lumbrical may be doubled
- Lumbricals may insert directly on the bone of the proximal phalanx instead of the extensor expansion

35

Two tendons of 2nd layer

- Flexor digitorum longus tendon
- Flexor hallucis longus tendon

36

Third layer

- Flexor hallucis brevis
- Adductor hallucis
- Flexor digiti minimi brevis

37

Flexor hallucis brevis

3rd layer
- Two heads of origin

38

Origin of flexor hallucis brevis

Lateral head
- Cuboid (near peroneal groove)
- Lateral cuneiform (area adjacent to cuboid)
- Long and short plantar ligaments (occasionally)

Medial head
- Deep fibers insert onto tibialis posterior tendon
- Superficial fibers insert onto intermuscular septum between the medial and central compartments

39

Course of flexor hallucis brevis

o As the muscle courses toward the 1st digit, fibers from the medial and lateral head fuse briefly before diving into two bellies

40

Insertion of flexor hallucis brevis

Lateral head
- Lateral side of plantar surface of base of proximal 1st phalanx
- Lateral sesamoid bone
- Plantar pad of hallux (same as AD-ductor hallucis)

Medial head
- Medial side of planar surface of base of proximal 1st phalanx
- Medial sesamoid bone
- Plantar pad of hallux (same as AB-ductor hallucis)

41

Innervation of flexor hallucis brevis

Medial plantar nerve

42

Function of flexor hallucis brevis

Flexes 1st MPJ

43

Variation in flexor hallucis brevis

o Attachment to cuboid may be absent
o Additional insertion into proximal phalanx of 2nd digit

44

Adductor hallucis

3rd layer
o Has two heads of origin (similar to flexor hallucis brevis)

45

Origin of adductor hallucis

Oblique head
- Plantar surface of the bases of 2nd, 3rd and 4th metatarsals
- Peroneus longus tendon (same as flexor digiti minimi brevis)

Transverse head
- Plantar plates
- Plantar metatarsophalangeal ligaments
- Deep transverse metatarsal ligament

NOTE: the origin of BOTH heads is HIGHLY variable

46

Insertion of adductor hallucis

o ALL are same as the insertion of lateral head of flexor hallucis brevis
o Lateral side of plantar surface of base of proximal 1st phalanx
o Lateral sesamoid bone
o Plantar pad of hallux (same as AD-ductor hallucis)

47

Innervation of adductor hallucis

o Deep branch of lateral plantar nerve

48

Function of adductor hallucis

o AD-ducts 1st toe at first metatarsophalangeal joint (MPJ)

49

Variation of adductor hallucis

Portion may insert into 1st metatarsal forming an opponens hallucis muscle

50

Flexor digiti minimi brevis

3rd layer
- This is the 3rd muscle of the 3rd layer

51

Origin of flexor digiti minimi brevis

o Plantar surface of base of 5th metatarsal
o Peroneus longus tendon
o Plantar aponeurosis

52

Insertion of flexor digiti minimi brevis

Plantar surface of proximal phalanx of 5th digit (same as abductor digiti minimi of 1st layer)

53

Innervation of flexor digiti minimi brevis

o Superficial branch of lateral plantar nerve (motor)

54

Function of flexor digiti minimi brevis

o Flex 5th digit
o AB-duct 5th digit

55

Variation in flexor digiti minimi brevis

o Deeper fibers may form part of a separate muscle, opponens digiti minimi

56

4th layer

- Plantar interossei
- Dorsal interossei

57

Plantar interossei origin

o Bases and medial sides of shafts of 3rd, 4th and 5th mets

PAd 'eM
P = plantar
Ad = adductors
M = medial aspect insertion

58

Plantar interossei insertion

Each attaches to only one bone – all insert on…
- Medial sides of bases of proximal phalanges
- Capsules of MPJ
- Extensor expansions

59

Innervation of plantar interossei

Lateral plantar nerve
- Deep branch = 1st and 2nd plantar interossei
- Superficial branch = 3rd plantar interossei

60

Function of plantar interossei

AD-ducts 3rd, 4th and 5th digits

61

Dorsal interossei origin

Adjacent sides of metatarsal bones
- 1st dorsal interossei – from 1st and 2nd metatarsals
- 2nd dorsal interossei – from 2nd and 3rd metatarsals
- 3rd dorsal interossei – from 3rd and 4th metatarsals
- 4th dorsal interossei – from 4th and 5th metatarsals

NOTE: the bones that make up the web spaces they are in

DAb L
D = dorsal interossei
Ab = abducts
L = lateral insertion

62

Dorsal interossei insertion

Base of proximal phalanx and extensor expansions:
- 1st dorsal interossei – medial side 2nd digit
- 2nd dorsal interossei – lateral side 2nd digit
- 3rd dorsal interossei – lateral side 3rd digit
- 4th dorsal interossei – lateral side 4th digit

63

Innervation of dorsal interossei

o Deep branch of lateral plantar nerve (1-3 dorsal interossei)
o Superficial branch of lateral plantar nerve (4th dorsal interossei only)

64

Function of dorsal interossei

AB-ducts the digits

65

Accessory muscles of the plantar foot

- Abductor os matatarsal digiti minimi
- Oppoens hallucis muscle
- Opponens digiti minimi

66

Abductor os metatarsal digiti minimi

- Accessory muscle from abductor digiti minimi
- Forms when part of muscle inserts on base of 5th metatarsal before continuing on to the proximal phalanx

67

Opponens hallucis muscle

- Accessory muscle from adductor hallucis
- Forms when part of the muscle inserts on base of 1st metatarsal before continuing on to the proximal phalanx

68

Opponens digiti minimi

- Accessory muscle from flexor digiti minimi brevis
- Forms when deep fibers of the muscle form a separate belly