Region 9 - Leg and Foot Flashcards
Where do the fibres of the interosseous membrane pass?
Inferolaterally from tibia to fibula
What is the function of the interosseous membrane?
Help resist downward pull of muscles attached to fibula
What type of joint is the superior tibiofibular joint?
Plane synovial
What is the superior tibiofibular joint between?
Flat articular surface on head of fibula
Articular facet on posterolateral aspect of lateral tibial condyle
What supports the joint capsule of the superior tibiofibular joint?
Anterior and posterior ligaments of head of fibula:
- Pass superomedially from head of fibula to lateral tibial condyle
When does the superior tibiofibular joint move and why?
During ankle dorsiflexion
Talus pushes up between malleoli of tibia and fibula
Where do the tendons of the anterior leg compartment pass?
Anterior to ankle
What is the general function of the anterior leg compartment?
Extensors of ankle and digits
What is the general function of the lateral leg compartment?
Evertors of foot
What are the origins of fibularis longus?
Head of fibula
Upper 2/3 of lateral fibula
What are the insertions of fibularis longus?
Base of 1st metatarsal
Medial cuneiform
What is fibularis longus innervated by?
Superficial fibular nerve (L5-S2)
What is the course of fibularis longus tendon?
Lies posterior to:
- Fibularis brevis tendon
- Fibular trochlea of calcaneus
What does fibularis longus tendon create a groove in?
Inferior surface of cuboid
What is the origin of fibularis brevis?
Inferior 2/3 of lateral fibula
What is the insertion of fibularis brevis?
Tuberosity on lateral side of base of 5th metatarsal
What is the innervation to fibularis brevis?
Superficial fibular nerve (L5-S2)
What are the relations of the fibularis brevis tendon?
Lies anterior to:
- Fibularis longus tendon
- Fibular trochlea of calcaneus
What are the muscles of the anterior compartment of the leg?
Tibialis anterior
Extensor digitorum longus
Fibularis tertius
Extensor hallucis longus
What is the innervation to the anterior compartment of the leg?
Deep fibular nerve (L4-L5)
What are the origins of tibialis anterior?
Lateral condyle of tibia
Superior 1/2 of lateral tibial surface
Interosseous membrane
What are the insertions of tibialis anterior?
Medial and inferior surfaces of medial cuneiform
Base of 1st metatarsal
What are the functions of tibialis anterior?
Dorsiflexes ankle
Inverts foot
What are the origins of extensor digitorum longus?
Lateral condyle of tibia
Superior 3/4 of medial surface of fibula
Interosseous membrane
What are the insertions of extensor digitorum longus?
Middle and distal phalanges of lateral 4 digits
What are the functions of EDL?
Extends lateral 4 digits
Dorsiflexes ankle
What are the origins of fibularis tertius?
Inferior 1/3 of anterior fibula
Interosseous membrane
What is the insertion of fibularis tertius?
Dorsal surface of the base of 5th metatarsal
What are the functions of fibularis tertius?
Dorsiflexes ankle
Assists in eversion of foot
What are the origins of extensor hallucis longus?
Middle anterior surface of fibula
Interosseous membrane
What is the insertion of EHL?
Dorsal aspect of distal phalanx of the hallux
What are the functions of EHL?
Extends hallux
Dorsiflexes ankle
What is the function of the extensor retinacula?
Prevent bowstringing of tendons
What are the origins and insertions of the superior extensor retinaculum?
Origin:
- Anterior border tibia
Insertion:
- Lower end of fibula
What are the origins and insertions of the inferior extensor retinaculum?
Origin: - Calcaneus laterally Insertions: - Medial malleolus (upper limb) - Blends with fascia over abductor hallucis (lower limb)
What is the shape of the inferior extensor retinaculum?
Y-shaped
What are the origins of the muscles on the dorsum of the foot?
Superior surface of calcaneus
Inferior extensor retinaculum
What are the insertions of the muscles on the dorsum of the foot?
Extensor hallucis brevis:
- Base of proximal phalanx of hallux
Extensor digitorum brevis:
- Long extensor tendons of digits 2-4
What is the innervation to EHB and EDB?
Deep fibular nerve (L5-S1)
Where does the superficial fibular nerve originate?
Between fibularis longus and neck of fibula
What are the functions of the superficial fibular nerve?
Motor to lateral leg compartment
Cutaneous:
- Distal anterior leg
- Most of dorsum of foot
What is the course of the deep fibular nerve?
Passes through EDL
Travels with anterior tibial artery on interosseous membrane
Supplies anterior leg compartment
Crosses ankle joint
What is the cutaneous distribution of the deep fibular nerve?
