Ankle and Subtalar Joint Mechanics

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Questions and Answers

What is the main component associated with dorsiflexion at the ankle joint?

Slight abduction (correct)

Slight inversion

Slight eversion

Slight adduction

Which of the following ligaments is NOT involved in the posterior translation of the talus during ankle dorsiflexion?

Deltoid ligament

Posterior talofibular ligament

Calcaneofibular ligament

Anterior talofibular ligament (correct)

What is the normal range of motion for plantarflexion at the ankle?

55 to 70 degrees

40 to 55 degrees (correct)

15 to 25 degrees

30 to 45 degrees

How many degrees of freedom does the talocrural joint exhibit?

One degree Signup and view all the answers

In which plane is the axis of rotation for the talocrural joint deviated by 10 degrees from the mediolateral axis?

Frontal plane Signup and view all the answers

What role does the fibularis longus play during active pronation of an unloaded foot?

It raises the medial side and lowers the lateral side of the foot. Signup and view all the answers

Which of the following bones forms part of the Medial Longitudinal Arch (MLA) of the foot?

Calcaneus Signup and view all the answers

During early to mid stance phase, what is the desired function of the STJ's action of pronation?

To enable foot function as a shock absorber. Signup and view all the answers

What is the keystone bone of the Medial Longitudinal Arch (MLA)?

Navicular Signup and view all the answers

How does the TTJ respond during early stance phase when counterforce is applied from the ground?

It undergoes relative supination. Signup and view all the answers

What is the primary change in the subtalar joint (STJ) during the early to mid stance phase?

Changing to supination Signup and view all the answers

What role does the transverse tarsal joint (TTJ) play during the mid to late stance phase?

Facilitates midfoot pronation Signup and view all the answers

Which joint is considered the keystone in the formation of the transverse arch of the midfoot?

Intermediate cuneiform Signup and view all the answers

During late stance, what is the typical movement combination at the first tarsometatarsal joint?

Plantarflexion with slight eversion Signup and view all the answers

What is a primary function of the distal intertarsal joints in the midfoot?

Support the arch during weight-bearing Signup and view all the answers

What movement occurs during subtalar joint pronation in a weight-bearing position?

Talar adduction Signup and view all the answers

What is the normal range of motion for eversion at the subtalar joint?

10 degrees Signup and view all the answers

Which coupled motion is observed during subtalar joint supination in a closed kinetic chain?

Talar internal rotation Signup and view all the answers

Which statement accurately describes the relationship of movement between the talus and calcaneus in the subtalar joint?

The direction of talar movement in weight-bearing is opposite to the calcaneal movement in non-weight-bearing. Signup and view all the answers

What is the typical coupled motion that occurs during calcaneal eversion in subtalar joint supination?

Talar adduction Signup and view all the answers

What is the primary motion of the subtalar joint during normal gait?

Calcaneal inversion and eversion Signup and view all the answers

In an open kinetic chain, what accompanies calcaneal inversion?

Calcaneal adduction Signup and view all the answers

Which of the following best describes the arthrokinematics at the subtalar joint during calcaneal pronation?

Convex calcaneus rolls posteriorly and slides anteriorly Signup and view all the answers

What occurs during talar abduction and dorsiflexion in closed kinetic chain (CKC) supination?

Superior and lateral slide of talus on calcaneus Signup and view all the answers

Which joint resembles a ball-and-socket joint and provides substantial mobility to the medial column of the foot?

Talonavicular Joint Signup and view all the answers

What type of joint is the Calcaneocuboid Joint and what is its primary function?

Saddle joint providing stability to the lateral column Signup and view all the answers

What is the main role of the Transverse Tarsal Joint (TTJ) relative to the subtalar joint (STJ)?

To control supination and pronation in tandem with STJ Signup and view all the answers

What are the axes of rotation associated with the Transverse Tarsal Joint osteokinematics?

Longitudinal and Oblique axes Signup and view all the answers

What role does the tibialis posterior play during the active supination of an unloaded foot?

It acts as the prime supinator of the foot Signup and view all the answers

During weight-bearing activities, what is the ratio of range of motion for supination to pronation at the Transverse Tarsal Joint (TTJ)?

2:1 ratio Signup and view all the answers

Which structure primarily stabilizes the lateral longitudinal arch?

Long plantar ligament and short plantar ligament Signup and view all the answers

Study Notes

Ankle: Talocrural Joint

One degree of freedom
Axis of rotation is oblique, through the body of the talus and the tips of both malleoli
Frontal plane: deviated 10 degrees from the ML axis
Horizontal plane: deviated 6 degrees from the ML axis
Dorsiflexion: associated with slight abduction and eversion (pronation)
Plantarflexion: associated with slight adduction and inversion (supination)
Normal ROM: Dorsiflexion (15-25 degrees), Plantarflexion (40-55 degrees)
Functional ROM: Gait (10 degrees DF, 20 degrees PF), Running (20 degrees DF, 30 degrees PF), Stair Descent (21-36 degrees DF)
During OKC (unloaded) dorsiflexion:
- Convex talar dome rolls anteriorly, slides posteriorly
- Deltoid ligament (tibiotalar fibers), calcaneofibular ligament, posterior talofibular ligament tense during dorsiflexion

