Lower Limbs Muscle Anatomy

Front view of the lower limb showing the main superficial muscles from thigh to foot.

In this guide, we will tell you about the anatomy of the lower limbs. This is a very important topic for artists because the position of the legs shapes the pose and figure of the character.

Muscles of the lower limb girdle

The muscles of the lower limb girdle connect the bones of the lower limb girdle and the free lower limb into a single mechanism. These muscles are divided into superficial and deep. The deep ones are not of fundamental importance for plastic anatomy, but we will analyze some of the superficial ones.

Gluteus maximus muscle

This rounded, raised muscle forms the contour of the back of the pelvis. This muscle is especially developed in powerlifters and gymnasts. The gluteus maximus is the most superficial of the pelvic muscles and is located just under the skin and adipose tissue.

The gluteus maximus muscle begins from the back sides of the bones of the pelvic girdle and from the tendon of the spinal erectors. The attachment points of this muscle are the gluteal tuberosity of the femur and the iliotibial tract.

Gluteal anatomy showing the gluteus maximus muscle.

Tensor fasciae latae muscle

This muscle occupies the most lateral position of all the muscles studied here. We can see a small muscle bundle that merges into a powerful connective tissue structure called the fascia lata and iliotibial tract.

The tensor fasciae latae begins from a small area on the wing of the ilium just below the anterior superior iliac spine. Going downward, it blends into the iliotibial tract, which reaches the knee joint.

Side view of the upper thigh showing the tensor fasciae latae muscle.

Thigh muscles

The muscles of the thigh are very strong and massive because they take on a significant part of the load associated with upright posture. The thigh muscles are divided into the front, back, and medial groups.

Front group

Quadriceps femoris muscle

It is the largest of the thigh muscles. As you can see from the name, the quadriceps muscle consists of four parts. Each part of the quadriceps muscle has its own name.

The constituent parts of the quadriceps muscle of the thigh start from different places, but as they descend, these parts connect into a powerful tendon that passes over the knee joint and attaches to the tuberosity of the tibia. The patella is located within this tendon.

Rectus femoris

This muscle occupies the front of the thigh. The rectus femoris begins with an elongated, thin tendon from the anterior inferior iliac spine of the pelvis. The tendon then passes into a wide, powerful muscle belly, which narrows again near the knee joint and blends into the common tendon of the quadriceps femoris muscle.

Vastus medialis

This part of the quadriceps muscle is located medial to the rectus femoris. A small area of the vastus medialis muscle is covered by the rectus femoris muscle. Below, the fibers of the vastus medialis are woven into the common tendon of the quadriceps muscle.

Vastus lateralis

This part of the quadriceps muscle is located lateral to the rectus femoris and occupies almost the entire anterolateral surface of the thigh. The vastus lateralis is partially covered in front by the rectus femoris muscle. It also borders the fascia lata and iliotibial tract.

The vastus lateralis starts from the greater trochanter of the femur and the intertrochanteric line. Like the other parts of the quadriceps muscle, the vastus lateralis passes into the common tendon and attaches to the tibial tuberosity.

Anterior thigh anatomy with the vastus lateralis, sartorius, quadriceps femoris, and vastus medialis labeled.

Back group

Biceps femoris muscle

The biceps femoris has a long and short head. The short head is located beneath the long head, so it is less important in plastic anatomy. The long head occupies the most lateral position on the back of the thigh. This part starts from the ischial tuberosity and attaches to the head of the fibula.

Semitendinosus muscle

This muscle is a long, elongated band that runs along the medial side of the back of the thigh. The semitendinosus muscle is located directly under the skin and partially overlaps the semimembranosus muscle. This muscle starts from the ischial tuberosity and attaches to the medial surface of the upper tibia.

The semitendinosus and biceps femoris muscles form a well-marked arch-like shape. This is especially noticeable when a person stands upright with the legs extended.

The semimembranosus muscle is located directly below the semitendinosus muscle.

Posterior thigh anatomy with the semimembranosus, semitendinosus, biceps femoris, and vastus lateralis labeled.

Shin muscles

The shin is the part of the leg located between the knee joint and the foot. Its bony base is made up of the tibia and fibula. The shin muscles control the movements of the foot and toes, so this is a fairly large group.

We will not study all the shin muscles because some are very deep and are not important for plastic anatomy. We will only study the superficial muscles that form the contours of the shin.

Anterior muscle group of the shin

These muscles are located on the front surface of the shin and extend the foot and toes.

Tibialis anterior muscle

It is a large and powerful muscle. The tibialis anterior forms the rounded contour on the front of the lower leg. This muscle fills the area lateral to the anterior edge of the tibia.

The tibialis anterior starts from the lateral condyle and the upper part of the lateral surface of the tibia. Downward, this muscle passes into a long, thin tendon that attaches to the medial cuneiform bone and the base of the first metatarsal bone.

Extensor digitorum longus muscle

This muscle lies lateral to the tibialis anterior. The extensor digitorum longus is a slightly thinner muscle that extends along much of the lower leg. Downward, it passes into four long, thin tendons that diverge toward the corresponding toes and attach to their distal phalanges.

The tendons of the extensor digitorum longus are clearly visible under the skin when the muscle contracts.

