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Lower Limb Bones
The bones of the lower limb form the skeletal framework for weight bearing, locomotion, balance, and transmission of body weight to the ground. They include the femur, patella, tibia, fibula, tarsal bones, metatarsals, and phalanges.
RegionLower Limb
SystemMusculoskeletal System
The bones of the lower limb form the rigid framework of the thigh, leg, ankle, and foot. They are specialized for supporting body weight, maintaining an upright posture, providing leverage for powerful muscles, and transmitting forces between the pelvis and the ground during standing, walking, running, and jumping.
The free lower limb contains the femur in the thigh, the patella at the knee, the tibia and fibula in the leg, and the tarsals, metatarsals, and phalanges in the foot. These bones articulate through the hip, knee, tibiofibular, ankle, and numerous joints of the foot.
Compared with the upper limb, the lower limb skeleton is generally adapted more strongly for stability and weight transmission. Its bones are correspondingly robust, particularly the femur, tibia, talus, and calcaneus.
Organization of the Lower Limb Skeleton
| Region | Bones |
|---|---|
| Thigh | Femur |
| Knee | Patella |
| Leg | Tibia and fibula |
| Ankle and hindfoot | Talus and calcaneus |
| Midfoot | Navicular, cuboid, and three cuneiforms |
| Forefoot | Five metatarsals and fourteen phalanges |
Number of Bones
Each free lower limb contains 30 bones: one femur, one patella, one tibia, one fibula, seven tarsal bones, five metatarsals, and fourteen phalanges.
Femur
The femur is the bone of the thigh and the longest and strongest bone in the human skeleton. It extends from the hip to the knee and transmits body weight from the hip bone to the tibia.
Its proximal end articulates with the acetabulum, while its distal end articulates with the tibia and patella.
Proximal Femur
The proximal femur consists of the head, neck, greater trochanter, lesser trochanter, and associated intertrochanteric landmarks.
Head of the Femur
The femoral head is rounded and forms approximately two-thirds of a sphere. It articulates with the acetabulum to form the hip joint.
A small depression called the fovea for the ligament of the head is located on the head and provides attachment for the ligament of the head of the femur.
Femoral Neck
The neck of the femur connects the femoral head to the shaft. Its oblique orientation positions the shaft away from the pelvis and provides space for movement at the hip.
The angle between the neck and shaft is clinically important because alterations can affect lower limb alignment and hip mechanics.
Greater Trochanter
The greater trochanter is a large lateral projection that serves as an attachment site for several muscles acting on the hip.
Lesser Trochanter
The lesser trochanter projects posteromedially from the proximal femur and provides insertion for the iliopsoas muscle.
Intertrochanteric Line and Crest
The intertrochanteric line lies anteriorly between the trochanters, while the intertrochanteric crest lies posteriorly.
Shaft of the Femur
The femoral shaft is long and slightly curved. Its posterior surface contains the prominent linea aspera, which provides attachment for numerous muscles and intermuscular septa.
Linea Aspera
The linea aspera consists principally of medial and lateral lips. Superiorly and inferiorly these diverge into additional ridges associated with muscular attachments and the distal femoral region.
Distal Femur
The distal femur expands into the medial and lateral condyles. These participate in formation of the knee joint.
Femoral Condyles
The medial and lateral femoral condyles articulate with the corresponding tibial condyles. Anteriorly, the condyles are connected by the patellar surface, while posteriorly they are separated by the intercondylar fossa.
Epicondyles
The medial and lateral epicondyles lie superior to the corresponding condyles and provide attachment sites for ligaments and muscles.
Adductor Tubercle
The adductor tubercle is located superior to the medial epicondyle and provides attachment for the hamstring portion of adductor magnus.
