Lower Leg Anatomy Flashcards
Osseous structures of the lower leg
- Tibia
- Fibula
- Talus
- Calcaneus
- Navicular
- Cuboid
- Cuneiforms (M/L/Int)
- Metatarsals
- Phalanges
- Sesamoids
structures of the proximal tibia
- Condyles
- Tibial Tuberosity
- Fibular Facet → posterio-lateral condyle
- Gerdy’s Tubercle
- Shaft is triangular at cross-section
- Tibial torsion:
- ~30 degrees external rotation at distal end
structures of the distal tibia
- medial malleolus projects inferiomedially from medial aspect of distal end
- lateral surface articulates with medial talar body
- Wider anteriorly
- Articulation with talus
- sagittal plane → concave
- transverse plane → convex
structure of the fibula
- long slender bone
- fibular head
- shaft
- lateral malleolus
- attaches to tibia at proximal and distal tibiofibular joints
- lateral component of talocrural joint’s proximal articulation
- not well suited for w/b
Navicular bone
- articulations
- talar head, cuneiform (+/-), cuboid
- proximal → oval and concave
- distal → convex with 3 facets
- lateral → irregular shaped
- navicular tuberosity
- primary attachment for tibialis posterior
Cuboid bone
- most lateral in distal tarsal row
- articulations
- 4th and 5th mets
- calcaneus
Cuneiform bones
- articulate with navicular, metatarsals 1-3, cuboid
medial cuneiform
- largest
- primary attachment of tibialis anterior (medial)
- slips from tibialis posterior and fibularis longus
intermediate cuneiform
- does not project as distally (recess for 2nd metatarsal)
- partial attachment tibialis posterior
lateral cuneiform
- partial attachment tibialis posterior (+/- flexor hallucis brevis)
metatarsals
- long bones → dorsal convexity and plantar concavity
- base, shaft, head
- 1-3 articulate with cuneiforms
- 4-5 articulate with cuboid
- 2nd is the longest
- styloid process on 5th
phalanges and sesamoids
- phalanges
- 2 in the great toe
- 3 in each of toes 2-5
- sesamoids
- common medial and lateral sesamoids of 1st MTPJ
- articulate with 1st met head, embeded in FHB
ankle stability
- rigid
- joint congruency
- capsular support
- ligamentous support
- muscular stability
- interaction of joint angles at varied positions
- perpendicular for stable platform
- yet flexible
- interaction of joint angles at varied positions
- parallel for load acceptance
- interaction of joint angles at varied positions
lower leg muscles in the anterior compartment
- tibialis anterior
- extensor hallucis longus
- extensor digitorum longus
- fibularis tertius
lower leg muscles in the lateral compartment
- fibularis longus
- fibularis brevis
lower leg muscles in the posterior compartment
- Superficial group
- gastrocnemius
- soleus
- plantaris
- Deep group
- popliteus
- tibialis posterior
- flexor digitorum longus
- flexor hallucis longus
muscles that dorsiflex
- tibialis anterior
- extensor digitorum longus
- extensor hallucis longus
- fibularis tertius
muscles that plantarflex
- gastrocnemius
- soleus
- flexor digitorum longus
- flexor hallicus longus
- Fibularis longus
- Tibialis posterior
muscles that perform inversion
- tibialis anterior
- tibialis posterior
muscles that perform eversion
- fibularis longus
- fibularis tertius
- fibularis brevis
Intrinsic foot muscles
- Layer 1
- abductor hallucis
- flexor digitorum brevis
- abductor digiti minimi
- Layer 2
- flexor digitorum accesorius (quadratus plantae)
- lumbricals
- Layer 3
- flexor hallucis brevis
- adductor hallucis
- flexor digiti minimi brevis
- Layer 4
- dorsal interiossei
- plantar interiossei
lower leg vasculature
- anterior tibial artery
- dorsalis pedis
- posterior tibial artery
- medial and lateral plantar arteries
- fibular artery
Lower leg nerves
- posterior tibial nerve
- common fibular nerve
- superficial fibular nerve
