Foot/Ankle Flashcards
Which 3 articulations are the bones of the leg involved with the foot?
- The Superior Tibiofibular Joint
- The Inferior Tibiofibular Joint
- The Talocrural Joint (more commonly known as the ankle joint)
How are the shafts of the tibia and fibula connected?
The shafts of the tibia and fibular are connected by a tough, fibrous sheet known as the interosseous membrane.
Is there any active movement between the tibia and fibula
No
What type of movement occurs between the tibia and fibula?
There is conjunct movement between them which occurs as a result of movement at the ankle joint, and as a result of muscle contractions pulling on the two bones.
What type of joint is an ankle joint?
True hinge joint
Which planes of movement does the ankle joint move in?
Medial-lateral
Inversion-eversion
What is the official joint name for the ankle joint?
Talocrural joint
Which ligaments connect the tibia and fibula?
The superior and inferior tibiofibular joints
How does passive movement occur at the superior and inferior tibiofibular joints?
Passive movements occur during movements the talocrural (ankle) joint
Classify the Superior tibiofibular joint
Synovial plane joint
GIve the location of the superior tibiofibular joint
Between an oval facet on the head of the fibula and a similar facet on the posterolateral aspect of the under surface of the lateral tibial condyle.
Which 2 ligaments support the superior tibiofibular joint?
- Anterior Superior Tibiofibular Ligament – short, thick, fibrous bands pass obliquely upwards
and medially between the anterior aspects of the fibular head and the lateral tibial condyle - Posterior Superior Tibiofibular Ligament – single fibrous band passing upwards and medially
between the posterior aspects of the fibular head and the lateral tibial condyle.
Classify the inferior tibiofibular joint?
Fibrous joint (syndesmosis)
Where is the inferior tibiofibular joint located?
Between a rough triangular convex surface on the medial aspect of the lower end of the fibula and a corresponding area (fibular notch) on the lateral side of the tibia
What are the 4 ligaments of the inferior tibifibular joint and give their attachments?
- Interosseous ligament – short, fibrous bands passing inferolaterally unites both bones
- Anterior & posterior tibiofibular ligaments – pass from the borders of the fibular notch to
the anterior and posterior surfaces of the lateral malleolus - Transverse tibiofibular ligament – lies deep to the posterior tibiofibular ligament and attaches to
the length of the posteroinferior tibial surface and the upper part of the malleolar fossa
Give the location of the interosseous membrane
Runs between the interosseous borders of the tibia and fibula, with fibres passing inferolaterally
from tibia to fibula. It does not reach the superior tibiofibular joint but is continuous with the
interosseous ligament of the inferior tibiofibular joint. Openings superiorly and inferiorly transmit
blood vessels from posterior to anterior.
Give the functions of the interousseous membrane
Stability – the IOM strongly unites the fibula and tibia, resisting separation. It resists excessive
rotational forces occurring at the fibula and transfers force between the two bones – preventing
peak forces from occurring and potentially causing fracture
Division – The IOM divides the lower leg into anterior and posterior compartments, separating
structures with common functions
Attachment – Due to its tough, fibrous nature the IOM provides a point of attachment for many
muscles of the lower leg. This increases the surface area available for muscle attachment in a
relatively congested anatomical area
Give the role of the transverse tibiofibular ligament
The transverse tibiofibular ligament is important because it deepens the posterior part of the tibial articular surface and so deepens the socket for the talus, thereby improving joint congruency.
Give the role of the transverse tibiofibular ligament
The transverse tibiofibular ligament is important because it deepens the posterior part of the tibial articular surface and so deepens the socket for the talus, thereby improving joint congruency and posterior stability.
Describe the shape, extent and nature of the articular surfaces of the talocrural joint
Trochlear surface of body of the Talus forms the entire distal surface of the Talocrural joint.
Superiorly and medially articulating with the tibia.
Laterally articulating with the fibula
Convex in A-P direction
Slightly concave transversely
Surface is broader anteriorly than posteriorly
Structural: Synovial
Classification: Mortise/hinge joint
Uni-Axial
Compound
Functional: Diarthrosis
Movements: Dorsiflexion and plantar flexion of foot
Give the static stabilisers of the talocrural joint
Bony configuration forming a ‘mortise’ joint
Fibrous capsule of the joint
Transverse tibiofibular ligament (deepening socket posteriorly)
Anterior & posterior ligaments (intracapsular thickenings)
Lateral Collateral Ligament
Medial Collateral (Deltoid) Ligament
Inferior tibiofibular joint ligaments
Interosseous membrane
Describe the lateral collateral ligament
Strong ligament comprising of 3 separate bands
Reinforces joint capsule laterally
-Anterior talofibular ligament
-Posterior talofibular ligament
-Calcaneus ligament
Describe the medial collateral ligament
Medial Collateral/Deltoid Ligament
Very strong
4 bands of fibres
-Tibiocalcneal
-Tibionavicular
-Anterior tibiotalar
-Posterior tibiotalar
Give the role of the collateral ligaments?
Maintaining stability at the ankle joint
Controlling movements of the ankle joint
Explain the mechanism behind dorsiflexion of the ankle joint
During dorsiflexion, the wider part of the trochlear surface of the talus rocks backwards into the narrower posterior part of the tibiofibular mortise. This pushes the tibia and fibula apart, which increases the tension in the interosseous and transverse tibiofibular ligaments. Consequently, the talus is held firmly between the malleoli. During dorsiflexion, there is also a tendency for the fibula to be lifted superiorly. At the same time the fibula undergoes some axial rotation, either medially or laterally. The direction of this rotation depends upon the orientation of the lateral articular surface of the talus and varies between different human beings.
