Foot and Ankle Flashcards
Osteology
Ankle - talocrural joint
Foot - all tarsal bones and joints distal to ankle
Rearfoot - calcaneus, talus, subtalar joint (subtalar motion occurs here)
Midfoot - remaining tarsal bones
Forefoot - metatarsals, phalanges
Foot - rigid and mobile (mobile enough to be shock absorber and accept weight/load during walking/running/cutting and rigid lever to propel us forward)
Functions of Foot
Acts as support base that provides necessary stability for upright posture w/ minimal muscle effort
Provides mechanism for rotation of tibia and fibula during stance phase of gait
Provides flexibility to adapt to uneven terrain
Provides flexibility for absorption of shock
Acts as lever during push-off
Fibula
Head is proximal
Distal end forms lateral malleolus (lateral aspect of ankle mortis)
10% of body weight
Distal Tibia
Expands distally to accommodate load (90% BW) - weight bearing surface to accept load
Distal end forms medial malleolus
Torsion of long axis 20-30 degrees (“toe out”) - naturally twists ER
Talus
Joins foot to leg
Lacks muscular attachments
Complex shape, 70% covered in articular cartilage
Any mvt that occurs is occurring by way of forces in surrounding joints
Mvt occurs due to motion of other joints
Almost all weight bearing surface
Trochlea/talar dome - articulates with talocrural space
Head - projects slightly medially and forward
Articular facets - inferior surface, articulates w/ calcaneus
Head and neck - contribute to MLA
Out Toeing
Sum of what’s occurring at tibia and femur
True foot positions - relies on entire limb, not just one or other
Tarsal Bones
Talus
Calcaneus - largest tarsal bone, attachment for Achilles
Navicular - tuberosity - attachment site for post tib (sit anteriorly to calcaneus)
Cuneiforms - medial, intermediate, lateral
Cuboid - 6 sides, 3 of them articulate w/ adjacent tarsal bones, provides lateral foot stability
Metatarsals
Concave on plantar side - gives us room to place soft-tissue structures there (helps to build arch)
Concave base (proximally) - shaft - convex head (distally)
Phalanges
14 in total
Concave base (proximally) - shaft - convex head (distally)
Motions
DF/PF - sagittal plane - M/L AoR
Inversion/eversion - frontal plane - ant/post AoR
Abd/add - transverse plane - vertical AoR
Pronation/Supination
Oblique AoR (at an angle to each of cardinal planes)
Triplanar motion
Pronation - DF, eversion, abd (coming up)
Supination - PF, inversion, add (coming down)
Joint is not triaxial, but mvt cuts through all 3 cardinal planes
Tibiofibular Joint - Proximal
Head of fibula with lateral aspect of tibia
Synovial jt
Firm articulation to ensure force from biceps fem and LCL are transferred effectively from fibula to tibia
Not a lot of mvt, but strong enough to withstand force of muscles that attach to it
Tibiofibular Joint - Distal
Fibular notch of tibia and distal fibula
Syndesmosis (fibrous union)
Ligamentous support - limit mvt (interosseous ligament, which is ext of interosseous membrane, and ant/post tibiofibular ligament)
Limited mvt - rotation/translation in 3 planes (restricted jt mobility associated w/ ankle pain)
Talocrural Joint
Articulation b/w trochlear dome and sides of talus w/ cavity formed by distal tibia and both malleoli (distal tibia creates top and medial malleolus and distal fibula creates lateral malleolus)
Must be stable enough to accept forces b/w leg/foot
90-95% of compressive forces pass through talus and tibia
3 mm of articular cartilage can compress by 30-40% to absorb force
Capsule reinforced by ligaments
Deltoid Ligament
Medial collateral ligament
Fan shaped
Prevents excessive eversion
Checks extreme ROM (prevents going into extreme ROM)
