Medial circumflex femoral artery

The anatomy of the the medial femoral circumflex artery  (a. circumflexa femoris medialis; internal circumflex artery) is described in Gray's as the artery that arises from the medial and posterior aspect of the profunda, and winds around the medial side of the femur, passing first between the Pectineus and Psoas major, and then between the Obturator externus and the Adductor brevis. At the upper border of the Adductor brevis it gives off two branches: one is distributed to the Adductores, the Gracilis, and Obturator externus, and anastomoses with the obturator artery; the other descends beneath the Adductor brevis, to supply it and the Adductor magnus; the continuation of the vessel passes backward and divides into superficial, deep, and acetabular branches:

• The superficial branch appears between the Quadratus femoris and upper border of the Adductor magnus, and anastomoses with the inferior gluteal, lateral femoral circumflex, and first perforating arteries (cruciate anastomosis).

• The deep branch runs obliquely upward upon the tendon of the Obturator externus and in front of the Quadratus femoris toward the trochanteric fossa, where it anastomoses with twigs from the gluteal arteries.

• The acetabular branch arises opposite the acetabular notch and enters the hip-joint beneath the transverse ligament in company with an articular branch from the obturator artery; it supplies the fat in the bottom of the acetabulum, and is continued along the round ligament to the head of the femur.

The anatomy of the the medial femoral circumflex artery (MFCA) is highly variable between sources !

• For some sources [2], the medial femoral circumflex artery (MFCA) may be subdivided into 3 segments: the transverse, ascending, and deep MFCA. The transverse segment (descending branch in TA2) travels posteriorly between the iliopsoas and pectineus muscles. The vessel then ascends posteriorly, as the ascending MFCA, toward the intertrochanteric crest, running within adipose tissue between the obturator externus and the quadratus femoris muscles. Proximally, the MFCA provides a trochanteric branch laterally, while the main artery crosses the obturator externus tendon posteriorly as the deep MFCA before continuing an intracapsular course, deep to the conjoined tendon of the short external rotators.

• Other sources [3] describe the medial femoral circumflex artery (MFCA) as follow:

  • The MFCA originates from the deep femoral artery, which is the first branch of the deep femoral artery.

  • The main trunk of the MFCA runs between the piriformis and iliopsoas muscles.

  • The first branch, the superficial branch, originates from the main trunk in all cases. This superficial branch does not go to the femoral head but supplies the adductor muscles via smaller branches. One of the smaller branches of the superficial branch forms an anastomosis with the obturator artery between the adductor longus and adductor brevis muscles (and may gives the acetabular branch for the fat in the bottom of the acetabulum).

  • Along the course of the main trunk of the MFCA, towards the lesser trochanter, we observe a consistent division into two main branches: the descending branch and the deep branch. The division is observed in 15 of 16 specimens and is very characteristic. Therefore, we divide the MFCA into two parts: the main trunk before bifurcation and the deep branch after bifurcation, which is the continuation of the main trunk. The bifurcation occurs at a mean of 48 mm (33 to 72) from the main trunk (Fig. 2).

  • The descending branch (15 of 16), which usually divides into two smaller branches, supplies the muscles of the posterior compartment of the thigh: semitendinosus, semimembranosus, and biceps femoris. In one specimen (1 of 16) where the bifurcation is not observed, the descending branch is also absent. In this case, the branch of the first perforating artery supplies the posterior compartment of the thigh muscles.

  • The deep branch, which plays a crucial role in the blood supply to the femoral head, runs posterior to the obturator externus muscle and anterior to the quadratus femoris muscle (sometimes termed in this part as ascending MFCA or ascending branch of medial circumflex femoral artery). It is easily identifiable in the adipose tissue between those two muscles and is usually closely associated with two veins. It then crosses the tendons of the gemellus inferior, obturator internus, and gemellus superior muscles on their anterior aspect and enters the hip capsule. Once in the capsule, it travels within the retinacular fibers, which lie on the surface of the femoral neck, where it divides into terminal branches that pass towards the junction between the femoral head and neck. According to Tucker1 and Howe, Lacey, and Schwartz2, we name the terminal branches of the deep branch of the MFCA the "posterior superior femoral head nutrient arteries". We change the term “retinacular artery”1 and “capital branch”2 to “femoral head nutrient artery”.