Illustrated Encyclopedia of Human Anatomic Variation: Opus II: Cardiovascular System: Veins: Lower Limb

Lateral and Medial Circumflex Veins

Ronald A. Bergman, PhD
Adel K. Afifi, MD, MS
Ryosuke Miyauchi, MD
Peer Review Status: Internally Peer Reviewed

Baird and Cope found four classes of termination of these veins of the thigh. They found that class 1, in which the circumflex veins terminate directly in the femoral vein, includes 86% of the 541 observations. This is in contradistinction to statements made in textbooks, which describe the circumflex veins as terminating in the deep femoral (Bairds and Copes, class 4. In the present series, only about 2% of the veins ended in this manner).

Of the six types making up class 1, type 1A constitutes about 65% of all observations. As seen in the illustration, there are in this type single medial and lateral circumflex veins, both terminating in the femoral, the medial circumflex vein being the more proximal.

Next in frequency is type 1B (about 13%), which is quite similar to 1A with the exception that there are two lateral circumflex veins distal to a single medial circumflex vein, all of which empty directly into the femoral. Type 1C (about 4%) has two medial circumflex veins proximal to a single lateral circumflex vein.

In all three types (1A, 1B and 1C), the termination of the medial circumflex vein or veins is proximal to that of the lateral circumflex vein. Since these three types together make up about 81 % of all cases observed, it may be concluded that in a large majority of cases the termination of the lateral circumflex is distal to that of the medial circumflex vein.

Type 1D is an interesting example of this tendency. In this type there are two medial circumflex veins and two lateral circumflex veins and although the two medial circumflex veins are not both proximal to the two lateral circumflex veins, each medial circumflex is proximal to its corresponding lateral circumflex. In addition, in classes other than class 1, where the circumflex veins do not characteristically end in the femoral, there is still a tendancy for the medial circumflex to end above the lateral circumflex.

In type 1E (about 3%) Baird and Cope found a change in this characteristic relationship of the medial and lateral circumflex veins, the lateral circumflex being proximal to the medial circumflex. In type 1F (about 1%) the medial circumflex vein is absent.

Classes 2 and 3 constitute, together, but about 11% of the observations, Class 3 predominating slightly (about 6% as compared with about 5%). Class 2 is made up of two types, the first and predominating (2A, 4%) having a single medial circumflex emptying into the femoral, and a single lateral circumflex emptying into the deep femoral. Type 2B (about 1%) differs from 2A only in having an accessory lateral circumflex ending in the femoral, just distal to the medial circumflex. Here again, in both these types the position of the medial circumflex is characteristically proximal to that of the lateral circumflex vein.

There are four types making up Class 3. type 3A being found most frequently (about 4%). This type has a single medial circumflex terminating in the deep femoral, while the lateral circumflex terminates superiorly in the femoral. Type 3B differs from 3A only in having an accessory medial circumflex emptying into the femoral itself, immediately proximal to the lateral circumflex vein. Again there is but a small variation that distinguishes 3B from 3C, namely, the presence of two adjacent lateral circumflex veins rather than a single vein. Type 3D has duplicate lateral circumflex veins emptying into the femoral and a single medial circumflex emptying into the deep femoral. These two last-named types are only rarely found, representing about 0.7% and 0.3% of the present series, respectively.

As prevously stated, in only about 2% of cases do both the lateral and medial circumflex veins end in the deep femoral (Class 4). The most common type in this class is type 4A, which has a single medial circumflex and a single lateral circumflex, both emptying into the deep femoral. The other type, 4B, has an accessory medial circumflex ending in the femoral, and was found in only one case.

The preceeding is taken from Baird and Cope, 1933.

Reference
Baird, R.D. and J.S. Cope. (1933) On the termination of the circumflex veins of the thigh and their relations to the origins of the circumflex arteries. Anat. Rec. 57:325-337.

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