- Saber, sabre shin or tibia (syphilitic), A50.56
- Sac lacrimal
- Saccharomyces infection, B37.9
- Saccharopinuria, E72.3
- Saccular
- Sacculation
- Sachs-Tay disease, E75.02
- Sachs\’ amaurotic familial idiocy or disease, E75.02
- Sacks-Libman disease, M32.11
- Sacralgia, M53.3
- Sacralization, Q76.49
- Sacrodynia, M53.3
- Sacroiliac joint
- Sacroiliitis NEC, M46.1
- Sacrum
- Saddle
- Sadism (sexual), F65.52
- Sadness, postpartal, O90.6
- Sadomasochism, F65.50
- Saemisch\’s ulcer (cornea)
- Sagging
- Sahib disease, B55.0
- Sailors\’ skin, L57.8
- Saint
- Salaam
- Salicylism
- Salivary duct or gland
- Salivation, excessive, K11.7
- Salmonella
- Salmonellosis, A02.0
- Salpingitis (catarrhal) (fallopian tube) (nodular) (pseudofollicular) (purulent) (septic), N70.91
- Salpingo-oophoritis (catarrhal) (purulent) (ruptured) (septic) (suppurative), N70.93
- Salpingo-ovaritis
- Salpingocele, N83.4-
- Salpingoperitonitis
- Salzmann\’s nodular dystrophy
- Sampson\’s cyst or tumor, N80.10-
- San Joaquin fever (Valley), B38.0
- Sandblaster\’s asthma, lung or pneumoconiosis, J62.8
- Sander\’s disease (paranoia), F22
- Sandfly fever, A93.1
- Sandhoff\’s disease, E75.01
- Sanfilippo syndrome (Type B) (Type C) (Type D), E76.22
- Sanger-Brown ataxia, G11.2
- Sao Paulo fever or typhus, A77.0
- Saponification, mesenteric, K65.8
- Sarcocele (benign)
- Sarcocystosis, A07.8
- Sarcoepiplocele
- Sarcoepiplomphalocele, Q79.2
- Sarcoglycanopathy, G71.0340
- Sarcoid
- Sarcoidosis, D86.9
- Sarcoma (of)
- Sarcomatosis
- Sarcopenia (age-related), M62.84
- Sarcosinemia, E72.59
- Sarcosporidiosis (intestinal), A07.8
- SARS-CoV-2
- Satiety, early, R68.81
- Saturnine
- Saturnism
- Satyriasis, F52.8
- Sauriasis
- Sézary disease, C84.1-
- SBE (subacute bacterial endocarditis), I33.0
- Scabies (any site), B86
- Scabs, R23.4
- Scaglietti-Dagnini syndrome, E22.0
- Scald
- Scalenus anticus syndrome (anterior), G54.0
- Scales, R23.4
- Scaling, skin, R23.4
- Scalp
- Scapegoating affecting child, Z62.3
- Scaphocephaly, Q75.0
- Scapulalgia, M89.8X1
- Scapulohumeral myopathy, G71.02
- Scar, scarring, L90.5
- Scarabiasis, B88.2
- Scarlatina (anginosa) (maligna), A38.9
- Scarlet fever (albuminuria) (angina), A38.9
- Schamberg\’s disease (progressive pigmentary dermatosis), L81.7
- Schatzki\’s ring (acquired) (esophagus) (lower), K22.2
- Schaufenster krankheit, I20.8
- Schaumann\’s
- Schönlein (-Henoch) disease or purpura (primary) (rheumatic), D69.0
- Schüller-Christian disease or syndrome, C96.5
- Scheie\’s syndrome, E76.03
- Schenck\’s disease, B42.1
- Scheuermann\’s disease or osteochondrosis
- Schilder disease (-Flatau), G37.0
- Schilling-type monocytic leukemia, C93.0-
- Schimmelbusch\’s disease, cystic mastitis, or hyperplasia
- Schistosoma infestation
- Schistosomiasis, B65.9
- Schizencephaly, Q04.6
- Schizoaffective psychosis, F25.9
- Schizodontia, K00.2
- Schizoid personality, F60.1
- Schizophrenia, schizophrenic, F20.9
- Schizothymia (persistent), F60.1
- Schlatter-Osgood disease or osteochondrosis, M92.52-
- Schlatter\’s tibia
- Schmidt\’s syndrome (polyglandular, autoimmune), E31.0
- Schmincke\’s carcinoma or tumor
- Schmitz dysentery (-Stutzer), A03.0
- Schmorl\’s disease or nodes
- Schneiderian
