The leg is the entire lower limb of the human body, including the foot, thigh or sometimes even the hip or buttock region. The major bones of the leg are the femur, tibia, and adjacent fibula. The thigh is between the hip and knee, while the calf (rear) and shin (front) are between the knee and foot.
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia, and one between the femur and patella. It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis.
The femoral artery is a large artery in the thigh and the main arterial supply to the thigh and leg. The femoral artery gives off the deep femoral artery and descends along the anteromedial part of the thigh in the femoral triangle. It enters and passes through the adductor canal, and becomes the popliteal artery as it passes through the adductor hiatus in the adductor magnus near the junction of the middle and distal thirds of the thigh.
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 ; it connects the knee with the ankle. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane. The tibia is connected to the fibula by the interosseous membrane of leg, forming a type of fibrous joint called a syndesmosis with very little movement. The tibia is named for the flute tibia. It is the second largest bone in the human body, after the femur. The leg bones are the strongest long bones as they support the rest of the body.
The popliteal artery is a deeply placed continuation of the femoral artery opening in the distal portion of the adductor magnus muscle. It courses through the popliteal fossa and ends at the lower border of the popliteus muscle, where it branches into the anterior and posterior tibial arteries.
The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus.
The semitendinosus is a long superficial muscle in the back of the thigh. It is so named because it has a very long tendon of insertion. It lies posteromedially in the thigh, superficial to the semimembranosus.
The popliteal fossa is a shallow depression located at the back of the knee joint. The bones of the popliteal fossa are the femur and the tibia. Like other flexion surfaces of large joints, it is an area where blood vessels and nerves pass relatively superficially, and with an increased number of lymph nodes.
The superior genicular arteries, two in number, arise one on either side of the popliteal artery, and wind around the femur immediately above its condyles to the front of the knee-joint. The medial superior genicular artery is on the inside of the knee and the lateral superior genicular artery is on the outside.
The lateral superior genicular artery is a branch of the popliteal artery that supplies a portion of the knee joint.
The medial superior genicular artery is a branch of the popliteal artery. It runs deep to the semimembranosus, semitendinosus, and tendon of the adductor magnus, and superior to the medial head of the gastrocnemius.
The inferior genicular arteries, two in number, arise from the popliteal beneath the gastrocnemius. On the inside of the knee, is the medial inferior genicular artery, and on the outer side is the lateral inferior genicular artery.
The lower extremity of femur is the lower end of the femur in human and other animals, closer to the knee. It is larger than the upper extremity of femur, is somewhat cuboid in form, but its transverse diameter is greater than its antero-posterior; it consists of two oblong eminences known as the lateral condyle and medial condyle.
The cruciate anastomosis is a circulatory anastomosis in the upper thigh formed by the inferior gluteal artery, the lateral and medial circumflex femoral arteries, the first perforating artery of the deep femoral artery, and the anastomotic branch of the posterior branch of the obturator artery.
The descending genicular artery arises from the femoral artery just before its passage through the adductor hiatus.
The saphenous nerve is the largest cutaneous branch of the femoral nerve. It is derived from the lumbar plexus (L3-L4). It is a strictly sensory nerve, and has no motor function. It commences in the proximal (upper) thigh and travels along the adductor canal. Upon exiting the adductor canal, the saphenous nerve terminates by splitting into two terminal branches: the sartorial nerve, and the infrapatellar nerve. The saphenous nerve is responsible for providing sensory innervation to the skin of the anteromedial leg.
In human anatomy, the adductor hiatus also known as hiatus magnus is a hiatus (gap) between the adductor magnus muscle and the femur that allows the passage of the femoral vessels from the anterior thigh to the posterior thigh and then the popliteal fossa. It is the termination of the adductor canal and lies about 8–13.5 cm (3.1–5.3 in) superior to the adductor tubercle.
The knee bursae are the fluid-filled sacs and synovial pockets that surround and sometimes communicate with the knee joint cavity. The bursae are thin-walled, and filled with synovial fluid. They represent the weak point of the joint, but also provide enlargements to the joint space. They can be grouped into either communicating and non-communicating bursae or, after their location – frontal, lateral, or medial.
The intercondylar fossa of femur is a deep notch between the rear surfaces of the medial and lateral epicondyle of the femur, two protrusions on the distal end of the femur that joins the knee. On the front of the femur, the condyles are but much less prominent and are separated from one another by a smooth shallow articular depression called the patellar surface because it articulates with the posterior surface of the patella (kneecap).
The genicular arteries are six arteries in the human leg, five of which are branches of the popliteal artery, that anastomose in the knee region in the patellar network or genicular anastomosis. They supply blood to the patella, together with contributions from the descending genicular artery, anterior tibial recurrent artery, and descending branch of lateral circumflex femoral artery.