Describe the stability of the ankle joint during dorsiflexion
The ankle joint is particularly stable during dorsiflexion because of its bony configuration, strong supporting ligaments and tendons which cross the joint and which are bound down by the ankle retinaculae.
Explain the mechanism behind plantarflexion of the ankle joint
During plantarflexion, the reverse movements occur with the two malleoli coming together again due to tension in the anterior, posterior and interosseous tibiofibular ligaments, and the contraction of tibialis posterior draw the two bones together. The fibula moves medially and inferiorly, with some axial rotation (the opposite of that occurring in dorsiflexion for that specific human being). These movements of the fibula at the inferior tibiofibular joint are transmitted to the superior tibiofibular joint, which has plane articular surfaces offering no resistance to the movements.
Describe the stability of the ankle joint during platarflexion
The ankle joint is therefore relatively unstable in plantarflexion since the grip of the malleoli on the talus is less strong and some sideways movement of the talus can be observed in full plantarflexion of the ankle. It is therefore more common to observe ankle sprains when the ankle is in plantarflexion (for example, landing following a jump) and also the reason why the ATFL of the lateral ligament is most commonly sprained.
List the limiting factors of dorsiflexion of the ankle joint
-Lateral Ligament
-Deltoid Ligament
-Posterior part of capsule
-Extent of articular surfaces
-Tension in opposing muscles:
Posterior crural muscle group
List the limiting factors of plantarflexion of the ankle joint
-Lateral ligament
-Deltoid ligament
-Anterior part of capsule
-Tension in opposing
Describe the close pack position of the ankle joint
The “Close-Pack” position of the ankle joint is full ROM dorsiflexion. This is due mostly to the wider part of the talus being forced between the malleoli and being gripped tightly by the tension generated in the anterior, posterior and interosseous tibiofibular ligaments.
Describe the sit to stand mechanism involving the ankle joint
-Plantar grade (slight dorsiflexion) when sat
-Dorsiflexion when accelerating to stand
-Plantar grade when stood
Which bones are located in the hindfoot?
-Calcaneous
-Talus
Which bones are located in the midfoot?
-Navicular
-Cuboid
-Cuniforms
Which bones are located in the forefoot/
Metatarsals
Phalanges
Give functions of the human foot
Support the weight of the body, absorb the forces transmitted to it and provide spring and lift during activity
Identify the bony components of the medial longitudinal arches
The medial part of the longitudinal arch originates at the calcaneus, rises to the talus and descends through the navicular, the 3 cuneiforms and the heads of the 3 medial metatarsals. So high that the medial portion of the foot between the ball and the heel doesn’t touch the ground when you walk.
Identify the bony components of the lateral longitudinal arhces
The lateral part of the of the longitudinal arch also originates at the calcaneus, rises at the cuboid and descends to the heads of the 2 lateral metatarsals.
Identify the bony components of the transverse arch
The transverse arch is found between the medial and lateral aspects of the foot and is formed by the navicular, 3 cuneiforms and the bases of the 5 metatarsals.
Give functions of the arches of the foot
- Distribute body weight to the weightbearing areas (heel, heads of 1st and 5th metatarsals)
- Absorbs forces and shock
- Stores force for use in propulsion (windlass effect) during locomotion
- Bone concavity provides safe passage for neurovascular structures (nerves, veins, arteries) throughout the foot
Lateral longitudinal arch is shorter and stiffer as weightbearing occurs more significantly on the lateral aspect of the foot.
Give the articulation of the subtalar joint
The articulation between the talus which rests on and articulates with the calcaneus.
Describe the capsule of the subtalar joint
- Loose, fibrous capsule attaches to all joint margins
- Anterior part is adjacent to the sinus tarsi and is the thinnest.
- Lined with synovial membrane
- Capsular thickenings occur laterally, medially, and posteriorly:
- Lateral talocalcaneal ligament; Lateral process of talus to lateral calcaneus
- Medial talocalcaneal ligament; Medial tubercule (of the posterior process) of the talus to posterior sustentaculum tali
- Posterior talocalcaneal ligament; Lateral tubercule (of the posterior process) of the talus to upper, posterior calcaneus
Classify the subtalar joint
Synovial articulation between the inferior surface of the body of the talus and the superior surface of the calcaneus. Simple, planar, multi-axial
Describe the shape, extent and nature of the articulating surfaces
Plane synovial simple multi-axial joint between an oval articular facet on the superior surface on the under surface of the body of the talus. The facet on the calcaneus is a concavo-convex about its long axis, matching the reciprocally shaped facet on the talus.
All surfaces covered in hyaline cartilgae
What is the role of the interosseous talocalcanean ligament
Plays an essential role in maintaining the stability of the subtalar joint, both at rest and during activity.
Describe the position and fearures of the interosseous talocalcanean ligament
It occupies a central position between the subtalar and talocalcaneonavicular joints, lying directly below the long axis of the leg. It acts as a fulcrum around which movements of the leg and foot occur, it is continually being subjected to twisting and stretching strains.
2 thick bands attaching to the floor of the sinus tarsi: anterior runs obliquely superiorly, anteriorly and medially to the neck of the talus; posterior runs superiorly, posteriorly and laterally to the talus anterior to the joint.
It is very thick and strong stabilising ligament, being at least 2.5 cm. in breadth from side to side, and serves to bind the calcaneus and talus firmly together.