The middle genicular artery (azygos articular artery) is a small branch of the

popliteal artery 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 branche ...

. It supplies parts of the

knee In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

joint.

Structure

The middle genicular artery (MGA) arises from the anterolateral surface of the

. This point of origin is distal to the

superior genicular arteries The superior genicular arteries (superior articular 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 In humans and other primate ...

, and between, equidistantly, the

medial condyle of femur The medial condyle is one of the two projections on the lower extremity of femur, the other being the lateral condyle. The medial condyle is larger than the lateral (outer) condyle due to more weight bearing caused by the centre of mass being ...

and the

lateral condyle of femur The lateral condyle is one of the two projections on the lower extremity of the femur. The other one is the medial condyle. The lateral condyle is the more prominent and is broader both in its front-to-back and transverse diameters. Clinical sig ...

. As a normal variation, the MGA may emerge from the popliteal artery at a common point of origin shared with the superior lateral genicular artery, or both vessels may arise at separate, distinct points. The angle at which the middle genicular artery leaves the popliteal artery varies with flexion and extension of the knee. It may form a near 90° angle when the knee is flexed, but an angle of only between 15° and 30° when the knee is extended. The

diameter In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions a ...

of the MGA is between , and its length between . It has two

venae comitantes Vena comitans (Latin for accompanying vein, also known as a satellite vein) refers to a vein that is usually paired, with both veins lying on the sides of an artery. Because they are generally found in pairs, they are often referred to by their ...

along its length. It pierces the

oblique popliteal ligament The oblique popliteal ligament (posterior ligament) is a broad, flat, fibrous ligament on the posterior knee. It is an extension of the tendon of the semimembranosus muscle. It attaches onto the intercondylar fossa and lateral condyle of the fem ...

and the joint capsule of the

Function

The middle genicular artery supplies the

anterior cruciate ligament The anterior cruciate ligament (ACL) is one of a pair of cruciate ligaments (the other being the posterior cruciate ligament) in the human knee. The two ligaments are called "cruciform" ligaments, as they are arranged in a crossed formation. In ...

and the

posterior cruciate ligament The posterior cruciate ligament (PCL) is a ligament in each knee of humans and various other animals. It works as a counterpart to the anterior cruciate ligament (ACL). It connects the posterior intercondylar area of the tibia to the Medial condyl ...

. It also supplies the

synovial membrane Synovial () may refer to: * Synovial fluid * Synovial joint A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer bou ...

at the bottom of the

Clinical significance

The middle genicular artery may be damaged during knee arthroscopy, particularly using a posterior approach through the

popliteal fossa The popliteal fossa (also referred to as hough or kneepit in analogy to the cubital 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 ...

. It may also be damaged in traumatic injuries to the knee, often caused by

sports Sport is a physical activity or game, often competitive and organized, that maintains or improves physical ability and skills. Sport may provide enjoyment to participants and entertainment to spectators. The number of participants in ...

References

Arteries of the lower limb {{circulatory-stub