Lower Limbs Skeleton Anatomy

Human lower limb skeleton with the pelvic bone, femur, lower leg, and foot.

The skeleton of the lower limbs, together with the upright spinal column, allows the human body to stand and move on two legs.

The lower limb skeleton includes the lower limb girdle (cingulum membri inferioris) and the skeleton of the free lower limb. The lower limb girdle is formed by the pelvic bones, which connect with the sacrum.

The free lower limb is divided into three parts – the thigh, lower leg, and foot. The skeleton of the thigh is formed by the femur, the lower leg by the tibia and fibula, and the foot by the bones collectively called ossa pedis.

Lower limb skeleton with the sacrum, hip bone, femur, patella, tibia, fibula, and foot bones labeled.

So let’s take a look at each component of the lower limb skeleton.

Lower Limb Girdle

The lower limb girdle consists of two pelvic bones (ossa coxae) – the right and left – which articulate with the sacrum. Each pelvic bone consists of three bones: the ilium, ischium, and pubis.

Front view of the pelvis with the sacrum and hip bones identified.

The pelvic bones are of great physiological importance. They form the bony walls of the pelvis, which contains pelvic organs, major blood vessels, and nerves. The pelvis also plays an important role in childbirth. In obstetrics, certain pelvic dimensions can be assessed to help evaluate the birth canal.

In addition, the pelvis, as you already know, forms the girdle of the lower limbs. The pelvic bones support the lower limbs and connect them to the axial skeleton.

Human pelvis shown from above with the sacrum and paired hip bones.

So, each pelvic bone consists of the ilium, ischium, and pubis. These three bones are connected by cartilage in childhood and gradually fuse into a single hip bone during adolescence and early adulthood.

Hip bone anatomy showing the ilium, ischium, and pubis.

Each of these bones has several component parts. For example, the ilium has a body and a wing. The ischium has a body and a ramus, while the pubis has a body and superior and inferior rami.

The three bones meet in the region of the acetabulum, the socket that articulates with the rounded head of the femur. Together, these structures form the hip joint.

The female pelvis has several typical differences from the male pelvis. We will focus on two of the most noticeable ones:

The angle formed below the pubic symphysis by the inferior pubic rami is generally narrower in men and wider in women;
The wings of the ilium are generally more vertical in men and more laterally flared in women, contributing to a broader pelvic shape.

Male and female pelvis compared from the front, showing differences in width and iliac flare.

It is always important to observe the individual characteristics of the figure you are drawing. On average, the female pelvis is relatively broader than the male pelvis, while a typical male figure often has broader shoulders in relation to the pelvis. These are general tendencies rather than fixed rules.

Femur

The femur, or thigh bone, is one of the largest and strongest bones in the body. At its proximal end, the femur articulates with the pelvic bone, while at its distal end it articulates with the tibia and patella.

At the proximal end is a large rounded structure called the head of the femur (caput femoris). Its rounded shape allows a wide range of movement at the hip joint.

The head of the femur is connected to the shaft by the neck, which forms an angle with the body of the bone. The exact angle varies between individuals and also changes with age. When drawing the lower limb, pay attention to this relationship because it influences the position of the femur beneath the pelvis.

The head of the femur continues into a narrower part called the neck of the femur (collum femoris). You can also see a large bony projection located laterally.

This is the greater trochanter (trochanter major), where several muscles attach. A smaller projection called the lesser trochanter (trochanter minor) is located more medially and posteriorly and also serves as a muscle attachment site.

Femur anatomy with the head, neck, greater and lesser trochanters, shaft, and medial and lateral epicondyles labeled.

The main part of the femur is called the body or shaft (corpus femoris). Downward, the shaft expands and forms the medial epicondyle (epicondylus medialis) and lateral epicondyle (epicondylus lateralis). These are elevations located above the articular surfaces of the femur. The articular surfaces themselves are the medial and lateral condyles.

Patella

The patella is a small, dense sesamoid bone located within the tendon of the quadriceps femoris muscle. It lies in front of the knee joint and articulates with the femur. The patella helps protect the front of the joint and increases the mechanical advantage of the quadriceps muscle during knee extension.