Skin between digits 1 and 2
What artery does the fibular artery arise from?
Posterior tibial artery
What is the origin of dorsalis pedis?
Continuation of anterior tibial artery
What are the branches of the dorsalis pedis artery?
Lateral tarsal artery
Deep plantar artery
Arcuate artery:
- Metatarsal arteries -> Digital arteries
What is the common insertion of the 3 superficial muscles in the posterior compartment of the leg?
Posterior calcaneus via tendocalcaneus
What structure do the tendons of the 4 deep muscles of the posterior leg compartment pass behind?
Medial malleolus
What are the origins of gastrocnemius?
Medial head:
- Popliteal (posterior) surface of femur (superior to medial condyle
Lateral head:
- Lateral aspect of lateral condyle of emur
What is the innervation to gastrocnemius?
Tibial nerve (S1-S2)
What are the functions of gastrocnemius?
Plantarflexes ankle
Flexes knee
What are the origins of plantaris?
Inferior end of lateral supracondylar line of femur
Oblique popliteal ligament
What is the innervation to plantaris?
Tibial nerve (S1-S2)
What is the function of plantaris?
Assists in plantarflexing the ankle
What are the origins of soleus?
Upper 1/3 of posterior fibula
Soleal line of tibia
Tendinous arch between bony attachments
What is the innervation to soleus?
Tibial nerve (S1-S2)
What is the function of soleus?
Plantarflexes ankle
What are the origins of popliteus?
Lateral surface of lateral femoral condyle (pit for popliteus)
Lateral meniscus
What is the insertion of popliteus?
Posterior surface of tibia:
- Superior to soleal line -> Popliteal area
What is the innervation to popliteus?
Deep fibular nerve (L4-S1)
What are the functions of popliteus?
Unlocks knee:
- Laterally rotates femur (5 degrees) on fixed tibia
Can medially rotate tibia if limb unplanted
What is the origin of FDL?
Posterior surface of tibia (inferior to soleal line)
What is the insertion of FDL?
Bases of distal phalanges of lateral 4 digits
What is the innervation to FDL?
Tibial nerve (L5-S2)
What are the functions of FDL?
Flexes lateral 4 digits
Weak plantarflexion ankle
Supports longitudinal arches of foot
What are the origins of FHL?
Inferior 2/3 of posterior fibula
Inferior interosseous membrane
What is the insertion of FHL?
Base of distal phalanx of hallux
What is the innervation to FHL?
Tibial nerve (L5-S2)
What are the functions of FHL?
Flexes hallux
Weak plantarflexion of ankle
Why is the muscle belly of FHL relatively large?
Flexion of hallux important for toe-off when walking
What are the origins of tibialis posterior?
Interosseous membrane
Posterior tibia (inferior to soleal line)
Posterior fibula
What are the insertions of tibialis posterior?
Every tarsal except talus: - Tuberosity of navicular - Cuneiforms - Cuboid - Sustentaculum tali of calcaneus Base of 2nd-4th metatarsals
What is the innervation to tibialis posterior?
Tibial nerve (L4-L5)
What are the functions of tibialis posterior?
Plantarflexes ankle
Inverts foot
What is the relation of the FDL and tibialis posterior tendons?
TP tendon deep to FDL in posterior compartment in groove posterior to medial malleolus
What does the FHL form grooves in>
Posterior surface of:
- Lower end of tibia
- Talus
What is the arrangement of the tendons of muscles in the posterior compartment of the leg at the medial malleolus from medial to lateral?
Tibialis posterior FDL (Posterior tibial artery) (Posterior tibial vein) (Tibial nerve) FHL
What is the course of the flexor retinaculum?
Medial malleolus -> Calcaneus
Where does the posterior tibial artery arise?
Between heads of gastrocnemius
Deep to soleus
What does the posterior tibial artery run on the surface of?
Tibialis posterior
FDL
What are the branches of the posterior tibial artery?
Fibular artery:
- Runs medial to fibula (within FHL)
Medial and lateral plantar arteries in foot
Where does the tibial nerve enter the leg?
Between heads of gastrocnemius
Deep to tendinous arch of soleus
Where does the tibial nerve run at the ankle?
Between FHL and FDL
What are the terminal branches of the tibial nerve?
Medial and lateral plantar nerves
What type of joint if the inferior tibiofibular joint?
Syndesmosis:
- Slightly movable fibrous joint
- Accommodates wedging of talar trochlea during ankle dorsiflexion
What ligament of the inferior tibiofibular joint is continuous with the interosseous membrane?
Interosseous tibiofibular ligament
What supports the inferior tibiofibular joint?
