European Journal of Cardiovascular Medicine

Middle cranial fossa is very important for the surgeons to be aware of extreme variability of the more commonly used anatomical landmarks. Anatomical variations in size and shape of Foramen Ovale could be explained by developmental reasons. Foramen Ovale is of clinical, anatomical significance and surgical importance in percutaneous trigeminal rhizotomy, in trigeminal neuralgias, and in diagnostic detection of tumours and abnormal bony outgrowths that may lead to ischemia, necrosis etc. Foramen Ovale transmits the mandibular division of the Trigeminal nerve, Lesser petrosal nerve, Accessory meningeal branch of the Maxillary artery and an Emissary vein which connects the Cavernous venous sinus to the Pterygoid venous plexus in the Infratemporal fossa. Foramen Spinosum lies posterolateral to the Foramen Ovale and transmits the middle meningeal artery and a recurrent meningeal branch of the mandibular nerve¹. The Foramen Ovale and Foramen Spinosum open into the underlying infratemporal fossa ². Foramen Ovale and Foramen Spinosum including their shape, incidence, relation to other foramina and any anomalies may represent a reliable anatomical landmark during surgical explorative maneuvers. At 22 weeks, Foramen Ovale is seen as a discrete foramen. In the 7th month of fetal life, the perfect ring-shaped formation is observed as earliest and at 3 years after birth the latest. Foramen Spinosum can be seen as a well-defined ring shape which is seen between 8th months to 7 years after birth³.

Aims And Objectives:

The present study aims to assess different morphometric parameters of foramina in middle cranial fossa of skull and to compile the results, analyse and formulate a baseline data for future studies with relevance to Indian population and also to compare the current data with accessible literature for pertinent surgical utilities. The parameters are: Anteroposterior diameter of Foramen Ovale, Mediolateral diameter of Foramen Ovale, Shapes of Foramen Ovale, Anteroposterior diameter of Foramen Spinosum, Mediolateral diameter of Foramen Spinosum and Shapes of Foramen Spinosum

55 adult human dry skulls of unknown sex, Digital Vernier caliper of 0.1 mm accuracy, Digital camera.

Collection of data: The present study is done on 55 dry skulls which were obtained from Department of Anatomy SVIMS- SPMC (W) Tirupati, Sri Venkateswara Medical College, Tirupati and from 1st MBBS students of these colleges and also from the Department of Anthropology, SV university, Tirupati in the region of Andhra Pradesh.

Inclusion criteria: Adult human skulls of unknown sex, Skulls without calvaria, Foramina were well defined.

Exclusion criteria: Damaged skulls, New born, infants, children’s skulls, very old skulls with obliterated foramina.

The present study has been carried out in 55 dried human skulls in the region of Andhra Pradesh   from the Department of Anatomy of SVIMS - SPMCW, Tirupati; Sri Venkateswara Medical College, Tirupati; Department of Anthropology, SV University, Tirupati. Morphology & Morphometry studies are conducted related to foramina in the middle cranial fossa. The selected foramina are Foramen Ovale, Foramen Spinosum.

FORAMEN OVALE: Regarding the morphology of Foramen Ovale, the study is conducted on both sides. On the right side 23 skulls exhibited oval shape amounting to 41.8% and in 20 skulls it is round in shape & in 8 skulls slit shape & rest 4 are almond in shape. On the left side, 20 skulls exhibited oval shape (36.3%), round in 17 skulls, slit in 11 skulls and the almond in 7 skulls. Regarding the morphometry of Foramen Ovale, Anteroposterior diameter (APD) of Foramen Ovale is more in right side than the left side, out of 55 skulls, the maximum distance on right side is 12.69mm and minimum of 5.31mm and on left side the maximum is 11.30mm and minimum is 4.76mm, the mean ± standard deviation on right side is 7.73 ± 1.32 mm and 7.80 ± 1.25mm on left side. The Mediolateral of Foramen Ovale is more in right side than the left side, out of 55 skulls, the maximum distance on right side is 8.20mm and minimum of 2.18mm and left side maximum of 6.80mm and minimum of 2.23mm, the mean ± standard deviation on right side is 4.58±1.11mm and the mean ± standard deviation of left side is 4.46±1.02mm.

FORAMEN SPINOSUM: With relevance to morphology of Foramen Spinosum, it is round in shape on both the sides and it is concluded that there is not much change in morphology of Foramen Spinosum.

