Fig 1.
The six specimen conditions for biomechanical testing and motion analysis.
Specimens were tested in intact condition (1), after removing the intercostal muscles (2), after median sternotomy (3), after removing the anterior rib cage up to rib stumps (4), after removing right sixth, seventh, and eighth rib head (5), as well as after removing all rib heads (6).
Fig 2.
Pure moments of 2 Nm were applied in flexion/extension, lateral bending, and axial rotation using a custom-built spine tester [18]. Motion analysis was performed using an optical motion tracking system with six cameras.
Fig 3.
The process of motion analysis.
Optical markers were transferred into a point cloud. Relative motions were determined by manual labeling.
Fig 4.
The ROM of the thoracic spine (T1-12, n = 6) for 2 Nm pure bending moment.
The ROM is depicted as mean with standard deviation for each the intact condition with entire rib cage and the condition without entire rib cage in all loading directions.
Table 1.
Ranges of motion (ROM) and neutral zones (NZ) of the thoracic spine (T1-T12) are shown for the single specimen conditions (IC = intact condition, W/o IM = without intercostal muscles, MST = after median sternotomy, W/o ARC = without anterior rib cage, W/o RH 6–8 = without 6th-8th right rib head, W/o RH = without all rib heads) in the single motion planes for 2 Nm pure bending moment (n = 6).
Table 2.
Ranges of motion are shown for intact condition (= IC) and the condition without the entire rib cage (= W/o RC) in the single motion planes for all functional spinal units and a pure bending moment of 2 Nm (n = 6).
Table 3.
Coupled motion ROM of the thoracic spine (T1-T12, n = 6) are shown for intact condition (= IC) and condition without the entire rib cage (= W/o RC) in the six main loading directions.
Table 4.
Comparison of ROM increase (%) after removing the anterior rib cage up to rib stumps relative to intact condition with literature data.
Table 5.
Comparison of monosegmental ROM with literature data.