Leg, Foot & Ankle Flashcards
What do you call the common accessory bone of the talus?
why does it form?
Os trigonum. unfused posterior process (lateral tubercle)
What attaches to the posterior process of the talus?
Posterior talofibular ligament. It attaches to the lateral tubercle of the posterior process
What runs in the posterior process of the talus?
Tendon of FHL - between lateral and medical tubercles
What structure wraps directly under the sustentaculum?
FHL tendon
What runs in the sinus tarsi? Name all structures.
Interosseous talocalcaneal ligament (cervical ligament)
artery of tarsal sinus
(artery of tarsal canal runs in the canal, which is the continuation of the sinus)
Describe the blood supply to the talus. What is the main supply?
all 3 terminal arteries:
posterior tibial a. (MAIN SUPPLY) - deltoid branch to BODY, artery of tarsal CANAL
dorsalis pedis a.–branch to dorsal head/neck, contributes to artery of tarsal SINUS
perforating peroneal a. - contributes to artery of tarsal SINUS - supply head/neck, lateral body
What is the Lisfranc ligament?
Interosseous portion of the oblique ligament from medial cuneiform to 2nd MT base
What are the components of the Lisfranc ligament? which is the strongest one? weakest?
Dorsal (weakest), plantar and interosseous (strongest)
What is the Chopart joint?
The midtarsal joint, comprising the talonavicular & Calcaneocuboid joints
What are the ligamentous components of the ankle syndesmosis?
AITFL
PITFL
Interosseous membrane (IoM)
Interosseous ligament (IoL)
Inferior transverse ligament (ITL) (really just the distal fibrocartilagenous component of the PITFL)
What are the components of the deltoid ligaments of the ankle?
Superficial: - Tibionavicular & Tibiocalcaneal
Deep: - Anterior & posterior tibiotalar
What is an Os Navicular? What are the types?
Accessory navicular. Type 1: Sesamoid within the distal part of the tendon
Type 2: Attachment to the posterior tibialis tendon, separated by synchondrosis
type 3: enlargement of navicular
What benign structure can often be confused with a Lisfranc Injury?
Os metatarsum
What is an os metatarsum?
Accessory bone found between the medial cuneiform and 1st/2nd metatarsals
What are the plantar layers of the foot?
4 layers:
1st: - Abductor hallucis brevis - Abductor digiti minimi - Flexor digitorum brevis , plantar fascia
2nd: - Quadratus plantae - Lumbricals , FHL and FDL tendons
3rd: - Flexor hallucis brevis - Flexor digiti minimi brevis - Adductor hallucis
4th: - Dorsal interossei - Plantar interossei (also tendons of per longus and tib post)
What are the muscles in the dorsal intrinsic compartment of the foot?
Extensor hallucis brevis Extensor digitorum brevis
What is the Master Knot of Henry? Why is it important?
which of the two structures is dorsal/volar?
Crossing between the FHL and FDL in the foot
Important as dividing it allows access to the deeper layers of the foot and because it can be a site of graft harvest (either FHL or FDL tendon transfers)
FHL is dorsal to FDL
What are the compartments of the foot and their key structures?
Hindfoot:
Calcaneal: quadratus plantae, posterior tibial NAV, lateral plantar NAV, +/- medial plantar nerve
Forefoot:
Interosseous x4 - each has an interossei
Adductor
Full length:
Superficial: FDB, lumbricals, FDL tendons +/- medial plantar nerve
Medial: FHB, AbH
Lateral: AbDQ, FDM
What are the borders and contents of the tarsal tunnel?
Floor: medial talus, sustentaculum tali, medial calcaneal wall Roof: Lacinate ligament (flexor retinaculum) Contents: TP, FDL, PT artery, vein, Tibial nerve, FHL “Tom Dick And Very Nervous Harry”
What is Baxter’s Nerve? What is it’s clinical significance?
