Dimensions of the cervical neural foramina in resting and retracted positions using magnetic resonance imaging.

STUDY DESIGN: Prospective within-subject experimental design using a sample of convenience. OBJECTIVES: To describe cervical foraminal dimensions in vivo of nonimpaired, asymptomatic individuals in a neutral cervical spine position using magnetic resonance images, and then to document dimensional changes of the foramina when placing the neck in a retracted position. BACKGROUND: Physical therapists frequently use movement interventions to treat spine dysfunctio The influence of positional changes of the head and neck on the dimensions of the cervical neuiural foramina is not well documented. METHODS AND MEASURES: Twenty asymptomatic subjects (10 men and 10 women), 22 to 25 yearrs of age (mean SD = 23.7 0.8), underwent magnetic resonance imaging of the cervical spine in both neutral and retracted positions. Bilateral measurements were documented in both positions and compared for height, width, and area of each subject's intervertebral foramen from C2-C3to C7-T1. RESULTS: No significant differences (P > 0.004) were found between the 2 neck positions. Withthe single exception of foraminal area at C3-C4, the mean values of height, width, and area in the retracted position were equal to or larger than those of the cervical neutral position. CONCLUSIONS: Therapeutic maneuvers using retraction of the cervical spine do not promote positional stenosis of the intervertebral foramen in the healthy neck.