- Scholte\’s syndrome (malignant carcinoid), E34.0
- Scholz disease or syndrome (-Bielchowsky-Henneberg), E75.25
- Schottmuller\’s disease, A01.4
- Schroeder\’s syndrome (endocrine hypertensive), E27.0
- Schultze\’s type acroparesthesia, simple, I73.89
- Schultz\’s disease or syndrome
- Schwalbe-Ziehen-Oppenheim disease, G24.1
- Schwannoma
- Schwannomatosis, Q85.03
- Schwartz syndrome (-Jampel), G71.13
- Schwartz-Bartter syndrome, E22.2
- Schweniger-Buzzi anetoderma, L90.1
- Sciatic
- Sciatica (infective), M54.3
- Scimitar syndrome, Q26.8
- Sclérose en plaques, G35
- Sclera
- Sclerectasia, H15.84-
- Scleredema
- Sclerema (adiposum) (edematosum) (neonatorum) (newborn), P83.0
- Scleriasis
- Scleritis, H15.00-
- Sclerochoroiditis, H31.8
- Scleroconjunctivitis
- Sclerocystic ovary syndrome, E28.2
- Sclerodactyly, sclerodactylia, L94.3
- Scleroderma, sclerodermia (acrosclerotic) (diffuse) (generalized) (progressive) (pulmonary), M34.9-
- Sclerokeratitis, H16.8
- Scleroma nasi, A48.8
- Scleromalacia (perforans), H15.05-
- Scleromyxedema, L98.5
- Sclerosis, sclerotic
- Scoliosis (acquired) (postural), M41.9
- Scoliotic pelvis
- Scorbutus, scorbutic
- Score, NIHSS (National Institutes of Health Stroke Scale), R29.7-
- Scotoma (arcuate) (Bjerrum) (central) (ring)
- Scratch
- Scratchy throat, R09.89
- Screening (for), Z13.9
- Scrofula, scrofulosis (tuberculosis of cervical lymph glands), A18.2
- Scrofulide (primary) (tuberculous), A18.4
- Scrofuloderma, scrofulodermia (any site) (primary), A18.4
- Scrofulosus lichen (primary) (tuberculous), A18.4
- Scrofulous
- Scrotal tongue, K14.5
- Scrotum
- Scurvy, scorbutic, E54
- Sealpox, B08.62
- Seasickness, T75.3
- Seatworm (infection) (infestation), B80
- Sebaceous
- Seborrhea, seborrheic, L21.9
- Seckel\’s syndrome, Q87.19
- Seclusion, pupil
- Second hand tobacco smoke exposure (acute) (chronic), Z77.22
- Secondary
- Secretion
- Section
- Sedative, hypnotic, or anxiolytic-induced
- Segmentation, incomplete (congenital)
- SEID (systemic exertion intolerance disease), G93.32
- Seitelberger\’s syndrome (infantile neuraxonal dystrophy), G31.89
- Seizure (s), R56.9
- Selenium deficiency, dietary, E59
- Self-damaging behavior (life-style), Z72.89
- Self-harm (attempted)
- Self-injury, nonsuicidal, R45.88
- Self-mutilation (attempted)
- Self-poisoning
- Semicoma, R40.1
- Seminal vesiculitis, N49.0
- Seminoma, C62.9-
- Senear-Usher disease or syndrome, L10.4
- Senectus, R54
- Senescence (without mention of psychosis), R54
- Senile, senility, R41.81
- Sensation
- Sense loss
- Sensibility disturbance (cortical) (deep) (vibratory), R20.9
- Sensitive, sensitivity
- Sensitiver Beziehungswahn, F22
- Sensitization, auto-erythrocytic, D69.2
- Separation
- Sepsis (generalized) (unspecified organism), A41.9
- Septate
- Septic
- Septicemia, A41.9
- Septum, septate (congenital)
- Sequelae (of)
- Sequestration
- Sequestrum
- Sequoiosis lung or pneumonitis, J67.8
- Serology for syphilis
- Seroma
- Seropurulent
- Serositis, multiple, K65.8
- Serous
- Sertoli cell
- Sertoli-Leydig cell tumor
- Serum
- Sesamoiditis, M25.8-
- Severe sepsis, R65.20
- Sever\’s disease or osteochondrosis
- Sex
- Sextuplet pregnancy
- Sexual
- Sexuality, pathologic
