See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/332172075
Bilateral Asymmetry in Sacrum and Handedness
Article · April 2019 CITATIONS 0 READS 22 3 authors, including:
Some of the authors of this publication are also working on these related projects: AuthorView project
Şükriye Deniz Mutluay Cukurova University 7PUBLICATIONS 5CITATIONS
SEE PROFILE
All content following this page was uploaded by Şükriye Deniz Mutluay on 13 May 2019. The user has requested enhancement of the downloaded file.
Bilateral Asymmetry in Sacrum and Handedness
S¸u¨kriye Deniz Akman, MS, Pınar Karaka ¸s, MD, and Memduha Gu¨lhal Bozkir, PhD
Abstract: The aim of this study was to determine the mean values of bilateral asymmetry of lateral part and auricular surface in sacrum. The measurements of right and left sides of the lateral and posterior breadths of the alae and the maximum height of the auricular surface were taken from a total of 37 male sacra with a millimetric compass. Then the asymmetry was
calculated with an equation as: [(left side right side)/right
side)] 100. As a result of this study, the mean values of the asymmetry of the maximum height of the auricular surface, lateral and posterior breadths of the lateral part were found to be 1.56 ± 0.4 0.16 ± 0.1 mm and 5.50 ± 1.1 mm, and respec-tively. The measurements determined in this study, posterior-lateral ala breadths and maximum auricular surface height, were identified statistically significant larger in the left side but little was found greater in the right side.
Key Words: sacral morphology, bilateral asymmetry, handed-ness
(Neurosurg Q 2008;18:66–68)
T
he sacrum is the primary region of weighttransmis-sion between the upper and lower body in human gross skeletal. It is affected by the mechanical environ-ment and physical activity patterns during the bone
growth related to handedness.1,2First, Broca claimed that
motor organization and brain functions of the right and
left hemispheres are different.3,4 Most of the humans
prefer their right hand. Because of this, the right side of the upper body is more developed than the left. More-over, it was considered that the lower limb opposite to the dominant upper limb is larger than the lower limb on the
same side of the dominant upper limb.5,6Some previous
studies have reported a correlation between asymmetry in
the lower body and handedness.7–13It was noted that this
asymmetry which is shown in the lumbosacral joint, appeared by the effects of the body weight and the dominant joint movements. Also, it was indicated that strong contractions of muscles that are piriformis, erector spinae, and gluteus maximus have an important role in
this asymmetry.1
The aim of this study was to investigate the mean values of the bilateral asymmetry in sacral alae and auricular surface to show the effects of mechanical loading on the morphology of the sacrum.
MATERIALS AND METHODS
The bones were collected from our department in this study. Different morphometric measurements from 37 male adult sacra between 30 and 60 years of ages were taken by the authors with a millimetric compass. Individuals with nonpathologic sacra were included in the study. Three measurements that were taken on each side of the sacrum are shown in Figures 1 and 2 and they were as follows:
Lateral breadth of the lateral part in sacral alae, the distance between the most anterior point to the most posterior point of the alae along the lateral border of the superior surface (Fig. 1).
Posterior breadth of the lateral part in sacral alae, the distance between maximum posterolateral projection of the alae from the posterolateral border of the lumbosacral joint (Fig 1).
Maximum height of the auricular surface (Fig 2). Each measurement was taken by the same author. After the measurements, directional asymmetry was
calculated with an equation as [(left side right side)/
right side] 100. A score of zero indicates the perfect symmetry. A positive value indicates that the left side is larger; on the contrary, a negative value indicates that the
right side is larger.1The program SPSS 10, 0 was used in
the statistical evaluation of measurement results. From these measurements, mean and standard deviations were calculated.
RESULTS
A total of 37 male sacra were included in this study with an age ranging from 30 to 60 years. To determine if the asymmetry values were significantly directional, a hypothesized value of zero was used. The measurements determined in this study, all 3 dimensions were identified statistically significant larger in the left side but little was found greater in the right side. With the morphometric evaluation of the sacrum, the mean values of directional asymmetry of dimensions were calculated with an
equation1 and were found to be 1.56 ± 0.4 mm,
5.50 ± 1.1 mm, and 0.16 ± 0.1 mm.
The first one was the distance between the most anterior point to the most posterior point of the alae along the lateral border of the superior surface and
Copyrightr2008 by Lippincott Williams & Wilkins
From the Department of Anatomy, C¸ukurova University, Faculty of Medicine, Adana, Turkey.
Reprints: Memduha Gu¨lhal Bozkir, PhD, Department of Anatomy, C¸ukurova University Faculty of Medicine, 01330 Adana, Turkey (e-mail: gbozkir@mail.cu.edu.tr).
