Anterior Pelvic Tilt Angle Research Articles

How do anterior/posterior translations of the thoracic cage affect the sagittal lumbar spine, pelvic tilt, and thoracic kyphosis?

Anterior and posterior thoracic cage translations in the sagittal plane have not been reported for their range of motion and effects on the lumbar spine and pelvis. Twenty subjects volunteered for full-spine radiography in neutral, anterior, and posterior thoracic cage translation postures in a standing position. While grasping an anterior vertical pole, with hands at elbow level, subjects were instructed on how to translate their thoracic cage without any flexion/extension, utilizing a full-length mirror. On the radiographs, all four vertebral body corners of T1 through S1 and the superior margin of the acetabulum were digitized. Segmental and global angles of thoracic kyphosis, sagittal lumbar curvature, and pelvic flexion/extension in translation postures were compared to alignment in the neutral posture. Using the femur heads as an origin, the mean range of thoracic cage translation, measured as horizontal movement of T12 from neutral posture, was found to be 85.1 mm anterior and 73 mm posterior. In anterior translation, the thoracic kyphosis is hypokyphotic (Cobb T1-T12 reduced by 16 degrees). In posterior translation, the segmental angles at T12-L1 and L1-L2 flexed, creating an "S" shape in the sagittal lumbar spine, while the thoracic kyphosis increased by 10 degrees. Using posterior tangents from L1 to L5 and T12 to S1, and Cobb angles at T12-S1, the lumbar curve reduced slightly (by less than 3.3 degrees for all global angle measurements) in anterior translation and reduced by 7.4 degrees, 5.7 degrees, and 8.1 degrees respectively in posterior thoracic translation. The angle of pelvic tilt (measured as the angle of intersection of a line through posterior-inferior S1 to the superior acetabulum and the horizontal) reduced by a mean of 15.9 degrees, and Ferguson's sacral base angle to horizontal reduced by a mean of 13.1 degrees in posterior translation. In anterior translation, pelvic tilt and Ferguson's sacral base angle increased by 15.1 degrees and 12.8 degrees, respectively. The findings of this study show that thoracic cage anterior/posterior translations cause significant changes in thoracic kyphosis (26 degrees ), lumbar curve, and pelvic tilt. An understanding of this main motion and consequent coupled movements might aid the understanding of spinal injury kinematics and spinal displacement analysis on full spine lateral radiographs of low back pain and spinal disorder populations.

Effect of Positive Heel Inclination on Posture

Millions of women wear high heels on a daily basis; however, few studies have analyzed the changes high heels (positive heel inclination) have on posture. The purpose of this study was to determine whether positive heel inclination changed the postural alignment of the head, spine, pelvis, and knees. Fifteen female college students ((mean age = 22.7, SD = 3.7 years) had sagittal plane angles measured for the cervical spine, thoracic spine, lumbar spine, sacral spine, and knee joints in addition to anterior/posterior displacements of the head and pelvis. All variables were assessed by a Metrecom Skeletal Analysis System, a three-dimensional electrogoniometer. Six randomized trials, three at zero heel inclination and three at 5 cm positive heel inclination, were measured. Analysis of variance results indicated positive heel inclination of subjects brought about significantly lower anterior pelvic tilt, lumbar lordosis, and sacral base angles when compared with zero heel inclination (p < .01). Clinically, patients with low back pain may be affected by high heel usage because of the reduction of the normal lumbar lordosis.

Intertester reliability for measuring pelvic tilt in standing.

The purpose of this study was to examine intertester reliability using a method of measuring the relaxed standing pelvic-tilt angle, active anterior and posterior pelvic-tilt angles and ranges of motion, and the total pelvic-tilt ROM in the sagittal plane. After an instructional session, 6 testers measured the pelvic-tilt angles of the right side of 12 subjects. Pelvic-tilt angles were calculated using trigonometric functions. Degrees of ROM were determined from the pelvic-tilt angles obtained. The intraclass correlation coefficient was .95 for standing pelvic-tilt angle, .93 for the anterior pelvic-tilt angle, .93 for the posterior pelvic-tilt angle, .88 for the anterior pelvic-tilt ROM, .93 for the posterior pelvic-tilt ROM, and .90 for the total pelvic-tilt ROM. We concluded that intertester reliability, using this method, was very high for measuring pelvic tilt in the sagittal plane.

Pelvic tilt. Intratester reliability of measuring the standing position and range of motion.

The purpose of this study was to examine intratester reliability of a test designed to measure the standing pelvic-tilt angle, active posterior and anterior pelvic-tilt angles and ranges of motion, and the total pelvic-tilt range of motion (ROM). After an instruction session, the pelvic-tilt angles of the right side of 20 men were calculated using trigonometric functions. Ranges of motion were determined from the pelvic-tilt angles. Intratester reliability coefficients (Pearson r) for test and retest measurements were .88 for the standing pelvic-tilt angle, .88 for the posterior pelvic-tilt angle, .92 for the anterior pelvic-tilt angle, .62 for the posterior pelvic-tilt ROM, .92 for the anterior pelvic-tilt ROM, and .87 for the total ROM. We discuss the factors that may have influenced the reliability of the measurements and the clinical implications and limitations of the test. We suggest additional research to examine intratester reliability of measuring the posterior pelvic-tilt ROM, intertester reliability of measuring all angles and ROM, and the pelvic tilt of many types of subjects.