1st branch of the lateral plantar nerve It runs obliquely on top of quadratus plantae It’s a cause of medial heel pain if impinged (dDx of plantar fascitis)
Where does the Plantaris tendon insert? be specific.
Medial to the achilles tendon. It may be a part of the achilles tendon but it will still be on the medial side
What structures combine to form the Sural Nerve?
Medial and lateral sural cutaneous nerves Lateral: branch of common peroneal nerve Medial: branch of tibial nerve
What does the Sural nerve run with? On which side is the nerve?
Runs with short saphenous vein and it is lateral to it
Where does the superficial peroneal nerve pierce the fascia and become subcutaneous?
10-12cm proximal to the tip of the lateral malleolus
What parts of the talus articulate with the calcaneus?
Anterior, middle and posterior articular surfaces
Describe the posterolateral approach to the Ankle:
Position: Prone or supine w/ large bump Incision: posterior border of fibula, centered around fracture
Plane: FHL (tibial) & peroneal muscles (sup. peroneal)
can also go anterior to peroneals depending on target anatomy
Dangers: Do not take off PITFL (devitalizes segments), Sural nerve
Describe the posteromedial approach to the ankle:
Position: supine Incision: 10cm longitudinal anteriorly curved incision Plane: pick optimal interval:
Tibialis posterior & flexor digitorum longus (both tibial) OR
FHL and NV bundle OR
FDL and NV bundle
Dangers: posterior tibial artery and vein, tibial nerve
Describe the anterior approach to the ankle:
Position: supine Incision: 15cm incision over ankle joint, between the 2 malleoli, beginning 10cm proximal to ankle joint Plane: EHL & EDL (both deep peroneal) Dangers: Superficial peroneal nerve, Neurovascular bundle
Where does the neurovascular bundle of the anterior compartment of the leg run above and below the ankle joint level?
Bundle includes deep peroneal nerve and anterior tibial artery
Above joint, runs between EHL and tib-ant. At the joint, crosses behind extensor hallucis longus then below, it runs between EHL and EDB (EDB is bit more medial than EDL)
What is the innervation of peroneus tertius?
Deep peroneal nerve
what are normal ankle syndesmosis measurements on XRay? what views?
tib/fib clear space <6mm on both AP and mortise
tib/fib overlap >6mm on AP, >1mm on mortise
talocrural angle 79-87 degrees
medial clear space 4mm or less on mortise
Lisfranc ORIF vs Arthrodesis. Whats the evidence?
Ly and Coetzee performed a Level 1 investigation of 41 patients with an isolated acute or subacute Lisfranc dislocation treated with ORIF or primary arthrodesis of the medial column of midfoot. Two years postoperatively, the mean AOFAS Midfoot score was 68.6 points in the open-reduction group and 88 points in the arthrodesis group (p < 0.005). Postoperative level of activities was significantly higher in the arthrodesis group and 25% of the ORIF group required a subsequent revision to an arthrodesis. They concluded that primary arthrodesis of the medial two or three rays has a better short and medium-term outcome than ORIF.
How much of the talus is covered with articular cartilage?
60%
What are parts of the posterior process of the calcaneus? What attaches here?
Medial and lateral tubercles - Posterior talocalcaneal ligament attaches to lateral tubercle
What are the different facets of the body of the talus?
anterior, middle and posterior
What bony structure supports the middle articular facet of the talus?
What attaches to it and runs underneath it?
Sustentaculum tali
Attachments:
Anteriorly: plantar calcaneonavicular ligament
Medially: deltoid ligament
Flexor hallucis longus runs in a groove under it - FHL runs between the medial and lateral tubercles of the posterior process of the calcaneus and then runs under sustentaculum tali of the medial calcaneus
From medial to lateral, what are the order of the extrinsic extensor tendons to the ankle distal to ankle joint?
Tibialis anterior, EHL, EDL, Per Tertius (EDB is intrinsic)
What bones does the talus articulate with?
