Anatomy Of Foot And Ankles: Bones, Ligaments And Joints Flashcards
How is the foot anatomically divided?
Into the tarsus, metatarsus, and phalanges
How many bones does the tarsus contain?
7
How many metatarsals are there?
5
How many phalanges are there?
14
Clinically what are the divisions of the foot?
Hindfoot, midfoot, and forefoot
What makes up the hindfoot?
Talus and calcaneus
What makes up the midfoot?
Navicular cuboid and 3 cuneiforms
What makes up the forefoot?
Metatarsals and phalanges
What is the only foot bone that articulates with the leg bones?
Talus
What 2 directions is body weight distributed through the talus?
- Directly inferior through its body to the calcaneus
- Anteroinferomedially through its neck and head to a gap between the navicular and sustentaculum tali, accompanied by the spring ligament
T/F: the talus has no muscles attached
True
What is the largest strongest bone of the foot?
Calcaneus
Where does the calcaneus transmit the majority of body weight to?
The ground
Where is the large tuberosity of the calcaneus located?
Posteriorly
What does the calcaneus articulate with anteriorly?
Cuboid
What does the calcaneus articulate with superiorly?
The talus
What does the talar shelf (sustentaculum tali) do?
Helps support the talus
The navicular receives what?
The head of the talus
Where is the tuberosity on the navicular?
Medically placed
Which side of the foot is in contact with the ground?
Lateral side
What does the navicular contact anteriorly?
Three cuneiforms
Where is the cuboid?
Lateral in the distal row of the tarsus
Where is the tuberosity on the cuboid?
Inferolaterally placed
What is anterior to the tuberosity on the cuboid?
The groove for the fibularis Longus tendon
How many joints are there in each foot?
30
What is the most important Intertrasal joints?
The subtalar the transverse tarsal joint
What 2 joints make up the transverse tarsal joint?
The talonavicular and calcaneocuboid
Explain calcaneal fractures
Often disrupt the subtalar joint
MOI usually due to fall, landing on the feet or heels
Fracture patterns are typically comminuted, meaning broken into several small segments
Explain metatarsal fractures
Many types and mechanisms
Dorsal side is vulnerable to falling objects- if heavy enough the metatarsals will fracture
Ballet dancers may experience fracture when the entire body weight is borne on the metatarsals
Prolonged walking may cause transverse fractures
What are transverse fractures called?
Fatigue fractures
Describe 5th metatarsal tuberosity allusion
With sudden, forceful inversion, the tendon of the fibularis brevis muscle may tear away the tuberosity of the 5th metatarsal.
Common in basketball players and tennis players
The bone Vesalius must be differentiated from fractures
Fibular gliding occurs with dorsiflexion of what joint as the trocéela of the talus wedges between the malleoli
The talocrural joint
While the distal end of the fibula glides superiorly where is there obligatory movement?
At the proximal end
Where is the tibiofibular syndesmosis?
Distal
What are the “syndesmotic ligaments”
The anterior and posterior tibiofibular ligaments and the crural tibiofibular interosseous ligament
what is the crural tibiofibular interosseous ligament continuous with?
The more superior interosseous membrane
Which ligament forms the posterior wall of the ankle “socket” or “mortise”?
Inferior posterior tibiofibular ligament
Why is there slight separation at the inferior joint?
To accommodate wedging of the trochlea with dorsiflexion
What type of joint is the talocrural joint?
A hinge synovial joint
How does the axis of the talocrural joint run?
Transversely though the malleoli
The tibia articulates in 2 places of the trochlea which are?
Its inferior surface transmits body weight to the superior surface of the trochlea and its medial malleolus articulates with the media surface of the trochlea
What is the distal continuation of the posterior tibiofibular ligament known as?
The inferior transverse ligament
What are the movements at the talocrural joint?
Dorsiflexion and plantarflexion
Which movement at the talocrural joint is very stable?
Dorsiflexion is very stable because the trochlea is widest anteriorly therefore it is wedged tightly into the mortise in this position. Plantarflexion is unstable because the more narrow posterior part of the trochlea lies loosely in the mortise in this position
In which direction is the trochlea of the talus wider?
Wider anteriorly than posteriorly
Where are the superior and medial articulations of the talocrural joint?
At the mortise on the talus with the tibia
Where is the lateral articulation of the talocrural joint?
Between the fibula and talus
When determining the side of the talus when looking from superiorly where does the head/neck point?
Towards the great toe (medially)
Where does the medial ligament of the ankle (deltoid ligament) run?
From the medial malleolus and attaches distally to the talus in 2 places, calcaneus at the talar shelf, and navicular bone
what is the deltoid ligament a check rein to?
Eversion of the foot
What is the most frequently injured joint?
The ankle
What do ankle sprains result from?
Trauma, tearing fibers of the ligaments.
What motion causes the most common ankle sprains?
Inversión injuries when the weightbearing foot twists (ATFL is weakest ligament= most commonly injured)
What are the lateral ligaments of the ankle?
