Ankle and Foot Flashcards
Name the bones in the hind foot, mid foot and fore foot
Hindfoot: -talus -calcaneus Midfoot: -Navicular -Cuboid -3 cuneiforms Forefoot: -Metatarsals -Phalanges
Calcaneus
- Largest bone in the foot. Projects backward beyond the bones of the lower leg so as to provide a lever for the plantar flexors of the foot (insert via the achilles tendon)
- On the medial side of the calcaneus there is a cantilevered bony shelf which carries the middle articular surface of the talus (cantilever – a projecting structure (like a beam) which carries load). ‘Sustentaculi tali’
- Between the anterior and posterior articulating surface is the calcaneal sulcus
Clinical Note - Calcaneal Spur
- Heel spurs or calcaneal exostosis (growth due to stress)
- Hook- like protrusion of the bone.
- Develops as a result of continuous strain between the bone and attachment of the fascia/muscle.
- Usually gives rise to heel pain, if serious, surgically treated
Subcutaneous Bursitis
Bursa – small sack of fluid between tendon and bone (or
between tendon and overlying skin) –
Anterior (deep) retro- calcaneal and Posterior (superficial) achilles bursa
Pain in area may be due to inflammation of bursa
Subtalar Joint
- Composite joint (covered by synovial fluid and hyaline cartilage) formed by three separate plane articulations between talus and calcaneus.
- 2 anterior talocalcaneal articulations.
- 1 posterior talocalcaneal articulation.
- Funnel shaped tunnel between the two is called as tarsal canal.
- The larger end , anterior to lateral malleolus is called as the sinus tarsi. (lots of ligaments, blood vessels, nerves and fatty tissue here)
- Tarsal canal artery formed from: anterior tibial, fibular and tibialis posterior arteries
Subtalar Joint: Articulations
• Anterior articulation share a capsule with the talonavicular joint.
• Posterior articulation has its own capsule.
• These articulations are separated by ligaments
– Cervical ligament- Strongest (connecting the neck)
– Interossoeus talocalcaneal ligament (medial to cervical, bind talus and calcaneum together)
• Ligaments can tear or sprain
•Joint prone to arthritic changes
Subtalar Axis
Triplanar motion of the talus around a single oblique joint axis, subtalar joint axis, producing supination and pronation.
Subtalar Joint Movements: Non- weight bearing
Non weight bearing joint motion
– Movement of the calcaneus on the stationary talus and lower leg.
– Reference point is the anteriorly located head of the calcaneus
Subtalar Joint Movements: Weight bearing
• Weight bearing joint motion
– Calcaneus on the ground, only free to move in a longitudinal axis ( inversion and eversion)
– PF/DF/Ab/Ad – accomplished by movement of the talus on the calcaneus.
– Head of the talus acts as the reference point.
Transverse Tarsal Joint
• Midtarsal joint/chopart joint • Articulations – Talonavicular – Calcaneocuboid • Both articulations form S- shaped joint line. • Divides the hind foot from the mid foot and the forefoot. • Movement- Motion of the talus and the calcaneus with a relatively fixed naviculocuboid unit.
Talonavicular Joint
• The head of the talus articulates
– Anteriorly – concavity of the navicular bone
– Inferiorly- concavities of the anterior and medial calcaneal facets and plantar calcaneonavicular ligament.
Spring Ligament **
• Triangular sheet of ligament extending from the anterior border of the sustentaculum tali onto the plantar aspect of the navicular bone
• Dorsal surface is fibrocartilagenous lined with synovial membrane, referred to as ‘spring ligament fibrocartilagenous complex’ - forms a secondary joint between the head of the talus and the ligament
• Supported by the TP tendon from below.
• Functions
– Supports head of the talus (prevents its downward collapse)
– Supports Talonavicular joint
– Medial longnitudnal arch
• Laxity of this ligament
– Partial or total collapse of the medial arch
Calceneocuboid Joint
Long plantar ligament Spans the calcaneus and the cuboid bone and continues distally on the bases of the second, third, and fourth metatarsal. Functions-
- Stability to transverse tarsal joint
- Lateral longitudinal arch
Tarsometatarsal Joints
• Plane synovial joints.
• Formed by the distal rows of
tarsal bones and bases of the metatarsal bones.