Anterior and posterior tibiofibular ligaments
What do the distal ends of the tibia and fibula form and what does this articulate with?
Malleolar mortise
Trochlea of talus
What is the range of motion at the ankle?
Dorsiflexion -> 20-30 degrees
Plantarflexion -> 30-50 degrees
What does the capsule of the ankle joint extend onto anteriorly?
Neck of talus
Where is the capsule of the ankle joint weak?
Anteriorly and posteriorly
What is the capsule of the ankle joint supported by and at what aspects?
Strong collateral ligaments:
- Laterally
- Medially
What are the 3 bands of the lateral collateral ligament of the ankle and where do they insert?
Anterior talofibular: - Neck of talus Posterior talofibular: - Lateral tubercle of talus Calcaneofibular: - Lateral surface of calcaneus
What is the alternate name for the medial collateral ligament of the ankle?
Deltoid ligament
What are the 4 parts of the medial collateral ligament?
Anterior tibiotalar
Tibionavicular
Tibiocalcaneal
Posterior tibiotalar
What forms the plantar aponeurosis?
Central portion of deep fascia in foot
What is the proximal attachment of the plantar aponeurosis?
Calcaneus
What are the distal attachments of the plantar aponeurosis?
Divides into 5 bands distally:
- Continuous with fibrous digital sheaths
What structures extend from the plantar aponeurosis in the midfoot and hindfoot? What do they form?
Vertical intermuscular septae forming compartments of the foot:
- Medial
- Central
- Lateral
What muscles are in the dorsal foot compartment?
EDB
EHB
What muscles are in the lateral foot compartment?
Muscles of little toe:
- Abductor digiti minimi
- Flexor digiti minimi brevis
What muscles are in the central foot compartment?
Flexor digitorum brevis Muscles associated with FDL tendon: - Lumbricals - Quadratus plantae Adductor hallucis
What muscles are in the medial foot compartment?
Muscles of great toe:
- Abductor hallucis
- FHB
What muscles form layer 1 of the foot muscles?
Abductor hallucis
FDB
Abductor digiti minimi
What are the origins of abductor hallucis?
Medial tubercle of calcaneus
Flexor retinaculum
What is the insertion of abductor hallucis?
Medial aspect of base of proximal phalanx of hallux
What is the origin and insertion of FDB?
Origin:
- Medial tubercle of calcaneus
Insertion:
- Middle phalanges of lateral 4 toes (medial and lateral aspects)
What is the origin and insertion of abductor digiti minimi?
Origin:
- Medial and lateral tubercles of calcaneus
Insertion:
- Lateral aspect of base of proximal phalanx of little toe
What muscles form layer 2 of the foot?
Long flexor tendons (FDL and FHL)
Lumbricals
Quadratus plantae
What are the origins and insertions of the lumbricals?
Origin:
- Tendons of FDL
Insertion:
- Medial aspect of dorsal tendon expansion of lateral 4 digits
What are the origins and insertions of the quadratus plantae?
Origins:
- Medial and lateral calcaneus
Insertion:
- Lateral side of FDL
What are the functions of quadratus plantae?
Assists FDL in flexion of digits 2-5
Straightens axis of FDL by pulling it laterally
What are the functions of the lumbricals?
Flex metatarsophalangeal joints of lateral 4 digits
Extends both interphalangeal joints of lateral 4 digits
What are the muscles in layer 3 of the foot?
Flexor hallucis brevis
Adductor hallucis
Flexor digiti minimi brevis
What are the origins of FHB?
Cuboid
Lateral cuneiform
What are the insertions of FHB?
Both sides of proximal phalanx of hallux
What is the function of the sesamoid bones in each tendon of FHB?
Create a tunnel to transfer weight to instead of onto FHL
What are the origins of adductor hallucis?
Transverse head:
- Plantar ligament of MTP joints
Oblique head:
- Base of metatarsals 2-4
What is the insertion of adductor hallucis?
Lateral side of base of proximal phalanx of hallux
What is the origin and insertion of flexor digiti minimi brevis?
Origin:
- Base of 5th metatarsal
Insertion:
- Base of proximal phalanx of 5th digit
What forms layer 4 of the foot?
3 plantar interossei 4 dorsal interossei Tendons of: - Fibularis longus - Tibialis posterior
What are the origins and insertions of the 3 plantar interossei?
Origins:
- Bases and medial sides of metatarsals 3-5
Insertions:
- Medial sides of proximal phalanx of 3rd-5th digits
What is the function of the plantar interossei?
Adduct digits 3-5 towards digit 2 (PAD)
What are the origins of the 4 dorsal interossei?
Adjacent sides of metatarsals 1-5
What are the insertions of the 4 dorsal interossei?