The anterior talofibular (ATFL)
The posterior talofibular (PTFL)
The calcaneofibular (CFL)
What is the ATFL?
A weak band that extends from the lateral malleolus to the neck of the talus
What is the PTFL?
A thick, fairly strong band running horizontally and medially from the malleolus to the lateral tubercle of the talus
What is the CFL?
A round cord like structure extending from the tip of the malleolus to the lateral surface of the calcaneus
What movement do the lateral ligaments of the ankle check rein?
Hyperinversion (ATFL when plantarflexed, CFL in ankle neutral, PTFL when dorsiflexed)
What makes up the subtalar joint?
The talus rests on and articulates with the calcaneuous
Does the subtalar joint function the same anatomically and functionally?
no anatomically the joint is discrete and has its own capsule and articular activity via the posterior facet. Functionally it includes the talocalcaneal part of the TCN since they cannot move independently
What are the 3 facets of the subtalar joint?
Anterior facet
Middle facet
Posterior facet
The TCN and subtalar joint combined make up the majority of what motions of the foot?
Inversion/eversion
Where does the axis of rotation for inv/ev?
Oblique from postrerolateral to anteromedial and slightly upward. Runs through the lateral malleolus, medial portion of the taras canal and middle of the navicular
What is club foot?
A congenital deformity, most commonly talipes equinovarus- foot is inverted and ankle PF and forefoot adducted (like horses hoof). Results in shortened tightened muscles, tendons and ligaments on the medial side of the ankle
What is the tarsal sinus (canal)?
Separa tes the the components of the clinical subtalar joint
Where is the interosseous talocalcaneal ligament?
Found within the tarsal sinus attaching to both the calcaneal sulcus and talar sulcus
When standing which tubercle of the calcaneus touches the ground?
Only the medial tubercle
What is the interosseous talocalcaneal ligament?
Very strong and separates the true anatomic subtalar joint (posterior facet) from the talocalcaneonavicular joint. Lies within the tarsal canal
What does the interosseous talocalcaneal ligament help do?
Limit eversion
Where is the cervical ligament?
Lies more lateral in the tarsal canal
What does the cervical ligament help do?
Limit inversion
What is the plantar calcaneonavicular ligament (spring)?
Extends across and fills a wedge shaped gap between the talar shelf and the inferior margin of the posterior articular surface of the navicular
What is the long plantar ligament?
Runa from the calcaneus to the cubrid with some fibers extending to the bases of the lateral metatarsals. Form a tunnel for tendon of fib longus
What is the short plantar ligament?
Lies in the plane between the long plantar and spring ligament. It extends from the calcaneus to the cuboid
What do the bifurcate and dorsal calcaneocuboid ligament do?
Support joints on the dorsal surface of the foot
What is the talocalcaneonavicular joint?
A compound joint involving 3 bones. Ball and socket type joint that allows for rotation
Where does gliding occur in the TCN joint?
Where the inferior surface of the talar head articulates with the calcaneus allowing for inversion eversion
which 2 joints make up the transverse tarsal joint?
the talonavicular and calcaneocuboid joint
what occurs at the TTJ?
the midfoot and forefoot rotate as a unit on the hindfoot around a longitudinal axis (supination/pronation movements)
what is the TTJ known as?
the surgeons tarsal joint since this is where amputation of the foot commonly occurs
what type of joint is the Tarsometatarsal joint and what kind of motion occurs?
plane synovial joint allows little movement
what type of joint are the MTPs and what kind of motion occurs?
condyloid synovial joint. allows flex/ext and abd/add
what type of joints are the PIPs and DIPs and what kind of motion occurs?
hinge synovial joints that allow flex/ext
what are the functions of the plantar arches of the foot?
distribute load, absorb shock, and aid in propulsion
what bones contribute to the medial longitudinal arch?
talus, calcaneus, navicular, the 3 cuneiforms, and metatarsals 1-3
what bones contribute to the lateral longitudinal arch?
calcaneus, cuboid, and metatarsals 4-5
what bones contribute to the transverse arch?
cuboid, 3 cuneiforms, and the bases of metatarsals 1-5
what provides passive support for arches?
ligaments
what provides active support for arches?
muscles
what ligament contributes to the medial longitudinal arch?
the spring ligament
which ligaments contributes to the lateral longitudinal arch?
the short and long plantar ligaments
what muscles contribute to the medial longitudinal arch?
FHL tendon, FHB muscle, FDB muscle, FDL tendon, tib post and ant tendon
what muscles contribute to the lateral longitudinal arch?
FDM muscles, and fib long tendon
what muscles contribute to the transverse arch?
transverse head of adductor hallucis muscle, fib long tendon, tib post tendon
what is pes planus?
flat feet usually resulting from over stretching of plantar ligaments and aponeurosis. the spring ligament cant fully support the talar head, and the medial longitudinal arch “falls” with the talar head displacing inferomedially. the forefoot is laterally deviated
