Hi,
I also found this when researching it's exact position:
"THYMUS GLAND…Lying beneath the sternum (breastbone) and above the treachea (windpipe) and heart is the two-lobed thymus gland; each lobe is made up of LYMPHATIC tissue. The thymus gland plays a significant part in the establishment of the immune system from the 12th week of gestation until PUBERTY, after which it begins to shrink gradually."
Hope it helps.
Gentle Blessings
Helen