4 bones: - Tibia: via trochlea and medial articular process - Fibula: via the lateral aticular facet - Calcanues - Navicular
What are the talar and calcaneal bony components of the sinus tarsi?
Talar: sulcus tali (talar sulcus) Calcaneus: calcaneal sulcus These 2 halves form the sinus tarsi
What is the sinus tarsi? What are its boundaries?
Anatomical space that is medially continuous with the much narrower tarsal canal
Boundaries:
Superior: talus
Inferior: calcaneus
Anterior: talocalcaneonavicular joint
Posterior: posterior facet of the subtalar joint
What inserts into the navicular tuberosity?
Tibialis posterior
What 2 muscles attaches to the medial cuneiform and first metatarsal of the foot?
Tibialis anterior, peroneus longus
What constitutes the deltoid ligaments of the ankle?
Medial ligament complex of the ankle 2 layers:
Superficial: tibionavicular & tibiocalcaneal ligaments
Deep: anterior and posterior tibiotalar ligaments
What constitutes the lateral fibular ligaments of the ankle? which is weakest? strongest?
Anterior talofibular ligament (ATFL) - weakest - an intracapsular thickening
Posterior talofibular ligament (PTFL) - deepest, strongest Calcaneofibular ligament
(CFL) - longest - narrow cord covered by peroneus longus and brevis
What position will tighten the anterior talofibular ligament (ATFL)?
Plantarflexion - So it’s crucial to make sure position is correct with testing
What position will tighten the calcaneofibular ligament (CFL)?
Inversion in neutral flexion
What is the origin and insertion of the spring ligament?
AKA plantar calcaneonavicular ligament - Origin: sustantaculum tali - Insertion: navicular
Which is stronger, deltoid complex or the lateral fibular ligaments?
Deltoid are stronger - Remember, it’s easier to have an inversion injury of the ankle
What is the lisfranc ligament?
Oblique interosseous ligament between MEDIAL cuneiform and 2nd MT - Strongest of the lisfranc ligaments
What is the order of failure of the lisfranc ligament?
Dorsal, then plantar, then interosseous - Interossous is the strongest component of the lisfranc ligament
What is an os intermetatarseum and what should it not be confused with?
Accessory bone found between the medial cuneiform and 1st/2nd metatarsal bases - May be independent or an exostosis-like process - Should not be confused with a fracture of the base of the 2nd MT in a lisfranc injury
How do you tell the difference between a fractured hallux sesamoid and a bipartite hallux sesamoid?
The 2 fracture fragments of a sesamoid fit together wheras a bipartite does not… - And also clinically (pain)
What is the innervation of the dorsal intrinsic layer of the foot?
Deep peroneal nerve
Describe the compartment release of the foot
midfoot dorsal incision over MT 2 (open interosseous compartments between 1,2 and 2,3) and MT4 (open interosseous compartment between 3,4 and 4,5)
medial calcaneus incision to access calcaneal compartment and all full length compartments (medial, lateral, superficial
What are the borders of the tarsal tunnel? It’s contents?
Floor: medial talus, sustentaculum tali, medial calcaneal wall
Roof: Lacinate ligament (flexor retinaculum)
Contents: Tom, Dick And Very Nervous Harry
What are the branches of the tibial nerve?
3 branches - Medial calcaneal branch - Medial plantar nerve - Lateral plantar nerve - 90% of the time, bifurcation is within the tarsal tunnel, otherwise, it’s proximal to it
what is the:
chaput fragment
Volkmann fragment
Wagstaff fragment
Chaput fragment: anteriolateral tubercle of the tibia
Wagstaff fragment: anterior tubercle of the fibula
Volkman’s fragment: posterolateral tubercle of the tibia
What is the constant fragment in the tibia? calcaneus? Why is it called that?
