L7: Functional Anatomy of the Foot Flashcards
What are the 3 groups bones in the foot?
Tarsal bones–> Calcaneous, Navicular, Talus, Cuneiforms and cuboid
Metatarsals–> 1-5
Phalanges–> Proximal, middle and distal
What are the 3 regions of the foot? What bones are found there?
Hindfoot–> Calcaneous and Talus
Midfoot–> Navicular, Cuboid and Cuneiforms
Forefoot–> Metatarsals and phalanges
What are the 3 articulations around the talus?
Superiorly–> ankle joint, between the tibia, fibula and talus (talocrural joint)
Inferiorly–> Subtalar joint, between talus and calcaneous
Anteriorly–> Talonavicular joint, between the talus and navicular
What is the main function of the talus?
Transmit the weight of the body to the foot–> calcaneous
How is structure of the talus related to its function?
Trochlear articulates with tibia and fibula
Anterior wider than posterior
Provides stability to dorsiflexed foot
What is significant about the blood supply to the talus?
Retrograde supply
Arteries enter at the distal end of bone
Avascular necorosis if fractured
What does the calcaneous articulate with?
Largest bone
Inferior to talus
Superiorly–> Subtalar–> (talocalcaneal joint)–> talus and calcaneous
Anteriorly–> Calcaneocuboidal joint –> between calcaneous and cuboid
What is an important feature of the calcaneous?
Calcaneal tuberosity–> Achilles tendon attaches
What are the articulations of the navicular? What is a feature of the navicular?
Positioned medially (intermediate row) Posteriorly--> talus Anteriorly--> 3 cuneiform bones Laterally--> Cuboid Inferior part--> tuberosity for insertion of tibialis posterior tendon
What are the cuneiforms? What do they articulate with?
Medial, intermediate (middle) and lateral
Wedge shaped bones–> helps to form transverse arch
Articulate with navicular–> proximally
1, 2 and 3 metatarsals distally
What inserts onto the medial cuneiform?
Tibilalis anterior, Tibialis posterior and peroneus (fibularis) longus
What is the cuboid? What does it articulate with?
Cuboidal shaped bone–> lateral
Proximally–> calcaneous
Distally–> 4 and 5 metatarsals
Inferior part–> groove for tendon of peroneus (fibularis) longus
What are the metatarsals?
Between phalanges and tarsal bones
Number I-V–> medial to lateral
Describe the anatomy of the metatarsals?
Convex dorsally
Base –> proximally
Shaft
Neck and head –> distally
What do the metatarsals articulate with?
Base of metatarsals and tarsals–> Tarsometatarsal joints
Between metatarsals–> Intermetatarsal joint
Between metatarsal and head of proximal phalange–> Metatarsophalangeal joints
What are the phalanges?
Bones of toes
2-5 have proximal, middle and distal phalanges
1- Great (big) toe only proximal and distal
Base, shaft and head
Describe the structure of the ankle joint?
Talocurral joint
Hinge joint –> dorsiflexion and plantar flexion
Tibia and fibular form ankle mortise–> bracket shaped socket
Trochlear of talus fits snugly into ankle mortise –> aka Malleolar fossa
When is the joint most stable? Why?
Dorsiflexion most stable–> anterior part of trochlear of talus is wider so fills ankle mortise better
Plantarflexion less stable–> posterior part narrower
What stablisies the ankle mortise?
Tibia and fibular held together by strong tibiofibular ligament at distal tibiofibular joint
What causes plantarflexion and dorsiflexion?
Plantarflexion–> Muscle in posterior compartment of leg–> gastrocnemius, soleus, plantaris and tibialis posterior
Dorsiflexion–> Anterior compartment–> Tibialis anterior, extensor hallus longus, extensor digitorum longus and peroneus tertius
What ligaments reinforce the ankle joint?
Lateral ligaments–> Resist inversion
- -> Anterior talofibular ligament - lateral malleolus and neck of talus
- -> Posterior talofibular ligament - malleolar fossa and lateral tubercle of the talus
- -> Calcaneofibular ligament - tip of lateral malleolus to the lateral surface of calcaneus
Medial ligament–> Resist eversion
–>Medial/ Deltoid ligament - Fibres span out from medial mallelous to talus, calcaneous and navicular
Where do inversion and eversion occur? What is there role?
Subtalar, calcaneocuboid and talocalcaneonavicular joint
Allows walking on uneven surfaces
Subtalar–> oblique axis–> major joint for inversion and eversion
What muscles help produce eversion?
Posterior compartment–> Peroneus Longus and peroneus brevis
Anterior compartment–> Peroneus tertius
Which muscles help produce inversion?
Tibialis anterior and tibialis posterior
What are the arches of the foot?
Transverse arch –> half arch
Medial longitudinal arch
Lateral longitudinal arch
Maintained by shape of bones, ligaments of the foot, intrinsic muscles of the foot and long tendon of the extrinsic muscles
What are the main weight bearing bones during standing?
Heel and heads of metatarsals
What forms the medial longitudinal arch?
