Human ocular motor nerves, extraocular muscles and ciliary ganglion topography, syntopy and morphology: A cadaver study

Detailed knowledge of the extraocular muscles morphology and relationships with the adjoining neurovascular elements is important for successful orbital surgical outcomes. This study aimed to measure and analyze the morphometric characteristics of the extraocular muscles and the intraorbital part of the ocular motor nerves. In particular, the location and the morphometric characteristics of the ciliary ganglion, branching pattern of the ocular motor nerves and their relationships with the adjoining neural and muscular elements. Twelve formaldehyde embalmed orbitae were used. Mean±SD of lengths and widths of the extraocular muscles: levator palpebrae superioris (42,98±4,45; prox: 3,45±0,62; mid:7,04±1,69; dist: 12,56±2,19 mm), superior oblique (54,31±2,02; 4,20±0,69 mm), superior rectus (36,74±2,76; 7,13±0,93 mm), inferior rectus (36,27±6,57; 6,31±0,83 mm), medial rectus (38,57±2,40; 7,77±0,95 mm), lateral rectus (37,66±3,10; 7,53± 1,36 mm), and inferior oblique (27,77±2,27; prox: 3,87±1,61; mid: 5,58±1,37; dist: 5,71±1,44 mm). The area nervosa was located on the posterior one third or the middle one third on the ocular surface of all extraocular muscles except for the obliquus superior where it was located on its orbital surface. Mean±SD of lengths, widths and thicknesses of the ocular motor nerves: oculomotor nerve superior division (18,48±4,53; 1,13±0,21; 0,58±0,16 mm), nerve to medial rectus (16,02±3,11; 1,04±0,28; 0,75±0,21 mm), nerve to inferior rectus (13,88±2,56; 1,17±0,26; 0,74±0,25 mm), nerve to inferior oblique (36,41±3,23; 0,98±0,29; 0,62±0,20 mm), trochlear nerve (15,92±2,82; 0,97±0,25; 0,40±0,10 mm), abducens nerve (14,17± 3,70; 1,26± 0,38; 0,58±0,15), and ciliary ganglion (4.28±0.84; 2.70±0.30; 0.85± 0.21 mm). These results should be considered for safe orbital surgeries.