Lecture 19 - Leg and ankle Flashcards
Role of the foot and the ankle
Stability
• Stable base to support body
weight during stance and locomotion (for walking and standing)
• Rigid lever for effective push-off during gait (e.g. standing to walking)
Mobility
• Influences other joints
• Flexible for shock absorption • Conform to changing surfaces (adjust to a non flat surface)
Summarised role of the foot and ankle (2 words)
Stability and mobility
Arches
reduce force when foot comes into contact with the ground
act like springs for shock absorption
Bones of the leg =
Tibia and fibula
Tibia is
medial
fibula is
lateral
interosseous membrane of the leg
Connective tissue between two bones (fibula and tibia)
Tibial tuberosity
attachment site for the patella tendon
Common peroneal/fibular nerve
can easily be damaged
supplies movement and sensation to the lower leg, foot and toes
on the lateral surface just below the head of the fibula
Joints of the leg
Superior tibiofibular joint: synovial joint
Inferior tibiofibular joint: syndesmosis (fibrous joint with
limited movement)
Superior tibiofiular joint is a
Synovial joint
inferior tibiofibular joint is a
syndesmosis (fibrous joint with
limited movement)
Inferior tibiofibular joint is strengthened by …
Anterior tibiofibular ligament
Posterior tibiofibular ligament
Malleolus
a bony projection with a shape likened to a hammer head, especially each of those on either side of the ankle.
there is a lateral malleolus and a medial malleolus
Tendon vs ligament
Ligaments attach one bone to another. Tendons attach a muscle to a bone.
Bone divisons of the foot
Phalanges (3, each toe has three)
Metatarsals
Tarsal
Phalanges
3
each toe has three
Metatarsals
Metatarsals are part of the bones of the mid-foot and are tubular in shape.
Tarsals
The tarsal bones are 7 in number. They are named the calcaneus, talus, cuboid, navicular, and the medial, middle, and lateral cuneiforms.
Medial longitudinal arch
The medial longitudinal arch is formed by specific structures that allow the foot to function effectively. The medial arch is composed of the first three metatarsals, three cuneiforms, navicular, talus, and calcaneus bones of the foot.
Lateral longitudinal arch
The lateral arch is the flatter of the two longitudinal arches, and lies on the ground in the standing position. It is formed by the calcaneus, cuboid and 4th and 5th metatarsal bones.
Transverse arch
The transverse arch is located in the coronal plane of the foot. It is formed by the metatarsal bases, the cuboid and the three cuneiform bones.
Arches of the foot - how many and their names
- Medial longitudinal
- Lateral longitudinal
- Transverse
Arches of the foot are formed and supported by
Bones, ligaments, plantar fascia, muscles, tendons
Arches of the foot - Dynamic structures….
- Stability and flexibility
- Absorb & distribute force
- Aid propulsion
Ankle joint is what type of joint
Hinge joint
What does the ankle joint allow
Plantarflexion and dorsiflexion
plantarflexion
Plantarflexion refers extension at the ankle, so that the foot points inferiorly.
Dorsiflexion
Dorsiflexion refers to flexion at the ankle, so that the foot points more superiorly.
Ankle joint and movement
The ankle joint is a hinge joint; allowing dorsiflexion and plantarflexion
Ankle joint movements - Muscles passing over the dorsal surface
- dorsiflex the ankle joint, and/or
* extend the toes
Ankle joint movements - Muscles passing over the plantar surface
- plantarflex the ankle joint, and/or
* flex the toes
Dorsal surface of the foot is the …
the area facing upwards while standing
Plantar surface of the foot is the …
the area facing downwards whilst standing
Dorsiflexion vs plantarflexion
Dorsiflexion refers to flexion at the ankle, so that the foot points more superiorly. Plantarflexion refers extension at the ankle, so that the foot points inferiorly.
Ankle joint - classification
Hinge
Movements of the ankle joint
Plantarflexion and dorsiflexion
What bones form the socket of the ankle joint?