Below the patella, the patellar ligament continues to the tibial tuberosity and transfers the force of the quadriceps muscle to the tibia.

Patella anatomy showing the broad base and pointed apex.

The patella has a base, an apex, and two surfaces. This small bone has a roughly triangular, flattened shape.

Tibia

The tibia is a very massive, strong bone that articulates with the femur, fibula, and talus. The proximal end articulates with the femur, while the distal end helps form the ankle joint with the talus. The fibula lies along the lateral side of the tibia.

Like other long bones, the tibia has a body (corpus tibiae) and two ends – proximal and distal. The powerful body of the tibia expands upward to form two large condyles, the lateral condyle (condylus lateralis) and medial condyle (condylus medialis), which articulate with the femur.

At the distal end, the tibia forms the medial malleolus on the medial side. On the lateral side of the distal tibia is the fibular notch (incisura fibularis), which articulates with the distal end of the fibula.

Tibia anatomy with the medial and lateral condyles, shaft, anterior border, fibular notch, and medial malleolus labeled.

The tibia has a roughly triangular shaft for most of its length. The anterior border of the tibia (margo anterior) is clearly visible beneath the skin and can also be easily palpated.

By the way, Muay Thai fighters, who practice a striking martial art, frequently use the shin to block and deliver kicks, making the anterior surface of the tibia an important visible landmark.

Figure in a blocking position with one leg raised.

Fibula

The fibula, like the tibia, has a body and proximal and distal ends. Its shaft is much thinner and less massive than that of the tibia.

The proximal end of the fibula is expanded to form the head of the fibula. On its medial side is an articular facet for articulation with the tibia.

The distal end of the fibula forms the lateral malleolus, which is clearly visible at the outer side of the ankle. Its medial articular surface contacts the talus, while the distal tibiofibular joint connects the fibula with the tibia.

Fibula anatomy with the head, shaft, and lateral malleolus labeled.

A strong interosseous membrane of connective tissue extends between the tibia and fibula. In addition to this membrane, many muscles are located around and between the bones. This is how the tibia and fibula look in a horizontal section through the middle of the lower leg:

Cross section of the lower leg showing the tibia and fibula among the surrounding soft tissues.

Foot Bones

The human foot is highly adapted for standing, walking, running, and jumping on two legs. Its skeleton consists of the tarsal bones, metatarsal bones, and phalanges of the toes.

Side view of the foot skeleton with the tarsal bones, metatarsals, and toe phalanges identified.

The tarsus contains seven bones: the talus, calcaneus, navicular, cuboid, and three cuneiform bones.

The talus and calcaneus are large, strong tarsal bones. At the ankle joint, the distal ends of the tibia and fibula form a mortise around the talus. The medial malleolus belongs to the tibia, while the lateral malleolus belongs to the fibula.

The talus articulates with the tibia and fibula above, the calcaneus below, and the navicular in front.

The calcaneus is the largest bone of the foot and forms the heel. Together with the other bones, joints, ligaments, tendons, and muscles of the foot, it helps support body weight and absorb forces during walking, running, and jumping.

Top view of the foot bones with the phalanges, metatarsals, intermediate and medial cuneiforms, navicular, calcaneus, and talus labeled.

Farther distally are the five metatarsal bones and the phalanges of the toes. Each toe except the first has three phalanges – proximal, middle, and distal. The big toe has only two phalanges: proximal and distal.

Side view of the foot bones with the phalanges, metatarsals, three cuneiforms, navicular, cuboid, calcaneus, and talus labeled.

The metatarsal bones contribute to the characteristic arches of the foot together with the tarsal bones, ligaments, tendons, and muscles. These arches help support body weight and absorb shock during movement.

The arch is especially noticeable when we look at the foot in profile:

Side view of the foot skeleton showing the longitudinal arch.

The metatarsal bones are numbered from first to fifth, beginning on the big-toe side and ending on the little-toe side. The phalanges are identified by the toe to which they belong and by their position as proximal, middle, or distal.