Complex sentence: In an elevated arm position the axillary neurovascular bundle can be seen at the posterior axillary fold just before it perforates the deltoideus, while the posterior course is well visible in the neutral position.
Split into simpler sentences: In an elevated arm position the axillary neurovascular bundle can be seen at the posterior axillary fold just before it perforates the deltoideus. While the posterior course is well visible in the neutral position.