Ankle/Foot Anatomy Flashcards
which parts of the foot are considered ‘midfoot’?
navicular
cuboid
3 cuneiforms
what is the name of the joint that separates the hindfoot and midfoot?
Chopart
what is the name of the joint that separates the midfoot and forefoot?
Lisfranc
3 ligaments that arise from distal fibula
ATFL
PTFL
CFL
when does the calcaneous ossify?
body at 6mo
tuberosity not until 9 years old!
which facet of the calcaneous is most vulnerable to #
posterior
where does FHL pass on the plantar surface of the foot?
between medial and lateral tubercles of the talus
which muscle passes through the groove on the plantar side of the cuboid?
peroneus longus
when do the distal fibula and tibia fuse?
18-20 years old
when do the metatarsals fuse?
birth
name 2 accessory ossicles in foot
os trigonum
accessory navicular
what is the ‘Mortise’?
the arch formed by the malleoli and the plafond
what is the incisura?
the lateral groove in the tibia into which the fibula fits
what does syndesmosis mean?
to bind together
what are the 4 components of the syndesmosis?
AITFL
PITFL
inferior transverse ligament
interosseous ligament
what are the names of the 3 common fragments that can avulse from the syndesmosis?
chaput = anterolateral tibial tubercle
wagstaff = anterior fibula tubercle
volkman = posterolateral tibial tubercle
only bone in the foot without muscular tendon attachments
talus
5 arteries that supply the talus
artery of tarsal canal
deltoid artery
direct superomedial artery
artery of tarsal sinus
direct posterior artery
perforating peroneal artery
anterior lateral malleolar artery
artery of the tarsal sinus
lateral tarsal artery
medial tarsal artery
artery of tarsal canal
deltoid artery
how many articulations does the talus have with the calcaneous?
3
anterior
posterior
middle
what is the sustenaculum tali?
an anteromedial shelf that supports the middle talar articular surface and under which passes the tendon of FHL
where is the sinus tarsi?
lateral to the anterior and middle facets of the calcaneous
it is a soft spot just distal to the fibular tip and an anatomical space that is medially continuous with the tarsal canal
boundaries:
superior - talus
inferior - calcaneous
anterior - talocalcaneonavicular joint
posterior - posterior facet of the subtalar joint
what motion occurs at chopart’s joint?
abduction/adduction
occuring at 2 joints:
talonavicular
calcaneocuboid
what is the consequence of the unique anatomy of the middle cuneiform?
it does not extend as far distally, so the 2nd MT becomes the keystone of the transverse arch of the foot
what are the plantar cristae?
the articular surfaces on the plantar 1st MT that articulate with the sesamoids
how is the Lisfranc joint held together?
with 3 groups of ligaments:
1) the transverse ligaments that attach adjacent metatarsal bases 2-5 (*nb none between 1-2)
2) longitudinal ligaments that attach MT bases to cuneiforms/cuboid (*nb one for each MT)
3) the oblique ligaments from the 2nd MT to the medial cuneiform. there are 3:
dorsal
plantar
Lisfranc
ligament that connects the metatarsal heads
deep transverse
what is a Morton neuroma?
entrapment of an intermetatarsal plantar nerve in the transverse metatarsal ligament
primary stabilizer of the MTP joint
plantar plate
describe the anatomy of FHB
originates from tendon of tib post
inserts into sesamoids on plantar surface of 1st MTP joint and then continues as the phalangealsesamoid ligament which are also stabilized by medial and lateral metarsosesmoid ligaments
only tendon that isn’t always black on MRI
FHL, because of fluid in its sheath
where is tibialis posterior tendon most vulnerable?
under medial malleolus
what is the knot of Henry?
where the FDL finally crosses the FHL in a tendon sheath communication on the plantar midfoot
Peroneus longus
peroneus brevis
EDL
EHL
tibialis anterior
tibialis posterior
FDL
posterior tibial artery
posterior tibial vein
tibial nerve
FHL
plantaris
achilles
what is unique about the achilles tendon?
a couple things:
largest tendon in the body
has a paratenon instead of a sheath - which means fat surrounding the tendon (associated with Kager’s fat pad anteriorly)
where do the peroneal tendons lie?
together as a common sheath 4cm above the joint as they pass under the lateral malleolus
PB is deep to PL
pass through the fibro-osseous tunnel inferior to fibula
split into individual sheaths just distal to lateral malleolus
the primary restraint to lateral instability of the peroneal tendons
the superficial peroneal retinacula
superior - from periosteum of distal fibula to lateral wall of calcaneous
inferior - over the lateral wall of calcaneous
3 ligaments deep to tendons in the fibro-osseous tunnel of the fibula?