- Medial malleolus (tibia)
- Lateral malleolus (fibula)
- Inferior surface of the distal end of tibia
Tibia and fibula articular with
Talus
Talus
tarsal bone in the hindfoot that articulates with the tibia, fibula, calcaneus, and navicular bones
Subtalar joint is between
talus and calcaneus
Subtalar joint allows
inversion and eversion
Inversion
Inversion involves the movement of the sole towards the median plane – so that the sole faces in a medial direction.
Eversion
Eversion involves the movement of the sole away from the median plane – so that the sole faces in a lateral direction.
Subtalar joint movements - medial
muscles inserting from the medial side invert the foot
Subtalar joint movements - lateral
muscles inserting from the lateral side evert the foot
Ankle joint ligaments
Lateral collateral ligaments - posterior talofibular ligament, anterior talofibular ligament, calcaneofibular ligament
Medial collateral (deltoid) ligaments
Lateral collateral ligaments
- Commonly damaged in ankle sprain
- Function: restrict INversion
Lateral collateral ligaments - posterior talofibular ligament, anterior talofibular ligament, calcaneofibular ligament
Weaker than medial because there are three of them, one can potentially be ruptured in injury
Medial collateral ligaments
- Stronger than the lateral collateral ligament
- Function: Restricts Eversion
Only one ligament but it is quite strong
posterior talofibular ligament
The posterior talofibular ligament is a ligament that connects the fibula to the talus bone. It runs almost horizontally from the malleolar fossa of the lateral malleolus of the fibula to the lateral tubercle on the posterior surface of the talus.
anterior talofibular ligament
It passes from the anterior margin of the fibular malleolus, anteriorly and laterally, to the talus bone
calcaneofibular ligament
running from the tip of the lateral malleolus of the fibula downward and slightly backward to a tubercle on the lateral surface of the calcaneus.
Ankle sprain
Nearly everyone’s had one!
Happens in inversion and often during plantarflexion - plantarflexion because the anterior part is wider than the posterior part of the head of the talus
Usually damage to one or more of the lateral ligaments
Incidence: Female > Male; Children > Adolescents > Adults (children have less developed ligaments and muscles so common)
High heels also puts people at higher risk - puts lots of pressure on different parts of the joints, hyperextension between the phalanges and the metatarsals (phalanges are horizontal and metatarsals are practically vertical), head of talus is no longer at the ankle joint it is very much plantarflexed which causes some instability to the ankle joint
What are the symptoms? Bruise, pain, swelling
Muscle compartments leg
Anterior = dorsiflexion
Lateral = (contraction brings) eversion
Posterior (largest one) = plantarflexion
Plantarflexors list
Gastrocnemius
Soleus
Gastrocnemius is a
plantarflexor
Gastrocnemius origin
(2 heads - medial and lateral)
Medial and lateral femoral condyles
Gastrocnemius insertion
Calcaneus via calcaneal (Achilles) tendon
Gastrocnemius functions
- Knee: Flexes - 2 heads cross the knee joint therefore knee flexion
- Ankle: Plantarflexes - attachment to calcaneus therefore can cause this movement
- Propulsion during gait
Gastrocnemius nerve
Tibial
Soleus …
• Deep to gastrocnemius; does not cross the knee joint
Soleus origins
- Tibia and fibula
* Interosseous membrane
Soleus insertion
• Calcaneus via calcaneal (Achilles) tendon
Soleus funtions
• Knee: No action (because no attachment)
• Ankle: Plantarflexion
• Important postural muscle
(e.g during standing, propulsion during gait)
Soleus nerve
Tibial
Extrinsic muscles are
muscles within the leg but have long tendons which is why they have the ability to control foot movement
Extrinsic muscles …
• Control various foot movements
• Each muscle has a muscle belly in the leg and a long tendon attaching to the foot
(Intrinsic foot muscles but won’t be covered in this course)
