- risus sardonicus
- rhone
- regression line
- regression curve
- robert peary
- reversed phase system
- radicular spinal syndrome
- recurrent ulnar artery
- renovascular
- rapid serial biplane angiocardiography
- republic of estonia
- river boulder
- rib_notching
- racemized
- racemose aneurysm
- rachitic dwarf pelvis
- retinitis pigmentosa inversa
- rheumatic aortitis
- rhinitis medicamentosa
- rhinitis sicca
- radicular artery
- radio pharmacy
- rydberg constant
- radio networking (rn) channel
- radial recurrent artery
- republic of singapore
- radio regulations
- radial transfer
- right_handedness
- rotary grinding motion
- radiated power
- radiation proctitis
- radiation sterilization
- radiation chimaera
- radioactive tracers
- radio_ulnar synostosis
- radioactive iodine
- radiographic pelvicephalometry
- radiosensitive
- radiocarpal
- radiodiagnositic contrast
- radiophotography
- radioprotective
- radioulnar joint
- red as a beet
- ritgen manoeuvre
- random data set
- random sequence
- respiratory unit
- record count