Cervical Curves:
Palpatory musculoskeletal findings in coronary artery disease: results of a double-blind study. Cox JM, Rogers FJ, Gorbis, SL et al. Journal of the American Osteopathic Association. July 1981 Vol. 80.
Consistent connection between hardening of the arteries and lack of range of motion and soft tissue texture at C3, T4, and T5.

Influence of a cervical mobilization technique on respiratory and cardiovascular function. McGuiness J, Vicenzino B, Wright A. Manual Therapy, Nov. 1997; 2(4), pp.216-20.
Significant changes in breathing, heart Rate, and Blood Pressure occur when C5 and C6 are mobilized.

Cortical Neural Plasticity with Spinal Adjustment
Haavik-Taylor and Murphy
Adjustments of cervical segments resulted in improved filtering of the cortex. Over time all patients showed improvement in complex motor skill testing.