• A ‘ray’ is defined as a functional unit formed by a metatarsal and its associated cuneiform bone (for the first through the third rays) - separate joints
• The fourth and the fifth rays are formed by the metatarsal alone. - cuboid not included, two joints share common capsule
• First and fifth rays are most mobile
Metatarsophalangeal Joints
• Condyloid synovial joints, btn MT heads and phalanges, with 2 dof: – PF/DF (sometimes called Plantar ligaments flex/ext) - 17°/80° – Abd/add – 2nd toe is reference • Stability: – Deep transverse ligaments – Plantar ligament – fibrocartilaginous plate – Flexor and extensor tendons – capsule
Metatarsophalangeal Joints: Sesamoid Bones and Volar Plates
- very important
- weight bearing
- develop in tendon of flexor hallucis brevis
- between the bones lies the intersesamoid ligament (protects flexor hallucis longs that passes under it from weight bearing)
- Volar Plates on head of other metatarsal bones for weight bearing
- held together by deep transverse ligaments
Hammer Toe Deformity
- Excessive extensionat MTP.
- Seen inpatients with diabetes and peripheral neuropathy.
- Results in increased pressure on heads of the metatarsal that result in pain and skin breakdown.
Hallux Valgus
• Enlargement of the joint at the base of the first MTP joint.(Bunions)
- due to inappropriate footwear e.g. heels
- excess adduction
- leads to pain and tenderness, callus can form
- serious = surgery
Interphalangeal joints
• Hinge synovial joints • Joint capsule reinforced by – Collateral ligaments – Plantar (plates) ligaments • Flex/ext
Plantar Aponeurosis
• Thick fascia which extends from medial tubercle of the calcaneus to the proximal phalanx of each toe via digital bands.
• Distal to the MTP joints these bands are connected to each other, which forms the superficial transverse metatarsal ligaments
• Clinical note- Plantar fasciitis
• If damaged - foot arch collapses
Functions of the arches of the foot
• Functions of the arches of foot
– Distribution of body weight
– Acts as segmented lever
– Protects the plantar vessels and nerves
– Arched foot is dynamic and pliable. - ability to walk on uneven surfaces
Longitudinal Foot Arches: Medial vs Longitudinal
– Medial (calcaneus, talus, navicular, cunieforms, med 3 MTs)
– Lateral (calcaneus, cuboid, lat 2 MTs)
-The medial arch is higher than the lateral one – foot prints
show medial arch off ground and lateral one in contact with ground.
Medial longitudinal arch
Summit – trochlear surface of the talus
• Anterior pillar- heads of the medial three metatarsal
• Posterior pillar- medial tubercle of the calcaneus.
• Most vulnerable part- head of the talus.
• Supports-
– Ligaments- spring ligament, plantar
aponeurosis
– Muscles-TP, TA, medial part of FDB,
FDL tendon, AH, FHL tendon
Lateral longitudinal arch
Summit – subtalar joint. • Anterior pillar- heads of the fourth and the fifth metatarsal bones • Posterior pillar- lateral tubercle of the calcaneum • Most vulnerable point- calcaneo- cuboid joint • Supports – Ligaments-longandshortplantar ligaments, plantar aponeurosis – Muscles- ADMinimi, lateral part of FDB and FDL tendons, FDMbrevis.
Transverse arch
• Bases of the metatarsal bones, cuboid and three cuneiforms.
• Supports
– Ligaments- intrinsic plantar ligaments
– Muscles- interossei, adductors, FL, TP..
Clinical note: Arches
- Pes cavus –high arches of the foot
* Pes planus – lowered arch
Ankle Invertors and their other movements
-tibialis anterior
-tibialis posterior
TA and TP - adductor and supinator of foot.
TA- dorsiflexion is only possible , when the adduction-
supination component is counteracted by peronei.
TP- weak plantarflexor
Lateral Compartment - Evertors
-fibularis longus
-fibularis brevis
• Peroneal retinaculum- The stability of the peroneal tendons depends upon the integrity of the retinaculum.
• Primary abductor and pronator of the foot
• Weak plantar flexors
Flexor Retinaculum
- a band-shaped thickening of deep fascia - upper attachment to the inferior border of the medial malleolus; lower attachment to the medial tubercle of the calcaneus
- Spans between the medial malleolus to the inferomedial margin of the calcaneus.
