Presentation
Incidental finding in a patient imaged for swelling over the lateral aspect of the right ankle.
Patient Data
Representative sections in the axial and coronal sections show variant right popliteal artery branching. It is seen dividing into anterior tibial and peroneal arteries. The right anterior tibial artery is normally seen opacifying for a short distance in the proximal leg, and rest is not visualized- suggesting hypoplasticity. The right posterior tibial artery is not seen from its origin. The right large peroneal artery is seen bifurcating in the distal leg, approximately 4.2 cm proximal to the ankle joint, with each coursing along the expected course of the distal anterior and posterior tibial artery.
MIP image showing the enlarged right peroneal artery bifurcating proximal to the ankle joint.
A well-defined soft tissue density lesion, isodense to the muscle, is seen lateral to the right calcaneum, measuring 2.6 x 1.5 cm, likely hemangioma.
Conventional branching pattern of the left popliteal artery into the tibial-peroneal trunk and anterior tibial artery.
Case Discussion
This case shows an anatomical variation in the popliteal artery branching pattern.
In its typical anatomical course, the popliteal artery traverses the popliteal fossa and bifurcates into the anterior tibial artery and the tibio-peroneal trunk. The tibio-peroneal trunk then splits into posterior tibial artery and peroneal artery 1.
Kim et al. classified the popliteal artery branching pattern into three types 2:
type 1: normal level of branching
type 2: high division of the popliteal artery
type 3: hypoplastic or aplastic branching with altered distal supply with further subdivisions
Our case falls into type III pattern with aplastic posterior tibial artery, hypoplastic anterior tibial artery and single large peroneal artery, also known as peronea arteria magna (PAM) .
Patients with congenital or acquired peroneal arterial dominance, especially PAM, are at risk of foot ischemia if this vessel is traumatized, affected by steno-occlusive disease, or harvested as part of a free fibular graft. Thus, preharvest imaging is advised routinely as patients with peroneal arterial dominance can have normal distal pulses 3.
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