Morphological and Morphometric Analysis of Supraorbital Foramen and Supraorbital Notch: A Study on Human Skulls

 

Pavithra H Dave¹, Dr. Saravana Kumar²

¹1BDS, Saveetha Dental College and Hospitals, No 162, PH Road, Chennai- 600077

²Professor, Department of Anatomy, Saveetha Dental College and Hospitals, No 162, PH Road, Chennai- 600077

 

ABSTRACT:

OBJECTIVE: Supraorbital foramen is an important site for various surgical and anesthetic procedures. In the present study, a detailed morphometric analysis of supraorbital notches and foramina were carried out and compared with the available literatures.

MATERIALS AND METHOD:  A total of 100 dry skulls were collected and observed for the study. Various parameters in the sagittal and transverse planes were noted from supraorbital foramen on both sides, together with its vertical and horizontal dimensions. In addition, the location of supraorbital foramen with respect to midline and front ozygomatic suture was noted.

RESULTS: The study of 100 adult skulls revealed that the SON (61% on right and 60% on left) was found more frequently than the SOF (39% on right and 40% on left).The distance between centre of SOF/SON and midline was found to be statistically significant on right and left sides.

CONCLUSION: This study makes possible the identification of exact position of supraorbital foramen and also discusses its racial variation.

 

 

 

INTRODUCTION:

Supraorbital foramen (SOF) or notch is present at the junction of lateral two-third and medial one third of supraorbital margin. According to previous studies in 25% of cases supraorbital notch is converted into foramen by ossification of periosteal ligament bridging  it ^[1-4].

 

The supraorbital nerve is one of the main cutaneous nerves supplying the forehead and scalp region. It exits through its foramen to innervate the skin and may be injured during various surgical and anesthetic  procedures ^[5].

 

The supraorbital nerve blocks are commonly performed in the region of supraorbital foramen during procedures such as closure of facial wounds, biopsies, and scar revisions, as absolute but temporary treatment for supraorbital neuralgia and other cosmetic cutaneous procedures ^[6-7]. No anatomical landmark is considered for locating exact position of SOF, thus increasing the rate of failure of the block ^[8-11].

 

In this study, measurements were made on dry skulls to determine the location and dimensions of the supraorbital notch (SON) or the supraorbital foramen (SOF).

 

Data obtained were compared and may be useful to anesthetists and surgeons for providing appropriate nerve blocks and planning the surgical flaps.

 

MATERIALS AND METHODS:

A total of 100 dry skulls of anatomy department of Saveetha Dental College and Hospitals, Chennai, Tamil Nadu. The parameters taken for this study were different types and combination of supraorbital notches and foramina, their distance from nasal midline, dimension of supraorbital notch(transverse diameter) and foramen(vertical and transverse diameter). Nasal midline was taken from vertex of the skull through the nasion to the anterior nasal spine and inter maxillary suture line. The measurements were done with the help of dividers and meter ruler. Observations thus made were tabulated and statistical data were calculated.

                                                                                                                                

RESULTS:

Table 1: Incidence of various types of combinations of supraorbital notches/foramina

COMBINATION IN THE SAME SKULL		NUMBER OF SKULLS n
RIGHT	LEFT
Notch	Notch	52
Foramen	Foramen	33
Notch	Foramen	8
Foramen	Notch	7

 

 

Table 2: Dimensions and distance of supraorbital notches/foramina from nasal midline

	Foramen dimension				Notch dimension			Distance of foramen or notch from midline
	Vertical diameter		Transverse diameter		Transverse diameter
	Right	Left	Right	Left	Right	Left	Right	Left
Mean ± SD (mm)	2.52 ± 0.41 mm	1.55 ± 0.21 mm	4.32 ± 0.63mm	4.36 ± 0.91mm	6.23 ± 1.21	6.31 ± 1.12	21.34 ± 4.10	20.12 ± 3.17
Range (mm)	1-5	1-5	2-6	2-6	3-9	3-9	10-15	10-15

 

The study of 100 adult skulls revealed that the SON (61% on right and 60% on left) was found more frequently than the SOF (39% on right and 40% on left). Of all the cases, 52% had bilateral SON (Figure 3), while 33% had bilateral SOF. 15% of skulls showed foramen on one side and notch on the other side (Table 1).

