The Contribution of the Perichondrium to the Structural Mechanical Behavior of the Costal-Cartilage

Abstract

The costal-cartilage in the human ribcage is a composite structure consisting of a cartilage substance surrounded by a fibrous, tendon-like perichondrium. Current computational models of the human ribcage represent the costal-cartilage as a homogeneous material, with no consideration for the mechanical contributions of the perichondrium. This study sought to investigate the role of the perichondrium in the structural mechanical behavior of the costal-cartilage. Twenty-two specimens of postmortem human costal-cartilage were subjected to cantilevered-like loading both with the perichondrium intact and with the perichondrium removed. The test method was chosen to approximate the cartilage loading that occurs when a concentrated, posteriorly directed load is applied to the midsternum. The removal of the perichondrium resulted in a statistically significant (two-tailed Student's t-test, p< or =0.05) decrease of approximately 47% (95% C.I. of 35-58%) in the peak anterior-posterior reaction forces generated during the tests. When tested with the perichondrium removed, the specimens also exhibited failure in the cartilage substance in the regions that experienced tension from bending. These results suggest that the perichondrium does contribute significantly to the stiffness and strength of the costal-cartilage structure under this type loading, and should be accounted for in computational models of the thorax and ribcage.

Changes in the Tangent Modulus of Rabbit Septal and Auricular Cartilage Following Electromechanical Reshaping

“…6) and even 6 V, when a temperature increase of $10 C was observed. This observed stability could also be the product of each auricular sample's intact perichondrium, a dense, fibrous tissue shown to significantly contribute to the tensile mechanical properties of both septal and costal cartilage under these measurement conditions [22,23]. Other differences between elastic and hyaline cartilage contributing to the chemical differences between the two types may include the increased glycosaminoglycan (GAG) content and permeability of septal cartilage, [24] which may have influenced the EMR reactions, though we suspect these subtle differences to have little impact.…”

“…Two electrode configurations for EMR have been studied: surface and needle electrodes ( Fig. 1(b)) [9][10][11]23]. Although negligible heat generation has been demonstrated in previous studies [9], other potential compromises to native tissue properties related to EMR are present.…”

“…To minimize and spatially localize cartilage injury, EMR using arrays of needle electrodes has been suggested ( Fig. 1(b)) [23].…”

Modeling costal cartilage using local material properties with consideration for gross heterogeneities

“…The boundary conditions chosen for this study were the same as those used by Forman et al (2010), and the impetus for these boundary conditions is described in detail therein. The whole cartilage segments were tested by displacing the sternal boundary posteriorly (in the x-direction), holding all other boundary degrees of freedom fixed (Fig.…”

“…First, what is commonly termed the ''costal cartilage'' is actually a composite structure composed of an inner cylinder of hyaline cartilage surrounded by a thick layer of fibrous perichondrium. In a series of structural tests with the perichondrium intact and with the perichondrium removed, Forman et al (2010) demonstrated that the perichondrium contributes an average of 50% of the structural stiffness of the costal cartilage in certain loading modes.…”