Lateral medullary branches of vertebral artery

The lateral medullary branches of vertebral artery usually encompass the anterolateral and lateral arterial groups supplying the medulla oblongata.

Anterolateral arteries

The anterolateral arteries (AL) are short, tortuous arterial twigs arising mainly from the vertebral artery (VA) and anterior spinal artery (ASA), although they may sometimes originate from posterior inferior cerebellar artery (PICA) or anterior inferior cerebellar artery (AICA). They supply the lateral region of the medulla oblongata and may share common stems with the perforating arteries.

Lateral arteries

The lateral arteries lie farther laterally than both the AL and medial perforating arteries. They arise most commonly from the VA and PICA, and less frequently from the ASA and its roots, and also supply the lateral region of the medulla.

Therefore, the vertebral artery contributes to lateral medullary supply through both AL and lateral arteries.

Distinction between medial and lateral medullary arteries and the dorsal medullary arteries

Within the complete four-group classification, there is a fourth dorsal group of medullary arteries, however, due to its posterior location, these arteries should be considered separately rather than included among the medial or lateral branches of the VA. They arise from PICA and the posterior spinal artery (PSA). PICA gives off several tiny dorsal medullary branches as well as branches to the inferior cerebellar peduncle, tela choroidea, choroid plexus, inferior medullary velum and adjacent structures.