The Lower Leg
- Bones of the lower leg are:
- Tibia - Weight bearing component
- Fibula - Non weight bearing component - role is to provide increased surface area for the attachment of muscle and stability to the ankle joint
Tibiofibular Articulations
- 3 to consider
1. Superior tibiofibular joint
- Synovial plane joint
- Between round facet on head of fibula with similar facet on lateral condyle of tibia - both covered with hyaline cartilage
- Simple capsule lined with SM reinforced by anterior and posterior tibiofibular ligaments
- Permits anterior and posterior glides
2. Interosseous membrane
- Collagenous membrane passing from interosseous border on tibia to interosseous border on fibula (continuous with interosseous ligament of inferior tibia / fibula joint
- Fibres pass downwards and laterally
- Function:
- Increase surface area for attachment of muscles
- Compartmentalisation
- Allows movement of fibula/stability
- Allows passage for vessels from posterior to anterior
3. Inferior tibiofibular joint
- Syndesmosis joint between triangular roughened facet on lower end of fibula and corresponding facet on tibia
- Joint space filled with interosseous ligament (continuous with IOM)
- Reinforced by anterior, posterior and transverse tibiofibular ligaments
Compartments of the Lower Leg
- Divided into 3 compartments by the intermuscular septa (planes of deep fascia)
- Anterior compartment - very tight containing the dorsiflexors
- Posterior compartment - containing the plantarflexors - further divided into deep and superficial
- Lateral compartment containing the peronei (evertors)
Skeleton of the Foot
- Made up of 26 bones + a variable number of sesamoid bones
- Divided into the tarsus, metatarsals and phalanges
- Allows the foot to vary from being a mobile adaptor to a rigid lever
The Tarsus
- Made up of 7 bones
- Large bones and very strong and stable arrangement for weight bearing and propulsion
- Arranged to form the posterior part of the arches of the foot
Talus
- Highest point of the skeleton of the foot
- Above articulates with the tibia and fibula to form the ankle joint
- Divided into a body and head/neck
- Palpable anterior to malleoli - neck
- Note: Talus and calcaneus are often collectively called the rearfoot
Calcaneus
- Largest bone of the tarsus forming a lever for propulsion for the calf muscles and posterior pillar of the longitudinal arches of the foot
- Clearly palpable
- Also palpate the medial and lateral tubercles (inferiorly)
- Sustentaculum tali
- Peroneal tubercle
- Note: Talus and calcaneus are often collectively called the rearfoot
Midfoot
- Formed by navicular (medially) and cuboid (laterally) lying anterior to the rearfoot with the 3 cuneiform bone lying anterior to navicular
- Navicular - identify the navicular tuberosity
- Palpate cuboid
- Palpate the 3 cuneiform bones
Forefoot
- Made up of 5 metatarsals and 14 phalanges
- Form a forward lever for propulsion
- Palptate
- Base of 5th metatarsal
- Metatarsal bases and heads
- Phalanges