Tarsal Tunnel Contents
Tibialis posterior, FDL, Posterior tibial artery, Tibial nerve, FHL
Causes and Consequences of Tarsal Tunnel Syndrome
- Causes-Synovitis of flexor tendon sheaths, Inflammatory arthritis, Fracture,Ankle venous stasis,
- Consequences- Retromalleolar pain, Pain along the distribution of the tibial nerve, Muscle weakness, Loss of sensation around heel
Ankle/Talocrural Joint
• Synovial hinge joint (motion in single plane - DF and PF)
• Participating bones
– Proximally– distal tibia and
fibula
– Distally- body of the talus.
• Distal end of the tibia and fibula form a deep bracket - shaped socket the ‘Mortise’ (maximises bony congruency)
• Upper expanded body of the talus forms the ‘tenon’
How many facets are there on the distal articular surface of the Talus?
Three
Distal articular surface of Talus: Features
• Three articular facets.
• Superior articular facet-
trochlear facet.
• This surface is broader
anteriorly.
• Medial and lateral articular surfaces for the malleoli
• Central groove makes an angle with head and neck of the talus.
Tibiofibular Joints
• Proximal tibiofibular joint
– Plane synovial joint
– Reinforcedbyanteriorandposterior tibiofibular ligaments.
–Actions, superior glide,inferior glide, anteroposterior glide
• Distal tibiofibular joint
– Syndesmosis (fibrous joint)
– Anteriortibiofibularligament
– posteriortibiofibularligament
– Interosseous ligament
– Action Separation of the malleoli with dorsiflexion at ankle to accommodate the anterior wider part of the talus.
Fibula portion = convex, tibia = concave
-interosseus membrane also gives stability to the joint
Ankle Collateral Ligaments
–Medial collateral ligament (MCL) /deltoid ligament (very strong)
–Lateral collateral ligament [LCL] (3 parts)
–Other supports • Retinacula
Deltoid Ligament
• Parts of the medial ligament
– Tibionavicular part
– Tibiocalcaneal part
– Posterior tibiotalar part – Anterior tibiotalar part
• Strong ligament
• valgus forces fracture malleolus before the ligament tears.
Lateral Ligament
• Composed of three separate ligaments –Anterior talofibular (weakest - frequently injured) –Posterior talofibular – Calcaneofibular • LCL weaker than MCL. • Resist varus forces
Ankle Sprains and common causes
Inversion sprains- Most common, due
to forced inversion of the foot. Eversion sprains- Forced evertion of
the foot
Grade 1- stretching of ligaments
Grade 2- partial tear of ligaments
Grade 3- complete tear
Common causes: sports where move side to side e.g.. tennis, basketball, netball
-medial ligament is very strong and by the time this is torn you would have already fractured the medial malleolus
Trimalleolar fracture/ Pott fracture dislocation of the ankle joints
- caused by excessive inversion/eversion
- trimalleolar- post/inf portion of tibia is considered as third malleolus
- fracture happens when move body around ankle, gets stuck around talus
Extensor hood - Complex dorsal digital expansions
- Givesattachmenttosmallmuscles of the foot.
* Lumbricals-Produceflexionat (metatarso-phalangeal joints) MTP and extension at (inter-phalangeal) IP joints.
Plantar aponeurosis
and fascitis
• Central triangular plantar fascia • Supports the foot arch • Runs from the medial tubercle of the calcaneus. • Plantar fascitis – Inflammation of the plantar fascia – one of the most common hind foot problems. – Painontheplantarsurfaceof the foot and heel located at the proximal attachment of the aponeurosis to the medial tubercle of the calcaneus
Morton’s Neuroma
• Enlargement of the
intermetatarsal plantar nerves
• usually between the 3rd and the 4th space.
Clinical anatomy - Talipes equinovarus
- Clubfoot-Twisted out of position
- Congenital
- Involves mostly subtler joint
- Needs correction
Avascular necrosis of the talus
• No muscle or tendon attached to the
talus to carry blood to the bone.
• Avascular necrosis of the talus is associated with fractures and dislocation of the talus.
Ankle - Functions
– Stability – gives stable BOS in variety of positions.
