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 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, 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 med ...

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 The lateral superior genicular artery is a branch of the popliteal artery that supplies a portion of the knee joint. Course It passes above the lateral condyle of the femur, beneath the tendon of the Biceps femoris. Branching It divides into a s ...

, 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 center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid fo ...

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

venae comitantes Vena comitans is Latin for accompanying vein. It refers to a vein that is usually paired, with both veins lying on the sides of an artery. They are found in close proximity to arteries so that the pulsations of the artery aid venous return. B ...

along its length. It pierces the

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

and the joint capsule of the knee.

Function

The middle genicular artery supplies the

anterior cruciate ligament The anterior cruciate ligament (ACL) is one of a pair of cruciate ligament Cruciate ligaments (also cruciform ligaments) are pairs of ligaments arranged like a letter X. They occur in several joints of the body, such as the knee joint and th ...

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 cond ...

. It also supplies the synovial membrane at the bottom of the knee.

Clinical significance

The middle genicular artery may be damaged during

knee arthroscopy Arthroscopy (also called arthroscopic or keyhole surgery) is a minimally invasive surgical procedure on a joint in which an examination and sometimes treatment of damage is performed using an arthroscope, an endoscope that is inserted into the j ...

, particularly using a posterior approach through the

popliteal fossa The popliteal fossa (also referred to as hough, .html" ;"title="/sup>">/sup> 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 ...

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

sports Sport pertains to any form of competitive physical activity or game that aims to use, maintain, or improve physical ability and skills while providing enjoyment to participants and, in some cases, entertainment to spectators. Sports can, ...

References

Arteries of the lower limb {{circulatory-stub