| PMB | papillomacular bundle; para-hydroxymercuribenzoate; polychrome methylene blue; polymorphonuclear bas... |
|---|---|
| RB | radiation burn; rating board; rebreathing; reticulate body; retinoblastoma; right bronchus; right bu... |
| RBB | right bundle branch |
| RBBB | right bundle-branch block |
| RBBsB | right bundle-branch system block |