Anatomy of the infraorbital artery and its orbital branch.

Background/objectives: To characterise the infraorbital artery (IOA) and its orbital branch, which are key structures encountered during inferior orbital explorations, with potential for orbital haemorrhage and vision loss if inappropriately handled.

Methods: Thirteen embalmed heads (26 orbits) were dissected. The following parameters were measured: orientation of the IOA in relation to the infraorbital nerve (ION); presence or absence of the orbital branch of the IOA; and the distance between the orbital branch of the IOA to the inferior orbital rim.

Results: In the pterygopalatine fossa, the orientation of the IOA relative to V2 was medial (n = 9, 34.6%), inferior (n = 4, 15.4%), lateral (n = 4, 15.4%), inferolateral (n = 3, 11.5%), superolateral (n = 3, 11.5%), inferomedial (n = 2, 7.7%) and superior (n = 1, 3.8%). In the infraorbital canal, the IOA in relation to the ION was as follows: superomedial (n = 12, 46.2%), medial (n = 9, 34.6%), superior (n = 2, 7.7%), inferomedial (n = 2, 7.7%) and superolateral (n = 1, 3.8%). An orbital branch of the IOA was identified in 21/26 orbits (80.8%). The mean distance of the orbital branch to the inferior orbital rim was 13.0 ± 4.8 mm (range 2.0-23.0 mm).

Conclusions: The IOA is an important vascular structure to recognise during inferior orbitotomies. The most common configuration is an IOA that runs medially to V2 in the pterygopalatine fossa, then superomedially to the ION within the infraorbital canal. The orbital branch of the IOA emerges 13 mm posterior to the inferior orbital rim. Recognition of these arterial branches and appropriate cauterization are paramount for avoiding significant operative complications.