Foot and Ankle Flashcards
What are the 7 tarsus of the foot?
- calcaneus
- talus
- navicular
- cuboid
- cuneiforms (3)
Why are there 5 metatarsus (3 phalanges per metatarsal), but only 14 phalanges?
Only 2 phalanges articulate with the first metatarsal, while the other 4 metatarsus articulate with 3 phalanges
Describe the fascia of the foot in terms of dorsal and plantar aspects:
- dorsal: thin and continuous with extensor retinaculum
- plantar: plantar fascia, central part thickens to form plantar aponeurosis (becomes tendinous)
- a part of the plantar fascia and arises from calcaneous posteriorly
- consists of longitudinally arranged band of dense connective tissue
- covers entire length of sole
- divides into five bands (enclose digital tendons)
- helps support the longitudinal foot arches
plantar aponeurosis
- plantar aponeurosis inflammation at proximal attachment (calcaneus)
- pain is most severe after sitting and getting out of bed
- causes: running, high impact exercise, worn out shoes, overweight
- may lead to: bony process (“heel spur” or “calcaneal spur”) may develop especially from medial calcaneal tubercle
plantar fasciitis
What are the 2 muscles present in the dorsum of foot?
- innervation?
- extensor hallucis brevis (1st phalanx)
- extensor digitorum brevis (2nd-4th phalanges): joins respective long tendons approximately at the MP joint
(these muscles form a fleshy mass on lateral part of dorsum of foot, anterior to lateral malleolus)
- innervation: deep fibular N.
What is the arrangement of the plantar foot muscles and what is their role?
- arranged in 4 layers
- these muscles are synergists: help maintain foot arches and stand on uneven ground
What are the plantar muscles of the first layer? (3)
(3 short muscles that extend from calcaneous to phalanges)
- abductor digiti minimi
- flexor digitorum brevis
- abductor hallucis
What are the plantar muscles of the second layer? (2)
(keeps toes in line and prevents them turning laterally when flexor digitorum longus is contracting)
- quadratus plantae: joins tendon of FDL to calcaneous, assits FDL in flexing lateral four digits
- lumbricals: originate from FDL tendons, medial aspect of extensor expansion, flex mp joint, extend pip and dip joints
*FHL and FDL tendons are located in this layer, but not considered a part of 2nd layer plantar muscles*
What are the plantar muscles present in the third layer? (3-4)
(3 short muscles to first and fifth digits (anterior half of foot))
- flexor digiti minimi brevis
- adductor hallucis: transverse head and oblique head
- flexor hallucis brevis: two heads (medial and lateral) cover plantar surface of first metatarsal, tendons have sesamoid bones, protect first metatarsal head and tendon of FHL when standing/walking
What are the plantar muscles of the fourth layer?
(interossei between metatarsals)
- 3 plantar interossei: “pad” digits 3, 4, and 5 toward 2nd digit
- 4 dorsal interossei: “dab” digits 2, 3, and 4 away from midline of 2nd digit
*fibularis longus and tibialis posterior tendons are also in this layer*
- a foot deformity characterized by lateral deviation of great toe
- surrounding tissues swell and resultant pressure/friction against shoe causes bursa to form
- if the bursa becomes tender/inflammed, this is a bursa
- inflammed areas of thick skin, corns, may form over proximal interphalangeal joints
- possible causes: wearing pointy heeled shoes
hallux valgus
What is one of the main causes of toe deformities?
What are the 4 main types of toe deformities?
- in part, because of shortened flexor muscles which can override lumbrical function
- mallet toe (flexion in distal IP joint), hammer toe, claw toe, trigger toe (extended mp, flex ip)
- toe deformity (usually of 2nd toe)
- proximal phalanx is permanently hyperextended at metatarso-phalangeal joint
- middle phalanx is plantarflexed at the proximal interphalangeal joint
- distal phalanx is extended
hammer toe
- toe deformity characterized by hyperextension of metatarso-phalangeal joints
- flexion of the distal and proximal interphalangeal joints
claw toes
What nerves innervate the plantar portion of the foot?
- tibial N. divides posterior to medial malleolus into: medial and lateral plantar Ns.
- supply all intrinsic muscles of foot (except 2 intrinsic dorsum muscles) by the deep branches
- supply plantar skin by the superficial branches
What nerves innervate the cutaneous dorsal portion of anterior ankle and foot?
- most of anterior foot: superficial fibular N.
- interspace between 1st and 2nd digits: deep fibular N.
- branches off sural N.: lateral aspect of foot
Medial plantar N.
- Course:
- Muscles innervated:
Medial plantar N.
- Course: passes deep to abductor hallucis, runs anteriorly between abdudctor hallucis and flexor digitorum brevis, terminates near metatarsal bases by dividing into four sensory branches (medial 3 and 1/2 digits)
- Muscles innervated: abductor hallucis and FDB (1st layer), medial 1st lumbrical (2nd layer), FHB (3rd layer)
Lateral plantar N.
- Course:
- Muscles innervated:
Lateral plantar N.
- Course: passes deep to abductor hallucis, runs anterolaterally deep to flexor digitorum brevis, terminates by dividing into superficial and deep branches
- Muscles innervated: abductor digiti minimi, quadratus plantae, lateral 3 lumbricals, adductor hallucis, FDMB, interossei
What arteries supply the foot?
terminals branches of anterior and posterior tibial As.