Lateral malleolus of fibula projects inferiorly - moving into eversion, fibula prevents it from going into further eversion
Lateral Collateral Ligament
Ant/post talofibular and calcaneofibular ligaments
Controls varus (inversion) stress
Checks extremes of motions
- ATFL - inversion and PF (#1 inversion ankle sprain)
- CFL - inversion and DF
- PTFL - stabilize talus in mortise
Weaker, more prone to injury (smaller and lack bony block)
Osteokinematics - Ankle Joint
1 DOF at talocrural joint (PF/DF)
Occurs about oblique axis (passing through oblique, more lateral)
Closed pack: DF
DF - occurs w/ slight abd/eversion, min 10 degrees necessary for normal function, normal range 10-20 degrees
PF - occurs w/ slight add/inversion, normal range 20-50 degrees
Arthrokinematics - Talocrural Joint
Open
DF - talus rolls anteriorly, glides posteriorly (CFL taut, ATFL slack)
PF - talus rolls posteriorly, glides anteriorly (ATFL taut, CFL slack)
Subtalar Joint
Formed by posterior, middle, and anterior facets of calcaneus and talus
Medial, posterior, and lateral talocalcaneal ligaments
Primarily stabilized by CF and deltoid ligaments
Substalar neutral
Close packed - supination
Inversion and eversion occur at this jt
Subtalar Neutral
Clinical position
Invert - lateral talar head pops out
Evert - medial talar head pops out
Patient works b/w inversion and eversion until talus feels symmetrical
AOR and Osteokinematics of Subtalar Joint
Triplanar motion about single oblique axis (uniaxial)
Motions of subtalar
- Supination: mostly inv and add
- Pronation: mostly ever and and
ROM - inversion (22 degrees) 2X eversion (12 degrees)
Transverse Tarsal (Midtarsal) Joint - Talonavicular Joint
Conves talus
Concave navicular bone
Spring ligament - undersurface to give support and stability
Mobility - twisting of midget relative to rearfoot
Transverse Tarsal (Midtarsal) Joint - Calcaneocuboid Joint
Anterior, distal calcaneus
Proximal cuboid
Stability to lateral column of foot
Transverse Tarsal (Midtarsal) Joint
Talonavicular and calcaneocuboid joints
Rarely functions in isolation - most often w/ subtler
Transition b/w hindfoot and forefoot
Adds to overall ROM of supination/pronation
Two AoR
Transverse Tarsal Joints - AOR
Longitudinal AOR inclined 15 degrees from horizontal and 9 degrees medially - inversion/eversion
Oblique AOR incline 52 degrees from horizontal and 57 degrees medially - abd/DF, add/PF
Amplify mvts
Augment inv/ever, add/PF, abd/DF
Distal Intertarsal Joints
Navicular, cuneiforms, intercuneiform
Amplifies pronation and supination
Tarsal coalition
Tarsal Coalition
Condition
Born w/ bony block b/w bones
Limited motion b/w intertarsal jts
Limited mobility in midfoot - compensation (laxity in other joints, hypermobile subtalar, more forefoot motion)
Causes chronic ankle inability at subtalar
Tarsometatarsal Joints
Articulation b/w bases of Mts and distal surfaces of 3 cuneiforms and cuboid
Synovial joints
Serve to positions MTs and phalanges relative to WB surface (helps to tell when one is on rocky surface - need rearfoot in one direction and forefoot in another)
Often called Lisfranc’s jts
Metatarsophalangeal Joints
Articulation between convos head of each MT and concave end of proximal phalanx
2 DOF - flex/ext, abd/add
2nd digit used to reference abd/add
1st MTP - ext: 55-95 (hyperext), flex: 17-34
2nd-5th MTPs - ext: 60-100 (hyperext), flex: 15-35
Hallux rigidus - limited 1st MTP ext (problematic in gait)
Interphalangeal Joints
Proximal (5) and distal (4) joints
1 DOF - flex/ext
Serve to smooth weight shift to opposite for during gait
Help to maintain stability
Medial Longitudinal Arch
Concave “instep” of medial foot
Loadbearing/shock absorbing structure
Formed by calcaneus, talus, navicular, cuneiforms, and 1st 3 MTs
