In human anatomy, the thigh is the area between the hip ( pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates ...

. This bone is very thick and strong (due to the high proportion of bone tissue), and forms a ball and socket joint at the hip, and a modified hinge joint at the knee.

Structure

Bones

The

is the only bone in the thigh and serves as an attachment site for all muscles in the thigh. The head of the femur articulates with the

acetabulum The acetabulum (), also called the cotyloid cavity, is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint. Structure There are three bones of the ''os coxae'' (hip bone) that c ...

in the pelvic bone forming the hip joint, while the distal part of the femur articulates with the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it conn ...

and

patella The patella, also known as the kneecap, is a flat, rounded triangular bone which articulates with the femur (thigh bone) and covers and protects the anterior articular surface of the knee joint. The patella is found in many tetrapods, such as ...

forming the knee. By most measures, the femur is the strongest bone in the body. The femur is also the longest bone in the body. The femur is categorised as a long bone and comprises a diaphysis, the shaft (or body) and two epiphysis or extremities that articulate with adjacent bones in the hip and knee.

Muscular compartments

In cross-section, the thigh is divided up into three separate compartments, divided by fascia, each containing muscles. These compartments use the femur as an axis and are separated by tough connective tissue membranes (or septa). Each of these compartments has its own

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...

and nerve supply, and contains a different group of muscles. * Medial fascial compartment of thigh, adductor * Posterior fascial compartment of thigh, flexion, hamstring * Anterior fascial compartment of thigh, extension Anterior compartment muscles of the thigh include sartorius, and the four muscles that comprise the quadriceps muscles- rectus femoris, vastus medialis, vastus intermedius and vastus lateralis. Posterior compartment muscles of the thigh are the

hamstring muscles In human anatomy, a hamstring () is any one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus, semitendinosus and biceps femoris). The hamstrings are susceptible to injury. In quadrupeds, ...

, which include semimembranosus, semitendinosus, and

biceps femoris The biceps femoris () is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, one of which (the long head) forms part of the hamstrings muscle group. Structure It has two heads of origin: *the ''long ...

. Medial compartment muscles are pectineus, adductor magnus, adductor longus and adductor brevis, and also gracilis. Because the major muscles of the thigh are the largest muscles of the body, resistance exercises (strength training) of them stimulate blood flow more than any other localized activity.

Blood supply

The arterial supply is by the femoral artery and the obturator artery. The lymphatic drainage closely follows the arterial supply and drains to the lumbar lymphatic trunks on the corresponding side, which in turn drains to the cisterna chyli. The deep venous system of the thigh consists of the femoral vein, the proximal part of the

popliteal vein The popliteal vein is a vein of the lower limb. It is formed from the anterior tibial vein and the posterior tibial vein. It travels medial to the popliteal artery, and becomes the femoral vein. It drains blood from the leg. It can be assessed ...

, and various smaller vessels; these are the site of proximal

deep venous thrombosis Deep vein thrombosis (DVT) is a type of venous thrombosis involving the formation of a blood clot in a deep vein, most commonly in the legs or pelvis. A minority of DVTs occur in the arms. Symptoms can include pain, swelling, redness, and enla ...

. The ''venae perfortantes'' connect the deep and the superficial system, which consists of the saphenous veins (the site of

varicose vein Varicose veins, also known as varicoses, are a medical condition in which superficial veins become enlarged and twisted. These veins typically develop in the legs, just under the skin. Varicose veins usually cause few symptoms. However, some indi ...

s).

Clinical significance

Thigh weakness can result in a positive Gowers' sign on physical examination. Regarding Sports injury, whether

acute Acute may refer to: Science and technology * Acute angle ** Acute triangle ** Acute, a leaf shape in the glossary of leaf morphology * Acute (medicine), a disease that it is of short duration and of recent onset. ** Acute toxicity, the adverse ef ...

or from overuse, a thigh injury can mean significant incapacity to perform. Soft tissue injury can encompass sprains, strains,

bruising A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises occur close ...

and tendinitis.

Runner's knee Runner's knee may refer to a number of overuse injuries involving pain around the kneecap (patella), such as: *Patellofemoral pain syndrome *Chondromalacia patellae *Iliotibial band syndrome *Plica syndrome Plica syndrome is a condition that occ ...

( Patellofemoral pain): is a direct consequence of the kneecap rubbing against the end of the thigh bone (”

”). Tight hamstrings and weak thigh muscles, required to stabilize the knee, risk development of runner's knee.

Food

The thigh meat of some animals such as chicken and cow is consumed as food in many parts of the world.

Society and culture

Western societies generally tolerate clothing that displays thighs, such as short shorts and

miniskirts A miniskirt (sometimes hyphenated as mini-skirt, separated as mini skirt, or sometimes shortened to simply mini) is a skirt with its hemline well above the knees, generally at mid-thigh level, normally no longer than below the buttocks; and a ...

. Beachwear and many athleisure styles often display thighs as well. Professional dress codes may require covering up bare thighs. Many Islamic countries disapprove of or prohibit the display of thighs, especially by women. Strategic covering or display of thighs is used in popular fashion around the world, such as

thigh-high boots Thigh-high boots, known also as thigh-length boots or simply thigh boots, are boots that extend above the knees to at least mid-thigh. Other terms for this footwear include '' over-the-knee boots'' (abbreviated OTK boots; the full term is also u ...

and '' zettai ryoiki''.

Additional images

Thigh muscles front.png, Front of thigh muscles from Gray's Anatomy of the human body from 1918. Thigh muscles back.png, Back thigh muscles of the gluteal and posterior femoral regions from Gray's Anatomy of the human body from 1918. Gray432.png, Cross-section through the middle of the thigh. File:Sobo 1909 573-574.png, Also showing major blood vessels and nerves. Thigh_cross_section.svg, Cross-section through the middle of the thigh. Gray436.png, The Obturator externus

References

{{Authority control Lower limb anatomy