Comparison of Cervical Motion Restriction and Interface Pressure Between Two Cervical Collars

Primary outcomes

1. Cervical range of motion

   Time frame: At enrollment

   The subjects will be seated in a backed chair and monitored to ensure their spine remains in contact with the backrest throughout the CROM assessment. Each subject will be instructed to perform a sequence of of neck flexion-extension, lateral flexion, and rotation movements. Each movement will be repeated six times until the motion is stopped by muscle tightness, discomfort or a substitution movement occurs, without a collar, and with each study collar chosen chosen in random order. Angular range of motion in degrees will be recorded in each plane. Flexion-extension - angle between maximum flexion and maximum extension. Lateral flexion - angle between maximum right lateral flexion and maximum left lateral flexion. Rotation - angle between maximum right rotation and maximum left rotation.

2. Tissue interface pressure

   Time frame: At enrollment

   With the subject seated, 3, 75 x 120mm pressure sensor pads, each pad each consisting of 40 individual sensors; will be placed over the anterior mandibles and occiput. The subject will be fit with an appropriately sized collar. The order of collar wear will be the same as for the CROM measurements. Pressure measurements and distribution of pressure will be recorded for a period of 30 seconds. The subject will then be placed in a supine position on a standard examination table without a pillow and pressure measurements and distribution of pressure will be collected for a period of 30 seconds while the subject maintains his/her head in a relaxed position.