Determination of the Material Properties of the Pediatric Rib

Links

URL: http://rave.ohiolink.edu/etdc/view?acc_num=osu1392019115

Abstract

Understanding the characteristics of the pediatric chest is of great importance for analyzing pediatric traumatic injury. As indicated by the increase in fatalities when thorax injury is accompanied with head and abdominal injuries, there is a correlation between the behavior of the thorax and the head. The initial motion of the thorax dictates the relative movement of the top of the spine, neck, and head. Also, the deflection of the pediatric rib cage may result in internal injuries to the abdomen and chest cavity without rib fracture. In order to realize the potential for internal injuries without visible rib fracture, the behavior of the pediatric thorax must be determined. The literature contains much data on the adult rib, but properties of the pediatric rib are lacking from previous studies. Due to the extreme differences in growth and development between children and adults, the scaling of adult properties to reflect those of children based strictly on size is not reasonable. Several other factors, including fracture mechanisms and bone development, must be taken into account.

The objective of this study is to determine the material properties of the excised pediatric rib as a function of age and to compare the results to the material properties of the excised porcine rib. A total of 150 porcine rib samples from 25 porcine subjects, and 31 rib samples from 9 pediatric subjects were loaded in 3-point bending at a quasi-static rate. All data were analyzed for rotation during testing, axis of moment of inertia, stiffness, Young’s modulus, flexural rigidity, peak force, bending strength, yield force, and yield stress.

The results of the study indicate that the rib cross-section undergoes minimal rotation during testing. However, the orientation of the bending axis does not always correspond to the orientation of the principal axis of the minimum moment of inertia. For the porcine subjects, moment of inertia, stiffness, flexural rigidity, peak force, and yield force showed a linear increase with age. The variables of Young’s modulus, bending strength, and yield stress are believed to be constant over all ages of porcine subjects. All variables analyzed for 3-point bending of the pediatric rib showed increase in value as a function of pediatric age.

The major finding of this study is that porcine subjects do not present an acceptable animal model for the behavior of the pediatric rib. Development rates between humans and the pig are vastly different. The conclusion from this study is that additional pediatric rib specimens are needed in order to fully understand the changes in the material properties of the pediatric rib as a function of age.

Cited Works (21)

Year	Entry
2005	Arbogast KB, Mong DA, Marigowda S, Kent RW, Stacey S, Mattice J, Tanji H, Higuchi K, Rouhana SW. Evaluating pediatric abdominal injuries. In: Proceedings of the 19th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 6-9, 2005; Washington, DC.
1972	Roberts SB, Chen PH. Global geometric characteristics of typical human ribs. J Biomech. March 1972;5(2):191-201.
2000	Margulies SS, Thibault KL. Infant skull and suture properties: measurements and implications for mechanisms of pediatric brain injury. J Biomech Eng. August 2000;122(4):364-371.
1989	Nordin M, Frankel VH, eds. Basic Biomechanics of the Musculoskeletal System. 2nd ed. Philadelphia, PA: Lea & Febiger; 1989.
2000	Pintar F, Mayer R, Yoganandan N, Sun E. Child neck strength characteristics using an animal model. Stapp Car Crash J. 2000;44:77-83. SAE 2000-01-SC06.
1974	Schultz AB, Benson DR, Hirsch C. Force-deformation properties of human ribs. J Biomech. 1974;7(3):303-309.
2002	Currey JD. Bones: Structure and Mechanics. Princeton, NJ: Princeton University Press; 2002.
1981	Kriewall TJ, McPherson GK, Tsai AC. Bending properties and ash content of fetal cranial bone. J Biomech. 1981;14(2):73-79.
2005	Cormier JM, Stitzel JD, Duma SM, Matsuoka F. Regional variation in the structural response and geometrical properties of human ribs. In: 49th Annual Proceedings, Association for the Advancement of Automotive Medicine (AAAM). September 12-14, 2005; Boston, MA.153-170.
1980	McPherson GK, Kriewall TJ. The elastic modulus of fetal cranial bone: a first step towards an understanding of the biomechanics of fetal head molding. J Biomech. 1980;13(1):9-16.
1970	Yamada H. Strength of Biological Materials. Evans FG, ed. Baltimore, MD: Williams & Wilkins Company; 1970.
1976	Stein ID, Granik G. Rib structure and bending strength: an autopsy study. Calcif Tiss Res. 1976;20(1):61-73.
1993	Turner CH, Burr DB. Basic biomechanical measurements of bone: a tutorial. Bone. 1993;14(4):595-608.
2004	Prange MT, Luck JF, Dibb A, Van Ee CA, Nightingale RW, Myers BS. Mechanical properties and anthropometry of the human infant head. Stapp Car Crash J. 2004;48:279-299. SAE 2004-22-0013.
1984	Pelker RR, Friedlaender GE, Markham TC, Panjabi MM, Moen CJ. Effects of freezing and freeze‐drying on the biomechanical properties of rat bone. J Orthop Res. 1984;1(4):405-411.
1999	Currey JD. What determines the bending strength of compact bone? J Exp Biol. September 1999;202(18):2495-2503.
1975	Currey JD, Butler G. The mechanical properties of bone tissue in children. J Bone Joint Surg. September 1975;57A(6):810-814.
2001	Cowin SC, ed. Bone Mechanics Handbook. 2nd ed. Boca Raton, FL: CRC Press; 2001.
1998	Yoganandan N, Pintar FA. Biomechanics of human thoracic ribs. J Biomech Eng. February 1998;120(1):100-104.
1966	Takahashi H, Frost HM. Age and sex related changes in the amount of cortex of normal human ribs. Acta Orthop Scand. 1966;37(2):122-130.
2005	Kemper AR, McNally C, Kennedy EA, Manoogian SJ, Rath AL, Ng TP, Stitzel JD, Smith EP, Duma SM, Matsuoka F. Material properties of human rib cortical bone from dynamic tension coupon testing. Stapp Car Crash J. 2005;49:199-230. SAE 2005-22-0010.

Cited By (3)

Year	Entry
2007	Pfefferle KL, Litsky A, Donnelly B, Bolte J IV. Biomechanical properties of the excised pediatric human rib. In: Proceedings of the 35th International Workshop on Human Subjects for Biomechanical Research. 2007.142-156.
2014	Schafman M, Kang Y-S, Moorhouse K, Agnew AM. The effect of age on the structural properties of ribs in dynamic frontal loading. In: Proceedings of the 10th Ohio State University Injury Biomechanics Symposium. May 18-20, 2014; Columbus, OH.
2015	Agnew AM, Schafman M, Moorhouse K, White SE, Kang Y-S. The effect of age on the structural properties of human ribs. J Mech Behav Biomed Mater. January 2015;41:302-314.