Effect of pillow height on the biomechanics of the head-neck complex: investigation of the cranio-cervical pressure and cervical spine alignment.
Level 4 - case-series / case-control
Small laboratory biomechanical crossover experiment with computational finite element modeling
PubMed 27635354 · doi:10.7717/peerj.2397
What was done
Ten healthy subjects (five males and five females; mean age 26 ± 3.6 years) were tested supine on pillows of four different heights: 110 mm (H0), 130 mm (H1), 150 mm (H2), and 170 mm (H3). Cranio-cervical contact pressure distribution was recorded and analyzed using repeated-measures one-way ANOVA. Cervical spine alignment parameters (cervical angle, lordosis distance, and kyphosis distance) across pillow heights were predicted using a computational finite element model based on Visible Human Project anatomical data.
What was found
Average cranial pressure at 170 mm was approximately 30% higher than at 110 mm (p < 0.05) and significantly different from 130 mm and 150 mm. Average cervical pressure at 110 mm was 65% lower than at 170 mm (p < 0.05) and significantly different from 130 mm and 150 mm. Peak cervical pressures at 150 mm and 170 mm were significantly different from that at 110 mm (p < 0.05). In the finite element model, raising pillow height from 110 mm to 170 mm caused an increase of 66.4% in cervical angle, a 25.1% increase in lordosis distance, and a 43.4% reduction in kyphosis distance.
Why it matters
The findings show that increasing pillow height increases cranial and cervical contact pressures while shifting simulated cervical spine alignment toward greater extension and lordosis.
Limits
The study had a very small sample size of 10 young healthy adults. Cervical spine alignment was derived from a computational model rather than direct in vivo imaging. Sleep quality, long-term comfort, muscle activity, and side-sleeping positions were not evaluated.
Cited by
- context A pillow that tilts the head out of alignment creates muscular strain that signals the brain and prevents deep sleep.