The extensor digitorum longus begins from the lateral condyle of the tibia and the anterior surface of the fibula.

Extensor hallucis longus muscle

We cannot see most of this muscle because it lies deep between the surrounding muscles. However, the tendon of the extensor hallucis longus can become noticeable under the skin, especially when the muscle contracts.

The extensor hallucis longus starts from the medial surface of the fibula and attaches to the distal phalanx of the big toe.

Anterior lower leg anatomy with the extensor digitorum longus, tibialis anterior, extensor hallucis longus, and tibia labeled.

Back muscle group of the shin

This group includes the most powerful and visible shin muscles. The muscles on the back of the shin are located in several layers, and we will look at the largest and most superficial of them.

Triceps surae muscle

The triceps surae is a large muscle group that forms much of the posterior contour of the lower leg. It consists of the two heads of the gastrocnemius and the soleus muscle. We will focus mainly on the more superficial gastrocnemius.

Gastrocnemius muscle

The gastrocnemius has two large heads located on the back of the lower leg: medial and lateral. When the gastrocnemius is sufficiently developed, it creates the characteristic contours of the calf with a pronounced narrowing toward the ankle.

The main function of the gastrocnemius muscle is plantar flexion of the foot. Its work is especially noticeable when you look at professional ballet dancers standing on their toes.

The lateral head of the gastrocnemius muscle starts from the lateral condyle of the femur. The medial head starts from the area above the medial condyle of the femur.

Under the lateral and medial heads of the gastrocnemius is a flat, broad muscle called the soleus. Although much of it lies beneath the gastrocnemius, parts of the soleus can contribute to the visible contour of the lower leg.

Back view of both lower legs showing the gastrocnemius muscles and calf contours.

Achilles tendon

The Achilles tendon is the strong tendon formed mainly by the gastrocnemius and soleus muscles. It attaches to the heel bone and is therefore also called the calcaneal tendon. The history of its name is connected with the Trojan War, more precisely, with the myth of Achilles, one of the main Greek warriors who besieged Troy.

According to the later version of the myth, Achilles’ mother, the goddess Thetis, dipped her son into the River Styx, making him invulnerable except for the heel by which she held him. Achilles was later mortally wounded in the heel by Paris.

It is from this ancient myth that the Achilles tendon gets its name.

Side view of the lower leg showing the Achilles tendon extending to the heel.

Muscles of the foot

The muscles of the foot are classified into muscles of the sole and muscles of the dorsum of the foot. We will study only those muscles that are located superficially, since these are the ones most important in plastic anatomy.

Muscles of the dorsum of the foot

The muscles on the dorsum of the foot help extend the toes. These muscles are located beneath the tendons of the anterior leg muscles and assist with similar movements.

Extensor digitorum brevis muscle

It is a broad muscle on the dorsum of the foot. Its tendons extend toward the lateral toes and join the extensor tendons. This muscle starts from the upper and lateral surface of the calcaneus.

Extensor hallucis brevis muscle

The extensor hallucis brevis is the part directed toward the big toe. It starts from the upper surface of the calcaneus and attaches to the proximal phalanx of the big toe.

Dorsal foot anatomy with the extensor digitorum brevis and extensor hallucis brevis labeled.

Plantar aponeurosis

Almost all the muscles on the sole are located under the plantar aponeurosis. It is a strong layer of connective tissue located beneath the skin of the sole.

The plantar aponeurosis is a dense sheet of connective tissue that extends from the heel toward the toes. Toward the front of the foot, it divides into several longitudinal bands that continue toward the toes.

When extending the toes or standing on tiptoe, the plantar aponeurosis can become more noticeable beneath the skin.

Sole of the foot showing the plantar aponeurosis extending from heel toward the toes.

Lower limb topography

The lower limb is bordered by the abdomen and back. The border separating the lower limb from the abdomen is the inguinal ligament. The border separating the back from the lower limb is a line drawn through the iliac crest and the apex of the coccyx.

Lower limb regions

Gluteal region

The gluteal region corresponds to the area of the gluteal muscles.

Thigh region

The thigh region has front and back surfaces. The front surface is bounded above by the inguinal ligament and below by a horizontal line drawn 3-5 centimeters above the patella.

The posterior surface is bounded above by the gluteal fold and below by a horizontal line drawn 3-5 centimeters above the projection of the patella onto the posterior surface.

Anterior lower limb with the thigh, knee, lower leg, ankle, and foot regions labeled.

Knee region

The knee region also has front and back surfaces.

The front region of the knee is bounded above by a horizontal line drawn 3-5 centimeters above the patella and below by a horizontal line drawn through the tuberosity of the tibia. The posterior region of the knee corresponds to the boundaries of the popliteal fossa.

The popliteal fossa is diamond-shaped. It is bounded above laterally by the biceps femoris, above medially by the semimembranosus and semitendinosus muscles, and below by the lateral and medial heads of the gastrocnemius muscle.

Shin region

The front region of the lower leg is bounded above by a horizontal line drawn through the tuberosity of the tibia and below by a line drawn through the bases of both ankles.

The posterior region of the lower leg is bounded above by a horizontal line drawn through the tuberosity of the tibia and below by a line drawn through the bases of both ankles.