My arms at 19" are probaly only 5-6" 'tall' MAX - nowhere near size of my head.
They're probably not 19''... maybe measure them properly?
You're probably wrong about the "height" too...
-the circumference of a circle with a 5'' diameter = 2piR = (2)x(3.1459)x(2.5'') = 15.7''
-the circumference of a circle with a 6'' diameter = 2piR = (2)x(3.1459)x(3.0'') = 18.8''
...if they are 19'', then considering the human arm is not tubular but more like an elipse in cross-section, they're probably taller than that... maybe 7'' or so.
Or perhaps they're just less 19'' in circumference.
Maybe Goudy you could give me your height; weight and bf % and I'll use the ratio I posted to estimate your arm circumference... then you could post a pic of your arm properly taped (arm at 90 degrees to the body and tape perpendicular to the humerus) and we could see how accuate the estimate is?
The Luke