Major Femoral Landmarks
| Landmark | Importance |
|---|---|
| Head | Articulates with acetabulum |
| Neck | Connects head to shaft |
| Greater trochanter | Major muscle attachment site |
| Lesser trochanter | Iliopsoas insertion |
| Linea aspera | Extensive muscular attachment |
| Medial and lateral condyles | Articulate with tibia |
| Patellar surface | Articulates with patella |
| Intercondylar fossa | Separates condyles posteriorly |
Patella
The patella is a triangular sesamoid bone embedded within the quadriceps femoris tendon. It lies anterior to the distal femur and participates in the patellofemoral articulation.
Its broad superior margin forms the base, while its inferior pointed portion forms the apex.
Articular Surface of the Patella
The posterior surface of the patella is largely covered by articular cartilage and contains medial and lateral articular facets that articulate with the patellar surface of the femur.
Function of the Patella
The patella protects the anterior knee and increases the mechanical advantage of the quadriceps mechanism by holding the tendon away from the axis of the knee joint.
Tibia
The tibia is the large medial bone of the leg. It is the principal weight-bearing bone between the knee and ankle.
Proximally it articulates with the femur and fibula. Distally it articulates with the talus and fibula.
Proximal Tibia
The proximal tibia is expanded to form medial and lateral condyles. Their superior surfaces articulate with the femoral condyles.
Tibial Plateau
The superior articular region of the proximal tibia is commonly described clinically as the tibial plateau. It includes the articular surfaces of the medial and lateral condyles and the intercondylar region.
Intercondylar Eminence
The intercondylar eminence lies between the medial and lateral tibial articular surfaces. It includes medial and lateral intercondylar tubercles and is associated with attachment areas for the menisci and cruciate ligaments.
Tibial Tuberosity
The tibial tuberosity is a prominent anterior projection below the condyles. The patellar ligament attaches here, transmitting the force of quadriceps femoris to the tibia.
Shaft of the Tibia
The tibial shaft is approximately triangular in cross-section and has three borders and three surfaces. Its anterior border is prominent and readily palpable along much of the leg.
Interosseous Border
The lateral or interosseous border of the tibia provides attachment for the interosseous membrane connecting the tibia and fibula.
Distal Tibia
The distal tibia expands to participate in the ankle joint. Its inferior surface articulates with the trochlea of the talus.
Medial Malleolus
The medial malleolus projects inferiorly from the medial side of the distal tibia. It forms the medial prominence of the ankle and articulates with the talus.
Fibular Notch
The lateral surface of the distal tibia contains the fibular notch, which receives the distal fibula and participates in the distal tibiofibular syndesmosis.
Major Tibial Landmarks
| Landmark | Importance |
|---|---|
| Medial condyle | Articulates with medial femoral condyle |
| Lateral condyle | Articulates with lateral femoral condyle |
| Intercondylar eminence | Central proximal tibial landmark |
| Tibial tuberosity | Attachment of patellar ligament |
| Anterior border | Subcutaneous palpable border |
| Medial malleolus | Forms medial ankle prominence |
| Fibular notch | Articulates with distal fibula |
Fibula
The fibula is the slender lateral bone of the leg. Unlike the tibia, it transmits relatively little body weight, but it is important for muscle attachment and stability of the ankle.
Head of the Fibula
The expanded proximal end forms the head of the fibula, which articulates with the lateral condyle of the tibia at the proximal tibiofibular joint.
Neck of the Fibula
The narrow region immediately distal to the head is the neck of the fibula. The common fibular nerve passes closely around this region, making the nerve vulnerable to injury associated with fibular neck trauma.
Shaft of the Fibula
The fibular shaft provides attachment for muscles of the leg and for the interosseous membrane connecting it to the tibia.
Lateral Malleolus
The distal fibula forms the lateral malleolus. It extends farther inferiorly than the medial malleolus and forms the lateral boundary of the ankle mortise.
