Table 3 Observed sectional ratios of muscle volume and CT density for patients with anterior shoulder instability (step B).

From: Sectional measurements of shoulder muscle volume and computed tomography density in anterior shoulder instability

 

Y section

Y + 2.5 cm section

Y + 5 cm section

Volume (ml)

 Ssc

34.3 ± 10.5

76.4 ± 15.2

109.3 ± 21.4

 Isp + TM

34.9 ± 11.2

65.8 ± 16.1

97.9 ± 19.1

CT density (HU)

 Ssc

59.9 ± 6.2

59.5 ± 5.1

59.4 ± 4.6

 Isp + TM

59.2 ± 5.6

65.1 ± 5.4

64.8 ± 5.1

Ratio of muscle volume and CT density

 VR Ssc/Isp+TM*

1.12 ± 0.55

1.21 ± 0.28

1.13 ± 0.16

 CT-DR Ssc/Isp+TM*

1.02 ± 0.11

0.92 ± 0.07

0.92 ± 0.05

  1. Data are presented as means ± standard deviations. Sectional measurement of each shoulder muscle is performed as follows: from the most lateral end of the muscles to the plane of Y-view (Y section), to the plane 2.5 cm medial to the Y-view (Y + 2.5 cm section), and to the plane 5 cm medial to the Y-view (Y + 5 cm section).
  2. CT-DR CT density ratio, HU Hounsfield unit, Isp infraspinatus, Ssc subscapular, TM teres minor, VR volume ratio.
  3. *VR Ssc/Isp+TM = ratio of the muscle volume between the subscapularis and infraspinatus or teres minor. CT-DR Ssc/Isp+TM = ratio of CT density between the subscapularis and infraspinatus or teres minor.
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