PITFL
PTFL
CFL
what is the tarsal tunnel?
fibroosseous tunnel created by the posterior medial malleolus, medial wall of the calcaneous and talus and the flexor retinaculum
second most commonly torn tendon of the lateral ankle
CFL
which motion tightens ATFL?
plantar flexion
which motion tightens CFL?
inversion
AITFL
ATFL
CFL
PTFL
PITFL
4 parts of the deltoid ligament
anterior tibiotalar
tibionavicular
tibiocalcaneal
posterior tibiotalar (deep)
posterior tibiotalar ligament
tibiocalcaneal ligament
anterior tibitalar ligament
tibionavicularligament
strongest subtalar ligament
interosseous talocalcaneal
(aka cervical ligament)
what is the bifurcate ligament?
the calcaneo-cuboid/navicular ligament
anatomy of the long plantar ligament
from calcaneous to cuboid and 1-5 metatarsals
anatomy of the short plantar ligament
from the calcaneous to the cuboid
what is the spring ligament
from the susentaculum tali to the navicular
frequency of os trigonum
5-15%
frequency of accessory navicular
10%
what is the os peroneum?
plantar to CC joint
list the intrinsic dorsal muscles of the foot
EDB
EHB
list the intrinsic plantar muscles of the foot
1st layer: abductor hallucis, abductor digiti minimi, FDB
2nd layer: quadratus plantae, lumbricals
3rd layer: FHB, FDM, adductor hallicus
4th layer: dorsal interossei, plantar interossei
which layer houses the knot of Henry?
the 2nd - this is where FHL and FDL tendons are
which tendons run in the 4th layer of the foot?
peroneus longus
posterior tibialis
insertion of quadratus plantae
lateral FDL tendon
where does the nerve to ADM get trapped?
fascia of abductor hallucis
which foot layer houses the medial and lateral plantar nerves?
2nd
which interossei are larger?
dorsal
muscles of the first plantar layer
flexor digitorum brevis
abductor hallucis
abductor digiti minimi
origin and insertion of plantar lumbicals
from medial FDL tendon to medial PP and EDL tendons
origin and insertion of flexor hallucis brevis
cuboid and lateral cuneiform to PP 1st toe
origin and insertion of adductor hallucis
2-4 MT to 1st PP
origin and insertion of flexor digiti minimi brevis
base of 5 MT head to 5 PP
3 portions of the plantar fascia
central band from calc to flexor tendon sheaths
medial band
lateral band
what is the truss and windlass mechanism?
where the plantar fascia pull together to force the arch of the foot rostral
9 compartments of the foot
medial - AbdH, FHB, FHL tendon
lateral - ADM, FDM
superficial central - FDB, lumbircals, FDL tendons
deep central - QP, posterior tibial NVB
adductor - AddH
interosseus 1-2 - dorsal only
interosseus 2-3 - both
interosseus 3-4 - both
interosseus 4-5 - both
where does the tibial nerve run in the foot?
between 1st and 2nd layers on QP
where does the tibial nerve split?
in tarsal tunnel (90%)
3 branches of the tibial nerve in the foot
medial calcaneal
medial plantar
lateral plantar
what is baxter’s nerve?
first branch of the lateral plantar nerve
supplies the quadratus, FDB and ADM
its impingement causes medial heel pain colloquially known as plantar fasciitis
1
saphenous nerve
2
deep peroneal
3
superficial peroneal
4
medial plantar
5
lateral plantar
6
medial calcaneal branch of tibial nerve
7
sural
course of the deep peroneal nerve in the foot
travels lateral to and with dorsalis pedis artery
emerges distal to inferior extensor retinaculum
travels lateral to EHL
tracks down first web space
4 main branches of the dorsalis pedis
medial tarsal
lateral tarsal
arcuate - forming the dorsal arch
deep plantar - forms the deep arch
weakness of hindfoot eversion
superficial peroneal nerve
weakness of hindfoot inversion
tibial nerve
weakness of great toe extension
deep peroneal
weakness of great toe flexion
tibial nerve
weakness of ankle plantar flexion
tibial nerve
borders of sinus tarsi
superior: talus
inferior: calcaneus
anterior: talocalcaneonavicular joint
posterior: posterior facet of the subtalar joint
4 ligaments of the syndesmosis
AITFL
PITFL
inferior transverse ligament
interosseous ligament
which facet of the subtalar joint is most often affected in tarsal coalition
middle
2 intrinsic muscles of the foot innervated by deep peroneal nerve
EDB
EHB