O
RIGINALA
RTICLEnamed as lateral breadth of the lateral part in sacral alae(Fig. 1). The second was the distance between maximum posterolateral projection of the alae from the posterolateral border of the lumbosacral joint and can be expressed as posterior breadth of the lateral part in sacral alae (Fig. 1). The latter 0.16 ± 0.1 is the maximum height of the auricular surface (Fig. 2). The mean values of directional asymmetry results of the lateral, posterior breadths and maximum height in auricular surface of the sacral alae are shown in Table 1.
DISCUSSION
The sacrum is a triangular bone located just below the lumbar vertebrae. It consists of 4 or 5 sacral vertebrae in childhood and become fused into a single bone after adulthood. Thus it forms the back wall of the pelvic girdle
and moves with it.13,14 Sacrum is the primary region of
weight transmission between the upper and lower body. It can show some morphologic changes during weight transmission and mechanical activities. One of the important morphologic changes is the directional
bilat-eral asymmetry.1 In the asymmetry, one side of the
skeleton is consistently more developed than the other
side.5 This asymmetry is appeared in the lumbosacral
joint by the effects of the body weight and the dominant joint movements. Furthermore, it was indicated that strong contractions of the piriformis, erector spinae, and gluteus maximus muscles that were attached to the
sacrum have had an important role in this asymmetry.1
It is also possible in relation to the other factors like poor
nutrition, several illnesses, and trauma.15,16 Moreover, it
was attributed to the mechanical loading of the dominant upper limb during endochondral bone growth associated with handedness.1,8,10,17,18
It is well known that the motor organization and functions of the right and left hemispheres are
differ-ent.3,6,19 It was demonstrated that right hemisphere is
specialized for somatosensory spatial ability, emotional expression, and motor functions, on the other hand the left hemisphere is related to specialized for exact control
of motor actions on both sides.2,20–22 Moreover, it was
reported that the left hemisphere is dominant in 95% of human population and rarely does the right side alone
become highly developed.6,19 Therefore, most of the
individuals are right-handed. Several investigations have shown a correlation between handedness and asymmetry
in the lower limb.9 Furthermore, it was reported that
lower limb opposite to the dominant upper limb is generally larger than the other side of the lower limb. In addition, it was shown that in the right-handed
indivi-duals, the left side was the weaker side of the body.23
According to this information, it is an important point that the left-handedness is an increased risk factor for injury, accident, and fracture of the forearm, foot,
and pelvis.4,24–30This increased risk may be possibly due
FIGURE 1. LBA indicates lateral breadth of the lateral part in sacral alae, the distance between the most anterior point to the most posterior point of the alae along the lateral border of the superior surface; PBA, posterior breadth of the lateral part in sacral alae, the distance between maximum posterolateral projection of the alae from the posterolateral border of the lumbosacral joint.
FIGURE 2. MAH indicates maximum height of the auricular surface.
TABLE 1. Morphometric Measurements of the Sacrum
Measurement Mean ± Stan-dard Deviation (mm) Minimum (mm) Maximum (mm) MAH 1.56 ± 0.4 8.67 11.18 PBA 5.50 ± 1.1 8.93 37.21 LBA 0.16 ± 0.1 14.54 26.19 n = 37.
LBA indicates lateral breadth of the lateral part in sacral alae, the distance between the most anterior point to the most posterior point of the alae along the lateral border of the superior surface; PBA, posterior breadth of the lateral part in sacral alae, the distance between maximum posterolateral projection of the alae from the posterolateral border of the lumbosacral joint; MAH, maximum height of the auricular surface.
Neurosurg Q Volume 18, Number 1, March 2008 Sacrum and Handedness
to left-handed people living in a world designed for right-handed.
In the report by Plochocki, who studied with sacrum and some different bones confirmed the presence of bilateral asymmetry. It was claimed that the dominant hand and effects of the greater mechanical stress are the main causes of the asymmetry. Therefore, it was considered that right or left-handedness is important for
this asymmetry.1 This could also be attributed to the
genetic or hormonal factors.7,10
The measurements determined in this study, poster-ior-lateral ala breadths and maximum auricular surface height, were identified statistically significant larger in the left side but little was found greater in the right side. Although dominant hand is not known for the samples, right hand dominance in the majority of the populations has been determined in most research, so we consider this
information to be valid in our population too.4,5,29 The
large mean values of our study in the right side are possible owing to left-handed people in the population.
According to the data obtained in the present study, we believe that the effects of mechanical environment, strong contractions of piriformis, gluteus maximus, and erector spinae muscles during dominant hand activities and the body weight cause the asymmetry in the sacrum. We can state that the data of the sacrum analysis support the hypothesis that the lower limb opposite side of the dominant upper limb is larger than the other side and documents the development of the asymmetry. As a result, the left side dimensions of the alae of the sacrum are consistently greater than the right. This knowledge could be helpful for the spine surgeon to avoid endanger adjacent neural and vascular structures to the treatment of sacral fractures while placing the iliosacral implants.
