L13: Bones, ligaments and joints of foot and ankle Flashcards
overview of foot
26 bones in total
7 tarsals
5 metatarsals
14 phalanges
tarsals
7 in total
proximal row:
talus
calcaneus
intermediate row:
navicular
cuboid
distal row:
cuneiform medial / intermediate / lateral
'’Tiger Cubs Need MILC’’
foot regions:
rearfoot
talus and calcaneus
foot regions:
midfoot
navicular
cuneiforms
cuboid
foot regions:
forefoot
metatarsals and phalanges
metatarsals
articulate with tarsals proximally and phalanges distally
numbered 1-5, 1=big toe, 5=little toe
features:
base
shaft
head
“March” fracture
metatarsal fracture
- repeated overuse
- bone healing cannot keep up
- bone becomes progressively weaker
- fracture occurs
- marching soldiers and long distance runners
phalanges
14 in total
big toe has 2 - proximal and distal
each other toe has 3 - proximal, middle and distal
features: base, shaft, head or tuberosity
movements of talocrural joint
dorsiflexion and plantarflexion
movements of subtalar joint and transverse tarsal joint
inversion and eversion
movements of tarsometatarsal joint
gliding movements
movements of metatarsophalangeal joints
flexion and extension, abduction and adduction
movements of interphalangeal joints
flexion and extension
anatomical subtalar joint
synovial joint
articulation between talus and calcaneus
allows for inversion and eversion of foot
anatomical subtalar joint
supported by what 4 ligaments:
- posterior talocalcaneal ligament
- medial talocalcaneal ligament
- lateral talocalcaneal ligament (LTL)
- interosseous talocalcaneal ligament (IOL)
functional subtalar joint consists of :
- anatomical subtalar joint
- talocalcaneonavicular joint
transverse tarsal joint
this is a compound joint, formed by 2 separate joints aligned transversely
- talonavicular part of the talonavicular joint (synovial)
- calcaneocuboid joint (plane synovial)
at this joint, the mid and forefoot rotate as a unit on the hind foot
this joint augments foot inversion and eversion
medial transverse tarsal joint
medial part - talocalcaneonavicular joint
- ball and socket synovial joint
- head of talus is ball shaped
- posterior navicular and anterior calcaneus are socker shaped
medial transverse tarsal joint
ligaments
- dorsal talonavicular ligament
- spring ligament
- aka plantar calcaneonavicular ligament
lateral transverse tarsal joint
lateral part - calcaneocuboid joint
- plane synovial joint
- gliding movements occurs here between calcaneus and cuboid
lateral transverse tarsal joint
ligaments:
- dorsal calcaneocuboid ligament
- long plantar ligament
aka long calcaneocuboid ligament - short plantar ligament
aka plantar calcaneocuboid ligament
tarsometatarsal joint
(Lisfranc Joint)
articulation between tarsals and bases of metatarsals 1-5
- cuneiforms - metatarsals 1,2,3
- cuboid - metatarsals 4,5
plane synovial joints, gliding movements, separate joint capsules
tarsometatarsal joint
ligaments
dorsal (8)
plantar (2)
interosseous (3)
tarsometatarsal joint / lisfranc joint injuries
can be injured with relatively low energy forces - twist and fall
or high energy forces - direct trauma to foot
intermetatarsal joints
plane synovial joints, between lateral metatarsals
NB: no joint between 1st and 2nd metatarsal
joint ligaments: many
- dorsal, plantar, interosseous
metatarsophalangeal joint / MTP
synovial condyloid joints:
- flexion / extension
- abduction / adduction
- circumduction
metatarsophalangeal joint / MTP
ligaments
collateral ligaments
plantar ligaments
MTP joint injuries
most common place for MTP joint injuries is:
‘‘bunions’’ = hallux valgus
hallucis = of the large toe
valgus = deformed away from midline
interphalangeal joints / IP joint
proximal and distal joints:
- proximal interphalangeal joint = PIP Joint
- Distal interphalangeal joint = DIP joint
synovial hinge joint
allow flexion and extension of digits
foot arches
If feet were rigid, each impact with the ground would generate large forces of a short duration (shocks) and these would damage the skeletal system.
Arches distribute forces around the foot, acting both as shock absorbers and springboards
Arches are elastic and recoil when weight is taken off the foot.
There are 3 arches.
medial longitudinal arch
highest arch, runs from heel to head of metatarsals 1-3
bony components:
- calcaneus, talus, navicular, cuneiforms, metatarsals 1-3
ligamentous components:
- long plantar ligament
- short plantar ligament
- spring ligament
- plantar aponeurosis
lateral longitudinal arch
lower and flatter than medial counterpart
bony components:
- calcaneus, cuboid, metatarsals 4+5
ligamentous components:
- long plantar ligament
- short plantar ligament
- plantar aponeurosis
transverse arch
this is an arch that runs from side to side
bony components:
- cuneiforms, cuboid, metatarsal bases
prevents the foot from flattening in the side to side direction (splayfoot)
when arches go bad…
Pes planus “flat foot, fallen arches”
- collapsed longitudinal arches
- talus and navicular displaces inferiorly
- increases tension on spring ligament
- deficient passive stabilisers, muscle work harder to compensate: pain in calf and foot
when arches go bad…
pes cavus “high arches”
- elevated longitudinal arches
- excessive pressure placed on ball and heel of foot which will likely from calluses
- associated with foot joint pain
surface anatomy of foot
- palpate your own calcaneal tendon
- palpate your own medial and lateral malleolus
- palpate your own medial and lateral longitudinal arches
- palpate your own transverse arch
