The pterygospinous foramen (Civinini) and the pterygoalar (crotaphitico-buccinatorius): laboratory findings / El foramen pterigoespinoso (Civinini) y el pterigoalar (crotafítico-buccinatorius): hallazgos de laboratorio

SUMMARY: The Pterygospinous foramen and pterygoalar foramen (crotaphitico-buccinatorius) are variant and atavic formations of the skull base and arise respectively from complete or incomplete idiopathic ossifications of the pterygospinous and pterygoalar ligaments. By proximity with areas of relevance for diagnosis and surgery, such as access pathways to the parapharyngeal and retropharyngeal spaces, it is necessary to be aware of these conditions due to the difficulties generated in surgical maneuvers and the promotion of compressive syndromes of mandibular nerve branches. This study was conducted on 45 samples of dry skulls and disarticulated sphenoid bones belonging to the collection of the Federal University of Juiz de Fora, Governador Valadares campus, Minas Gerais, Brazil. Our results indicated a total incidence of complete and incomplete pterygospinous and pterygoalar foramen (crotaphitico- buccinatorius) in 15, 5 % (7 skulls), with a higher incidence for the incomplete form of pterygospinous foramen (Civinini foramen) in 4 skulls (8.8 %), with 3 presenting unilaterally and 3 presenting bilaterally. The pterygoalar foramen (crotaphitico-buccinatorius or Hyrtl) was noted bilaterally in 1 of the skulls (2.2 %). The pterygospinous foramen and pterygoalar foramen are important findings, sometimes incidental, of an area of great anatomical expressiveness and pathological occurrences, besides the indispensable and unclear studies of phylogenetic order.

RESUMEN: El foramen pterigoespinoso y el foramen pterigoalar (crotafítico-buccinatorius) son formaciones variantes y atávicas de la base del cráneo y surgen respectivamente de osificaciones idiopáticas completas o incompletas, de los ligamentos pterigoespinoso y pterigoalar. Debido a la proximidad con áreas de relevancia para el diagnóstico y la cirugía, como las vías de acceso a los espacios parafaríngeo y retrofaríngeo, es necesario conocer estas condiciones por las dificultades que se generan en las maniobras quirúrgicas. Este estudio se realizó en 45 muestras de cráneos secos y huesos esfenoides desarticulados pertenecientes a la colección de la Universidad Federal de Juiz de Fora, campus Governador Valadares, Minas Gerais, Brasil. Nuestros resultados indicaron una incidencia total de foramen pterigoespinoso y pterigoalar completo e incompleto (crotafítico-buccinatorius) en el 15,5 % (7 cráneos), con una mayor incidencia de la forma incompleta de foramen pterigoespinoso (agujero de Civinini) en 4 cráneos (8,8 %), con 3 de presentación unilateral y 3 de presentación bilateral. El foramen pterigoalar (crotaphitico-buccinatorius o Hyrtl) se observó bilateralmente en 1 de los cráneos (2,2 %). El foramen pterigoespinoso y pterigoalar son hallazgos importantes, a veces incidentales, de un área de gran expresividad anatómica y ocurrencias patológicas, además de los estudios indispensables y poco claros de orden filogenético.

Incidence of the ossified pterygoalar ligamentin Brazilian human skulls and its clinical implications

The ossified pterygoalar ligament is formed between the lateral lamina of the pterygoid process and theinfratemporal surface of the sphenoid bone or its greater wing and was not connected to the sphenoid spine.The aim of this study was to evaluate the incidence of the ossified pterygoalar ligament in Brazilian humanskulls and analyzing its clinical importance. 183 Brazilian adult (between 30 to 60 years old) dry human skullswere evaluated. Was evaluated the incidence of skulls with complete or partial ossification of the pterygoalarligament, bilaterally and unilaterally and in the presence on the right and left sides. Were found 5 skulls had theossified pterygoalar ligament, resulting in an overall incidence of 2.73%. There was 1 skull in the presence ofthe incomplete ossification of the pterygoalar ligament, unilaterally and on the left side resulting in incidence of0.54%. There were 4 skulls in the presence of the complete ossification of the pterygoalar ligament, unilaterallyand on the right side resulting in incidence of 2.18%. The ossified pterygoalar ligament is a major cause of theentrapment of the lingual nerve or a branch of the mandibular nerve and may cause mandibular neuralgia. Theincidence of the ossified pterygoalar ligament and the pterygoalar foramen is low in the Brazilian population.However, these structures have clinical significance as this ligament establish relationships with the ovaleforamen and difficulty in accessing in this foramen in a therapeutic approach.

Anatomical study of the pterygospinous and pterygoalar bony bridges and foramens in dried crania and its clinical relevance / Estudio anatómico de los puentes óseos y forámenes pterigoespinoso y pterigoalar en cráneos secos y su relevancia clínica

The ossification of the intrinsic ligaments of the sphenoid bone has been reported in the literature. The presence of bony bridges by ossification of the pterygospinous and pterygoalar ligaments has clinical significance in the infratemporal fossa contents. The purpose of this study is to analyze the prevalence of ossification of these ligaments and assess morphometrically the pterygospinous (Civinini's) and pterygoalar (crotaphitico-buccinatorius) foramens. A total of 312 human skulls from the collection of Universidade Federal de São Paulo (UNIFESP) were used to assess the presence of total or partial ossification in pterygospinous (Types I and II) and pterygoalar (Types III and IV) ligaments. Of the sample, 37.18 percent had some degree of ossification; in Type I, ossification was found in 1.6 percent, while Types II, III and IV had 13.14, 3.84, and 22.43 percent, respectively. The pterygospinous foramen presented an average diameter between 10.626ð7.366 mm, whereas for the pterygoalar foramen it was between 5.202ð3.793 mm. The presence of these formations must be considered in the therapeutic procedures that are performed in the infratemporal region, in assessing pain affecting the territory innervated by the mandibular nerve.

