Anatomy - Foot

Question 1

26 bones of the foot

Answer 1

1. Tarsal (7 bones)
   i. Calcaneum
   ii. Talus
   iii. Navicular
   iv. Cuboid
   v. Cuneiform (middle, intermediate, lateral)
2. Metatarsal (5 bones)
   (first to fifth)
3. Phalanges (14 bones)
   (proximal, middle, distal)
   *except first phalanges, has no intermediate

Question 2

Tibialis anterior insertion?

Answer 2

Base of first metatarsal (plantar aspect)

Question 3

Extensor hallucis longus insertion?

Answer 3

Base of first distal phalange toe

Question 4

Extensor hallucis brevis insertion?

Answer 4

Base of first proximal phalange toe

Question 5

Extensor digitorum longus insertion?

Answer 5

Base of proximal and middle phalanx of 2nd to 5th toes

Question 7

Extensor digitorum brevis insertion?

Answer 7

Anterior surface of calcaneal body

Question 8

Peroneus brevis and tertius insertion?

Answer 8

Base of fifth metatarsals (Dorsal aspect)

Question 9

Flexor hallucis longus insertion?

Answer 9

Base of distal phalange of first toe

Question 10

Flexor hallucis brevis insertion?

Answer 10

Base of proximal phalange of first toe

Question 11

Flexor digitorum longus insertion?

Answer 11

Base of distal phalanx of 2nd to 5th toes

Question 12

Flexor digitorum brevis insertion?

Answer 12

Body of middle phalanx of 2nd to 5th toes

Question 13

Layers of the sole of the foot?

Answer 13

1. Skin
2. Deep fascia (plantar aponeurosis)
3. Muscles of the foot
   (4 layers)

Question 14

First muscular layer of foot?

Answer 14

1. Abductor hallucis
2. Flexor digitorum brevis
3. Abductor digiti minimi

Question 15

Second muscular layer of sole foot?

Answer 15

1. Quadratus plantae
2. Lumbricals
3. Flexor digitorum longus
4. Flexor hallucis longus

Question 16

Third muscular layer of sole foot?

Answer 16

1. Flexor hallucis brevis
2. Adductor hallucis
3. Flexor digiti minimi

Question 17

Fourth muscular layer of sole foot?

Answer 17

1. Interossei
2. Peroneus longus
3. Tibialis posterior

Question 18

Sole muscles supplied by medial plantar nerve?

Answer 18

1. Abductor hallucis
2. Flexor hallucis brevis
3. Flexor digitorum brevis
4. First interossei

(Others are by lateral plantar)
*Both are branch of tibial nerve

Question 19

Arterial supply of plantar foot?

Answer 19

1. Medial plantar artery
2. Lateral plantar artery

(Both from posterior tibial artery)

Question 20

Plantar fascia origin and insertion?

Answer 20

Origin - medial calcaneal tuberosity
Insertion -
i. base of 5th metatarsal (lateral band)
ii. base of all proximal phalanx

Question 21

Function of plantar fascia?

Answer 21

1. Protects above muscles, nerve, arteries

2. Medial arch support

Question 22

Bones and joints of hindfoot

Answer 22

Bones

• talus
• calcaneus

Joints

1. Subtalar: inversion, eversion
2. Transverse tarsal (Chopart): works with subtalar
   - made up of talonavicular, calcaneocuboid joints

• inversion cause bone to locked
• eversion cause bone to unlocked (allow conformity to ground surface)

Question 23

Bones and joints of midfoot

Answer 23

Bones

• cuneiform (3)
• navicular
• cuboid

Joints

1. Naviculocuneiform
2. Intercuneiform
3. Tarsometatarsal (Lis Franc)

Question 24

Lis Franc joint?

Answer 24

Has 3 columns:

1. Medial: 1st meta, medial cuneiform, navicular
   - most load on standing
2. Middle: 2nd and 3rd meta, middle, lateral cuneiform
   - least mobile, allow rigidity during push-off
3. Lateral: 4th and 5th meta, cuboid
   - most mobile, allow walking on uneven ground

Supported by 3 ligaments:

1. Dorsal tarsometatarsal layer: weakest
2. Interosseus/Lis Franc ligament: strongest
3. Plantar tarsometatarsal layer: 2nd strongest
4. Intermetatarsal ligament: between 2nd to 5th metatarsal bases

Question 25

Origin and insertion of Lis Franc ligament?

Answer 25

Origin: Medial cuneiform plantar
Insertion: Base of 2nd metatarsal

Function:

• stabilize 2nd metatarsal
• maintains roman/modfoot arch

Question 26

Bones and joints of forefoot?

Answer 26

Bones - metatarsal - phalanges Joints 1. MTP 2. Proximal IP 3. Distal IP

Question 27

Dorsum of foot

Answer 27

``` 1 artery forms 3 branches 1 nerve 1 venous arch from 2 veins 2 muscles 4 tendons ``` ``` Artery Dorsalis pedis forms - first dorsal metatarsal - arcuate - lateral tarsal ``` Veins Dorsal venous arch from - great saphenous vein (medial) - small saphenous vein (lateral) Nerve - Deep peroneal nerve Muscles - Extensor hallucis brevis - Extensor digitorum brevis Tendons - Tibialis anterior - Extensor hallucis longus - Extensor digitorum longus - Peroneus tertius

Question 28

Tibialis posterior insertion

Answer 28

1. Anterior limb to - navicular tuberosity - medial cuneiform 2. Middle limb to - middle and lateral cuneiform - cuboid - 2nd to 4th metatarsal 3. Posterior limb to - sustentaculum tali

Question 29

Talus articulation surfaces

Answer 29

1. Inferior surface: posterior facet of calcaneus 2. Talar head: navicular bone 3. Lateral process: lateral malleolus, posterior facet of calcaneus 4. Posterior process: groove for FHL

Question 30

4 Talus blood supply

Answer 30

1. Posterior tibial artery -> artery of tarsal canal (most important) -> talar body 2. Deltoid artery -> talar body 3. Anterior tibial artery -> head, neck of talus 4. Perforating peroneal artery -> artery of tarsal sinus -> head, neck of talus

Question 31

Sesamoid bone

Answer 31

1. Two sesamoid bone below head of 1st metatarsal - tibial/medial sesamoid - fibular/lateral sesamoid 2. Function - reduce friction at metatarsal head - protect FHL (in between) - weight bearing 3. Attachment - FHB to both sesamoid - Adductor hallucis to tibial - Abductor hallucis to fibular