1st:
- Medial proximal phalanx of 2nd digit
2nd-4th:
- Lateral proximal phalanges of 2nd-4th digits
What are the functions of the 4 dorsal interossei?
Abduct digits 2-4
Digit 2 can abduct laterally or medially since it is the axial digit in the foot
What is the course of the plantar nerves in the foot?
Terminal branches of tibial nerve deep to flexor retinaculum
Enter foot deep to abductor hallucis
Where does the medial plantar nerve run?
Between abductor hallucis and FDB
Where does the lateral plantar nerve run?
Between layers 1 and 2
Deep and superficial branches:
- Deep branch between layers 3 and 4
What muscles are supplied by the medial plantar nerve?
Abductor hallucis
FDB
1st lumbrical
FHB
What are the root values of the medial and lateral plantar nerves?
S2-S3
What does the medial plantar artery supply
Muscles of hallux and overlying skin
What is the course of the lateral plantar artery?
Initially runs between layers 1 and 2
Deep arch between layers 3 and 4
What does the deep plantar arch join with and branch off to form?
Joins deep plantar artery from dorsalis pedis
Gives off:
- Metatarsal arteries -> Digital arteries
What are the functions of the foot arches?
Distribute weight
Act as shock absorbers
Act as spring boards
What supports the transverse arch?
Tarsal arch: - Tendon of tibialis posterior - Tendon of fibularis longus Metatarsal arch: - Adductor hallucis Anterior arch: - Deep transverse metatarsal ligament
What bones form the lateral longitudinal arch?
Calcaneus
Cuboid
4th and 5th metatarsals
What bones form the medial longitudinal arch?
Calcaneus Talus Navicular Cuneiforms 1st-3rd metatarsals
What structures provide DYNAMIC support to the longitudinal foot arches?
Intrinsic foot muscles
FHL
FDL
What structures provide PASSIVE support to the longitudinal foot arches?
Plantar calcaneonavicular (spring) ligament
Short plantar ligament (calcaneocuboid)
Long plantar ligament
Plantar aponeurosis
What is the anatomical subtalar joint between?
Slightly concave posterior calcaneal articular surface of talus
AND
Convex posterior articular facet of calcaneus
What type of joint is the anatomical subtalar joint?
Plane synovial
What joint, lying more anteriorly, is included in the surgical subtalar joint?
Talocalcaneal part of talocalcaneonavicular joint
What ligaments support the weak capsule of the subtalar joint?
Medial talocalcaneal
Lateral talocalcaneal
Posterior talocalcaneal
Interosseous talocalcaneal
Where does the interosseous talocalcaneal ligament lie and what does it do?
In tarsal sinus:
- Separates the two parts of the surgical subtalar joint
What forms the transverse tarsal joint?
Talocalcaneonavicular joint
Calcaneoucuboid joint
What types of joint are present in the talocalcaneonavicular joint?
Talocalcaneal joint -> Plane synovial
Talonavicular joint -> Ball and socket
What type of joint is the calcaneocuboid joint?
Plane synovial
What are the ligaments of the transverse tarsal joint?
Bifurcate ligament Dorsal calcaneocuboid ligament Long plantar ligament Short plantar ligament Spring ligament
What is the course of the bifurcate ligament?
Calcaneus -> Navicular and Cuboid
What is the course of the long plantar ligament?
Calcaneus -> Cuboid and Metatarsals
What is the course of the short plantar ligament?
Calcaneus -> Cuboid
What movements are possible at the subtarsal and talocalcaneal part of the talocalcaneonavicular joints?
Inversion/Eversion
What is the function of the midtarsal joint?
Augments inversion/eversion
How does the midtarsal joint carry out its function?
- Muscles attach on midfoot/forefoot:
- Start of inversion/eversion is midfoot/forefoot rotating on hindfoot at midtarsal joint - Ligaments tighten
- Force transferred to calcaneus
- Forefoot, midfoot and calcaneus rotate under talus (subtalar joint)
What is Lisfranc’s joint?
The collective tarsometatarsal joints:
- Medial cuneiform -> 1st metatarsal
- Intermediate cuneiform -> 2nd metatarsal
- Lateral cuneiform -> 3rd metatarsal
- Cuboid -> 4th and 5th metatarsals
What are the ligaments of the tarsometatarsal joints?
Dorsal
Plantar
Interosseous
What types of joints are the metatarsophalangeal joints?
Synovial condyloid
What movements do the metatarsophalangeal joints allow?
Flexion/Extension
Abduction/Adduction
What types of joints are the interphalangeal joints?
Synovial hinge
What movements do the interphalangeal joints allow?
Flexion/Extension