Tibia and Fibula Comparison
| Feature | Tibia | Fibula |
|---|---|---|
| Position | Medial | Lateral |
| Size | Large and robust | Slender |
| Weight bearing | Major weight-bearing bone | Minimal direct weight bearing |
| Knee articulation | Articulates with femur | Does not articulate with femur |
| Ankle contribution | Forms medial malleolus and superior ankle surface | Forms lateral malleolus |
Interosseous Membrane
The tibia and fibula are connected along much of their shafts by the interosseous membrane of the leg. This strong fibrous sheet provides muscle attachment and helps stabilize the relationship between the two bones.
Bones of the Foot
The skeleton of each foot contains 26 bones: seven tarsals, five metatarsals, and fourteen phalanges.
These bones form a flexible but stable platform capable of supporting body weight and adapting to uneven surfaces while also functioning as a lever during propulsion.
Tarsal Bones
The seven tarsal bones form the proximal part of the foot. They are arranged into hindfoot and midfoot regions.
Seven Tarsal Bones
| Bone | General Position |
|---|---|
| Talus | Proximal, between leg and foot |
| Calcaneus | Posteroinferior, forms heel |
| Navicular | Anterior to talus |
| Cuboid | Lateral midfoot |
| Medial cuneiform | Medial distal tarsal row |
| Intermediate cuneiform | Central distal tarsal row |
| Lateral cuneiform | Lateral part of cuneiform group |
Talus
The talus transmits body weight from the tibia to the foot. It articulates superiorly with the tibia and fibula, inferiorly with the calcaneus, and anteriorly with the navicular.
It consists of a body, neck, and head. Its superior trochlear surface participates in the ankle joint.
Trochlea of the Talus
The trochlea is the superior articular surface of the talar body. It fits within the ankle mortise formed by the distal tibia and fibula.
Calcaneus
The calcaneus is the largest tarsal bone and forms the skeletal foundation of the heel. It receives forces from the talus and transmits them toward the ground and forefoot.
Calcaneal Tuberosity
The posterior and inferior portion of the calcaneus contains the calcaneal tuberosity, an important weight-bearing region and attachment area.
Sustentaculum Tali
The sustentaculum tali is a shelf-like projection from the medial calcaneus that supports part of the talus.
Navicular
The navicular lies anterior to the talar head and posterior to the three cuneiform bones. Its medial tuberosity is an important palpable landmark and attachment site for the tibialis posterior tendon.
Cuboid
The cuboid lies on the lateral side of the midfoot, anterior to the calcaneus and proximal to the fourth and fifth metatarsals.
Its plantar surface contains a groove associated with the tendon of fibularis longus.
Cuneiform Bones
The three cuneiform bones are the medial, intermediate, and lateral cuneiforms. They lie between the navicular proximally and the medial metatarsals distally.
Metatarsals
Five metatarsal bones form the skeletal framework of the forefoot. They are numbered I through V from medial to lateral.
Each typical metatarsal has a base proximally, a shaft, and a head distally.
First Metatarsal
The first metatarsal is relatively short and robust because of its important role in weight bearing and propulsion through the great toe.
Fifth Metatarsal
The fifth metatarsal has a prominent tuberosity at its base. This projection provides attachment for the fibularis brevis tendon and is an important clinical landmark.
Phalanges of the Foot
The toes contain 14 phalanges. The great toe, or hallux, has proximal and distal phalanges, while each of the other four toes has proximal, middle, and distal phalanges.
Distribution of Phalanges
| Digit | Phalanges |
|---|---|
| Great toe | Proximal and distal |
| Second toe | Proximal, middle, distal |
| Third toe | Proximal, middle, distal |
| Fourth toe | Proximal, middle, distal |
| Fifth toe | Proximal, middle, distal |
Sesamoid Bones of the Foot
Small sesamoid bones occur within certain tendons of the foot. The most consistent pair lies beneath the head of the first metatarsal within the tendons associated with flexor hallucis brevis.
These sesamoids help protect tendons and modify mechanical forces around the first metatarsophalangeal joint.