Bony arch primarily reinforced by plantar aponeurosis
Extrinsic muscle reinforcement during impact
Plantar Aponeurosis
Dense fascia
Runs length of foot (starts at calcaneus and runs to proximal phalanx of each toe)
Active/passive toe ext increases tension (PA taut in toe ext)
Supports MLA
MLA Movement
In normal WB, BW falls at midfoot, around talonavicular joint - BW then distributed thru MLA
MLA rises/falls cyclically during gait
Rearfoot shock absorption func: WB depresses talus interiorly, flattening MLA - results in slight rearfoot pronation and returns to normal calcaneal inversion in NWB position
Weight on foot - arch lowers
Weight off ground - arch rises
Standing - loss of MLA height
Transverse Arch
Formed by intercuneiform and cuneocuboid jt complex
Provides transverse stability
Flattens during WB, allowing weight distribution across all 5 MT heads (allows for all 5 MT heads get contact w/ ground)
ER of Tibia and Fixed Foot
Tibia ER on fixed foot - rearfoot supination (inversion) and MLA rises - FF, MF pronate to maintain contact w/ ground
IR of Tibia and Fixed Foot
Tibia IR on fixed foot - rearfoot pronation (eversion), valgus at knee, lowering MLA - floor pushes FF/MF into relative supinated position
Ankle PFs and Supinatos
Superficial - gastroc, soleus, plantaris
Deep - tib post, FDL, FHL
Roles - decelerates forward tibial translation during gait (eccentric), accelerates body forward/upward (concentric), stabilize knee ext
Dorsiflexors
Tib ant, EDL, EHL
Tib ant - functional perspective
- -Use it all day during gait
- Foot hits the ground - eccentric PF
- Foot through swing - pulling foot up in order to clear toe
Evertors
Fibularis longus and brevis
Provides active lateral ankle stability
Most active during mid- to late-stance
Decelerate rate and extend of supination at subtalar jt
Prevent inversion sprain by brining foot back into neutral position
Plantar Fasciitis
Heel pain
Greatest in AM
Decreases w/ walking, but increases w/ prolonged walking
Sitting for periods of time - pain after
Commonly occurs w/ heel spurs
Heel Spurs
Hook of bone that develops in calcaneus
Coincident w/ plantar fasciitis
Hallux Valgus
Bunion
Progressive valgus deformity of great tor (lateral deviation relative to midline of body(
Inflammed or painful MTP joint
Hallux Rigidus
OA/limited motion at 1st MTP
Major impact on gait
Pes Planus
Abnormally dropped MLA
Associated w/ MF/proximal FF laxity - weakened plantar fascia, spring ligament or post tib
Flat foot - stretching of fascia/tissues across bottom of jt, weakened plantar fascia, weakened/stretched out spring ligament
Pes Cavus
Abnormally high MLA
Associated w/ refract various
More vulnerable to stress fractures associated w/ increased rigidity
Lateral Ankle Sprain/CAI
ATFL injury caused by excessive inv/PF
CFL - excessive inversion/DF
Nerve Injury
Common fibular nerve (pes varus, pes equinovarus)
Tibial nerve or branches (pes valgus)
Weight-Bearing - Standing
Normally, in standing, 50-60% of weight is taken on heel and 40-50% is taken by metatarsal heads
Foot assumes slight toe-out position
Fick angle - approx. 12-18 degrees from sagittal axis of body, developing from 5 degrees in children
Tibial torsion - toe out - Fick angle
Anterior Drawer Test
Purpose - test injury for ATFL and deltoid ligaments
Procedure - pt supine w/ ankle in 20 degree PF, stabilize distal tib/fib while other provides force to draw talus anteriorly
Positive findings - pain/excessive excursion laterally indicates ATFL injury, pain/excursion medially indicates deltoid, pain/excursion both M/L indicated M/L ligaments
Morton’s Sign
Purpose - screen for stress fracture or neuroma
Procedure - pt supine, examiner grasps foot around MT heads and squeezes heads together
Postive findins - pain