Volkman’s fragment (posterolateral tubercle of the tibia)
or
sustentaculum fragment in a calcaneus
Called that b/c in a pilon fracture, it stays in it’s anatomic location, being “constant” - only if fibula already anatomically reduced. You can use it to build off of.
similiarly in a calc frx
What is the OI of the Bifurcate ligament?
Calcaneocuboid/calcaneunavicular ligament
O: Calaneus
I: cuboid/navicular
What is the OI of the long plantar ligament?
Calcaneocuboid-metatarsal ligament
O: calcaneus
O: Cuboid & 1st-5th MT
What is the OI of the short plantar ligament?
Plantar calcaneocuboid ligament
O: calcaneus
I: Cuboid
What is the OI of the spring ligament?
Plantar calcaneonavicular ligament
O: Calcaneus
I: Navicular
What is Morton’s neuroma?
Neuroma of a digital nerve, most commonly between 2nd/3rd MT
What is the primary stabilizer of the MTP joints?
Plantar plate (primary stabilizer)
Also collaterals: MCL/LCL
What muscle inserts onto the tibial and fibular sesamoids of the 1st MT head?
FHB
Peroneus longus runs anterior/posterior to brevis through the fibroosseous tunnel?
Posterior
What is the primary restraint to lateral instability of the peroneal tendons?
Superior peroneal retinaculum, 3.5mm proximal to the tip of the distal fibula
What is the OINA of extensor digitorum brevis?
O: superolateral calcaneus
I: base of proximal phalanges
N: Deep peroneal nerve
A: Extends MTPJ
What is the OINA of extensor hallucis brevis?
O: Superolateral calcaneus
I: Base of proximal 1st phalanx
N: Deep peroneal nerve
A: Extends great toe MTPJ
Plantar Aponeurosis OI:
O: Calcaneal tubercle
I: thick fibrous structure sending slips to each of the toes
OINA abductor hallucis
O: Calcaneal tuberosity
I: Base of great toe, proximal phalanx
N: Medial plantar
A: Abducts great toe
OINA Flexor digitorum brevis
O: Calcaneal tuberosity
I: middle phalanges of 2-5th toes
N: Medial plantar
A: Flex toes at PIPJ
analagous to FDS of the hand - it splits to allow FDL tendon passing thru to distal phalanx
OINA abductor digiti minimi
O: Calcanea tuberosity
I: Base of 5th toe (prox phal)
N: Lateral plantar
A: Abducts 5th toe
OINA lumbricals
O: FDL: medial side
I: proximal phalanx: medial side
N: medial and lateral plantar nerves
A: Flex MTP, extend IP (same as in hand)
OINA Quadratus plantae
O: Medial and lateral calcaneus
I: FDL tendon
N: Lateral plantar nerve
A: Flex distal phalanges
OINA flexor hallucis brevis
O: Cuboid, lateral cuneiform
I: Proximal phalanx great toe
N: Medial plantar
A: flex great toe
OINA adductor hallucis
O: Oblique head: 2-4th proximal MT
transverse head: plantar MTP lig of 3-5
I: Lateral proximal phalanx great toe
N: Lateral plantar nerve
A: adduct great toe
OINA flexor digiti minimi brevis
O: Base 5th MT
I: 5th toe, proximal phalanx
N: Lateral plantar nerve
A: Flex 5th MTPJ
OINA dorsal interossei?
x4
O: Metatarsals
I: Dorsal extensors
N: Lateral plantar nerve
A: abduct toes
OINA plantar interossei
x3
O: 3-5th MT
I: Proximal phalanges medially
N: Lateral plantar nerve
A: Adduct toes
What are the terminal branches of the tibial nerve?
Medial calcaneal
Medial plantar
Lateral plantar
Where does the tibial nerve bifurcate into its terminal branches?
90% of the time, bifurcation is within tarsal tunnel
Otherwise, proximal to it
What innervates the plantar foot muscles?
Tibial nerve
Medial plantar nerve: medial foot:
- Abductor hallucis brevis
- FDB
- FHB
- 1st lumbrical
Lateral plantar nerve: all the rest
What are the terminal branches of the tibial artery?