REFERENCES
1. Plochocki JH. Directional bilateral asymmetry in human sacral morphology. Int J Osteoarchaeol. 2002;12:349–355.
2. White MJ. Hemispheric asymmetries in tachistoscopic information processing. Br J Psychol. 1972;63:497–508.
3. Broca P. Sur le sie´ge de la faculte´ du langage articule´. Bull Soc Anthropology.1865;6:377–393.
4. Luetters CM, Kelsey JL, Kegan THM, et al. Left-handedness as a risk factor for fractures. Osteoporos Int. 2003;14:918–922. 5. Coren S, Porac C. Fifty centuries of right handedness: the historical
record. Science. 1977;198:632–633.
6. Guyton AC. Textbook of Medical Physiology. 8th ed. Philadelphia: Saunders; 1991:638–639.
7. Cuk T, Leben-Seljak P, Stefancic M. Lateral asymmetry of human long bones. Variability Evol. 2001;9:19–32.
8. Ingelmark BE. Asymmetries in the length of the extremities and their relation to right- and left-handedness. Upsala Laekarefoerening Forhandlingar.1974;52:17–82.
9. Mays S, Steele J, Ford MJ. Directional asymmetry in the human clavicle. Int J Osteoarchaeol. 1999;9:18–28.
10. Plochocki JH. Bilateral variation in limb articular surface dimen-sions. Am J Hum Biol. 2004;16:328–333.
11. Sakaue K. Bilateral asymmetry in the Jomon people and modern Japanese. Anthropol Sci. 1998;105:231–246.
12. Steele J. Handedness in past human populations: skeletal markers. Laterality.2000;5:193–220.
13. Van De Graaff KM. Human Anatomy. 5th ed. Boston MA: WEB McGraw-Hill; 1998.
14. Sadeghi H, Allard P, Prince F, et al. Symmetry and limb dominance in able-bodied gait: a review. Gait Posture. 2000;12:35–45. 15. Graham CJ. Left-handedness as an injury risk factor in adolescents.
J Adolesc Health.1995;16:50–53.
16. Taras J. Left hand dominance and hand trauma. J Hand Surg. 1995;20A:1043–1045.
17. Hemenway D, Azrael DR, Rim EB, et al. Risk factors for wrist fracture: effect of age, cigarettes, alcohol, body height, and handedness on the risk for distal forearm fractures in men. Am J Epidemiol.1994;140:361–367.
18. Garn SM, Mayor GH, Shav HA. Paradoxical bilateral asymmetry in bone size and bone mass in the hand. Am J Phys Anthropol. 1976;45:209–210.
19. Van Valen L. A study of fluctuating asymmetry. Evolution. 1962;16:125–142.
20. Cavagna GA, Tesio L, Fujimoto T, et al. Ergometric evaluation of pathological gait. J Appl Physiol Resp Env Exerc Physiol. 1983; 55:607–613.
21. Colborne GR, Naumann S, Longmuir PE, et al. Analysis of mechanical and metabolic factors in the gait of congenital below knee amputees: a comparison of the SACH and the Seattle feet. Am J Phy Med Rehabil.1992;71:272–278.
22. Colborne GR, Wright FV, Naumann S. Feedback of triceps square EMG in gait of children with cerebral palsy: a controlled study. Arch Phys Med Rehabil.1994;75:40–45.
23. McManus IC. The incidence of left-handedness. Ciba Found Symp. 1991;162:251–267.
24. Roy TA, Ruff CB, Plato CC. Hand dominance and bilateral asymmetry in the structure of the second metacarpal. Am J Phys Antropol.1994;94:203–211.
25. Williams PL, Bannister LH, Berry MM, et al. Thoracic vertebrae. Gray’s Anatomy. 38th ed. New York: Churchill Livingstone; 1995:528–529.
26. King JW, Brelsford HJ, Tullos HS. Analysis of the pitching arm of the Professional baseball pitcher. Clin Orthop. 1969;67: 116–123.
27. Chyatte C, Smith V. Brain asymmetry predicts suicide among navy alcohol abusers. Mild Med. 1981;146:277–278.
28. Coren S, Halpern DF. Left-handedness: a marker for decreased survival fitness. Psychol Bull. 1991;109:90–106.
29. Bell C. The Hand; Its Mechanism and Vital Endowments, as Evincing Design and Illustrating the Power, Wisdom, and Goodness of God. London: Bell and Daldy; 1870.
30. Coren S. Left-handedness and accident related injury risk. Am J Public Health.1989;79:1040–1041.
Akman et al Neurosurg Q Volume 18, Number 1, March 2008
68
r2008 Lippincott Williams & WilkinsView publication stats View publication stats
