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Volume 10 Supplement 1

IRSSD 2014 Meeting Abstracts

  • Poster presentation
  • Open Access

Does trunk muscle strength affect spinal deformity in adult female patients?: Evaluation of cross sectional area of psoas major and lumbar extensor muscles

  • 1,
  • 1,
  • 1,
  • 1,
  • 2,
  • 3 and
  • 1
Scoliosis201510 (Suppl 1) :P13

  • Published:


  • Cross Sectional Area
  • Pelvic Tilt
  • Lumbar Lordosis
  • Thoracic Kyphosis
  • Trunk Muscle


The purpose of this study was to evaluate cross sectional area (CSA) of psoas major and lumbar extensor muscles, and investigate the relation between truck muscles and spinal deformity in female patients with adult spinal deformity (ASD).

Material and methods

Twenty-five female patients with ASD (mean age 64.3 years) who underwent fusion surgery were included for analysis. Diagnosis was lumbar scoliosis in 10 patients, kyphoscoliosis in 11, and kyphosis in 4. Radiographic measurement of spinal alignment and CSA of lumbar trunk muscles including psoas major and lumbar extensor muscles measured by Magnetic Resonance Imaging (MRI) were evaluated. The CSAs of trunk muscles were measured at the cranial endplate of L4 vertebra for a comparative estimation of muscle size. A negative value indicated lordosis in evaluation of spinal alignment.


CSA of the psoas major adjusted by mean height was 546.2mm2 (296~769.3), and that of the lumbar extensor was 1389.9mm2 (913.6~2518.4). The mean radiographic parameters showed as follows; C7 plum line: 5.47mm, major Cobb angle: 40.0º, SVA: 93.0mm, upper thoracic kyphosis (T2-5): 8.1º, thoracic kyphosis (T5-12): 13.9º, thoracolumbar kyphosis (T10-L2): 10.6º, lumbar lordosis (L1-S1): -8.5º, pelvic incidence: 53.2º, pelvic tilt: 36.6º, and sacral slope: 16.6º. The CSA of psoas major was correlated with thoracolumbar kyohosis (rs=0.562, p<0.01), and pelvic tilt (rs=-0.481, p<0.05). The CSA of lumbar extensor was correlated with lumbar lordosis (rs=-0.533, p<0.05), and pelvic tilt (rs=-0.433, p<0.05). The CSAs of trunk muscles demonstrated no correlations with age, and body mass index.


There are significant correlation between lumbo-pelvic alignment and CSAs of trunk muscles including psoas major and lumbar extensor muscles. The trunk muscles may play an important role in supportive tissue of lumbar spine and pelvis, and affect progression of adult spinal deformity.

Authors’ Affiliations

Department of Orthopaedic Surgery, Niigata University Medical and Dental General Hospital, Japan
Department of Orthopaedic Surgery, Niigata Rehabilitation Hospital, Japan
Department of Physical Therapy, Niigata University of Health and Welfare, Japan


© Watanabe et al; licensee BioMed Central Ltd. 2015

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.