Pleats

 
   Nobody wants a pleat in their anastomosis but when joining one tiny tube to another it is difficult to assess the fit .The most common problem is simply that the harvested vein is wider than the artery it will join.
  When making clothes the attaching of the sleeve to the body section is a big anastomosis .The problem of mismatched sizing is on a bigger scale. This is usually deliberate e.g. when you want 'ease' over the shoulder blade in a man's suit, the fibres of the material can be compressed in that area to add volume without pleating.
    A problem to avoid though is when the sleeve fabric gets pushed around the armhole during attachment so that you end up with a pleat at the point where you started. Some fabrics stretch more than others and the effect is rather like the dragging on the handrail of an escalator which is moving at a slightly different speed. To prevent this you use marker points called notches. These quarter mark the armhole with corresponding marks on the sleeve so spreading out any excess evenly. Best practise is to tack (also known as basting) the sleeve in first (see image) but most people just pin baste and then sew.