- Shadow, lung, R91.8
- Shaking palsy or paralysis
- Shallowness, acetabulum
- Shaver\’s disease, J63.1
- Sheath (tendon)
- Sheathing, retinal vessels, H35.01-
- Shedding
- Sheehan\’s disease or syndrome, E23.0
- Shelf, rectal, K62.89
- Shell teeth, K00.5
- Shellshock (current), F43.0
- Shield kidney, Q63.1
- Shift
- Shifting sleep-work schedule (affecting sleep), G47.26
- Shiga dysentery (-Kruse), A03.0
- Shiga\’s bacillus, A03.0
- Shigella (dysentery)
- Shigellosis, A03.9
- Shin splints, S86.89
- Shingles
- Shipyard disease or eye, B30.0
- Shirodkar suture, in pregnancy
- Shock, R57.9
- Shoemaker\’s chest, M95.4
- Short, shortening, shortness
- Shortsightedness
- Shoshin (acute fulminating beriberi), E51.11
- Shoulder
- Shovel-shaped incisors, K00.2
- Shower, thromboembolic
- Shunt
- Shutdown, renal, N28.9
- Shy-Drager syndrome, G90.3
- Sialadenitis, sialadenosis (any gland) (chronic) (periodic) (suppurative)
- Sialectasia, K11.8
- Sialidosis, E77.1
- Sialitis, silitis (any gland) (chronic) (suppurative)
- Sialoadenitis (any gland) (periodic) (suppurative), K11.20
- Sialoadenopathy, K11.9
- Sialoangitis
- Sialodochitis (fibrinosa)
- Sialodocholithiasis, K11.5
- Sialolithiasis, K11.5
- Sialometaplasia, necrotizing, K11.8
- Sialorrhea
- Sialosis, K11.7
- Siamese twin, Q89.4
- Sibling rivalry, Z62.891
- Sicard\’s syndrome, G52.7
- Sicca syndrome
- Sick, R69
- Sick-euthyroid syndrome, E07.81
- Sickle-cell
- Sicklemia
- Sickness
- Sideropenia
- Siderosilicosis, J62.8
- Siderosis (lung), J63.4
- Siemens\’ syndrome (ectodermal dysplasia), Q82.8
- Sighing, R06.89
- Sigmoid
- Sigmoiditis, K52.9
- Silfversköld\’s syndrome, Q78.9
- Silicosiderosis, J62.8
- Silicosis, silicotic (simple) (complicated), J62.8
- Silicotuberculosis, J65
- Silo-fillers\’ disease, J68.8
- Silver\’s syndrome, Q87.19
- Simian malaria, B53.1
- Simmonds\’ cachexia or disease, E23.0
- Simons\’ disease or syndrome (progressive lipodystrophy), E88.1
- Simple, simplex
- Simulation, conscious (of illness), Z76.5
- Simultanagnosia (asimultagnosia), R48.3
- Sin Nombre virus disease (Hantavirus) (cardio)-pulmonary syndrome), B33.4
- Sinding-Larsen disease or osteochondrosis
- Singapore hemorrhagic fever, A91
- Singer\’s node or nodule, J38.2
- Single
- Singultus, R06.6
- Sinus
- Sinusitis (accessory) (chronic) (hyperplastic) (nasal) (nonpurulent) (purulent), J32.9
- Sinusitis-bronchiectasis-situs inversus (syndrome) (triad), Q89.3
- Sipple\’s syndrome, E31.22
- Sirenomelia (syndrome), Q87.2
- Siriasis, T67.01
- Sirkari\’s disease, B55.0
- Siti, A65
- Situation, psychiatric, F99
- Situational
- Situs inversus or transversus (abdominalis) (thoracis), Q89.3
- Sixth disease, B08.20
- Sjögren-Larsson syndrome, Q87.19
- Sjögren\’s syndrome or disease
- Skeletal
- Skene\’s gland
- Skenitis
- Skerljevo, A65
- Skevas-Zerfus disease
- Skin
- Slate-dressers\’ or slate-miners\’ lung, J62.8
- Sleep
- Sleep hygiene
- Sleep-wake schedule disorder, G47.20
- Sleeping sickness
- Sleeplessness
- Slim disease (in HIV infection), B20
- Slipped, slipping
- Slocumb\’s syndrome, E27.0
- Sloughing (multiple) (phagedena) (skin)
- Slow
- Slowing, urinary stream, R39.198
- Sluder\’s neuralgia (syndrome), G44.89
