脚の解剖学：部位、名称、図解の完全ガイド

Leg Anatomy: Complete Guide with Parts, Names & Diagram Skip to content 📅 Published on May 16, 2024 | 🕒 Last updated on November 12, 2025 Table of Contents Toggle Overview of Leg Anatomy The legs are a part of the lower limbs of the human body , located between the knee and ankle. They play a vital role in supporting body weight and maintaining balance.[1] It also enables movement such as standing, walking, running, climbing, and even complex activities like dancing or jumping.[1] The parts of leg anatomy comprise several key components, including bones, muscles, tendons, ligaments, joints, and nerves. They work together to provide strength, flexibility, and coordination.[1][11] The largest bone in the body , the femur (thigh bone) , connects the hip to the knee .[2] Below the knee , the tibia (shin bone) and the thinner fibula form the lower leg.[4][5] The thigh lies between the hip and the knee , while the calf comprises the back portion of the lower leg.[1] The shin refers to the front part of the lower leg where the tibia is located.[1][4] Human legs are unique in evolution because they are specially adapted for bipedal locomotion (walking on two feet). This adaptation gives us efficiency in movement compared to most animals.[1][2][19] Anatomical differences exist between male and female legs—for example, in hip angle, knee alignment, and bone length—but the overall structure and function remain the same.[17][2] In this article, we will explore leg anatomy in detail , covering the major bones, muscles, tendons, ligaments, joints, and nerves , to understand how our legs work and why they are so essential for daily activities and overall mobility. Leg Anatomy Diagram An anatomical diagram of the human leg, highlighting key parts such as bones, muscles, and joints for a better understanding of leg structure and function. Parts of the Leg Leg Bones Femur Patella Tibia Fibula Joints Hip Joint Knee Joint Ankle Joint Subtalar Joint Leg Muscles Thigh Gastrocnemius Soleus Tibialis Anterior Peroneus Longus Peroneus Brevis Tendons Achilles Tendon Tibialis Posterior Tendon Ligaments Anterior Cruciate Ligament (ACL) Posterior Cruciate Ligament (PCL) Medial Collateral Ligament (MCL) Lateral Collateral Ligament (LCL) Leg Bone Anatomy Femur The femur or thigh bone is the longest, heaviest, and strongest bone in the human body . It plays a crucial role in supporting body weight, maintaining posture, and enabling smooth movements like walking, running, and jumping.[2][1] The femur is divided into three main parts : Proximal end (upper part): It connects with the hip bone at the hip joint .[2][15] Shaft (middle portion): It is the long, cylindrical body of the bone.[2][15] Distal end (lower part): It connects with the tibia and patella (knee cap) to form the knee joint .[2][15] The femur also acts as a weight-bearing bone , transmitting forces from the hip to the knee and giving the body strength and stability.[2] It serves as an anchor point for several muscles, ligaments, and tendons that control leg movement and balance.[15] Inside the femoral shaft , there are two types of bone marrow: Red bone marrow – It is responsible for producing red blood cells, white blood cells, and platelets (essential for oxygen transport and immunity).[2] Yellow bone marrow – It mainly stores fat and serves as an energy reserve.[2] Because of its strength and vital functions, the femur is often studied in orthopedics, anatomy, and sports medicine to understand mobility, fractures, and overall skeletal health. Illustration of the human femur bone with labeled parts and structure for better understanding of anatomy. Read More – Femur Anatomy: Complete Guide with Parts, Names, Functions & Diagram What is a Femur Shaft Fracture (Broken Thighbone) & its Types? How to do Femur fracture repair? All you need to know about the Femur X-Ray. Patella The patella or kneecap is a triangular and flat bone in a central position at the front of the knee joint . It helps to connect the femur and tibia in the knee area.[3][11][16] The main role of the patella comes during the process of knee extension.[3][11][16] Also, it has another critical function, which is to facilitate the easy movement of the knee during both flexion and extension.[3][11][16] Additionally, it acts as a protective shield for the anterior surface of the knee joint , safeguarding it from potential harm.[16] Patella Fractures: Approach to Treatment. Patella fractures treated with suture tension band fixation. Tibia The tibia , commonly known as the shin bone , is one of the two major bones in the lower leg. It serves as the main weight-bearing bone of the body . It is larger, stronger, and more vital for support compared to the fibula. The tibia connects with the femur at the knee joint and with the fibula and talus at the ankle joint. It is positioned on the inner side of the leg and runs parallel to the fibula, stretching from just below the knee down to the ankle.