Download The Leg

The Leg
Anatomical region between the
knee and the foot
Bones of the Leg
• Tibia
– 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
• Proximal and distal
phalanges
– Other four toes
• Proximal, middle and
distal phalanges