Course Outline
§ Ankle Joint
§ Superior & Inferior Tibio-fibular Joints
§ Joints of Foot
Learning Objectives
§ Describe the Ankle Joint
§ Discuss the Superior and Inferior Tibio-Fibular Joints
§ Discuss Sub-talar Joint
§ Discuss transverse tarsal joint or mid-tarsal joint.
Talocrural Joint (ankle joint)
§ Type:
- hinge type of synovial joint.
§ Articular Surfaces: - between inferior ends of tibia and fibula and superior part of talus.
Articular Surfaces
Tibia articulates with talus in two places:
(1)Inferior surface forms roof of mortise, which is wider anteriorly than posteriorly
(2) Lateral surface of its medial malleolus articulates with talus.
Ø Talus has three articular facets, which articulate with inferior surface of tibia and malleoli.
Ø Trochlea of talus is wider anteriorly than posteriorly and slightly concave side to side.
Articular Capsule
§ Fibrous capsule is supported on each side by strong collateral ligaments (medial or deltoid and lateral ligaments).
§ Attached superiorly to borders of articular surfaces of tibia and malleoli.
§ Attached inferiorly to talus, except antero inferiorly.
Synovial Capsule
§ Synovial capsule of ankle joint lines fibrous capsule.
§ Synovial cavity of ankle joint is superficial on each side of tendo calcaneus.
Medial or Deltoid Ligament
§ Apex of ligament is attached to margins and tip of medial malleolus.
§ Broad base fans out and attaches to three tarsal bones (talus, navicular, and calcaneus).
§ Function:
- Strengthens joint and hold calcaneus and navicular bones against talus.
- Help to maintain medial side of foot against longitudinal arch.
Deltoid ligament consists of four parts:
• Tibio navicular Ligament
• Anterior tibio talar Ligament
• Posterior tibio talar Ligament
• Tibio calcanean ligaments.
Lateral Ligament of the Ankle
§ Attach lateral malleolus to talus and calcaneus.
§ Three distinct parts of lateral ligament are:
• Anterior talo fibular ligaments
• Posterior talo fibular ligaments
• Calcaneo fibular ligaments.
Joint Stability
q Ankle joint is very strong during dorsi flexion because:
- it is supported by powerful ligaments.
- it is crossed by several tendons.
- tightly bound down by thickenings of deep fascia called retinacula.
- trochlea of talus fills mortise formed by malleoli.
- Anterior part of trochlea forces malleoli of leg bones apart slightly.
Ankle Joint Movements
• Movements:
- dorsi flexion and plantar flexion.
Movements in plantar flexion:
- rotation, abduction, and adduction.
Movements in dorsi flexion :
- trochlea of talus rocks posteriorly in three-sided mortise.
- malleoli are forced apart because superior articular surface of talus is wider anteriorly than posteriorly.
-Thus, range of plantar flexion is greater than that of dorsi flexion.
Blood & Nerve Supply
Blood Supply:
- Malleolar branches of fibular (peroneal) artery.
- Anterior and posterior tibial artery.
Nerve Supply:
- Tibial nerve.
- Deep peroneal nerve, a division of common peroneal nerve.
Tibio fibular Joints
Ø Tibia and fibula articulate at their proximal and distal ends.
Ø Movement at proximal tibio fibular joint is impossible without movement at distal one.
Proximal (Superior) Tibio fibular Joint
Type:
- plane type of synovial joint between head of fibula and lateral condyle of tibia.
Articular surface:- Facet on head of fibula articulates with facet located postero laterally on inferior aspect of lateral condyle of tibia.
Articular Capsule
- Fibrous capsule surrounds joint and is attached to margins of articular facets on fibula and tibia.
- Strengthened by anterior and posterior ligaments of head of fibula.
- Fibers of these ligaments run supero- medially from fibula to tibia.
Synovial Membrane
- Synovial membrane lines fibrous capsule.
