Is it feasible to use the supratrochlear artery for inducing intra-arterial fibrinolysis in cases of central retinal artery occlusion? An anatomical investigation

Background In order to investigate a possible alternative approach for catheterizing the ophthalmic artery, the detailed anatomy of the intraorbital arteries was examined in eight half-heads.Results The supratrochlear artery was found beneath or at the lateral border of the superior oblique muscle. In six cases the supratrochlear artery was the largest branch of the ophthalmic artery, continuing in the same direction as the latter vessel. In the other two orbits it branched off from the parent vessel at angles of 900 and 1150. In five orbits, the ophthalmic artery divided distally into the supratrochlear and supraorbital arteries, the angles between the two measuring 25o, 300, 400, 400 and 6o. In one case the supraorbital followed a course at right-angles to the supratrochlear, and in two cases it was absent.The mean intraorbital length of the vessels was as follows: supratrochlear: 3.94 cm (1.8 to 6.4 cm); ophthalmic: 3.13 cm (2.1 to 4.3 cm); supraorbital: 3.06 cm (2.1 to 3.8 cm).The following mean external diameters were measured: supratrochlear artery: 0.96 mm (0.6 to 1.5 mm) proximally and 0.72 mm (0.5 to 1.0 mm) distally; ophthalmic artery: 1.79 mm (1.5 to 2.0) proximally and 1.34 mm (1.0 to 1.5 mm) distally; supraorbital artery: 0.68 mm (0.5 to 1.0 mm) throughout its length.Conclusion The orbital arteries investigated varied greatly in external diameter, course, length and pattern of distribution. It is very difficult to catheterize the supratrochlear artery because of its highly tortuous intraorbital course and its narrow diameter.