Flashcards in Foot and Ankle Deck (57):
What joint does the "ankle" refer to?
Rearfoot: bones and joints?
Talus, calcaneus, subtalar joint
Tarsal bones aside from calcaneus and talus
Osteology of the Fibula
Proximal head, distal lateral malleolus, takes on 10% of the body weight
Osteology of the Distal Tibia
Expands distally to accommodate load (90% of body weight), distal medial malleolus, torsion of long axis approx 20-30 degrees (causing toe-out)
What are the 7 Tarsal Bones?
Talus, calcaneus, navicular, cuboid, medial/lateral/intermediate cuneiforms
Osteology of the Talus
Joins foot to leg, does not have muscular attachments, 70% covered in articular cartilage, forms joint with ankle mortis
Trochlea/Talar dome, head (articulates with navicular), articular facets (inferior surface to articulate with calcaneus)
Osteology of the Calcaneus
Largest tarsal bone, attachment for Achilles
Osteology of Navicular
Medial side of foot, navicular tuberosity (attachment site for tibialis posterior)
6 sides, 3 articulate with adjacent tarsal bones
Osteology of the Metatarsals
Concave on plantar side, concave base (proximal), shaft, convex head (distal)
Osteology of Phalanges
14 in total, concave base (proximal), shaft, convex head (distal)
Dorsiflexion, eversion, abduction
Plantarflexion, inversion, adduction
Proximal Tibiofibular Joint
Head of fibula with lateral aspect of tibia, synovial joint, firm articulation to ensure force from biceps Femoris and LCL are transferred effectively from fibula to tibia
Distal Tibiofibular Joint
Syndesmosis (fibrous), ligament ours support to limit movement (interosseus ligament, ATFL and PTFL), limited movement (restricted movement associated with pain)
Articulation between trochlear dome and sides of talus with cavity formed by distal tibia and both malleoli
Must be stable!
90-95% of compressive force passes through
3mm of cartilage can compress by 30-40%
Capsule reinforced by ligaments
Also called MCL, fan shaped, limit excessive eversion, checks extreme ranges of motion
ATFL, PTFL, CFL
Controls varus (inversion) stress, weaker and more prone to injury
ATFL- inversion with PF
CFL- inversion with DF
PTFL- stabilizes talus in mortise
Osteokinematics at Ankle Joint
1 DOF at talocrural
Close packed= DF
Dorsiflexion occurs with slight abduction/eversion
Minimum 10 degrees necessary, normal ROM= 10-20
Plantarflexion occurs with slight adduction/inversion
Normal ROM= 20-50
Axes for Motion at Talocrural Joint
Abd/add= vertical axis
DF/PF= ML axis
Ev/Inv= AP axis
Arthrokinematics of Talocrural Joint
DF: talus rolls anteriorly, glides posteriorly
PF: talus rolls posteriorly, glides anteriorly
Formed by posterior, middle and anterior facets of calcaneus and talus
Posterior and lateral talocalcaneal ligaments (primarily stabilized by CF and Deltoid)
Subtalar neutral occurs when neither inversion or eversion occurs
Close packed= supination
Osteokinematics of Subtalar Joint
Triplanar motion about single oblique axis (uniaxial)
Motions= Supination (mainly inv. and add.)
Pronation (mainly ever. and abd.)
ROM: inversion 2x eversion
AOR of Subtalar Joint Motions
Abd/add= vertical axis
Ev/inv= AP axis
DF/PF= ML axis (but main components are abd/add and inv/ev!!!)
Transverse Tarsal (Midtarsal) Joints
Talonavicular and Calcaneocuboid
Convex talus, concave navicular, bone and spring ligament (when you step on unstable surface this adjusts)
Anterior distal calcaneus, proximal cuboid
Allows less motion than the talonavicular
Transverse Tarsal Joints--what do they do?
Rarely function in isolation (most often with Subtalar joint)
Transition between hindfoot and forefoot
Add to the overall ROM of sup/pron
In open chain, the midtarsal joints with augment inv/ev
Distal Intertarsal Joints
Navicular and cuneiforms, intercuneiform
Amplify pronation and supination
May experience tarsal coalition (restricted motion so may get excessive motion either proximally or distally)
Articulation between bases of metatarsals and distal surfaces of the 3 cuneiforms and the cuboid
-serve to position metatarsals and phalanges relative to weight bearing surface
-DO NOT contribute to pron/sup.
Articulation between convex head of metatarsals with concave base of proximal phalanges
-2 DOF (flex/ext; abd/add)
-2nd digit used as reference for abd/add
ROM for MTP Joints
1st MTP: ext= 55-95 (hyper)
2nd-5th MTP: ext= 60-100
5 proximal, 4 distal
1 DOF (flex/ext)
Serve to smooth the weight shift to the opposite foot during gait
Help maintain stability
Medial Longitudinal Arch (MLA)
Concave "instep" of medial foot
Loadbearing/shock absorbing structure (can quickly flatten out and absorb shock)
Formed by calcaneus, talus, navicular, cuneiforms, and associated 3 metatarsals
Bonds arch primarily reinforced by the plantar aponeurosis
Extrinsic muscles will also help during impact
What is the main reinforcement for the MLA?
Dense fascia, runs length of foot (originates on calcaneus and runs to proximal phalanx of each toe)
Active or passive toe extension increases the tension
How can you increase tension in the plantar Aponeurosis?
Passively or actively extend the toes
What happens to MLA during gait?
Cyclically rises and falls; rear foot shock absorption function--as WB depresses talus inferiorly, the MLA flattens
When MLA flattens, there is slight rearfoot pronation; returns to normal calcaneal inversion in NWB position
What occurs if someone has a low arch or "flat feet"?
Arch gets flattened much more than it should and there is more stretch on the plantar fascia
Plantar fascia cannot adequately accept or dissipate body weight
Formed by intercuneiform and cuneocuboid joint complex
Provides transverse stability
Flattens during WB, allowing weight distribution across all 5 metatarsal heads (so they can all touch ground)
What happens to the tibia during rearfoot inversion?
Tibia external rotation
Ankle Plantarflexors and Supinators primary roles functionally?
Decelerate forward tibial translation during gait (eccentric), accelerate body forward/upward (concentric), and stabilize knee extension.
Gastrocnemius, soleus, plantaris
Tibialis posterior, FDL, FHL
Dorsiflexors and Evertors role?
Toe clearance in gait (dorsiflexors) and protect us (ankle stability--lateral)
Which muscles are the primary Evertors?
Fibularis Longus and Brevis
When are the dorsiflexors most active during gait?
Mid- to late-stance; decelerate the rate and extent of supination at subtalar joint
Plantar fasciitis, heel Spurs, hallux valgus, hallux limitus/rigidus, pes planus, Pes cavus, lateral ankle sprain/CAI
Heel pain, greatest in a.m. Decreases with walking but increases agin with prolonged walking
Hook of bone that develops in calcaneus; most often seen in middle aged men and women, coincident with plantar fasciitis (some of calcaneus can peel off)
Hallux valgus (bunion)
Progressive valgus deformity of the great toe (lateral deviation relative to midline of body)
---inflamed or painful MTP joint
OA/limited motion at 1st MTP; major impact on gait!
Abnormally dropped MLA; associated with mid foot/proximal forefoot laxity--weakened plantar fascia, spring ligaments, or posterior tibialis
Abnormally high MLA, associated with rearfoot varus, most vulnerable to stress fractures associated with increased rigidity