FORAMEN OVALE MORPHOLOGY: Yanagi S³ observed that foramen ovale is oval-shaped in majority of skulls and it is irregular in shape compared with the rest of two shapes of foramina. Biswabina ray, N gupta etal⁴ stated shape of foramen ovale was typically Oval in 43, (22 on right, 21 on left) Almond shape in 24 (11 right, 13 left), Round in 2(1 right, 1 left) and Slit-like in 1. Bilateral oval foramen was observed in 15 and bilateral almond was in 7. Magi Murugan et al⁵ observed that prevalence of shape of foramen oval is oval shape - 69%, almond shape - 29%, round - 2%. Raval et al⁶ observed that shape of foramen ovale is oval shape 76.5%, Irregular shape 13.5%, Almond shape 7.5%, Round shape 1.5% & Triangular 1%. Roma Patel et al⁷ stated that shape of FO is Oval in 59.5%, Almond 12%, Round 27.5% and Slit 1%. Suniti Raj et al⁸ observed that most common shape of foramen ovale was for Oval (66%), remaining as follows Almond 22%, D shaped 2%, Slit like 2%, Round 3% and Irregular 3%. Lattupalli Hema et al⁹, found that the most common shape is Oval (59.5%) followed by almond 12%, round 27.5% and slit shapes 1%.  The present study reveals that in majority of skulls both in right and left sides it is oval in shape and the least is almond shape and this study is closely related with the Yanagi etal³, Biswabin ray etal⁴., Lattupalli hema etal⁹.

TABLE NO.5: VARIOUS MORPHOMETRIC STUDIES OF FO AMONG AUTHORS

The current study is closely correlating with the studies done by Biswabina ray⁴, Nguptaetal¹⁰, Osunwokeetal¹¹., Somesh etal¹², Ambica wadhwa etal¹⁴, Jyothsna patil etal¹⁵, Phalguni srimani etal¹⁶, Mamatha.Y. etal¹⁷, K.Prakash etal¹⁸.

FORAMEN SPINOSUM MORPHOLOGY: Yanagi S ³ the earliest perfect ring-shaped formation of the foramen spinosum is observed in the 8th month after birth and the latest in 7 years after birth. The majority of the foramen spinosum is round in shape. Desai S.D. et al¹³ (2012) conducted a study on the shape of FS in 125 skulls and found them to be as being round (52%), Oval (42%) and irregular (16%). Anju Lata Rai et al¹⁹ reported absence of foramen Spinosum in 2.85% of skulls. Most common shape of FS observed were round -57% on Right side and 51.4% on Left side, Oval 34 .2% on Right side and 31.4% on Left side, pinhole -5.7% (Right side) & 8.5% (Left side), irregular -2.8% (Right side) & 2.8% (Left side). Our present study is closely corelated with Yanag³, Anjulata rai etal¹⁹

MORPHOMETRY: In the present study morphometry of foramen spinosum, is observed that the AP dimensions of foramen spinosum is 3.24 and 3.22 on right and left sides respectively and ML dimensions is 3.24 & 3.66 on the right and left sides respectively. This study is closely correlated with the studies of Agarwal deepa rani etal²⁰, Anju latarai etal¹⁹, Jayanthi Krishnamuthy²¹, Somesh etal¹² and Sidharath tewari etal²².

TABLE NO.6: VARIOUS MORPHOMETRIC STUDIES OF FS AMONG AUTHORS

The Present study is carried out with the sample size of 55 dried human skulls of unknown gender in the Region of Andhra Pradesh. Morphology & Morphometric studies are conducted related to foramina in the middle cranial fossa. The selected foramina are Foramen Ovale, Foramen Spinosum.

Regarding the morphology of Foramen Ovale, the study is conducted on both sides. On right side 23 skulls exhibited oval shape amounting to 41.8% and in 20 skulls it is round in shape& in 8 skulls slit shape & rest 4 are almond in shape. On the left side, 20 skulls exhibited oval shape (36.3%), round in 17 skulls, slit in 11 skulls and the almond in 7 skulls. This analysis reveals that in majority of skulls on both sides it is oval in shape and the least is almond shape.The data of morphometric analysis of AP Diameter of foramen ovale on both sides revealed almost same measurements and mean being 7.73mm on right side and 7.80 mm on left side.The morphometric study of ML dimension of foramen ovale revealed 4.58 mm on right and 4.46 on left side. This revealed that it is of uniform measurement on both the sides.

With relevance to morphology of foramen spinosum, it is round in shape on both the sides and it is concluded that there is not much change in morphology of foramen spinosum. It is observed that the AP dimensions of foramen spinosum are slightly more on right side than the left side. The ML dimensions are slightly more on left side than the right side. The present study of morphology and morphometric dimensions of the various foramina in the middle cranial fossa of dried human skulls gives very pertinent information for various neurological surgeries related to middle cranial fossa and it is of immense use and forms the basis for various neurological surgeries. Though the study is confined to gross observation and morphometry relevant conclusions are drawn to its level though much accuracy can be obtained by various advanced diagnostic tools and it is beyond the scope of the present study.

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