Subtalar Joint

Pronation (unlocking of the foot)
- Calcaneal eversion (valgus)
- Talar adduction (internal rotation of talus, coupled with internal rotation of tibia and fibula)
- Talar plantarflexion: anterior/inferior translation, lowering of the MLA
Supination
- Calcaneal inversion
- Talar abduction
- Talar dorsiflexion
- Tibiofibular external rotation
Normal ROM: 20 degrees inversion, 10 degrees eversion
Functional ROM: 4-6 degrees inversion and eversion during normal gait
In OKC (non-weight bearing) supination:
- Calcaneal inversion, calcaneal adduction, calcaneal plantarflexion
In OKC pronation:
- Calcaneal eversion, calcaneal abduction, calcaneal dorsiflexion
In WB (weight bearing) supination:
- Calcaneal inversion, talar abduction, talar dorsiflexion, tibiofibular external rotation
In WB pronation:
- Calcaneal eversion, talar adduction, talar plantarflexion, tibiofibular internal rotation
In WB, talar movement is opposite to calcaneal movement in NWB
In the posterior articulation of the subtalar joint:
- Talar plantarflexion (posterior facet): concave
- Calcaneal plantarflexion: convex
During calcaneal inversion:
- Calcaneus rolls medially
- Calcaneus slides laterally
During calcaneal eversion:
- Calcaneus rolls laterally
- Calcaneus slides medially
During talar abduction and dorsiflexion (CKC supination):
- Talus slides superiorly and laterally on calcaneus
During talar adduction and plantarflexion (CKC pronation):
- Talus slides inferiorly and medially on calcaneus

Transverse Tarsal Joint (TTJ)

AKA midtarsal joint
Acts as the transitional link between rearfoot and forefoot
Mechanically linked to the subtalar joint
Controls most of supination and pronation
Allows the foot to adapt to uneven surfaces during weight-bearing activities
Two axes of rotation: longitudinal and oblique
Supination/pronation ROM: about 2:1 ratio
Most weight-bearing activities involve a blending of movements across both axes
Longitudinal axis: almost straight anteroposterior axis of rotation
Oblique axis: strong vertical and medial-lateral pitch

Talonavicular Joint (TNJ)

Resembles a ball-and-socket joint
Provides substantial mobility to the medial column of the foot
Spring ligament supports the talar "acetabulum", the talonavicular joint and the medial longitudinal arch

Calcaneocuboid Joint (CCJ)

Resembles a saddle joint
Allows less motion compared to the TNJ
Provides stability to the lateral column of the foot
Lateral fibers of the bifurcate ligament form the primary bond between calcaneus and cuboid
Stabilized by the long plantar ligament and short plantar ligament (important for the lateral longitudinal arch)

Combined Action of STJ and TTJ (OKC)

Active supination of an unloaded foot
- Supination at both TTJ and STJ
- Tibialis posterior muscle: prime supinator of the foot
- TTJ: relatively rigid calcaneocuboid joint acts as a pivot point for the talonavicular joint
- Tibialis posterior contributes to the navicular spin and raising of the medial longitudinal arch
- TNJ: Concave navicular and spring ligament spin around the convex talar head
Active pronation of an unloaded foot
- Pronation at both TTJ and STJ
- Fibularis longus: lowers the medial side and raises the lateral side of the foot
- TNJ: Concave navicular and spring ligament spin in the opposite direction (compared to supination) around the convex talar head

Medial Longitudinal Arch (MLA) of the Foot

Primary load-bearing and shock-absorbing structure
Formed by calcaneus, talus, navicular, cuneiforms, and three medial metatarsals
Keystone: talonavicular joint
Plantar fascia acts like a semi-elastic tie-rod
Responds to larger and more dynamic loads

Combined Action of STJ & TTJ (CKC): Osteokinematics during Early to Mid Stance Phase

STJ pronation and lowering of the MLA: coupled with internal rotation of the leg, allows the foot to function as a shock absorber and produces a pliable midfoot.
TTJ relative supination: acts as a counterforce from the ground and allows full STJ pronation.
STJ pronation helps to lower the MLA and internally rotate the leg, which allows for shock absorption and a flexible midfoot.
Relative supination at the TTJ allows the STJ to fully pronate while still maintaining contact with the ground.

Combined Action of STJ & TTJ (CKC): Osteokinematics during Mid to Late Stance Phase

STJ supination and raising of the MLA: coupled with external rotation of the leg, converts the midfoot to a rigid lever for push off.
TTJ relative pronation: allows the midfoot and forefoot to maintain firm contact with the ground during push off.

Distal Intertarsal Joints

Three joints or joint complexes in the midfoot:
- Cuneonavicular joint
- Cuboideonavicular joint
- Intercuneiform and cuneocuboid joint complex
Functions:
- Assist the TTJ in pronating and supinating the midfoot
- Provide stability across the midfoot by forming the transverse arch (keystone: intermediate cuneiform)

Tarsometatarsal Joints and Intermetatarsal Joints

Least mobility at the 2nd and 3rd tarsometatarsal joints for longitudinal stability (useful in late stance)
1st tarsometatarsal joint:
- Plantarflexion with slight eversion
- Dorsiflexion with slight inversion (These movement combinations are atypical for the foot)

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Description

This quiz covers the anatomy and biomechanics of the talocrural and subtalar joints. It includes details on their range of motion, functional implications for activities like walking and running, and ligament involvement during dorsiflexion. Perfect for students studying kinesiology or physical therapy.