- Slurred, slurring speech, R47.81
- Small (ness)
- Small-and-light-for-dates
- Small-for-dates (infant), P05.10
- Smallpox, B03
- Smearing, fecal, R15.1
- SMEI (severe myoclonic epilepsy in infancy), G40.83-
- Smith-Lemli-Opitz syndrome, E78.72
- Smith\’s fracture, S52.54-
- Smoker
- Smoker\’s
- Smoking
- Smothering spells, R06.81
- Snaggle teeth, tooth, M26.39
- Snapping
- Sneddon-Wilkinson disease or syndrome (sub-corneal pustular dermatosis), L13.1
- Sneezing (intractable), R06.7
- Sniffing
- Sniffles
- Snoring, R06.83
- Snow blindness
- Snuffles (non-syphilitic), R06.5
- Social
- Sodoku, A25.0
- Soemmerring\’s ring
- Soft
- Softening
- Soldier\’s
- Solitary
- Solvent abuse
- Somatization reaction, somatic reaction
- Somnambulism, F51.3
- Somnolence, R40.0
- Sonne dysentery, A03.3
- Soor, B37.0
- Sore
- Soto\’s syndrome (cerebral gigantism), Q87.3
- South African cardiomyopathy syndrome, I42.8
- Southeast Asian hemorrhagic fever, A91
- Spacing
- Spade-like hand (congenital), Q68.1
- Spading nail, L60.8
- Spanish collar, N47.1
- Sparganosis, B70.1
- Spasm, spastic, spasticity (s), R25.2
- Spasmodic
- Spasmophilia
- Spasmus nutans, F98.4
- Spastic, spasticity
- Speaker\’s throat, R49.8
- Specific, specified
- Speech
- Spells, transient oxygen desaturation of newborn, P28.40
- Spencer\’s disease, A08.19
- Spens\’ syndrome (syncope with heart block), I45.9
- Sperm counts (fertility testing), Z31.41
- Spermatic cord
- Spermatocele, N43.40
- Spermatocystitis, N49.0
- Spermatocytoma, C62.9-
- Spermatorrhea, N50.89
- Sphacelus
- Sphenoidal
- Sphenoiditis (chronic)
- Sphenopalatine ganglion neuralgia, G90.09
- Sphericity, increased, lens (congenital), Q12.4
- Spherocytosis (congenital) (familial) (hereditary), D58.0
- Spherophakia, Q12.4
- Sphincter
- Sphincteritis, sphincter of Oddi
- Sphingolipidosis, E75.3
- Sphingomyelinosis, E75.3
- Spicule tooth, K00.2
- Spider
- Spiegler-Fendt
- Spielmeyer-Vogt disease, E75.4
- Spina bifida (aperta), Q05.9
- Spindle, Krukenberg\’s
- Spine, spinal
- Spiradenoma (eccrine)
- Spirillosis, A25.0
- Spirillum
- Spirochetal
- Spirochetosis, A69.9
- Spirometrosis, B70.1
- Spitting blood
- Splanchnoptosis, K63.4
- Spleen, splenic
- Splenectasis
- Splenitis (interstitial) (malignant) (nonspecific), D73.89
- Splenocele, D73.89
- Splenomegaly, splenomegalia (Bengal) (cryptogenic) (idiopathic) (tropical), R16.1
- Splenopathy, D73.9
- Splenoptosis, D73.89
- Splenosis, D73.89
- Splinter
- Split, splitting
- Spondylarthrosis
- Spondylitis (chronic)
- Spondyloarthritis
- Spondylolisthesis (acquired) (degenerative), M43.10
- Spondylolysis (acquired), M43.00
- Spondylopathy, M48.9
- Spondylosis, M47.9
- Sponge
- Sponge-diver\’s disease
- Spongioblastoma (any type)
- Spongioneuroblastoma
- Spontaneous
- Spoon nail, L60.3
- Sporadic
- Sporothrix schenckii infection
- Sporotrichosis, B42.9
- Spots, spotting (in) (of)
- Spotted fever, A77.9
- Sprain (joint) (ligament)
- Sprengel\’s deformity (congenital), Q74.0
- Sprue (tropical), K90.1
- Spur, bone
- Spurway\’s syndrome, Q78.0
- Sputum
- Squamous
- Squashed nose, M95.0
- Squeeze, diver\’s, T70.3
- Squint
- SSADHD (succinic semialdehyde dehydrogenase deficiency), E72.81
- St. Hubert\’s disease, A82.9
- Stab