Describe the foot As. in terms of branching and anastamoses:
- tibial A. branches off into lateral malleolar A. and lateral tarsal A.
- tibial A. continues to descend into the dorsal pedis A. which runs anteromedially to first interosseous space and divides into: arcuate A. and deep plantar A.
- loops between these As. create the dorsal arch
- plantar and dorsal artery arch interact and create anastamosis
- dorsal pedis A. branch
- runs laterally across metatarsal bases (deep to extensor tendons)
- gives rise to 2nd-5th dorsal metatarsal As. which give rise to dorsal digital As.
arcuate A.
- dorsal pedis A. branch
- passes through first interosseous space
- joins lateral plantar A. to form the plantar arch
- gives rise to first dorsal metatarsal A.
deep plantar A.
- artery derived from posterior tibial A.
- passes distally between abductor hallucis and FDB
- gives rise to medial 2 plantar metatarsal and plantar digital As.
medial plantar A.
- artery derived from posterior tibial A.
- runs w/ lateral plantar nerve (superficial to quadratus plantae)
- terminates by joining deep plantar A. forming the plantar arterial arch
- gives rise to 3rd-6th plantar metatarsal and plantar digital As.
lateral plantar A.
What the functions of foot arches?
What are the 2 different kinds of foot arches?
- functions: absorb shock during weightbearing, makes foot adaptable to surface/weight changes
- longitudinal arch (medial/lateral parts) and transverse arch
- type of foot arch
- medial part formed by calcaneus, talus, navicular, 3 cuneiforms, and medial 3 metatarsals
- lateral part formed by calcaneus, cuboid, and lateral 2 metatarsals
longitudinal arch
What are the “important” dyanmic stabilizers of longitudinal foot arch?
Passive stabilizers?
- dynamic: flexor hallucis longus and tibialis posterior
- passive: long plantar ligament, plantar calcaneocuboid ligament (short plantar L.), plantar calcaneonavicular ligament (spring L.)
- type of foot arch
- runs between medial and lateral longitudinal arches
- formed by cuboid, 3 cuneiforms, and metatarsal bones
transverse arch
What are stabilizers of the transverse arch in the tarsal arch, metatarsal arch, and forefoot?
- tarsal: tibialis posterior and fibularis longus (active/dynamic)
- metatarsal: adductor hallucis (oblique and transverse head) (active/dynamic)
- forefoot: plantar ligaments and deep transverse metatarsal ligament (passive)
Loss of transverse arch:
Loss of longitudinal arch:
- pes transversoplanus
- pes planus
- condition that results usually from fallen medial parts of longitudinal arch
- plantar ligaments and plantar aponeurosis become abnormally stretched
- plantar calcaneonavicular ligament can no longer support talus head, causing talar head to displace inferomedially and becomes prominent
pes planus (flatfeet)
Ankle (talocrural) joint
- Articulating bones and associated dynamics:
- Type of joint:
- Capsule type:
Ankle (talocrural) joint
- Articulating bones and associated dynamics: tibia and fibula (inferior ends) and talus (trochlea): 3-sided mortise (deep socket) formed by 2 malleoli and inferior tibia, malleoli grip on trochlea strongest during dorsiflexion (wide anterior part moves posteriorly, spreading leg bones)
- Type of joint: hinge synovial joint (dorsiflexion and plantarflexion)
- Capsule type: articular capsule (thin anteriorly and posteriorly, each side supported by strong medial/lateral collateral ligaments)
Medial/Deltoid ligament:
- Stabilization:
- Four parts:
Medial/Deltoid ligament:
- Stabilization: of the ankle joint during eversion
- Four parts (named from leg bone to foot bone): anterior tibiotalar, tibionavicular, tibiocalcaneal, posterior tibiotalar
Lateral ankle ligaments:
- 3 discrete ligaments:
- named from:
- clinical relevance:
Lateral ankle ligaments:
- 3 discrete ligaments (that attach to lateral malleolus to talus and calcaneus): posterior tibiofibular L. and anterior tibiofibular L. (tibiofibular syndesmosis Ls.), and anterior talofibular L.
- named from: foot bone to leg bone
- clinical relevance: likely where the tearing/injury occurs for high ankle sprains
Describe the joints in the foot that involve tarsus, metatarsus, and phalanges:
What are the 2 important intertarsal joints?
- Describe the joints in the foot that involve tarsus, metatarsus, and phalanges: small and tightly joined by ligaments, only slight movement occurs between them
- 2 important intertarsal joints: transverse tarsal joint and subtalar joint (talocalcanean joint)
- important intertarsal joint in the foot
- formed by two separate joints aligned transversely: talonavicular joint and calcaneocuboid joint
- together, they permit slight rotation and add to inversion and eversion at the talocalcaneal joint
- transection across this joint is standard method for surgical amputation of foot
transverse tarsal joint
- important intertarsal joint
- where talus rests on calcaneus
- main movements: inversion and eversion
- fibrous capsule supported by interosseous talocalcaneal L.
subtalar (talocalcanean) joint
- most frequent injured joint in the body
- ligament fiber tears are almost always due to inversion injury
ankle sprain