Longitudinal Arches
The arrangement of the tarsal and metatarsal bones contributes to the medial and lateral longitudinal arches of the foot.
Medial Longitudinal Arch
The medial longitudinal arch is relatively high and elastic. Its principal bony components include the calcaneus, talus, navicular, cuneiforms, and medial three metatarsals.
Lateral Longitudinal Arch
The lateral longitudinal arch is lower and more closely related to the ground. It includes the calcaneus, cuboid, and lateral metatarsals.
Transverse Arch
The transverse arch extends across the foot and is formed by the arrangement of the cuneiforms, cuboid, and bases of the metatarsals.
Functions of the Foot Arches
| Function | Importance |
|---|---|
| Weight distribution | Distributes forces across the foot |
| Shock absorption | Helps attenuate impact during gait |
| Elasticity | Stores and releases mechanical energy |
| Adaptation | Allows the foot to accommodate uneven surfaces |
| Propulsion | Creates a stable lever during push-off |
Weight Transmission Through the Lower Limb
Body weight is transmitted from the axial skeleton through the pelvis to the femoral heads. Forces then pass through the femora toward the knee joints and predominantly into the tibiae.
At the ankle, the tibia transfers load to the talus. From the talus, forces are distributed posteriorly toward the calcaneus and anteriorly through the remaining tarsal and metatarsal bones.
General Weight-Bearing Pathway
| Step | Major Structure |
|---|---|
| 1 | Pelvis |
| 2 | Femoral head and femur |
| 3 | Tibiofemoral joint |
| 4 | Tibia |
| 5 | Talus |
| 6 | Calcaneus and remaining foot skeleton |
| 7 | Ground |
Hip Joint
The proximal femur participates in the hip joint, where the femoral head articulates with the acetabulum. This ball-and-socket joint combines substantial mobility with the stability required for weight bearing.
Knee Joint
The knee includes articulations between the femur and tibia and between the femur and patella. The fibula does not articulate directly with the femur.
Ankle Joint
The ankle, or talocrural joint, is formed principally by the distal tibia and fibula articulating with the talus. The medial and lateral malleoli stabilize the talus within the ankle mortise.
Major Bone Articulations
| Bone | Major Articulations |
|---|---|
| Femur | Hip bone, tibia, patella |
| Patella | Femur |
| Tibia | Femur, fibula, talus |
| Fibula | Tibia, talus |
| Talus | Tibia, fibula, calcaneus, navicular |
| Calcaneus | Talus, cuboid |
Palpable Bony Landmarks
Numerous lower limb bones have superficial landmarks that can be identified during physical examination and used for anatomical orientation.
Important Palpable Landmarks
| Landmark | Region |
|---|---|
| Greater trochanter | Lateral proximal thigh |
| Patella | Anterior knee |
| Tibial tuberosity | Anterior proximal leg |
| Anterior tibial border | Anterior leg |
| Head of fibula | Lateral proximal leg |
| Medial malleolus | Medial ankle |
| Lateral malleolus | Lateral ankle |
| Calcaneal tuberosity | Heel |
| Navicular tuberosity | Medial foot |
| Base of fifth metatarsal | Lateral foot |
Femoral Neck Fractures
Fractures of the femoral neck are clinically important because they can disrupt blood vessels supplying the femoral head. Compromise of this blood supply can contribute to osteonecrosis of the femoral head.
Intertrochanteric Fractures
Intertrochanteric fractures occur through the proximal femur between the greater and lesser trochanters. Their anatomical location differs from intracapsular femoral neck fractures and influences clinical management and complications.
Femoral Shaft Fractures
The femoral shaft is surrounded by large muscles and major neurovascular structures. Fractures can be associated with substantial bleeding and displacement because of muscular forces acting on the fragments.
Patellar Fractures
The superficial location of the patella makes it susceptible to direct trauma. Fractures can also occur through powerful contraction of the quadriceps mechanism.