- Stafne\’s cyst or cavity, M27.0
- Staggering gait, R26.0
- Staghorn calculus
- Stain, staining
- Stammering, F80.81
- Standstill
- Stannosis, J63.5
- Stanton\’s disease
- Staphylitis (acute) (catarrhal) (chronic) (gangrenous) (membranous) (suppurative) (ulcerative), K12.2
- Staphylococcal scalded skin syndrome, L00
- Staphylococcemia, A41.2
- Staphylococcus, staphylococcal
- Staphyloma (sclera)
- Stargardt\’s disease
- Starvation (inanition) (due to lack of food), T73.0
- Stasis
- State (of)
- Status (post)
- Stähli\’s line (cornea) (pigment)
- Stealing
- Steam burn
- Steatocystoma multiplex, L72.2
- Steatohepatitis (nonalcoholic) (NASH), K75.81
- Steatoma, L72.3
- Steatorrhea (chronic), K90.9
- Steatosis, E88.89
- Steele-Richardson-Olszewski disease or syndrome, G23.1
- Stein-Leventhal syndrome, E28.2
- Steinbrocker\’s syndrome, G90.8
- Steinert\’s disease, G71.11
- Stein\’s syndrome, E28.2
- STEMI, I21.3
- Stenocardia, I20.8
- Stenocephaly, Q75.8
- Stenosis, stenotic (cicatricial)
- Stent jail, T82.897
- Stercolith (impaction), K56.41
- Stercoraceous, stercoral ulcer, K63.3
- Stereotypies NEC, F98.4
- Sterility
- Sterilization
- Sternalgia
- Sternopagus, Q89.4
- Sternum bifidum, Q76.7
- Steroid
- Stevens-Johnson disease or syndrome, L51.1
- Stewart-Morel syndrome, M85.2
- Sticker\’s disease, B08.3
- Sticky eye
- Stieda\’s disease
- Stiff neck
- Stiff-man syndrome, G25.82
- Stiffness, joint NEC, M25.60-
- Stigmata congenital syphilis, A50.59
- Still-Felty syndrome
- Stillbirth, P95
- Still\’s disease or syndrome (juvenile), M08.20
- Stimulation, ovary, E28.1
- Sting (venomous) (with allergic or anaphylactic shock)
- Stippled epiphyses, Q78.8
- Stitch
- Stokes-Adams disease or syndrome, I45.9
- Stokes\’ disease, E05.00
- Stokvis disease (-Talma), D74.8
- Stoma malfunction
- Stomach
- Stomatitis (denture) (ulcerative), K12.1
- Stomatocytosis, D58.8
- Stomatomycosis, B37.0
- Stomatorrhagia, K13.79
- Stone (s)
- Stonecutter\’s lung, J62.8
- Stonemason\’s asthma, disease, lung or pneumoconiosis, J62.8
- Stoppage
- Storm, thyroid
- Strabismus (congenital) (nonparalytic), H50.9
- Strain
- Straining, on urination, R39.16
- Strand, vitreous
- Strangulation, strangulated
- Strangury, R30.0
- Straw itch, B88.0
- Strawberry
- Strümpell-Marie spine
- Strümpell-Westphal pseudosclerosis, E83.01
- Streak (s)
- Strephosymbolia, F81.0
- Streptobacillary fever, A25.1
- Streptobacillosis, A25.1
- Streptobacillus moniliformis, A25.1
- Streptococcus, streptococcal
- Streptomycosis, B47.1
- Streptotrichosis, A48.8
- Stress, F43.9
- Stretching, nerve
- Striae albicantes, atrophicae or distensae (cutis), L90.6
- Stricture
- Stridor, R06.1
- Stridulous
- Stroke (apoplectic) (brain) (embolic) (ischemic) (paralytic) (thrombotic), I63.9
- Stromatosis, endometrial, D39.0
- Strongyloidiasis, strongyloidosis, B78.9
- Strophulus pruriginosus, L28.2
- Struck by lightning
- Struma
- Strumipriva cachexia, E03.4
- Stuart deficiency disease (factor X), D68.2
- Stuart-Prower factor deficiency (factor X), D68.2
- Student\’s elbow
- Stump
- Stunting, nutritional, E45
- Stupor (catatonic), R40.1
- Sturge disease or syndrome (-Weber) (-Dimitri) (-Kalischer), Q85.89
- Stuttering, F80.81
