A study was conducted to investigate the effects of a sagittal position of the body gravity center (GCP) and manual weight-load on postural control during rapid arm-lifting. The subjects were five males aged 21 to 36 years. They stood on a force plate while maintaining the GCP at 30%, 45% and 60% from the heel, regarding the fool length as 100%, and anteriorly lifted both arms spontaneously as rapidly as possible. These trials were carried out ten times under a 5 kg weight or no weight. EMGs of the biceps femoris muscle (BFM) and anterior deltoid muscle (ADM), the fluctuation of the center of foot pressure (CFP) and body motion were analyzed by focusing on their time sequences.
At 45% and 60% GCP the BFM action started prior to the ADM action, whereas at 30% GCP it tended to lag behind. The lag times under no weight were 13.9±12.75 ms (mean±SD) at 30% GCP, -32.7±18.18 ms at 45% GCP and -46.0±19.40 ms at 60% GCP. Those under 5 kg weight were 15.0±11.40 ms at 30% GCP, -22.0±6.74 ms at 45% GCP and -28.9±7.63 ms at 60% GCP. These results indicate that the anticipatory action of the muscle related to postural control arises only at specific GCPs.
The difference of starting points for BFM action to ADM action showed no significant difference between 45% and 60% GCP for either as 5 kg or no weight. The CFP position moving in a forward direction during arm-lifting showed a marked difference between 45% and 60% GCP. The time for arm-lifting showed a marked difference between 5 kg and no weight. These results suggest that the starting point of anticipatory muscle action related to postural control does not change according to the magnitude and time course of the distance to the body equilibrium as a result of arm-lifting.

A 52-year-old man had a history that included aortic valve replacement due to infectious endocarditis in 1987. Chest X-ray showed slight enlargement of the superior mediastinum in 1998, but the enlargement was very mild and there had not been any significant change since 1998. However, chest X-ray demonstrated an extremely protruding mass on the right side of the superior mediastinum in May 2004 and a pseudoaneurysm located in the ascending aorta was demonstrated by computed tomography. We considered this aneurysm had been caused by ascending aortic cannulation for blood return from cardiopulmonary bypass (CPB) during the previous surgery. On re-operation, CPB was established by femoro-femoral bypass and median sternotomy was performed. The pseudoaneurysm measured 60mm in diameter and there was a felt-pledget on top of the aneurysm. Under deep hypothermic cardiac arrest, we incised the aneurysm and closed the orifice of the pseudoaneurysm using a patch (Hemashield Woven Fabrics). On pathological examination, the wall of the pseudoaneurysm showed a structural loss of the blood vessel and the felt-pledget had been exposed to the inferior of the aneurysm breaking through the wall. We considered this a non-mycotic pseudoaneurysm because of this patient's clinical course, surgical and pathological findings. We encountered a pseudoaneurysm in the ascending aorta that was detected and treated surgically about 20 years after aortic valve replacement.