Medial and lateral plantar arteries
- These follow the same path as the corresponding nerves
Name and describe the windows of the posteromedial approach to the ankle
Lateral to FHL:
- Between FHL (medial) and peroneals (lateral)
Medial to FHL:
- Between FHL (lateral) and NV bundle (medial)
- Between FHL/NV bundle (lateral) and FDL (Medial)
Cut all tendons
Describe the arthroscopic portals for ankle arthroscopy and their main dangers
Anterolateral portal:
Medial to lateral malleolus, lateral to peroneus tertius
Danger: dorsal intermediate cutaneous branch of superficial peroneal nerve
Anteromedial portal:
Medial to tibialis anterior and lateral to medial malleolus
Danger: Saphenous nerve & vein
Posterolateral portal:
Medial to peroneal tendons, lateral to achilles
Danger: sural nerve, small saphenous vein
Posteromedial portal:
Can injure posterior tibial artery
Describe the course of the dorsalis pedis artery?
Continuation of Anterior tibial artery
Travels down foot lateral to EHL
Gives off branches:
Medial and lateral Tarsal branhces
Arcuate artery: passes over dorsal TMT joint, deep to tendons
Deep Plantar artery - large branch that dives deep through 1st/2nd webspace at MT bases
- This forms the deep plantar arch
DP ends as digital arteries
what muscle(s)/tendon(s) attach to the talus?
nothing
cuboid has a groove along its plantar aspect - what runs in it?
peron. longus
proximal tibia fractures deform into what position?
why?
procurvatum (quads tendon) and valgus (Pes anserinus)
what does the lateral compartment of the leg contain?
peroneus longus
peroneus brevis
superficial peroneal nerve
(no arteries)
what neurovascular bundle(s) are in the deep posterior compartment of the leg? Name each component
tibial nerve, posterior tibial artery, posterior tibial veins
peroneal artery and veins
describe the path of the tibial nerve from start to finish
starts as bundle of the sciatic nerve which splits into tibial nerve and common peroneal nerve at top of popliteal fossa
tibial nerve gives off medial sural cutaneous nerve in popliteal fossa, then goes between heads of gastroc
lies superficial to plantaris and popliteus
dives deep to soleus through fibrous arch
enters deep posterior compartment, travels just deep to transverse IM septum
runs with posterior tibial a and v, between FHL and FDL
stays between them and wraps behind medial malle in tarsal tunnel
gives off calcaneal branch
enters tarsal tunnel, bifurcates into medial and lateral plantar nerves
exits tunnel (both) and runs between 1st and 2nd plantar layer
MPN is deep to abductor hallucis
LPN is obliquely superficial to quad plantae
LPN gives off baxter’s nerve
descreibe the sensory distribution of the plantar foot–be specific
central and medial heel: medial calcaneal branch of tibial nerve
lateral foot and heel: sural nerve
medla foot: saphenous nerve
D1-half of D4: medial plantar nerve
D5 to half of D4: lateral plantar nerve
describe the path of the common peroneal n.
branches from sciatic nerve at top of popliteal fossa
runs posterior to bicep sfemoris tendon
crosses superfiical to lateral head of gastroc
here it gives off lateral sural cutaneous nerve
main nerve continues just lateral to soleus and winds around fibular neck, deep to peroneus longus
divides into sup and deep per. n.
describe the path of the deep peroneal n from start to finish
common peroneal n splits deep to peroneus longus after wraps around fibular neck
deep peroneal n pierces the anterior IM septum (going from lateral to anterior compartment) and travels along anterior surface of IOM
travels with anterior tibia a and branches to each muscle in that compartment
passes deep to the extensor retinaculums (superior and inferior)
above ankle joint, travels between tib-ant and EHL
crosses under EHL at ankle and below it travels between EHL and EDL
continues down to first web space for senation
describe the path of the superficial peroneal n from start to finish
branches from common peroneal deep to peroneus longus.