- Sty, stye (external) (internal) (meibomian) (zeisian)
- Subacidity, gastric, K31.89
- Subacute
- Subarachnoid
- Subcortical
- Subcostal syndrome, nerve compression
- Subcutaneous, subcuticular
- Subdural
- Subendocardium
- Subependymoma
- Suberosis, J67.3
- Subglossitis
- Subhemophilia, D66
- Subinvolution
- Sublingual
- Sublinguitis
- Subluxatable hip, Q65.6
- Subluxation
- Submaxillary
- Submersion (fatal) (nonfatal), T75.1
- Submucous
- Subnormal, subnormality
- Subphrenic
- Subscapular nerve
- Subseptus uterus, Q51.28
- Subsiding appendicitis, K36
- Substance-induced (other psychoactive)
- Substernal thyroid, E04.9
- Substitution disorder, F44.9
- Subtentorial
- Subthyroidism (acquired)
- Succenturiate placenta, O43.19-
- Sucking thumb, child (excessive), F98.8
- Sudamen, sudamina, L74.1
- Sudanese kala-azar, B55.0
- Sudden
- Sudeck\’s atrophy, disease, or syndrome
- Suffocation
- Sugar
- Suicide, suicidal (attempted), T14.91
- Suipestifer infection
- Sulfhemoglobinemia, sulphemoglobinemia (acquired) (with methemoglobinemia), D74.8
- Sumatran mite fever, A75.3
- Summer
- Sunburn, L55.9
- SUNCT (short lasting unilateral neuralgiform headache with conjunctival injection and tearing), G44.059
- Sundowning, F05
- Sunken acetabulum
- Sunstroke, T67.01
- Superfecundation
- Superfetation
- Superinvolution (uterus), N85.8
- Supernumerary (congenital)
- Supervision (of)
- Supplemental teeth, K00.1
- Suppression
- Suppuration, suppurative
- Supraeruption of tooth (teeth), M26.34
- Supraglottitis, J04.30
- Suprarenal (gland)
- Suprascapular nerve
- Suprasellar
- Surfer\’s knots or nodules, S89.8-
- Surgical
- Surveillance (of) (for)
- Susceptibility to disease, genetic, Z15.89
- Suspected condition, ruled out
- Suspended uterus
- Sutton\’s nevus, D22.9
- Suture
- Swab inadvertently left in operation wound
- Swallowed, swallowing
- Swan-neck deformity (finger)
- Swearing, compulsive, F42.8
- Sweat, sweats
- Sweating, excessive, R61
- Sweeley-Klionsky disease, E75.21
- Sweet\’s disease or dermatosis, L98.2
- Swelling (of), R60.9
- Swift disease (-Feer)
- Swimmer\’s
- Swimming in the head, R42
- Swollen
- Swyer syndrome, Q99.1
- Sycosis, L73.8
- Sydenham\’s chorea
- Sylvatic yellow fever, A95.0
- Sylvest\’s disease, B33.0
- Symblepharon, H11.23-
- Symond\’s syndrome, G93.2
- Sympathetic
- Sympatheticotonia, G90.8
- Sympathicoblastoma
- Sympathogonioma
- Symphalangy (fingers) (toes), Q70.9
- Symptoms NEC, R68.89
- Sympus, Q74.2
- Syncephalus, Q89.4
- Synchondrosis
- Synchysis (scintillans) (senile) (vitreous body), H43.89
- Syncope (near) (pre-), R55
- Syndactylism, syndactyly, Q70.9
- Syndrome
- Synechia (anterior) (iris) (posterior) (pupil)
- Synesthesia, R20.8
- Syngamiasis, syngamosis, B83.3
- Synodontia, K00.2
- Synorchidism, synorchism, Q55.1
- Synostosis (congenital), Q78.8
- Synovial sarcoma
- Synovioma (malignant)
- Synoviosarcoma
- Synovitis, M65.9
- Syphilid, A51.39
- Syphilis, syphilitic (acquired), A53.9
- Syphiloma, A52.79
- Syphilophobia, F45.29
- Syringadenoma
- Syringobulbia, G95.0
- Syringocystadenoma
- Syringoma
- Syringomyelia, G95.0
- Syringomyelitis
- Syringomyelocele
- Syringopontia, G95.0
- System, systemic
- Systemic exertion intolerance disease [SEID], G93.32