Regions of the lower limb

Contents

The gluteal region is composed of the bony pelvis, muscles, ligaments and associated neurovasculature. 

Muscles of the gluteal region can be organized into superficial and deep layers. Superficial muscles of the gluteal region consist of the three large overlapping gluteus maximus, medius and minimus muscles and the tensor fasciae latae muscle. 

Deep muscles of the gluteal region consist of a series of smaller muscles (piriformis, obturator internus, superior and inferior gemelli, and quadratus femoris) which lie beneath the inferior half of the gluteus maximus muscle. 

Stabilizing the bony pelvis are a number of ligaments which lie within the gluteal region. The three main ligaments of the gluteal region include the posterior sacroiliac, sacrotuberous and sacrospinous ligaments which aid in stabilizing the hip bones, sacrum and coccyx. 

One of the main neurovascular structures of this area is the large sciatic nerve, which exits the pelvic region to enter the gluteal region through the greater sciatic foramen

Contents

The thigh houses the largest bone of the human body, the femur. Surrounding the femur are the large muscles of the thigh which are grouped by fasciae and intermuscular septa into three compartments: the anterior, posterior and medial compartments of the thigh. The muscles of the femoral region include the quadriceps femoris muscle anteriorly, the adductor muscle group medially and the hamstring muscles posteriorly. 

Within the anterior thigh region, there is a small triangular sub-region known as the femoral triangle, also known as the femoral trigone. The femoral triangle is located on the anteromedial aspect of the thigh and is bordered by the inguinal ligament superiorly, the sartorius muscle laterally, and the adductor longus muscle medially. Contents of the femoral triangle, from lateral to medial include the femoral nerve, femoral artery, femoral vein, and the femoral lymph nodes, which are more commonly known as the inguinal lymph nodes. 

Posteriorly, the sciatic nerve continues from the gluteal region to enter the posterior thigh.

Contents

The knee region is mainly composed of the knee joint which is formed by the articulations between the distal femur, proximal tibia and patella. While the fibula does not take part in the formation of the knee joint, the head of the fibula is included as a component of the knee region. 

The posterior surface of the knee region is marked by a diamond shaped fossa known as the popliteal fossa, which is also known as the popliteal region. The popliteal fossa is a fat filled space bounded superiorly by the tendons of the hamstring muscles and inferiorly by the  tendons of the gastrocnemius muscle. The popliteal region houses the popliteal artery and vein as well as the two main nerves of the leg: the tibial and common fibular nerves.

Contents

The bony framework of the leg consists of the tibia medially and the fibula laterally. Muscles of the leg are divided into anterior, posterior and lateral groups. Muscles of the posterior group (gastrocnemius, soleus, plantaris, popliteus, tibialis posterior, flexor hallucis longus, flexor digitorum longus) mainly plantarflex and invert the foot and flex the toes, while muscles of the anterior group (tibialis anterior, extensor digitorum longus, extensor hallucis longus and fibularis tertius) collectively dorsiflex and invert the foot at the ankle joint and extend the toes. The lateral group of muscles (fibularis longus and fibularis brevis) function to evert the foot. 

Neurovascular structures of the leg include the anterior and posterior tibial arteries and anterior and posterior tibial veins as well as the tibial, common fibular, superficial fibular and deep fibular nerves.

Contents

The anterior talocrural region is defined by the distal ends of the tibia and fibula which form the bony protrusions of the ankle region known as the medial and lateral malleoli, respectively. Between them is the most proximal bone of the foot, the talus. 

The posterior talocrural region is similarly marked by the medial and lateral malleoli, which are separated by the calcaneal tendon which is commonly referred to as the Achilles tendon. Between the calcaneal tendon and both malleoli are two small subregions known as the medial and lateral retromalleolar regions.

Tendons of the anterior, posterior and lateral leg muscles pass through the talocrural region to insert onto the foot. Important vessels (anterior and posterior tibial artery, anterior and posterior tibial vein, deep fibular nerve and tibial nerve) also pass through this region to supply and drain structures of the foot.

Contents

The tarsus refers to the cluster of seven tarsal bones which include the calcaneus, talus, navicular, cuboid and the medial, intermediate and lateral cuneiform bones. 

The metatarsal region of the foot is formed by the five metatarsal bones. The metatarsal bones are numbered from I to V. Each metatarsal has a head at the distal end, an elongated shaft in the middle, and a proximal base. 

The phalanges are the bones of the toes. Each toe has three phalanges (proximal, middle and distal phalanges) except for the great toe, which only has a proximal and distal phalanx. Similar to the metatarsals, the phalanges also consist of a head, shaft and base. 

The muscles contained in the foot can be subdivided into plantar and dorsal groups. The dorsal group is comprised of only two muscles, while the plantar muscles are further subdivided into three groups; lateral, central, and medial.

A terminal branch of the anterior tibial artery, dorsalis pedis traverses the dorsum of the foot alongside the deep fibular nerve to supply structures of this area. Posteromedially, a neurovascular bundle containing the posterior tibial artery and vein and tibial nerve curves around the medial malleolus to enter the sole of the foot.

Test your knowledge on the regions of the lower limb with this quiz.