- deep fibular nerve
- deep fibular nerve
describe the plantar fascia
- dense aponeurosis
- longitudinally oriented, originating from the plantar calcaneus
- strongest and most dense centrally
- distally it is broader and thinner
- splits into 5 bands that diverge to the toes
describe the proximal tibiofibular joint
- lateral tibial condyle and fibular head
- plane synovial joint
- transverse vs oblique joint line
- has a capsule
describe the distal tibiofibular joint
- concave tibia and convex fibula
- syndesmosis joint
- ligaments:
- anterior and posterior tibiofibular ligaments
- interosseous ligament
- no capsule present
describe the talocrural joint
- uniaxial hinge joint
- mortise
- inferior tibia
- medial malleolus,
- lateral malleoulus of fibula
- inferior transverse tibiofibular ligament
- body of talus fits in mortise
- dynamic axis of rotation
motion at the transverse tarsal joint
- pronation
- supination
what occurs during supination
- talus drags along cuboid via naviculocuboid ligaments
- cuboid pulls under calcaneus and anteriorly under talus
- naviculocuboid pair rotates around a-p axis
what occurs during pronation
- N-C pair pulled laterally so forefoot faces anteriorly and laterally
- N-C pair rotates with navicular depression and cuboid abduction
describe the arthrology of the subtalar joint
- movements occur simultaneously in 3 planes
- supination
- slight depression causes slight extension of foot
- medial displacement causes adduction of foot
- rotation as calcaneus lies down flat on lateral surface with inversion of foot
- calcaneus pitches, turns, and rolls under talus
- axis oblique inferiorly, laterally, posteriorly
- partial sphere and cylinder
Arthrology of IPs and MTPs
concave proximally
convex distally
describe the osteokinematics of DF and PF
- DF/PF
- sagital movement primarily at the talocrural, MTP and IP joints
osteokinematics of inversion
tilting of the plantar surface of the foot towards the midline (coronal plane, in the subtalar and transverse tarsal joints)
osteokinematics of eversion
eversion is tilting away from the midline
at what joint does ABD/ADD of the foot occur?
transverse tarsal joints
and to a limited degree, the first tarsometatarsal joint and MTP joints
supination is a combo of what 3 movements?
Adduction, inversion, and plantarflexion
pronation is a combo of what 3 movements?
Abduction, eversion, and dorsiflexion
resting position and closed pack position of the Tibiofibular joint
- Resting → 10º plantarflexion
- Closed → full dorsiflexion
resting and closed-pack position of the talocural joint?
- Resting → ~10º plantarflexion
- Closed → full dorsiflexion
resting and closed pack position of the midfoot
- Resting → ~10º PF
- Closed → full dorsiflexion
resting and closed-pack position of the IP joints?
- resting → slight flexion
- closed → full extension
normal ROM for motions at the LE
- PF → 50
- DF → 20
- Supination → 45-60
- Pronation → 15-30
- Great Toe Flexion → MTP 40, IP 90
- Great Toe Extension → MTP 70, IP 0
dorsiflexion ranges with function
- walking → 10º
- standing up from a chair → 17-20º
- descend stairs → 20º
what are some things that may limit dorsiflexion?
- Bony factors
- superior surface of talar neck hits anterior margin of tibia
- mortise
- Capsuloligamentous factors
- posterior capsule
- posterior fibers of collateral ligaments
- Muscular factors
- triceps surae
list the arches at the foot and what bones make them up
- Medial arch
- calcaneus
- talar head
- navicular
- mets 1-3
- Lateral arch
- calcaneus
- cuboid
- 4-5th mets
- Transverse arch
- bases of mets
- cuboids
- cuneiforms
what is the windlass effect?
occurs in the medial longitudinal arch
plantar fascia resist flattening of the longitudinal arch and stores energy for propulsion