Muscles of the Plantar Foot Flashcards

1
Q

Layer 1 (3)

A
  • Abductor hallucis
  • Abductor digiti minimi
  • Flexor digitorum brevis

“ABs Flex”

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2
Q

Layer 2 (4)

A
  • 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

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3
Q

Layer 3 (3)

A
  • Adductor hallucis
  • Flexor digiti minimi brevis
  • Flexor hallucis brevis

“AD Flexes”

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4
Q

Layer 4 (2)

A
  • Dorsal interosseous

- Plantar interosseous

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5
Q

Abductor hallucis

A

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
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6
Q

Origin of abductor hallucis

A
  • Medial process of calcaneal tuberosity (FFA)
  • Flexor retinaculum
  • Plantar aponeurosis
  • Intermuscular septum between itself and flexor digitorum brevis (1st layer)
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7
Q

Insertion of abductor hallucis

A
  • Medial side, plantar surface of the base of the proximal phalanx
  • Medial sesamoid of the 1st MPJ (possibly)
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8
Q

Innervation of abductor hallucis

A
  • Medial plantar nerve
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9
Q

Action of abductor hallucis

A
  • Abducts the first digit
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10
Q

Flexor digitorum brevis

A

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

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11
Q

Origin of flexor digitorum brevis

A

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

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12
Q

Insertion of flexor digitorum brevis

A

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
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13
Q

Innervation of flexor digitorum brevis

A

Medial plantar nerve

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14
Q

Function of flexor digitorum brevis

A

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

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15
Q

Variation of flexor digitorum brevis

A

o The tendon to the 5th digit may be absent

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16
Q

Abductor digiti minimi

A

1st layer

o Lies superficial along the lateral margin of the foot

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17
Q

Origin of abductor digiti minimi

A

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

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18
Q

Insertion of abductor digiti minimi

A

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)

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19
Q

Function of abductor digiti minimi

A
  • Abduct 5th digit

- Flex 5th digit

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20
Q

Variation in abductor digiti minimi

A
  • May be an accessory insertion into base of 5th metatarsal

- If present, forms a separate muscle: abductor os metatarsal digiti minimi

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21
Q

Second layer

A

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
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22
Q

Quadratus plantae

A

2nd layer

  • AKA flexor accessorius
  • Two heads of origin, which are separated by the long plantar ligament
  • Medial head is larger
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23
Q

Origin of quadratus plantae

A
  • Medial head: medial process of calcaneal tuberosity

- Lateral head: lateral process of calcaneal tuberosity

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24
Q

Insertion of quadratus plantae

A
  • Tendon of flexor digitorum longus

- Note that fivers from both heads unite together to insert

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25
Q

Innervation of quadratus plantae

A

Trunk of lateral plantar nerve

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26
Q

Function of quadratus plantae

A
  • 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

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27
Q

Variation of quadratus plantae

A
  • The entire muscle, or just the lateral head may be absent
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28
Q

Lumbricals

A

2nd layer

- 4 lumbricals, numbered medial to lateral

29
Q

Origin of lumbricals

A
  • 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
Q

Course of lumbricals

A
  • 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
Q

insertion of lumbricals

A

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
Q

Innervation of lumbricals

A

1st lumbrical
- Medial plantar nerve

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

33
Q

Function of lumbricals

A
  • Flex the metatarsophalangeal joints

- Extend the interphalangeal joints

34
Q

Variation in lumbricals

A
  • 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
Q

Two tendons of 2nd layer

A
  • Flexor digitorum longus tendon

- Flexor hallucis longus tendon

36
Q

Third layer

A
  • Flexor hallucis brevis
  • Adductor hallucis
  • Flexor digiti minimi brevis
37
Q

Flexor hallucis brevis

A

3rd layer

- Two heads of origin

38
Q

Origin of flexor hallucis brevis

A

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
Q

Course of flexor hallucis brevis

A

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

40
Q

Insertion of flexor hallucis brevis

A

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
Q

Innervation of flexor hallucis brevis

A

Medial plantar nerve

42
Q

Function of flexor hallucis brevis

A

Flexes 1st MPJ

43
Q

Variation in flexor hallucis brevis

A

o Attachment to cuboid may be absent

o Additional insertion into proximal phalanx of 2nd digit

44
Q

Adductor hallucis

A

3rd layer

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

45
Q

Origin of adductor hallucis

A

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
Q

Insertion of adductor hallucis

A

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
Q

Innervation of adductor hallucis

A

o Deep branch of lateral plantar nerve

48
Q

Function of adductor hallucis

A

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

49
Q

Variation of adductor hallucis

A

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

50
Q

Flexor digiti minimi brevis

A

3rd layer

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

51
Q

Origin of flexor digiti minimi brevis

A

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

52
Q

Insertion of flexor digiti minimi brevis

A

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

53
Q

Innervation of flexor digiti minimi brevis

A

o Superficial branch of lateral plantar nerve (motor)

54
Q

Function of flexor digiti minimi brevis

A

o Flex 5th digit

o AB-duct 5th digit

55
Q

Variation in flexor digiti minimi brevis

A

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

56
Q

4th layer

A
  • Plantar interossei

- Dorsal interossei

57
Q

Plantar interossei origin

A

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

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

58
Q

Plantar interossei insertion

A

Each attaches to only one bone – all insert on…

  • Medial sides of bases of proximal phalanges
  • Capsules of MPJ
  • Extensor expansions
59
Q

Innervation of plantar interossei

A

Lateral plantar nerve

  • Deep branch = 1st and 2nd plantar interossei
  • Superficial branch = 3rd plantar interossei
60
Q

Function of plantar interossei

A

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

61
Q

Dorsal interossei origin

A

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
Q

Dorsal interossei insertion

A

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
Q

Innervation of dorsal interossei

A

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

64
Q

Function of dorsal interossei

A

AB-ducts the digits

65
Q

Accessory muscles of the plantar foot

A
  • Abductor os matatarsal digiti minimi
  • Oppoens hallucis muscle
  • Opponens digiti minimi
66
Q

Abductor os metatarsal digiti minimi

A
  • 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
Q

Opponens hallucis muscle

A
  • 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
Q

Opponens digiti minimi

A
  • Accessory muscle from flexor digiti minimi brevis

- Forms when deep fibers of the muscle form a separate belly