La osificación de los ligamentos intrínsecos del hueso esfenoides ha sido reportada en la literatura. La presencia de puentes óseos por osificación de los ligamentos pterigoespinoso y pterigoalar tiene importancia clínica debido a las relaciones que éstas formaciones establecen con el contenido de la fosa infratemporal. El propósito de este estudio fue analizar la prevalencia de la osificación de estos ligamentos y evaluar morfométricamente los forámenes pterigoespinoso (Cinivini's) y pterigoalar (crotaphitico-buccinatorius). Se utilizaron 312 cráneos humanos de la colección de la UNIFESP, se evaluó la presencia de osificación total o parcial de los ligamentos pterigoespinoso (Tipos I y II) y pterigoalar (Tipos III y IV). Un 37,18 por ciento de la muestra presentó algún grado de osificación, el tipo I se encontró en un 1,6 por ciento por ciento, el tipo II en un 13,14 por ciento, el tipo III en un 3,84 por ciento por ciento y el tipo IV en un 22,43 por ciento. El foramen pterigoespinoso presentó un diámetro medio de entre 10,626 ð 7,366 mm, mientras que para el foramen pterigoalar estuvieron entre 5,202 ð 3,793 mm. La presencia de estas formaciones debe ser considerada en los procedimientos terapéuticos que se realicen en la región infratemporal y en la evaluación de cuadros dolorosos que afectan al territorio inervado por el nervio mandibular.

Radiographic study of ossification of the pterygospinous and pterygoalar ligaments by the hirtz axial technique

The correct radiographic identification of ossification of the pterygospinous and pterygoalar ligaments plays an important role in surgical procedures for the treatment of trigeminal neuralgia. Most of these procedures are performed through the foramen ovale, a site where these ligaments can be found to be partially or completely ossified. We studied the radiographic features of these ossified ligaments and their location in relation to the foramen ovale by the Hirtz axial technique. For this purpose, 93 dry skulls from the Discipline of Anatomy, Sao Jose dos Campos Dental School, UNESP, which presented partial or complete ossification of these ligaments, were radiographed. The pterygospinous ligament was detected on 27.97% of radiographs and was partially ossified in 19.36% of cases and completely ossified in 8.61%. The pterygoalar ligament was present in 62.35% of radiographs, being partially ossified in 49.44% and completely ossified in 12.91%. The pterygospinous ligaments was found to be partially and completely ossified on the same radiograph in 3.23% of cases, whereas the pterygoalar ligament appeared partially and completely ossified on the same radiograph in 6.45%. Furthermore, the pterygospinous ligament was thinner than the pterygoalar ligament and located more medially in relation to the foramen ovale. The pterygoalar ligament formed a large bone bar lateral to the foramen ovale, often obliterating the lumen of the latter. The Hirtz axial technique is an excellent tool for the observation of complete or partial ossification of the pterygospinous and pterygoalar ligaments in surgical procedures for the treatment of trigeminal neuralgia performed through the foramen ovale.

A correta identificacao radiografica da ossificacao dos ligamentos pterigoespinhoso e pterigoalar e de grande importancia nos procedimentos cirurgicos no tratamento da nevralgia trigeminal. A maioria desses procedimentos e feita via forame oval, local onde podemos encontrar esses ligamentos ossificados, parcial ou totalmente. Estudamos, pela tecnica axial de Hirtz, as caracteristicas radiograficas desses ligamentos ossificados e sua localizacao em relacao ao forame oval. Para isso foram radiografados 93 cranios secos, pertencentes a Disciplina de Anatomia da Faculdade de Odontologia de Sao Jose dos Campos - UNESP, que apresentavam a ossificacao parcial ou total dos referidos ligamentos. Encontramos o ligamento pterigoespinhoso em 27,97% das radiografias, sendo parcialmente ossificado em 19,36% e totalmente em 8,61%. O ligamento pterigoalar estava presente em 62,35% das radiografias, estando parcialmente ossificado em 49,44% e totalmente em 12,91%. O ligamento pterigoespinhoso foi encontrado parcial e totalmente ossificado, numa mesma radiografia, em 3,23% dos casos, enquanto o ligamento pterigoalar apareceu parcial e totalmente ossificado, na mesma radiografia, em 6,45% dos casos. Observamos ainda que o ligamento pterigoespinhoso era menos espesso, em relacao ao ligamento pterigoalar, e localizado mais para medial, em relacao ao forame oval, enquanto que o ligamento pterigoalar formava uma larga barra ossea lateralmente ao forame oval, obliterando muitas vezes o lumen do mesmo. A tecnica axial de Hirtz e um excelente meio para a observacao da ossificacao total ou parcial destes ligamentos, quando de procedimentos cirurgicos que utilizam o forame oval para o tratamento da nevralgia trigeminal.