 

The dimensions of SOF and its linear relationship with surrounding anatomical landmarks on the skull are summarized in (Table 2). The mean vertical and horizontal diameters of SOF on the right side are 2.52 ± 0.41 and 4.32 ± 0.63mm respectively, while those on the left side are 1.55 ± 0.21 and 4.36 ± 0.91mm, respectively (Table 2).

 

The mean distance between the right and left SON/SOF and the midline; mean distance between right and left SON/SOF and fronto-zygomatic sutures are shown in Table 2. When these parameters were compared between the right and left sides, the distance between centre of SOF/SON and midline was found to be statistically significant.

 

                

Table 3: Comparison of types of combination between present study and other studies ^[3]                       

TYPES OF COMBINATION		Present study % (2016)	Nidhi Sharma et al.(%) (2014)	S. Singh et al. % (2013)	D.J.Trivedi et al. (%)(2010)	Bilodi et al. (%) (2002)	Rao et al. (%)  (1997)
Right	Left
N	N	52	62	32.33	35.62	4.6	38.5
F	F	33	21	17.5	21.42	16	6.5
N	F	8	9	9.17	7.72	1.5	3.63
F	N	7	8	1.66	9.01	3.6	3

 

DISCUSSION:

In our study we observed the incidence of various combinations of SOF/SON found in Indian skulls and compared our findings with previous studies in Table 3. Our findings emphasize the ethnic variations in the occurrence of SOF/SON as supported by other studies. The various studies showed that the position of supraorbital foramina/ notches is not constant ^[3]. A detailed morphometric analysis can ascertain the site and dimensions of foramina/notches as an important landmark for both diagnostic and surgical procedures ^[10-12]. This can prevent the complications due to injury of neurovascular bundle i.e, anesthesia or hypoesthesia of the forehead, hematoma formation in subgaleal plane, ischemia or necrosis in portions of the forehead flap ^[13].

 

Table 3 shows the comparison between the present study and the previous studies.

 

We measured the shortest distance between the SOF and midline which was found to be 21.34 ± 4.10 mm and 20.12 ± 3.17 mm on right and left sides respectively. It is interesting to note that in one of the studies conducted on North Indian skulls, the average distance between the SOF/SON and the midline was 24 mm, which is slightly higher than the current observation. However, a much longer (29 mm) distance between the SOF and midline was observed in a study conducted on a Korean population ^[14].

 

The transverse and vertical diameters of the SOF displayed significant results while comparing both sides. Information regarding the size and symmetry of the skull foramina is helpful for radiologists when diagnosing difficult pathologies of the skull foramina by using computed tomography/ magnetic resonance           imaging ^[15-16].

 

We additionally analyzed our observations using statistical parameters to improve the accuracy for the location of supraorbital foramen. The mean distance indicates the location of foramen while standard deviation provides the variability in its position. Such parameters prove to be very informative in locating the position of foramen during anesthetic block and surgical interventions.

 

CONCLUSION:

Overall, it can be stated that the position of the SOF/SON is not constant and it varies between different races and people of different regions. SON is observed more frequently compared to the SOF, though there is a slight difference in the frequency rate and accordingly the exit point of supraorbital nerves and vessels also varies. The occurrence of accessory supraorbital foramina is very common and is more frequently seen lateral to the main SOF/SON.

 

This study helps determine the precise location of SOF in relation to various anatomical structures, particularly midline and fronto-zygomatic suture. The landmarks described could be identified and effectively applied with success in various clinical scenarios, thereby decreasing the risk of failures and complications. The present study can serve as a guide for anesthetic, therapeutic, diagnostic or invasive surgical purpose. It can also helpful for anthropologists and forensic scientists in the localization and characterization of these foramina and notches.