[4] From a functional perspective, the tibia is responsible for supporting body weight, maintaining balance, and ensuring stability during standing, walking, and running .[4] It acts as a crucial link between the thigh and the foot. It allows smooth movement while protecting the internal structures of the leg.[4] Cross-Union Surgery for Congenital Pseudarthrosis of the Tibia. Knee Pain After Intramedullary Nailing in the Tibia. Tibia (Shinbone) Shaft Fractures. Fibula The fibula is a long, thin bone in the lower leg, located on the outer side next to the larger tibia. Unlike the tibia, it does not carry much body weight, but it is essential for leg stability, balance, and ankle movement .[5] Upper End (Head & Neck): At the top, the fibula has a rounded head just behind the tibia’s head, followed by a narrow neck.[5] Shaft: The middle section of the fibula is called the shaft. It is triangular in shape with three surfaces—lateral (outer), medial (facing the tibia), and posterior (back). Lower End (Lateral Malleolus): At the ankle, the fibula widens to form the lateral malleolus, the bony bump on the outer side of the ankle. This part connects with the talus bone, helping form the ankle joint and preventing excessive side-to-side movement. The fibula is tightly linked to the tibia by the interosseous membrane. [5] It is a strong sheet of connective tissue that runs between the two bones. This connection provides stability and ensures proper leg function during walking, running, and standing.[5] Nutrient foramina of human fibula: morphometric analysis and clinical relevance. Innovative approach to intramedullary nailing of the fibula: a technical note. 0 % Leg Anatomy Leg Bone Anatomy Start the Quiz on Leg Bones Anatomy. 1 / 10 1. Which bone forms part of both the hip joint and the knee joint? 1. Femur 2. Fibula 3. Patella 4. Tibia 2 / 10 2. The interosseous membrane between tibia and fibula helps bind the bones together. Which bone anatomy source mentions this? 1. No 2. Yes 3 / 10 3. During a “hip fracture” in elderly persons, which bone is fractured? 1. Femur 2. Tibia 3. Patella 4. Fibula 4 / 10 4. Which bone is most vulnerable to fractures in severe trauma because of its weight-bearing and load-transmitting role? 1. Fibula 2. Tibia 3. Femur 4. Patella 5 / 10 5. What is the longest bone in the human leg? 1. Fibula 2. Tibia 3. Femur 4. Patella 6 / 10 6. The fibula provides which of these functions? 1. Lateral border of ankle & muscle attachment support 2. Primary muscle attachment for quadriceps 3. Forms the hip joint 4. Major weight-bearing 7 / 10 7. The femur articulates with the hip bone via its head. What is the name of that joint? 1. Elbow joint 2. Ankle joint 3. Knee joint 4. Hip joint 8 / 10 8. Which bone’s proximal end forms the patellar surface (trochlea) where the patella glides during knee movement? 1. Fibula 2. Femur 3. Tibia 4. Patella 9 / 10 9. The femur has two rounded projections at its lower end that articulate with the tibia. What are those called? 1. Malleoli 2. Condyles 3. Tubercles 4. Trochanters 10 / 10 10. Which bone is often involved in the condition known as tibial plateau fracture (a fracture near the knee joint)? 1. Fibula 2. Patella 3. Femur 4. Tibia Your score is The average score is 60% 0% Restart quiz Leg Muscle Anatomy Thigh The thigh is the upper part of the leg, located between the hip and the knee . Its main bone is the femur , the longest and strongest bone in the human body . The femur supports body weight and helps with movement. The thigh is divided into three main compartments , and each has its own muscles, nerves, and blood vessels that work together for movement and stability: Anterior Compartment – It contains the quadriceps muscles , which straighten the knee . They are important for walking, running, climbing, and kicking.[7][15] Medial Compartment – It is known as the adductor group. T hese muscles pull the legs inward toward the body’s midline. They help with balance, side-to-side motion, and controlled leg positioning.[7][15] Posterior Compartment – It includes the hamstring muscles , which bend the knee and extend the hip . These muscles are essential for sitting, standing, jumping, and sprinting.[7][15] All these compartments are separated by a strong connective tissue called fascia , which gives structure, protection, and support to the thigh muscle . An anatomical diagram of the thigh muscles, highlighting quadriceps, hamstrings, adductors, and sartorius with their key functions. Read More – Complete Guide to Thigh Muscle Anatomy: Learn Parts, Names & Diagram How to do a Thigh stretch? Thigh muscle features in female patients with severe knee osteoarthritis Gastrocnemius The gastrocnemius muscle , commonly called the calf muscle , is one of the largest and strongest muscles in the lower leg. It has two parts (the medial and lateral heads) that start just above the knee and join together at the back of the leg, attaching to the Achilles tendon at the heel.[6][10] This muscle c