# The structure of the foramen ovale of the sphenoid bone is

The structure of the foramen ovale of the sphenoid bone is clinically important, particularly with regard to surgical procedures that cannulate of the foramen such as percutaneous trigeminal rhizotomy for the treatment of trigeminal neuralgia, percutaneous biopsy of parasellar lesions, and electroencephalographic analysis of the temporal lobe among patients undergoing selective amygdalohippocampectomy. percentage, and roundness. The shape descriptors reported herein may aid in recognition and description of structural variance in FO including bony projections encroaching upon the foramina and may improve surgical approaches to transovale cannulation. Keywords: anatomic variance, cannulation, skull foundation, stereotactic surgery, trigeminal neuralgia Intro The foramen ovale (FO) of the sphenoid bone is located anteromedial to the foramen spinosum (FS) and posterolateral to the foramen rotundum.1 The FO transmits several anatomical structures including the mandibular branch of the trigeminal nerve (V3), accessory middle meningeal artery, and sometimes the smaller petrosal nerve, emissary veins, and the anterior trunk of the middle meningeal sinus.2C3 The FO has variable morphology. In some cases the border of the FO is definitely irregular and sometimes incisures are visible along its edges.4 Likewise, bony spurs, spines, tubercles, plates, etc. have been noted to project into the FO.5C8 Occasionally the FO is separated into two or three separate compartments, sometimes separated by thin bony spicules, most often happening in one common osseous market.1,4,6,8 The FO has also been reported to be absent from one side of the sphenoid bone.8 Also, the FO may be confluent with the FS.8 Although there is fantastic variety in the morphology of the FO, when an enlargement of the FO happens, neurinoma of the trigeminal nerve and parasellar tumors should be considered inside a differential analysis.9C10 The structure of the FO is also particularly important with regard buy Ibutilide fumarate to surgical procedures that cannulate the foramen such as percutaneous trigeminal rhizotomy for the treatment of trigeminal neuralgia,11C12 percutaneous biopsy of parasellar lesions,10,13C14 electroencephalographic analysis of the temporal lobe among patients undergoing selective amygdalohippocampectomy.15 Moreover, differences in the morphology of the FO have been reported to contribute to difficulties in the cannulation of the foramen.16 The morphology of the FO has been described by numerous subjective or otherwise ambiguous terms including oval, truly oval, elongated oval, elongated, semicircular, almond, round, rounded, slit, irregular, D shape, and pear.1,5C8,17C19 The prevalence of the aforementioned morphological variations can be found in Table 1. With regard to morphometrics – size, width, and area are the guidelines which have typically been reported in the literature. Table 1 Morphology of the foramen ovale relating to studies utilizing numerous subjective and ambiguous nomenclatures. The structure of the FO is definitely clinically important; however, descriptive terms used to describe its structure are mainly subjective and ambiguous. Likewise, size, width, and area provide an incomplete morphometric representation of the FO. Consequently, this study assesses the structure of the FO with regard to objective shape characteristics including circularity, roundness, solidity, size measurements of major and small axes of a best match ellipse, aspect percentage of a best fit ellipse, in addition to the area contained within the FO and the perimeter of the FO. Materials and Methods The study analyzed FO from 91 dry adult sphenoid bones of undetermined age-at-death, sex, and race from Western Liberty University, Western Virginia University School of Medicine, Franciscan University or college of Steubenville, Ohio University or college C Eastern, Bethany College, and Washington & Jefferson College. Some sphenoid bones were hemissected and therefore experts were not usually able to buy Ibutilide fumarate analyze foramina bilaterally. FO which were confluent with the FS were excluded from the study. A total buy Ibutilide fumarate of 169 FO were analyzed (83 left-sided FO and 86 right-sided FO). Digital calipers (Mitutoyo 0C8 in (0C203.2mm) Total? digimatic caliper series 500, accuracy 0.001 in (0.025 mm)) were fixed to a known range of 5.00 mm, held flush to the FO, and then macrophotography was performed with a digital camera (Canon PowerShot SX50 HS, 12.1 Megapixel). Digital photos were then assessed with the built-in functions of ImageJ software (NIH) by using the 5.00 mm calibration like a reference. Measurements were taken of the following parameters: area contained within the foramen, perimeter of the foramen, circularity, and solidity. Additionally, the axes and element percentage of a best match ellipse as well as roundness were determined. Circularity Circularity is definitely a shape descriptor that can mathematically show the degree of similarity to a perfect circle. A value of 1 1.0 designates a perfect circle. As the circularity value methods 0.0, the shape is increasingly less circular. Circularity can be defined from the equation:

$4*[Area][Perimeter]2$

Solidity Solidity describes the extent to which a shape is usually convex or concave. Taking the area within the foramen and dividing it by the area enclosed by a convex hull can provide information concerning Mouse monoclonal to CD247 the solidity of the shape. A convex hull can be seen in Figure.