continues here within superficial compartment up against anterior IM septum
travels along lateral fibula for proximal 1/3
then between per longus and brevis
heads anterior distally and travels between EDL and per brevis (still within superficial compartment, along IOM)
pierces fascia 10-12cm above lateral malleolus to become superifical within fat
just anterior to fibula
bifurcates (variable location) into medial dorsal cutaneous n. (supplies medial foot dorsum) and intermediate dorsal cutaneous n (supplies lateral foot dorsum
describe the path of the sural nerve from start to finish (all branches and how they relate)
common peroneal n gives off lateral sural cutaneous n in popliteal fossa and then travels subcutaneously along lateral gastroc
tibial n gives off medial sural cutaneous n in popliteal fossa which travels between heads of gastroc along with short saphenous v DEEP to deep fascia (no sensory fxn yet)
pierces fascia in middle of calf to become subcutaneous
joins up with a branch from lateral sural cutaneous - becomes the sural nerve itself
sural n travels with short saphenous v (lateral to v) and runs between lateral malle and achilles - more proximal=closer to achilles, more distal=closer to lateral malle
gives off lateral calcaneal branches
terminates as lateral dorsal cutaneous n on latedral side of foot/5th toe
describe the path of the saphenous nerve from where it exits hunter’s canal to finish
exits hunter’s canal, becomes subcutaneous
gives off infrapatellar branch that crosses inferior to patella
the rest travels as medial cutanous nerve of leg AKA medial crural cutaneous branches
supplies sensation to medial leg, running with great saphenous vein
continues just anterior to medial malle to innervate skin on medial/dorsal foot.
describe the path of the great saphenous vein
starts as dorsal vein of hallux and merges with dorsal venous arch
passes anterior to medial malle (with saphenous n) and goes up medial side of leg
at level of knee, lies posterior to medial epicondyle
goes up medial thigh
passes through fossa ovalis AKA saphenous opening
drains into femoral vein
describe the path of the popliteal artery
superficial femoral artery becomes popliteal artery when it enters popliteal foss abetween biceps and semi-M
in popliteal fossa (lateral to medial)
tibial n, pop v, pop ARTERY (most medial)
lies behind posterior horn of lateral meniscus, about 9mm from the posterior tib plateau with knee flexed to 90
superfiical to popliteus (like popliteal n)
deep to gastroc/soleus, passes under fibrous arch of soleus
bifurcates at distal aspect of poplitues into anterio tibial a. and tibioperoneal trunk
tibioperoneal trunk divides into posterior tiibal a. and peroneal a about 2.5cm below pop fossa
describe the path of the anterior tibial artery
branches from popliteal artery and passes between 2 heads of tib post
pierces IOM into anterior compartment
runs down with deep peroneal n (medial to nerve) along anterior aspect of IOM
first branch: anterior tibial recurrent artery
stays between EHL and tib ant until ankle
crosses under EHL at ankle then lies between EHL and EDL
becomes dorsalis pedis artery
describe the path of the posterior tibial artery
tibioperoneal trunk divides, giving off posterior tibial artery (deep to soleus, superficial to tib post but within deep posterior compartment)
posterior tibial artery runs with tibial nerve, still superficial to tib post
gives off nutrient artery to tibia itself
follows path of tibial nerve- becomes medial and lateral plantar arteries
at tarsal tunnel - tom dick And very nervous harry
describe the path of the peroneal artery
tibioperoneal trunk giveso ff this branch, superficial to tib post, deep to soleus
stays within deep posterior compartment
runs deep to FHL
becomes perforating peroneal artery - passes from posterior to anterior compartment through IOM
supplies talus
gives off lateral calcaneal branch
what muscles does the medial plantar n supply?
abd hallucis
fdb
fhb
1st lumbrical
(all others on plantar foot supplied by lateral plantar n)
