The Lower Extremity: The Ankle and Foot [2] Flashcards
How many bones in the foot, and how many of each type?
26 bones in the foot
- 7 tarsals
- 5 metatarsals
- 14 phalanges
Review the diagram of the bones
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What are the major movements of the foot and ankle (TC, ST, MTP, & IP)?
- Talocrural (TC): dorsiflexion and plantarflexion
- Subtalar (ST): inversion and eversion
- Ankle pronation: EV + AB + DF
- Ankle supination: IN + AD + PF
- MTP & IP: toe flexion and toe extension
- MTP: toe abduction and toe adduction
Describe the talocrural joint?
It includes the distal tibia + the distal fibula + the talus dome (which all equate to make the ankle mortise which is the “house of the ankle”)
* it is a hinge joint
* so it does plantar flexion (45-50 degrees)
* it dorsiflexes (20 degrees)
Describe the Subtalar (ST) Joint and its movements?
It is between the talus and calcaneus. It’s movements include:
* inversion (20-30 degrees)
* Eversion (5-10 degrees), the lateral malleolus extends so far down that it crosses the subtalar joint and restricts furtherh motion in eversion
Describe the toe joints and their motions
- Metatarsophalangeal joints (MTP) do flexion, extension, abduction, and adduction
- Interphalangeal joints (IP) do flexion, extension, include proximal interpahalngeal and distal interphalangeal
What is the OIA of the plantar fascia?
- O: (plantar medial) calcaneal tuberosity
- I: base of proximal phalanx of toes 1-5
- A: supports the foot against downward forces
Bonus: it is non-contractile, there are no muscle fibers, just inert muscle tissue
What is the OIA of the Plantar Calcaneonavicular (spring ligament)?
- O: sustentaculum tali of calcaneous
- I: medial plantar surface of navicular
- A: supports medial plantar surface of longitudinal arch
What are the 3 lateral ankle ligaments?
- Anterior talofibular ligament (more commonly sprained)
- Calcaneofibular ligament
- Posterior talofibular ligament
What are the 4 medial ankle ligaments?
Deltoid complex: much broader, more closely packed and stronger
1. Tibionavicular
2. Tibiocalcaneal
3. Anterior Tibiotalar
4. Posterior Tibiotalar
What are the 4 compartments of the lower leg and what muscles are in each of them?
Anterior:
1. tibialis anterior
2. Extensor Digitorum longus
3. extensor hallucis longus
4. peroneus tertius
Lateral:
1. peroneus brevis
2. peroneus longus
Posterior superficial:
1. gastrocnemius
2. soleus
3. plantaris
Posterior deep:
1. flexor digitorum longus
2. flexor hallicus longus
3. tibialis posterior
What is the OIA of the Anterior Compartment
Extensor Hallicus Longus
* O: midshaft of the fibula
* I: distal phange of big toe
* A: extends the big toe and helps dorsiflex
Anterior Tibialis:
* O: lateral crest of the tibia and fibular head
* I: plantar asprct of the 1st metatarsal
* A: crosses medially so it inverts
Extensor Digitorum Longus:
* O: fibular head
* I: distal phalanges of toes 2-5
* A: toe extension & dorsiflexion
Fibularis Tertius:
* O: midshaft fibula
* I: styloid process on 5th metatarsal
* A: dorsiflex & eversion
What is IOA for the lateral compartement?
Peroneus Brevis:
* O: midshaft of the fibula
* I: styloid process of the 5th metatarsal
* A: eversion, & plantar flexion
Peroneus Longus:
* O: fibular head
* I: base of the 1st metatarsal
* A: eversion & plantar flexion
What is the OIA of the posterior deep compartment?
Posterior Tibialis:
* O: proximal tibia and fibula
* I: base of 1st metatarsal, navicular, cuboid, medial cuneiform (just pick 1)
* A: plantar flexion & inversion
Flexor Hallicus longus:
* O: fibular mid-shaft
* I: distal phalanx of 1st digit
* A: flex the big toe, plantar flexion, eversion
Flexor digitorum longus:
* O: mid-shaft of tibia
* I: distal phalanges 2-5
* A: plantarfelxion & inversion & toe flexion
What is OIA for posterior superfical compartment?
