L10: Ankle and Foot Bones

How many bones in the foot? How is body weight transferred?

• What are the bones?

There are 26 bones in each foot.

Body weight is transferred from the tibia into the talus and out the calcaneus.

Rear and midfoot tarsal bones (5): Navicular, cuboid, and 3 cuneiforms.

5 metatarsals

5 phalanges

• 3 phalanxes (2-5)

• 2 sesamoid bones beneath 1st metatarsophalangeal joint

What does the lateral and medial malleoli of the fibula and tibia provide?

They are enlarged and protrude horizontally and medially.

1) Provides general medial and lateral stability

2) Serves as a pulley for tendons that wrap around posteriorly, increasing the MA of muscles.

• Increased L/T relationship and lengthening the moment/force arm.

• Primarily in inversion and eversion actions

Pulley: MA greatly increases for which evertors? Invertors?

Peroneus brevis and longus wraps around posteriorly on the lateral malleoli, greatly increasing the MA of eversion

Tibialis posterior, flexor digitorum longus, and flexor hallucis longus wrap around posteriorly on medial malleolus, greatly increasing the MA of inversion

Distal tibiofemoral joint

• Is it the ankle joint?

• What is its classification?

• Are injuries common? How are they classified?

Not the ankle joint, but it is close, so it is often associated.

Is a syndesmotic, amphiarthrodial joint.

Often gets injured in high contact sports, and is classified as a “High Ankle Sprain,” when the anterior inferior tibiofibular, posterior tibiofibular, interosseus ligament, and interosseus membrane get injured.

Ankle/ Talocrural Joint.

• Consists of?

• Classified

  • What are the degrees

  • Greater range of dorsiflexion when

    • why?

Consists of the distal tibia, distal fibula, and the talus

It is classified as a hinge joint, so only plantar/dorsi -flexion

• PF: 50 degrees

• DF: 15-20 degrees

  • Greater range of dorsiflexion when the knee is flexed

    • With the gastroc shorter at the knee, tension reduces, allowing it to be longer at the ankle.

What is the motion potential of the distal tibiofibular joint?

During dorsiflexion, the talus moves up towards the tibia, and the fibula externally rotates (3-5 degrees), creating space and allowing a greater range of dorsiflexion.

During plantarflexion, the talus moves down. The fibula internally rotates (3-5 degrees) and moves medially back into place, closing the space.

Opens and closes by 1-2mm

Subtalar joint and transverse tarsal joints

• Created by…

• What movement occurs?

• Classified as

Subtalar: talus and calcaneus

Transverse tarsal: Between the talus & navicular + calcaneus & cuboid

Where inversion (20-30) and eversion ( 5-15) occurs

Classified as gliding joints

Intertarsal and tarsometatarsal joints are classified as..

Gliding joints.

Metatarsophalangeal joints

• Are between?

• Classified as

Are between phalanges and metatarsals

Condyloid classification

Ankle proper and foot joint injuries

Ankle sprains are common, which consists of stretching or tearing a ligament(s)

What are the type of sprains?

Low ankle excessive inversion ankle sprain

• injury to ligaments on low, lateral side of foot

Low ankle excessive eversion ankle sprain

• injury to ligaments on low, medial side of foot.

How many arches does the foot have?

There are three arches.

Most people have one or all, but some people may also be flat-footed.

What are the arches of the foot?

Longitudinal arches (2)

• 1) Medial longitudinal arch: from the calcaneus to the talus, 3 cuneiforms, and proximal ends of metatarsals 1-3.

  • is the most common arch

• 2) lateral longitudinal arch: from the calcaneus to the cuboid, and proximal ends of 4th and 5th metatarsals

Transverse arch

• extends across foot from 1st to 5th metatarsal.

What are the movements of ankle?foot?

Dorsi- and plantar- flexion

Eversion: decrease in angle laterally

Inversion: decrease in angle medially

Toe flexion/extension

Supination: combo of ankle doing plantarflexion, subtalar inversion, and forefoot adduction

Pronation: combo of ankle dorsiflexion, subtalar eversion, and forefoot abduction

How are the muscles divided?

Muscles are divided into four compartments by dense fascia. This facilitates venous return and prevents swelling of muscles during exercise.

Anterior, lateral, superficial posterior, and deep posterior compartment.

Anterior compartment

Dorsiflexor group: tibialis anterior, peroneus tertius, extensor digitorum longus, and extensor hallucis longus.

Lateral compartment

Peroneus longus and brevis, the two most powerful evertors

Superficial posterior compartment

Gastrocnemius, soleus, and plantaris

Plantarflexors

Deep posterior compartment

Flexor digitorum longus, flexor hallucis longus, popliteus, and tibialis posterior.

All are plantarflexors and invertors.

What injuries are common

Acute and chronic injuries are common

• Shin splints, achilles tendon, and cramps

What are shin splints

• most often involves

• may be partially prevented by

Shin splints is a common term describing pain in the shank. It is a non specific diagnosis of muscle-tendon pain.

Most often involves the tibialis posterior, medial soleus, anterior tibialis, and/or extensor digitorum longus. Occurs by getting microtears and strain from running and jumping with poor mechanics.

May be partially prevented by strengthening and stretching plantar- and dorsi- flexors.

Rupture of Achilles tendon

• occurs

It is a very disabling injury that often happens when someone jumps and lands wrong.

Painful cramps/Charly Horses

• they are

• may be due to

• may be relieved by

They are acute muscle spasms in the gastrocnemius and soleus muscles (mostly)

May be due to random AP, dehydration, K+ deficiency, overworked muscles, etc.

May be relieved through active and passive dorsiflexion.

Muscle grouping according to location and function

Anterior ankle and foot: dorsiflexors

Posterior: plantarflexors

Lateral: Evertors

Medial: Invertors

Gastrocnemius

• A

Knee flexor and plantarflexor

Soleus

• A

Plantar flexor

Peroneus longus

• A

Eversion of foot (gets MA)

Plantarflexor

Peroneus brevis

• A

A: eversion of foot (gets MA)

plantarflexor

Peroneus tertius

Eversion of foot

Dorsiflexion of ankle (no MA)

Extensor digitorum longus

• A

Eversion of foot

Dorsiflexion of ankle

Extensor of four lesser toes

Extensor hallucis longus

Dorsiflexion of ankle

Weak invertor of foot

Extension of hallux

Tibialis anterior

• A

Dorsiflexor and Invertor

Tibialis posterior

• A

Plantarflexor and invertor

Flexor digitorum longus

• A

Inversion of foot

Plantarflexion of ankle

Flexion of four lesser toes

Flexor hallucis longus

• a

Inversion of foot

plantarflexion of ankle

flexion of hallux

Agonists: Dorsiflexors

Tibialis anterior

Extensor digitorum longus

• Peroneus tertius

• Extensor hallucis longus

Agonists: Plantarflexors

Gastrocnemius

Soleus

Tibialis posterior

• peroneus longus

• peroneus brevis

• Flexor digitorum longus

• Flexor hallucis longus

Agonists: Invertors

Tibialis posterior

Tibialis anterior

• flexor digitorum longus

• flexor hallucis longus

Agonists: Evertors

Peroneus longus

Peroneus brevis

Peroneus tertius

• Extensor digitorum longus

Segment moved

• close chain

• open chain

CC: shank

OP: foot