Long tendons - extrinsic foot muscles
- These tendons are held in place by retinaculum (fibrous tissue)
- Have associated bursae to reduce friction
- Bones and muscles create pulleys – biomechanical advantage (reduce load and the amount of force that you have to lift)
Deep flexors - ankle and toes pass through
tarsal tunnel (under flexor retinaculum)
contains the deep posterior muscles and the VAN
Deep flexors - ankle and toes =
Tibialis posterior
Flexor digitorum longus
Artery (posterior tibial), nerve (tibial)
Flexor hallicus longus
Tom Dick And Very Nervous Harry stands for …
Deep flexors - ankle and toes .... Tibialis posterior Flexor digitorum longus Artery (posterior tibial), vein, nerve (tibial) Flexor hallicus longus
Deep flexors - deep posterior compartment of the leg
- Tibialis posterior (TP)
- Flexor Digitorum longus (FDL)
- Flexor Hallucis longus (FHL);
Their tendons pass posterior to medial malleolus
Flexor Digitorum longus (FDL) tendon
tendon splits into 4 and goes to toes 2-5
Flexor Hallucis longus (FHL) tendon
tendon only goes to the big toe (hallux toe)
Hallux
Big toe
tibialis posterior and movement =
inversion
Deep flexors - ankle and toes functions
- Ankle: Plantarflexion (all)
- Toes: Flexion of big toe (FHL), and toes 2-5 (FDL)
- Stabilise medial longitudinal arch (especially TP)
- Propulsion at toe-off (FHL)
Tibialis posterior tendon
- Spring ligament supports the head of talus. - damage causes flat food as head of talus comes down
- Further supported by the TP tendon to maintain the medial arch.
Spring ligament = plantar calcaneonavicular ligament
FHL and FDL support the
medial arch
Flat foot deformity
- If ruptured, the spring ligament can’t support the head of the talus anymore
- Flat foot deformity could be due to ruptured TP tendon, as a result of aging, trauma or denervation
Anterior compartment of leg muscles (3)
- Tibialis anterior (TA) - medial side therefore inversion
- Extensor digitorum longus (EDL) - to extend lateral 4 digits
- Extensor hallucis longus (EHL) - big toe extension
Three muscles of the anterior compartment of the leg are supplied by the
deep fibular nerve
Anterior compartment of leg muscles (3) and their insertions (dorsal surface)
- TA: Medial cuneiform, base of 1st metatarsal
- EDL: Distal phalanges of toes 2-5
- EHL: Distal phalanx big toe
Anterior compartment muscles - the muscle tendons pass
under extensor retinacula
Anterior compartment muscles function
- Ankle: dorsiflexion (all)
- Toes: extension of the hallux (EHL), toes 2-5 (EDL)
- Subtalar joint: INversion (TA)
- Stabilise medial longitudinal arch (TA)
Lateral compartment muscles (2)
Two muscles
• Fibularis (peroneus) longus
• Fibularis (peroneus) brevis
Lateral compartment muscles origins
Both originate from the fibula
Lateral compartment muscles insertions
• Fibularis longus: base of 1st metatarsal
(passes under foot) (goes deep into foot)
• Fibularis brevis: base of 5th metatarsal
Insertion of fibularis longus
• Fibularis longus: base of 1st metatarsal
(passes under foot)
• Help stabilize the transverse arch
curves and crosses foot to the 1st metatarsal
Lateral compartment muscles function
• Ankle: weak plantarflexion (both)
• Subtalar joint: Eversion (both)
• Toes: No action
• Both stabilize lateral longitudinal arch
• Fibularis longus stabilizes transverse arch
(due to its course along plantar surface of foot)
Which tendons stabilise medial longitudinal arch?
Medial longitudinal arch is supported by tendons that pass on medial aspect of foot • Tibialis anterior • Tibialis posterior • Long toe flexor tendons (when walking)
Which tendons stabilise lateral longitudinal arch?
Lateral longitudinal arch is supported by tendons that pass on lateral aspect of foot
• Fibularis longus
• Fibularis brevis
Which tendons stabilise transverse arch?
Transverse arch is supported by tendons that pass transversely
• Fibularis longus
• Small intrinsic muscles of foot
Arch support is critical for
stability when weight bearing
