Lower Limb: Tibiofibular & Ankle Joints Flashcards
What is the main role of the tibia & fibula?
Tibia = weight bearing Fibula = muscle attachment
What are the features of the TIBIA proximally, along the shaft & distally?
Proximally
- condyles + plateau with intervening intercondylar eminence
- tibial tuberosity anteriorly
Shaft
- anterior border = shin bone, palpable
- posterior shaft = soleal line - attachment of soleus muscle
- distal shaft 1/3 thinner than rest
Distally
- medial malleolus
Which of the tibia & fibula are medial & lateral?
Tibia - medial
Fibula - lateral
What are the features of the FIBULA ?
head - tapers down to a long shaft & hamstrings attach distally - lateral malleolus 9 muscles attach highly vascularised used in bone grafting
Which malleolus extends more distally?
Lateral malleolus (of fibula) extends more distally than the medial malleolus (of tibia)
What links the tibia & fibula only the shaft?
interosseous membrane
strong link
has foramen for passage of anterior tibial artery
Is it possible to break one of the tibia or fibula and not the other?
Due to joints between the 2 bones forming a ‘ring structure’ and the strong interoessous membrane, a fracture of one COMMONLY leads to fracture of other
What are the tibiofibular joints?
Superior & inferior joints
Superior = plane synovial
Inferior = fibrous joint
What movements occur at/what are the roles of the tibiofibular joints?
Superior = some gliding movement Inferior = strong stable joint - will break bone before it is injured (syndesmosis)
What important structure does the inferior tibiofibular joint form?
The malleolar mortise = socket critical for ankle joint function
What pathology occurs at the tibial tuberosity?
Where the patella tendon attaches and is a traction epiphysis
Ossifies late & inflammation can occur = Osgood Schlatter’s disease
What is the difference between the tarsal bones of the hand & foot?
The tarsals of the foot are larger, stronger and more stable - purpose of standing & walking
What are the tarsal bones within each 3 ‘groups’ (proximal, intermediate & distal)?
Name them medially to laterally
Proximal - Talus & calcaneus
Intermediate - navicular
Distal - Medial, intermediate, lateral cuneiforms
Which tarsal bones is important in weight bearing & distribution?
Talus - takes body weight & distributes it to heel & forefoot
Which tarsal bone is considered the heel bone?
Calcaneus
How are the metatarsals of the foot named?
Medial to lateral - different to upper limb Big toe (hallux) is medial
which metatarsal has a common stress fracture site?
2nd metatarsal = March fracture
longest & thinnest metatarsal that is wedged between 1st & 3rd
Prone to stress fractures
How many phalanges in the foot?
14
2 in hallux
3 in each digit
What are the joints involving the talus bone & how are they arranged?
Above bone = ankle joint = talocrural joint
below bone = subtalar joint = talocalcaneal joint
in front of bone = midtarsal joint = talocalcaneonavicular & calcaneocuboid
Describe the ankle joint
body of talus articulating with the tibia & fibular
Body sits in the mortise malleolus created by the inferior tibiofibular joint
synovial hinge joint
What movements are permitted at the ankle joint & what is significant about the axis of movement?
Dorsiflexion (extension)
plantar flexion
Oblique axis of movement (not horizontal) due to the lateral malleolus extending further distally
Which ankle joint movement is more stable & which more prone to injury?
Dorsiflexion is more stable as the body of the talus is wedged into the malleolus mortise
It is less stable and more prone to injury in plantar flexion
What is significant about the subtalar & talocalcaneonavicular joint (TCN)?
They are functionally paired - movement at the subtalar means movement at TCN
What types of joints are the subtalar & talocalcaneonavicular joint (TCN)?
Modified ball & socket joints
What movements are permitted by the TCN & subtalar joints?
Inversion & eversion
oblique axis of movement
When are inversion & eversion movements important?
Running
Land on slightly everted foot, transfer weight to forefoot and then become relatively inverted
What ligament is associated with the Subtalar joint & TCN joint?
spring ligament (plantar calcaneonavicular ligament maintains the position of the head of talus
What is the sinus tarsi & what is its significance?
gap between the subtalar & TCN joint
contains the vascular supply (vascular sling) & thick strong ligament that firmly binds the calcaneus & talus (interosseous talocalcaneal)
What is the calcaneocuboid joint?
Plane synovial joint between the calcaneus & cuboid bones
What movements does the calcaneocuboid joint permit?
Rotation gliding movements
What is pronation & supination of the foot?
pronation = eversion + lateral rotation
Supination = inversion + medial rotation
PEL SIM
What permits pronation & supination of the foot?
Subtalar + TCN (eversion/inversion) and Calcaneocuboid (medial/lateral rotation)
What movements are the relative movement between the hind and forefoot?
Supination & pronation
What is another name for the tarsometatarsal joints?
Lisfranc joints
Can be fractured
What kind of joints are the metatarsophalangeal and what movements do they permit?
Condylar joints
Ab/Ad + F/E
What type of joint & what movements do the interphalangeal joints permit?
Hinge
F/E
What are the arches of the foot and what are their purpose?
2 longitudinal (medial + lateral)
1 transverse
Provide a stable base for standing
Absorb & distribute downwards forces when standing & moving
What structures are required for support of the arches of the foot?
Ligamentous support during static activity
Muscular support during dynamic activity
Plantar aponeurosis maintains the longitudinal arches (runs between calcaneus & metatarsal heads