– Mobility
a) dampens rotational forces; b) absorbs shock on HS;
c) conforms to terrain
Tibiofibular Joints
- Functionally part of ankle complex
- Only 10% WB from femur goes through fibula (not main weight bearing structure, Wolf’s law - Size)
- No active movement between the Fibula and Tibia (when invert angle, pull on lat ligaments, pull on fibula eg. if roll, and pull fib down, pot to develop knee problem)
- Slight movement between the 2 bones is mechanically linked to movement at ankle joint (too much movement and stability is affected)
Superior Tibiofibular Joint
– Movements = accessory – gliding and rotation of fibula. • Inferior glide with inversion/PF
• Superior glide with eversion/DF
• Ant-post glide of fibula on tibia
– Stability – ant and post ligts of Head of fibula, lat/fibular collateral ligt
Inferior Tibiofibular Joints
– Syndesmosis – very stable – fibrous union
– Functions – almost entirely as one of pincers in mortise – Provides firm union btn tibia and fibula
– Contributes to the integrity of the malleolar mortise
Movement and stability of tibiofibular joints
Movement – allows small amount of gliding and separation of tib and fib – accommodates motion of talus
• With d/f – separation for wider ant talus plus sup glide of fib related to lig fibre direction (more bone = good stability in system)
• With p/f – malleoli come together plus inf glide, related to ligts and tib post action (narrower part at back - allows more movement. give = good for uneven surfaces and prevents rupture when go over on inverted ankle, but lack of bone means more likely to sprain)
Stability provided by:
• Interosseus lig and membrane
• Ant, post and transverse tibiofibular ligts
Talocrural Joint
- One of the most congruent joints in the human body (most bone on bone articulation)
- Single axis, 1 dof (one movement)
- Prox surface concave across distal tib and the tib and fib malleoli
- Distal – body of talus – 3 artic surfaces
Talocrural Joint Axis
Axis through fibula, below lat malleolus, oblique so movement is triplanar (combination of three movements)
– Dorsiflexion ~ 20-30° (with lateral motion – toe out, abd + ev) (axis isn’t completely straight, open kinetic chain)
– Plantarflexion ~ 30-50° (with medial motion – toe in, add + inv)
Talocrural Joint Movements
• Distal tibia twisted laterally (torsion) accounts for toe out position in normal stance (if didn’t, would be walking in a cross pattern)
• Movement of knee and ankle on fixed foot
– Needs to compensate for oblique axis of ankle joint
– Occurs at subtalar joint – PF and supination, DF and pronation (to compensate for the oblique axis of the talocrural joint)
– Also tibial rotation occurs with PF/DF on fixed foot
• Related to shape of talus (trochlea is cone shaped)
• MR of leg with DF
• LR of leg with PF
Talocrural Joint - DF and PF
- DF/PF movement largely determined by articular surfaces, variable due to motion at other distal joints
- DF checked by gastrocs/soleus (~knee position), plus bone and weak post capsule
- PF checked by Tib ant, EHL, EDL plus post tubercle of talus weak ant capsule
Ankle Dorsiflexors
– Tibialis anterior, extensor digitorum longus, extensor hallucis longus, peroneus tertius
– Main function is to assist in foot clearance in swing
Ankle Plantarflexors
- Triceps surae – gastrocnemius (also knee flex), fast twitch, prone to tightness and soleus – doesnt cross knee, slow twitch, postural muscle
- Has good lever arm as tendoachilles is 4-5cm from axis of ankle joint
- Other plantarflexors have a poor lever arm so don’t assist greatly (without achilles, can still plantar flex but can’t push down on ground)
- If triceps surae paralysed – cant rise on toes, hard to walk run or cimb stairs
Talocrural Stability - Anterior-posterior
– Effect of gravity keeps tibia pressed against talus – Tibia shape with bony spurs (congruency) (tibia pressed against talus)
– Collateral ligaments
– Triceps surae
Talocrural Stability - Medial - Lateral
– Interlocking articular surfaces – highly congruent – Inf tibiofibular joint
– Collateral ligts
• Medial collateral = Deltoid ligament, very strong
• Lateral collateral lig = ant talofib (weaker), post talofib (stronger), calcaneofib. **know three bands
Ant talofibular - when plantar flex, produces most of sideways stability
Soleus vs Gastrocnemius
Soleus • contains over 60% slow fibers. • One joint muscle • Multi-pennate (able to sustain pressure) Gastrocnemius • Larger proportion of fast twitch fibres • Two joint muscle • Bipennate
