Part 11: Ankle and Foot Joints Flashcards
What type of joint is the ankle joint (talocrural joint)?
Hinge joint with a moving axis of rotation. has synovial membrane which encapsulates articular margins and attaches higher anteriorly on tibia.
Describe the medial ligaments of the ankle joint
Deltoid ligament
Deep: narrow, medial mal to side of talus
Superficial: triangular from medial mal to medial tubercle of talus with a band to navicular and a band to calcaneus
Describe the lateral ligaments of the ankle
ATFL - fibula to lat tubercle talus
PTFL
Calcaneofibular ligament
Also posterior talofibular ligament - strong ligament lies horazontally between malleolar fossa
In full plantarflexion the ankle is also everted or inverted slightly?
slight degree of inversion, the reverse is true in dorsiflexion
What sort of joint is the talocalcaneonavicular joint?
Synovial joint of ball and socket variety. Ball is talus and socket is navicular and calcaneus. Has two components - the T-C part and the T-N part.
What forms the midtarsal joint?
Calcaneocuboid joint (own joint) and the talocalcaneonavicular joint
Where is the short and long plantar ligaments?
Short plantar - Anterior tubercle of calcaneus to posterior ridge cuboid
Long Plantar - covers short planar, from both M+L posterior tubercles of calcaneus to cuboid with superficial fibres to base 1-3 MTs
What does the spring ligament do?
Strong band between sustentaculum tali to navicular. Has articular margin with talus. Helps maintain medial longitudinal arch.
What are the 4 lines of pull that invert/evert and ankle and tarsal joints?
- Tib anterior - inverts and dorsiflexes
- Peroneus tertius - everts and dorsiflexes
- Tib posterior - inverts and plantarflexes
- Peroneus longus and brevis - everts and plantarflexes
The muscles combine in groups of 2 to produce movements. eg 1+2 dorsiflexes ankle where as 2+4 everts tarsals
Where does the movement of inversion and eversion occur?
Mostly at joints beneath talus
Begins at midtarsal joints due to attachments of tendons but little movement achieved in midtarsal and movement occurs in subtalar joints
How does 1st MTJ differ from others?
Has own capsule and synovial membrane, is therefore more mobile with movement in vertical plane. Mobility in no way compares to that of in hand.
What arches exist in the foot?
Medial longitudinal arch - consists ot calcaneus, talus, navicular, 3 cuneiforms and their MT
Lateral longitudinal arch - consists of calcaneus, cuboid and lateral 2 MT
Transverse arch - consists of bases of 5 MT and adjacent cuboid and cuneiforms
What maintains medial longitudinal arch?
Bony factor = 0
Ligaments are important - mainly plantar aponeurosis and then spring ligament
Muscles are indispensable as they allow ligaments rest, prevent over stretching. Mainly tendon FHL, with small slips to 2nd and 3rd toe to keep tension on arch. Abductor hallucis and FDB also aid in maintaining arch. Tibialis anterior + posterior play a part but more by inversion of arch than approximating the pillars
What maintains lateral longitudinal arch
Plantar aponeurosis acts as bowstring and plantar ligaments also play part. Peroneus longus depresses medial arch and pulls up on lateral arch being most important muscle factor. Lateral FDL and FDB are also of assistance but ligaments are more important in lateral arch than medial arch
What maintains transverse arch?
Bones appear to help given wedge shape but ligaments still most important. Ligaments that bind 5 MT bones and cuneiforms are most important.
