- Spongioneuroblastoma (M9504/3) - see Neoplasm, by site, malignant
- Spontaneous - see also condition
- Spoon nail 703.8
- Sporadic - see condition
- Sporotrichosis (bones) (cutaneous) (disseminated) (epidermal) (lymphatic) (lymphocutaneous) (mucous membranes) (pulmonary) (skeletal) (visceral) 117.1
- Sporotrichum schenckii infection 117.1
- Spots, spotting
- Spotted fever - see Fever, spotted
- Sprain, strain (joint) (ligament) (muscle) (tendon) 848.9
- Sprengel's deformity (congenital) 755.52
- Spring fever 309.23
- Sprue 579.1
- Spur - see also Exostosis
- Spuria placenta - see Placenta, abnormal
- Spurway's syndrome (brittle bones and blue sclera) 756.51
- Sputum, abnormal (amount) (color) (excessive) (odor) (purulent) 786.4
- Squamous - see also condition
- Squashed nose 738.0
- Squeeze, divers' 993.3
- Squint (see also Strabismus) 378.9
- Stab - see also Wound, open, by site
- Staggering gait 781.2