Anatomical region between the knee and the foot The Leg Anatomical region between the knee and the foot

Bones of the Leg Tibia Fibula Interosseous membrane Shin bone Supports most of the weight of the body Articulates with the condyles of the femur superiorly and the talus inferiorly Fibula Mainly muscle attachment Ankle stability Interosseous membrane Strong, angulated connective tissue that connects the shafts of the tibia and the fibula

Structures related to the tibia Medial and lateral condyles Medial and lateral tibial plateaus Intercondylar eminence Facet on inferior lateral condyle for head of fibula

Tibial tuberosity Distal tibia – facets for fibula and talus Medial malleolus

More tibia Body of tibia – triangular in cross section Medial surface Lateral surface Posterior surface Borders of tibia Lateral border – attachment of interosseous membrane Soleal line

Fibula Lies posterolateral to the tibia Function Stability of ankle by holding the talus in its joint with the lateral malleolus Provide attachment sites for muscles Some support by enabling the tibia to withstand twisting forces

Structures on fibula Neck of fibula Interosseous border of fibula Head of the fibula Facet for articulation with inferior lateral tibial condyle Lateral malleolus of fibula Facets on medial surface for tibia and talus Malleolar fossa – posteroinferior to talar facet Attachment for posterior talofibular ligament

Surface anatomy of leg Anterior border (crest) of tibia Tibial tuberosity 5 cm distal to apex of patella Patellar ligament Head of the fibula Level of tibial tuberosity Neck of the fibula Common fibular nerve

Bones of the foot Tarsal bones (7) Metatarsals (5) Phalanges (14)

The Tarsal bones Talus Calcaneus Cuboid Navicular Cuneiforms (3)

Talus Has body, neck and head Rests on anterior 2/3rd of calcaneus Articulates with calcaneus, tibia, fibula, and navicular bone The superior talus articulates with the tibia, and bears the weight of the body Talus articulates with the ‘shelf-like’ projection of the calcaneus, the sustentaculum tali

Talus On posterior surface Groove for tendon of flexor hallucis longus Medial tubercle Lateral tubercle Os trigonum

The ankle joint Joint between the talus with the tibia and fibula The ankle joint is a hinge-type synovial joint Note the axis of the ankle joint is not straight

Calcaneus Largest and strongest bone of the foot Articulates Talus superiorly Cuboid anteriorly

Structures on calcaneus Sustentaculum tali Medial surface (superior part) Shelf-like structure Helps support talus Groove on inferior side for the tendon of flexor hallucis longus

Peroneal or fibular trochlea Lateral surface – oblique ridge Tendon of fibularis longus muscle passes inferior to the trochlea

Navicular bone Boat-like bone Located between talus and 3 cuneiform bones has facets that articulate with each of them

Structures on navicular bone Navicular tuberosity Palpated medially and inferiorly Tendon of tibialis posterior muscle attaches here

Cuboid bone Most lateral in distal row of tarsus bone Articulates with: Calcaneus posteriorly 4th and 5th metatarsal bones anteriorly Lateral (3rd cuneiform) and navicular bone medially

Tuberosity of the cuboid Groove on lateral and inferior surfaces for tendon of fibularis longus muscle

Cuneiform bones 3 wedge-shaped bones Medial (1st) cuneiform - largest Intermediate (2nd) cuneiform - smallest Lateral (3rd) cuneiform

All articulate with the navicular bone and their corresponding metatarsal bone Lateral cuneiform is the only cuneiform that articulates with the cuboid bone

Metatarsal bones Numbered from medial side of the foot Each bone Base – proximally Body or shaft Head – distally Bases of metatarsal bones articulate with the cuneiforms (metatarsals 1, 2 and 3) and the cuboid bone (metatarsals 4 and 5)

2nd metatarsal bone Longest metatarsal Articulates with intermediate cuneiform Base is wedged between the medial and lateral cuneiform bones

1st metatarsal bone 2 Sesamoid bones (medial and lateral) in the tendons of the flexor hallucis brevis muscle Bear some of the body weight Anatomical pulleys increase the moment arm of the FHbr muscle

5th metatarsal Tuberosity on base of 5th metatarsal Protrudes over the lateral margin of cuboid bone The dorsal surface serves as the attachment site for the tendon of the peroneus brevis muscle

Phalanges 14 bones in each foot Great toe Other four toes Proximal and distal phalanges Other four toes Proximal, middle and distal phalanges