Soleus:
* O: posterior tibia and fibula (proximally)
* I: calcaneous
* A: plantarflexion
Plantaris:
* O: lateral femoral epicondyle
* I: calcaneous
* A: plantarflexion, and knee flexion (useless tho and used in tommy john surgery)
Gastrocnemius:
* O: medial head at the medial femoral epicondyle & lateral head at the lateral femoral epicondyle
* I: calcaneus
* A: plantarflexion and knee flexion
What muscle dorsiflexes and inverts?
- Tibialis anterior
What 2 muscles dorsiflex and evert?
- peroneus tertius
- extensor digitorum longus
What 6 muscles plantarflex and invert? And why are there so many more muscles used for this?
We use these all the time to run, jump, walk, ect..
* gastrocnemius
* soleus
* plantaris
* posterior tibialis
* Flexor digitorum longus
* Flexor hallicus longus
What 2 muscles plantarflex and evert?
- peroneus brevis
- peroneus longus
What is the role of the retinacula?
- it is connective tissue that holds tendons into place
- our musles are curved so they want to be straight, the retinaculum holds them down
- example “bloody sock”
What are the names of the intrinsic Flexor muscles of the foot?
- flexor digitorum brevis
- flexor hallicus brevis
- flexor digiti minimi brevis
- quadratus plantae
What are the names of the intrinsic extensor muscles of the foot?
- Extensor digitorum brevis
- extensor hallicus brevis
What are the other just general intrinsic muscles of the foot?
- Abductor hallicus
- adductor hallicus
- abductor digit minimi
- plantar interossei
- Dorsal interossei
- Lumbricals
What is the purspose and function of the foot?
Purpose:
* support and propulsion
Function:
* adapt to terrain
* absorb ground reaction forces (mid-stance)
* rigid lever (toe-off)
* it can be pliable in sand, but also ridgid to move us off the ground
What is a toe splay and what type of muscle controls this?
A splay creates a stable, controlled foot gait
- instrinsics control it
Narrow shoes can lead to hallux valgus, bunions, nad hallux limitus
What is the ROM for Normal, hallux limitus, and hallux rigidus?
Normal: 70-90 degrees
Hallux Limitus: less than 45-60 degrees (limits the windlass effect)
Hallux rigidus: less than 30 degres
Describe what a foot can do when it is rigid?
Motion:
* supinate (IN, ADD, PF)
NWB:
* calcaneal inversion, adduction, plantarflexion
Describe what a foot can do when it is pliable?
Motion:
* pronation (EV, ABD, DF)
NWB:
* calcaneal eversion
* abduction
* dorsiflexion
What 2 things do you need for walking?
- pronation and supination
What are the different arches of the foot?
- the longitudinal medial arch (big arch on inside of foot)
- The longitudinal lateral arch
- The transverese metatarsal arch
Explain how the medial longitudinal arch is maintained and what it interacts with?
Maintained by passive and active forces
* passive= articulations of the bone & plantar ligaments + spring ligamements
* Active: muscles like the instrinsics and post/anterior tibialis
What are the 2 types of pes planus?
- Rigid: congenital, bony or joint malformations (the foot is always flat)
- Flexible: dropped arch when WB
What are the signs of Pes Planus?
- Too many toes
- rearfoot valgus (arch collapses and caves inwards)
- compensated foot varus (non WB the big toe is higher than the pinky)
- Navicular drop test (more than 1cm)
What are the effects of pes planus?
- unstable foot
- arch collapses with each step
- excessive motion with each step
- BUT good adaptation to terrain
What are the pathomechnaics of the pes planus and wear pattern?
- overstretched plantar fascia
- muscles must be hyperactive
- related injuries (shin splints and plantar fasciitis)
Wear pattern: lateral heel strike and medial toe off
(you can use orthotics to help)
What is pes cavus?
- high arches
- related injuries like lateral ankle sprains and stress fractires
- we get a valgus stress here (ankle goes outwards)
- not good at absorbing forces
- we dont see any toes bc the foot is so supinated
Wear pattern: plantar pressure stays latreal on both superior and inferior parts of the shoes
What diagnoses falls under valgus and which under varus stress on the rearfoot?
Valgus = pes plantar
Varus= pes cavernus
How does the plantar fascia affect gait?
- Distal attachment of plantar fascia onto the flexor muscles
- Activates the intrinisc muscles
Describe the windlass effect?
The plantar fascia bows the foot’s longitudinal arch
* tested in a flat position and have them go up on their toes in Non-WB.
* then the plantar fascia bows and mechanically raises the arch up a little bit
* this helps create a rigid structure
