Teudt & Richter 2014 — Basilar membrane and tectorial membrane stiffness in the CBA/CaJ mouse
AUDIT NOTE (2026-04-25): This paper is the confirmed primary source for TM Young’s modulus values including 24 kPa (basal). The literature table tectorial-membrane.md previously attributed “24–210 kPa” to “Masaki 2009 PLoS One 4:e4877” — which is a phantom (that DOI = Gavara & Chadwick 2009). Teudt & Richter 2014 reports 24.3 kPa for the basal turn, not apical. The 210 kPa figure remains unconfirmed — it does not appear in this paper.
TL;DR. Direct stiffness measurements via probe indentation in isolated CBA/CaJ mouse cochlea. TM plateau stiffness gradient 0.6 (basal) → 0.09 N/m (apical). Derived Young’s modulus: basal 24.3 ± 25.2 kPa, middle 5.1 ± 4.5 kPa, apical 1.9 ± 1.6 kPa. BM is ~3× stiffer than TM at each turn.
Key finding. The TM Young’s modulus is highest at the base (24 kPa) and decreases toward the apex (1.9 kPa), consistent with the tonotopic gradient. The wide standard deviation (±25 kPa at base) reflects high sample-to-sample variability in ex-vivo measurements.
Numbers that matter
| Parameter | Value | Units | Source location | Conditions |
|---|---|---|---|---|
| TM plateau stiffness, basal turn | 0.6 ± 0.5 | N/m | Table 1 | CBA/CaJ mouse, probe indentation |
| TM plateau stiffness, middle turn | 0.2 ± 0.1 | N/m | Table 1 | CBA/CaJ mouse |
| TM plateau stiffness, apical turn | 0.09 ± 0.09 | N/m | Table 1 | CBA/CaJ mouse |
| TM Young’s modulus, basal | 24.3 ± 25.2 | kPa | Table 1 | CBA/CaJ mouse, derived |
| TM Young’s modulus, middle | 5.1 ± 4.5 | kPa | Table 1 | CBA/CaJ mouse, derived |
| TM Young’s modulus, apical | 1.9 ± 1.6 | kPa | Table 1 | CBA/CaJ mouse, derived |
| BM plateau stiffness, basal | 3.7 ± 2.2 | N/m | Table 1 | CBA/CaJ mouse |
| BM plateau stiffness, apical | 0.5 ± 0.5 | N/m | Table 1 | CBA/CaJ mouse |
| BM Young’s modulus, basal | 76.8 ± 72 | kPa | Table 1 | CBA/CaJ mouse |
| BM Young’s modulus, apical | 9.4 ± 6.2 | kPa | Table 1 | CBA/CaJ mouse |
On the “210 kPa” figure. The 210 kPa value cited in h02 scripts has NO primary source in either this paper or Gavara 2009 or Shoelson 2004. Teudt & Richter 2014 gives a maximum TM modulus of 24.3 kPa (basal, ±25.2). The 210 kPa may originate from BaTiO3 or bulk polymer analogies — it is unsupported.
Limitations
- Ex vivo; TM detached from hair bundles and supporting structures. In-vivo stiffness likely different.
- Large standard deviations suggest high measurement variability (±25 kPa at base is 100% CV).
- Young’s modulus derived from probe indentation; assumption of homogeneous isotropic material is a simplification (TM is anisotropic, see Gueta 2008, Gavara 2009).
Connections
[source]tectorial-membrane — real primary source for TM Young’s modulus 24 kPa (basal); replaces phantom “Masaki 2009” attribution[see-also]2026-04-25-gavara-2009-tm-collagen-anisotropy-afm — fiber modulus ~1 kPa (complementary AFM measurement)[see-also]2026-04-25-gueta-2008-tm-anisotropy-stereocilia-deflection — TM anisotropy (vertical 300 kPa, lateral 45–75 kPa)[see-also]2026-04-25-shoelson-2004-tm-elasticity-inhomogeneity-biophysj — AFM shear modulus ~2–6 kPa (guinea pig)[applies]STRC Piezoelectric TM Bioelectronic Amplifier