Delineation of the lacrimal vein: a magnetic resonance imaging study.

ABSTRACT

PURPOSE: To our knowledge, anatomical knowledge about the lacrimal vein (LV) is missed. Therefore, this retrospective study aimed to explore them using magnetic resonance imaging (MRI). MATERIALS AND METHODS: Eighty-one patients who underwent contrast-enhanced MRI and three donated bodies to science were enrolled. RESULTS: On the sagittal images, the measured mean right long (LD) and short diameters (SD) of the lacrimal gland (LG) were 17.3 ± 2.4 mm and 13.7 ± 2.1 mm, while the left LD and SD were 17.0 ± 2.6 mm and 13.6 ± 2.6 mm, respectively. Laterality or sex differences were not found in the LD and SD groups. In addition, no specific age range was associated with a significantly longer LD or SD. LVs were identified in 94% of axial images. Their course was classified into as follows three types connecting to the superolateral cavernous sinus (CS), to the superior ophthalmic vein (SOV), and the diploic channels of the greater wing of the sphenoid bone (DCGW). The CS type was the most frequently identified, followed by the SOV and DCGW types. In dissected specimens, the LVs consistently coursed between the posterior margin of the LG and the superolateral part of the CS, above the upper margin of the lateral rectus muscle. CONCLUSIONS: The LV may consistently emerge from the upper posterior margin of the LG. It commonly pours into the SOV or superolateral part of the CS.