Morphometric study of the ciliary ganglion and its pertinent intraorbital procedure

Abstract

Background: Ciliary ganglion (CG) can be easily injured without notice in many intraorbital procedures. Surgical procedures approaching the lateral side of the orbit are at risk of CG injury which results in transient mydriasis and tonic pupil. This study aims to focus on the morphometric study of the CG which is pertinent to intraoperative procedure. Materials and methods:Forty embalmed cadaveric globes were dissected to observe the location, shape and size of CG, characteristics and number of roots reaching CG, number of short ciliary nerve in the orbit. Distances from CG to posterior end of globe, optic nerve, lateral rectus muscle and its scleral insertion were measured.Results: CG was located between optic nerve and lateral rectus in every case. Its shape could be oval, round and irregular. Mean width of CG was 2.24 mm and mean length was 3.50 mm.Concerning the roots, all three roots were present in 29 cases (72.5 %). Absence of motor root was found in 7 cases (17.5 %). Absence of sympathetic root was found in 4 cases (5%).The number of motor root could be one, two and also three roots. Three motor roots were found in one case which originated from nerve to inferior oblique muscle. Only one sensory root was found in every specimen. One sympathetic root could be observed in most of the 2 specimens and 6-14 short ciliary nerves were found. Mean distances from CG to posterior end of globe, optic nerve, lateral rectus muscle and its scleral insertion were 16.04 mm, 1.47 mm, 2.88 mm. and 31.53 mm, respectively. Conclusions:This study described the characteristic of CG, number of its nerve root and some measurements relevant to intraorbital procedures in Asian population. Moreover, a new parameter was the distance between CG and scleral insertion of the lateral rectus muscle. This parameter should be considered when performing operation involved the lateral rectus muscle and BTX-A injection to lateral rectus muscle to reduce CG injury.

Anatomical study on branching pattern and variations of orbital segment of the oculomotor nerve

“…Regarding the parasympathetic root of the ciliary ganglion, variations in number, shape and diameter of this root were reported [11,14,17,25]. Occasionally, duplication or triplication of the parasympathetic root may be observed [3,11].…”

“…Those fibres enter the ciliary ganglion through the motor (parasympathetic) root of the ganglion. The postganglionic fibres leave the ganglion and reach the eyeball through via the short ciliary nerves [11,17,25].…”

“…The inferior branch, in turn, is thicker and gives off three muscular branches: the branch to the medial rectus muscle which runs under the optic nerve; the branch to the inferior rectus which is the shortest; and the branch to the inferior oblique muscle (also called the nerve to the inferior oblique muscle) which courses along the lateral side of the inferior rectus muscle. In most of cases the parasympathetic root of the oculomotor nerve branches off the muscular branch to the inferior oblique muscle [11,17,25].…”

Identification of cranial nerve ganglia using sectioned images and three-dimensional models of a cadaver

“…The first step was to identify all 12 pairs of the ganglia of the cranial nerves: the ciliary ganglion, trigeminal ganglion, pterygopalatine ganglion, otic ganglion, submandibular ganglion, geniculate ganglion, vestibular ganglion, spiral ganglion, superior and inferior glossopharyngeal ganglia, and superior and inferior vagal ganglia (Table 1) [12][13][14][15][16][17][18][19][20][21][22][23]. For this, sectioned images of the brainstem were examined to determine the origins of the cranial nerves (Fig.…”

“…The ophthalmic artery was observed superomedial to the ganglion, and the optic nerve was visible more superomedially [27]. In the sagittally sectioned volume model, the optic nerve The ciliary ganglion can be injured during surgical intervention such as lateral orbitotomy, inferolateral endoscopic orbital approach, transmaxillary approach to the orbit [12].…”