- Pouch of synovial membrane passing under tendon of popliteus muscle, known as popliteus bursa.
Blood & Nerve Supply
Blood Supply:
- Inferior lateral genicular artery.
- anterior tibial recurrent artery.
Nerve Supply:
- Common peroneal nerve.
- Nerve to popliteus muscle.
Distal (Inferior) Tibio fibular Joint
Type:
- Fibrous joint of syndosmosis type.
- Located between inferior ends of tibia and fibula.
Articular Surfaces:
- Rough, convex, triangular articular area on medial surface of inferior end of fibula articulates with facet on inferior end of tibia.
Ligaments
Interosseous ligament: - continuous superiorly with interosseous membrane.
- Forms principal connection between tibia and fibula at this joint
§ Strong anterior and posterior tibio fibular ligaments strengthen distal tibio fibular joint anteriorly and posteriorly.
- Inferior, deep part of posterior tibio fibular ligament is called transverse tibio fibular ligament.
- This strong band closes posterior angle between tibia and fibula.
§ Joint Stability:
- This articulation forms a strong union between distal ends of tibia and fibula.
- Strength of ankle joint is dependent on this union.
§ Joint Movement:
- Slight movement of distal tibio fibular joint occurs to accommodate talus during dorsi flexion of foot at ankle joint.
Blood & Nerve Supply
§ Blood Supply:
- Perforating branch of fibular (peroneal) artery
- medial malleolar branches of anterior and posterior tibial arteries.
§ Nerve Supply:
- Deep fibular (peroneal), tibial, saphenous nerves
Sub talar (talo calcanean) Joint
- Sub talar (talo calcanean) joint is distal to ankle joint.
- Talus rests on and articulates with calcaneus.
Type:
Synovial joint between inferior surface of body of talus and superior surface of calcaneus.
Articular Capsule
- surrounded by an articular capsule.
- attached near margins of articular facets.
- fibrous capsule is weak.
- supported by medial, lateral and posterior talo calcanean and
anteriorly by interosseous talo calcanean ligament.
Joint Movements
§ Inversion and eversion:
- main movements at Sub talar joint.
§ Gliding and rotation :
- assist with inversion and eversion of posterior part of foot.
Transverse Tarsal Joint
§ Talo navicular and
Calcaneo cuboid joint are separate joints.
- together they constitute transverse tarsal joint or mid-tarsal joint.
- extend across tarsus in almost same transverse plane.
Talo navicular Joint
Forms between:
- head of talus and socket of posterior surface of navicular bone.
- superior surface of plantar calcaneo navicular ligament ("spring ligament").
- sustentaculum tali
articular surface of calcaneus.
Talo calcaneo navicular Joint
Type:
-synovial joint of ball and socket type.
- surrounded by a single articular capsule that blends with interosseous talo calcanean ligament posteriorly.
-Talo calcaneo navicular joint is reinforced dorsally by dorsal talo navicular ligament.
Calcaneo navicular ligament
§ Triangular band extends from sustentaculum tali to postero inferior surface of navicular bone.
§ Blends with deltoid ligament medially and forms part of socket for head of talus.
§ Plays an important role in maintaining longitudinal arch of foot.
Calcaneo cuboid Joint
Type:
Synovial joint between anterior surface of calcaneus and posterior surface of cuboid.
Function:
Dorsal calcaneo cuboid ligament and plantar calcaneo cuboid ligament (short plantar ligament) strengthen capsule of calcaneo cuboid joint.
Movements of Transverse Tarsal Joint
q Inversion and eversion of foot:
- During inversion:
foot is adducted and directed so that its medial border is raised and its lateral border is depressed.
- During eversion:
foot is abducted and directed so that lateral border is raised and medial border is depressed.
- Strong medial (deltoid) ligament prevents over eversion of foot.
- Weaker lateral ligaments prevent over inversion of foot.
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