Calcaneous, talus, navicular, 3 cuneiforms and medial 3 metatarsals
How is the integrity of the medial longitudinal arch maintained?
Plantar aponeurosis and spring ligaments (plantar calcaneonavicular ligament– binds calcaneum and navicular together)
Tibilalis anterior and peroneus (fibularis) longus tendons
What muscles support the medial longitudinal arch?
Tibialis anterior, tibialis posterior, peroneus (fibularis) longus and flexor hallucis longus
What forms the lateral longitudinal arch? What helps support this arch?
Calcaneous, cuboid and lateral two metatarsals
Support- Contraction of peroneus (fibularis) brevis muscle
What happens to the arches when standing? What happens when walking?
Arches sink under weight of the body
Individual bones lock together
Ligaments binding them under maximum tension
Foot is immobile pedestal
Tension released–> arches unlock–> mobile lever system with spring-like action
What are the muscles in the anterior compartment of the leg?
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Peroneus (fibularis) tertius
What is the main function of the anterior leg muscles?
Dorsiflex and invert foot at ankle joint
Extensors–> Extension of the toes
What nerves innervate the anterior leg muscles? What is the blood supply?
Deep peroneal (fibular) nerve L4-5 Anterior tibial artery
What is the origin, insertion, innervation and function of the Tibilais anterior?
O: Lateral surface of tibia
I: Medial cuneiform and base of first metatarsal
Passes deep to extensor retinacula at the ankle
Innervation: Deep peroneal (fibular) nerve
F: Dorsiflexion and inversion of the foot
What is the origin, insertion, innervation and function of the extensor digitorum longus?
Lateral and deep to Tibialis anterior
O: Lateral condyle of tibia, medial surface of fibula and interosseous membrane
I: Fibres converge into single tendon which passes deep to extensor retinaculum and splits into 4 tendons–> Middle and distal phalanges of 2-5th toes
Innervation: Deep fibular nerve
F: Extension of toes and assists in dorsiflexion
What is the origin, insertion, innervation and function of the extensor hallus longus?
Deep to EDL and TA O: Medial surface of fibular shaft I: Base of distal phalanyx of great toe under the extensor retinaculum Innervation: Deep fibular nerve F: Extension of the great toe
What is the origin, insertion, innervation and function of the peroneus (fibularis) tertius?
Not present in all
O: Medial surface of fibula, inferior to EDL origin
I: Base of 5th metatarsal
Travels with EDL tendon until reaches dorsum of foot, passes deep to extensor retinaculum
Innervation: Deep fibular nerve
F: Eversion and assists in dorsiflexion
What muscles are in the lateral compartment of the leg?
Two muscles
Peroneus (fibularis) Longus
Peroneus (fibularis) Brevis
What is the innervation of the lateral compartment?
Superficial peroneal (fibular) nerve L4-S1
What is the origin, insertion, innervation and function of the peroneus (fibularis) longus?
Larger and more superficial
O: Upper lateral surface of fibula, lateral tibia condyle
I: Posterior to lateral mallelous, across plantar surface of foot onto the medial cuneiform and base of 1st metatarsal
Innervation: Superficial peroneal nerve (L4-S1)
F: Everts and assists in plantarflexion, supports medial and transverse arch of foot
What is the origin, insertion and innervation of the peroneus (fibularis) brevis?
Deeper and shorter
O: Inferolateral surface of fibular shaft
I: descends with PL tendon, posterior to lateral mallelous onto tubercle on base of 5th metatarsal
Innervation: Superficial peroneal nerve (L4-S1)
F: Everts foot, support lateral longitudinal arch
What muscles are found in the posterior compartment of the leg?
7 muscles –> tibial nerve innervation
Divided into superficial and deep–> layer of fascia
Superficial–> common tendon Calcaneal (Achilles) tendon onto calcaneal tuberosity
–> Gastrocnemius
–> Plantaris
–> Soleus
Deep
- -> Popliteus
- -> Tibialis posterior
- -> Flexor Digitorium Longus
- -> Flexor Hallucis Longus
What is the origin, insertion, innervation and function of the Gastrocnemius muscle?
Most superficial
O: Lateral head–> lateral femoral condyle
Medial head–> Medial femoral condyle
I: Calcaneal tendon onto calcaneal tuberosity
Innervation: Tibial nerve
F: Plantarflexion, also assist in knee flexion
What is the origin, insertion, innervation and function of the plantaris?
Small muscle, absent 10%, long thin tendon
O: Lateral supracondylar line of the femur
I: Descend medially to insert into calcaneal tendon onto calcaneal tuberosity
Innervation: Tibia nerve
F: Weak plantarflexion, and flexion of leg at knee
What is the origin, insertion, innervation and function of the Soleus?
Deep to others O: Soleal line of tibia I: common tendon onto calcaneal tuberosity Innervation: Tibial nerve F: Plantarflexion of foot
What are the names of the bursae found in the superficial posterior compartment and what is there function?
Subcutaneous calcaneal bursae–> skin and calcaneal tendon
Deep calcaneal bursae–> Calcaneal tendon and calcaneus
Minimise friction