Lecture 3.6 - The Foot Flashcards
What are the parts of the foot?
Hindfoot - talus, calceneus Midfoot - navicular, cuboid, cuneiforms Forefoot - metatarsals, phalanges
What are the movements of ankle and foot?
Dorsiflexion (flexing foot) Plantarflexion (pointing toes) Eversion (turn out) Inversion (turn in) Circumduction
What is eversion?
in eversion, the foot is abducted and directed so that the lateral border is raised and the medial border is lowered; the sole is thus turned away from the medial plane
What is inversion?
in inversion, the foot is adducted and directed so that the medial border is raised and the lateral border is depressed; the sole is thus turned to the median plane
What are the movements of the digits?
Extension/Flexion
Abduction/Adduction
What are the tarsus bones?
7 bones
- talus, calcaneus, navicular, cuboid, cuneiform (medial/intermediate/lateral)
What does the talus articulate with? What does it do? What is unique to the talus?
- body of talus articulates with tibia and fibula
- transmits weight of body from tibia to foot
- only tarsal bone without muscle attachment
- What is unique to calcaneus? What does it articulate with and what does it do?
- largest and strongest bone of foot
- articulates with talus (superiorly) and cuboid (anteriorly)
- transmits weight from talus to ground
- sustentaculum tail: “pulley” for flexor hallucis longus
Where is navicular? Cuboid? Cuneiform?
Navicular
- boat-shaped, between talus and cuniforms
Cuboid
- most lateral bone, keystone of lateral longitudinal arch
Cuneiform
- wedge shaped, transverse arch
- between navicular and medial 3 metatarsals
What are the metatarsus and how many are there?
5 bones
- connect tarsus and phalanges
- numbered medial to lateral
- head, shaft, base
- 1 is shorter and stouter
- 2 is longest
- 5 has large tuberosity
What are the phalanges and how many are there?
14 bones
- 2 for big toe (hallux)
- 3 for others (proximal/middle/distal)
- each has head, shaft, and base
- phalanges of big toe are shorter and stouter
What are the fascia of the foot and their function?
- medial plantar fascia
- lateral plantar fascia
- planter aponeurosis
Function:
- holds parts of foot together
- helps protect the plantar surface of foot from injury
- helps support the longitudinal arch of foot
Where is the plantar aponeurosis?
- from calcaneus to the metatarsal heads
- splits into 5 bands
- enclose digital tendons
- vertical septa extend to compartmentalize the sole of the foot
What are the plantar compartments of the foot?
- Medial compartment
- abductor hallucis and flexor brevis hallucis - Central compartment
- flexor digitorum longus/brevis, quadratus plantae, lumbricals, adductor hallucis, interossei - Lateral compartment
- adductor digiti minimi and flexor digiti minimi
What is the purpose of the layers of muscle on the sole of the foot? What is their innervations?
4 muscular layers
- highly specialized for bipedal locomotion
- maintain arches of foot
- assists with standing on uneven ground
- not used for “fine control”
- innervation: lateral and medial plantar nerves
What are the nerves of the foot?
- Tibial nerve
- medial plantar
- lateral plantar
- supply intrinsic foot muscles except dorsum muscles (deep fibular nerve) and also the skin of the sole of foot
What muscles are in Layer 1 of the foot?
Abductor hallucis - calcaneus to big toe - abducts and flexes big toe - medial plantar nerve Flexor digitorum brevis - calcaneus to lateral 4 digits - flexes lateral 4 digits - medial plantar nerve Abductor digiti minimi - calcaneus to 5th digit - abducts and flexes 5th digit - lateral plantar nerve
What consists of Layer 2 of the foot?
Flexor digitorum longus tendon
Flexor hallucis tendon
Quadratus plantae
- calcaneus to tendon of flexor digitorum longus
- modifies the effect of flexor digotrum longus:
– flexing lateral 4 digits
– changes direction of force so it is parallel to long axis of foot
- lateral plantar nerve
Lumbricals
- tendon of flexor digitorum longus to lateral 4 digits
- flex MTP joints; extend prox and distal interphalangeal joints
- medial one: medial plantar n.; other 3: lateral plantar n.
What muscles are in Layer 3 of the foot?
Flexor hallucis brevis - cuboid and cuneiforms to big toe - flexes big toe - medial plantar n. Adductor hallucis - metatarsals to big toe - adducts big toe; helps to maintain curvature of transverse arch - lateral plantar n. Flexor digiti minimi - 5th metatarsal to 5th digit - flexes 5th digit - lateral plantar n.
What muscles are in Layer 4 of the foot?
Plantar interossei (3) - between toes - adducts digits (PAD) - lateral plantar n. Dorsal interossei (4) - between toes - abducts digits (DAB) - lateral plantar n.
What are the nerves of the dorsal surface of the foot?
- superficial fibular nerve supplies dorsal skin
- deep fibular nerve supplies dorsal muscles (and skin between 1st and 2nd toes)
Extensor digitorum brevis (OINA)
O: calcaneus, deep part of inferior extensor retinaculum
I: digits 2-4
N: deep fibular n.
A: extends digits 2-4
Extensor hallucis brevis (OINA)
O: calcaneus, deep part of inferior extensor retinaculum
I: big toe
N: deep fibular n.
A; extends big toes
Where does dorsalis pedis artery come from and how does it divide?
- continuation of anterior tibial artery, supplies the dorsum of foot
- divides into deep plantar artery and arcuate artery
- deep plantar artery joins with lateral plantar artery of sole to form the deep plantar arch
Where does the posterior tibial artery pass through and how does it divide?
- posterior tibial artery passes posterior to the medial malleolus of ankle
- divides into lateral plantar artery and medial plantar artery
- deep plantar arch sends forward plantar and dorsal digital arteries between the toes