Tibial Plateau Fractures
Fractures of the tibial plateau involve the proximal articular surface of the tibia and can affect alignment, stability, and congruity of the knee joint.
Tibial Shaft Fractures
The anterior and medial surfaces of the tibia are relatively subcutaneous. This limited soft tissue covering contributes to the clinical significance of tibial fractures and associated soft tissue injury.
Fibular Neck Injury
Trauma near the fibular neck can injure the common fibular nerve, which passes around the lateral aspect of this region.
Such nerve injury can impair muscles responsible for dorsiflexion and eversion and may produce characteristic sensory deficits.
Ankle Fractures
Fractures involving the medial malleolus, lateral malleolus, posterior distal tibia, or combinations of these structures can disrupt the ankle mortise and affect joint stability.
Calcaneal Fractures
The calcaneus may fracture after substantial axial loading, such as a fall from height. Because the calcaneus participates in subtalar and calcaneocuboid articulations, fracture can significantly affect hindfoot mechanics.
Fifth Metatarsal Fractures
The proximal fifth metatarsal is a common site of injury. Fracture patterns vary according to their precise location and mechanism, making anatomical localization important.
Stress Fractures
Repetitive loading can produce stress fractures in lower limb bones, particularly in individuals exposed to repeated running, marching, or jumping. Commonly affected sites include portions of the tibia and metatarsals.
Development and Ossification
The lower limb bones develop primarily through endochondral ossification. Cartilaginous models are progressively replaced by bone through primary and secondary ossification centers.
Epiphyseal growth plates permit longitudinal growth during childhood and adolescence before eventually closing.
Sex and Individual Variation
The dimensions, proportions, alignment, and surface features of lower limb bones vary among individuals. Age, sex, genetics, body size, mechanical loading, and activity can influence skeletal morphology.
Functions of Lower Limb Bones
| Function | Role |
|---|---|
| Weight bearing | Supports body mass during standing and movement |
| Locomotion | Provides rigid levers for muscles |
| Force transmission | Transfers loads from pelvis to ground |
| Joint formation | Forms hip, knee, ankle, and foot articulations |
| Muscle attachment | Provides origins and insertions for lower limb muscles |
| Protection | Provides structural protection and support for regional tissues |
| Balance | Creates a stable skeletal base for upright posture |
Key Features of Lower Limb Bones
| Feature | Key Point |
|---|---|
| Thigh bone | Femur |
| Knee sesamoid bone | Patella |
| Primary weight-bearing leg bone | Tibia |
| Lateral leg bone | Fibula |
| Number of tarsals | 7 |
| Number of metatarsals | 5 |
| Number of phalanges | 14 |
| Largest tarsal | Calcaneus |
| Bone receiving weight from tibia | Talus |
| Total bones in each free lower limb | 30 |
Anatomical and Functional Importance
The lower limb skeleton combines robust weight-bearing structures with joints capable of the movements required for efficient locomotion. The femur transfers loads from the pelvis to the knee, while the tibia carries most of the load through the leg. The fibula provides important attachment sites and contributes substantially to ankle stability despite carrying relatively little body weight.
At the ankle, forces pass primarily from the tibia to the talus and are then distributed through the calcaneus and the remaining bones of the foot. The arrangement of the tarsals and metatarsals creates the longitudinal and transverse arches that allow the foot to function both as an adaptable platform and a rigid lever.
Distinctive landmarks such as the greater trochanter, linea aspera, tibial tuberosity, malleoli, sustentaculum tali, navicular tuberosity, and fifth metatarsal tuberosity provide attachment sites and important clinical reference points.
The bones of the lower limb therefore integrate weight transmission, posture, joint stability, muscle leverage, locomotion, shock absorption, balance, and adaptation of the foot to the supporting surface.
Published on October 16, 2026
Last updated on October 16, 2026
Last updated on October 16, 2026