 

 

Figure 1: Line a represents the distance between SOF and fronto-zygomatic suture

 

Figure 2:Bilateral supraorbital notch

 

 

Figure 3: Line b represents the distance between SOF and midline

 

 

Figure 4: Bilateral supraorbital foramen

 

REFERENCES:

1.       Ashwini LS, Mohandas Rao KG, Sharmila Saran, and Somayaji SN. Morphological and morphometric analysis os supraorbital foramen and supraorbital notch: A study on dry human skulls, Oman medical journal.2012;27(2).

2.       Sharma N, Varshney R, Faruqi NA, Ghaus F. Supraorbital foramen - Morphometric study  and clinical implications in adult Indian skulls, Acta Medica International. 2014;1(1):6-9.

3.       Singh S, Bilodi AK, Suman P. Morphometric analysis on supra-orbital notches and foramina in south Indian Skull. Int J Cur Res Rev. 2013;5(10): 43-50

4.       Sudha R, Vasudev Anand SR, Shelvakumaran T.S, et al. Study of Supraorbital Notch and Foramen in 200 Human Skulls in South India. Anatomical Adjuncts. 1997;2(3):15-22.

5.       Trivedi DJ, Shrimankar PS, Kariya VK., Pensi CA. A Study Of Supraorbital Notches And Foramina In Gujarati Human Skulls,  National J of  Integrated Research in Medicine. 2010;1(3): p 21-30.

6.       Bilodi AKS., Sanikop MB. Some Obsrevations on Supra Orbital Foramina in Human Skulls in Karnataka. Anatomica Karnataka. 2002;1(13):17-23.

7.       Rao Sudha, Shaligram, Rao Vasudev Anand, Shelvakumaran T.S et al. Study of Supra orbital Notch and Foramen in 200 Human Skulls in South India. Anatomical Adjuncts.1997; 2(3): 15-22.

8.       Moore K L, Anne AM.R .Essentials of clinical Anatomy. Williams and wilkins 351 West Camden street, Baltimore, Maryland 21201-2436, USA. (1995): 349-354.

9.       Gupta T. Localization of important facial foramina encountered in maxillofacial surgery. Clin Anat 2008 Oct;21(7):633-640.

10.     Agthong S, Huanmanop T, Chentanez V. Anatomical variations of the supraorbital, infraorbital and mental foramina related to gender and side. J Oral Maxillofac Surg 2005;63:800-4.

11.     Smith JD, Surek CC, Cortez EA. Withdrawn. Localization of the supraorbital, infraorbital, and mental foramina using palpable, bony landmarks. Clin Anat 2010 May;23(4):495.

12.     Chrcanovic BR, Abreu MH, Custodio AL. A morphometric analysis of supraorbital and infraorbital foramina relative to surgical landmarks. Surg Radiol Anat 2011 May;33(4):329-335.

13.     Guyuron B, Kriegler JS, Davis J, Amini SB. Comprehensive surgical treatment of migraine headaches. Plast Reconstr Surg 2005 Jan;115(1):1-9.

14.     Chung M.S. (1995): Locational relationship of the supraorbital notch/foramen and infraorbital and mental foramina in Koreans   Acta anatomica; 154(2):162-66.

15.     Berry AC. Factors affecting the incidence of non-metrical skeletal variants. JAnat 1975 Dec;120(Pt 3):519-535.

16.     Caputi CA, Firetto V. Therapeutic blockade of greater occipital and supraorbital nerves in migraine patients. Headache 1997 Mar;37(3):174-179.

17.     Agthong S, Huanmanop T, Chentanez V. Anatomical variations of the supraorbital, infraorbital, and mental foramina related to gender and side. J Oral Maxillofac Surg 2005 Jun;63(6):800-804

 

 

 

 

 

Accepted on 04.06.2016        © RJPT All right reserved

Research J. Pharm. and Tech 2016; 9(8):1027-1030.