Are flashcards effective for COMLEX Level 1?

Yes. Flashcards use active recall — retrieving an answer from memory — which research shows is one of the most effective ways to make facts stick, especially in short sessions spread over several days. That matters for the COMLEX rule sets: the sympathetic levels, the four tenets, Fryette's principles, and the OMT technique definitions.

What topics do the COMLEX Level 1 flashcards cover?

Both dimensions of the blueprint: the foundational sciences within Application of Knowledge (anatomy, physiology, biochemistry, microbiology and immunology, pathology, pharmacology) and the distinctive osteopathic content — the tenets, five models, somatic dysfunction, viscerosomatic reflexes, Chapman's points, and OMT techniques like muscle energy, counterstrain, and HVLA.

Do these flashcards reflect what COMLEX actually tests?

Yes. Every card is written to the level the NBOME expects of an osteopathic medical student progressing toward licensure — the high-yield mechanisms, the rule sets, and the osteopathic principles — and the science is framed the way COMLEX tests it, through clinical presentations.

How should I study with these flashcards?

Mix the modes: flip to learn, type to test recall, match for speed, and quiz to check yourself. Spend most of your time on the foundational sciences (about 60% of the exam), and treat the OMM cards — autonomic levels, tenets, models, technique definitions — as guaranteed points to bank.

Are the COMLEX Level 1 flashcards free?

Yes — 100% free, all four study modes, no paywall.

The four signs of somatic dysfunction: Tissue texture change, Asymmetry, Restriction of motion, Tenderness.

Sympathetic outflow levels

T1–L2 (thoracolumbar) — ALL sympathetic preganglionic cell bodies are here.

Parasympathetic outflow

Craniosacral: cranial nerves III, VII, IX, X and sacral S2–S4.

Four tenets of osteopathic medicine

1) Body is a unit; 2) self-regulation/self-healing; 3) structure & function interrelated; 4) rational treatment based on these three.

Five osteopathic models

Biomechanical, Respiratory–Circulatory, Neurological, Metabolic–Energy, Behavioral.

Somatic dysfunction (definition)

Impaired or altered function of related components of the somatic system: skeletal, arthrodial, myofascial structures + their vascular, lymphatic, neural elements.

Sensitivity (tenderness), Tissue texture change, Asymmetry, Restriction of motion — same findings as TART.

Fryette Type I dysfunction

Neutral spine; rotation & sidebending to OPPOSITE sides; a GROUP of vertebrae; often chronic compensatory curve.

Fryette Type II dysfunction

Flexed or extended spine; rotation & sidebending to the SAME side; usually a SINGLE vertebra; often acute (named FRS or ERS).

Fryette's third principle

Initiating motion in one plane reduces the range of motion in the other two planes.

Naming somatic dysfunction

By the direction of FREEST motion (where the segment moves best), not the restriction.

The point in the range of motion where motion is limited by the dysfunction — short of the anatomic barrier.

The limit of active motion the patient can produce voluntarily.

The limit of passive motion set by bone/ligament — beyond it, injury occurs.

Somatovisceral reflex

Somatic (musculoskeletal) input that produces an altered visceral function — the reverse of viscerosomatic.

Tender, smooth, firm neurolymphatic nodules at predictable anterior/posterior sites; each points to a specific organ.

Facilitation (osteopathic)

A spinal segment held at a lowered firing threshold, perpetuating heightened sympathetic output to related tissues.

Heart sympathetic level

T1–T5 — basis of the cardiac viscerosomatic reflex.

Lung sympathetic level

T2–T7 — pulmonary viscerosomatic reflex.

Foregut sympathetic level

T5–T9 (stomach, liver, gallbladder, spleen, proximal duodenum).

Midgut & kidney sympathetic level

T10–T11 (small bowel to proximal colon, kidney, upper ureter).

Hindgut & pelvis sympathetic level

T12–L2 (descending/sigmoid colon, bladder, reproductive organs).

Head & neck sympathetic level

T1–T4 — fibers ascend the chain to the superior cervical ganglion.

Vagus nerve (CN X) territory

Parasympathetic supply to head, neck, thorax, and abdomen to the splenic flexure (proximal 2/3 of transverse colon).

Pelvic splanchnics (S2–S4)

Parasympathetic supply to the descending colon, pelvis, bladder, and reproductive organs.

Adrenal medulla innervation

Preganglionic sympathetic fibers synapse directly on chromaffin cells (no postganglionic neuron) — they ARE modified neurons.

Acute vs chronic tissue texture

Acute: warm, boggy, edematous. Chronic: cool, ropy, fibrotic.

Zink common compensatory pattern

Alternating fascial preferences at the 4 transition zones (OA, cervicothoracic, thoracolumbar, lumbosacral): L/R/L/R.

Sacral diagnosis tests

Seated flexion test localizes sacroiliac (sacrum on ilium) dysfunction; standing flexion test localizes iliosacral.

Structure–function tenet

A structural problem can impair function, and altered function can change structure — they are reciprocal.

DIRECT technique: patient actively contracts against the physician's counterforce; post-isometric relaxation lets the barrier be re-engaged.

INDIRECT technique: position into ease away from the tender point, hold ~90 seconds, then slowly return to neutral.

Counterstrain return rule

Return the patient to neutral SLOWLY and passively, or the tender point/dysfunction can recur.

High-Velocity, Low-Amplitude — DIRECT: a quick, short thrust through the restrictive barrier, often with an audible cavitation.

Cavitation — release of gas from the synovial joint, NOT a bone moving back into place.

HVLA absolute contraindication

Bony instability: e.g., spinal metastasis, fracture, severe osteoporosis, or atlantoaxial instability (Down syndrome, RA).

Can be DIRECT (load fascia to its barrier) or INDIRECT (move into ease); felt as palpable tissue softening (creep/release).

Based on the primary respiratory mechanism / cranial rhythmic impulse palpated at the sphenobasilar synchondrosis.

A sequenced articulatory treatment for the shoulder (glenohumeral joint), patient in lateral recumbent.

Lymphatic pump (thoracic/pedal)

Promotes lymph flow; avoid directly over an acute infection site or in fragile patients who cannot tolerate it.

Combines an INDIRECT start (into ease) with a final DIRECT movement through the barrier.

Facilitated positional release (FPR)

Indirect: neutral position + compression/torsion to shorten tissue, then move into ease for ~3–5 seconds.

Soft tissue technique

Stretch, kneading, or inhibition of hypertonic muscle — addresses myofascial tissue, not the bony segment directly.

Articulatory technique (LVHA)

Low-Velocity, High-Amplitude: repetitive springing through the restrictive barrier to restore range of motion.

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TART: The four signs of somatic dysfunction: Tissue texture change, Asymmetry, Restriction of motion, Tenderness.
Sympathetic outflow levels: T1–L2 (thoracolumbar) — ALL sympathetic preganglionic cell bodies are here.
Parasympathetic outflow: Craniosacral: cranial nerves III, VII, IX, X and sacral S2–S4.
Four tenets of osteopathic medicine: 1) Body is a unit; 2) self-regulation/self-healing; 3) structure & function interrelated; 4) rational treatment based on these three.
Five osteopathic models: Biomechanical, Respiratory–Circulatory, Neurological, Metabolic–Energy, Behavioral.
Somatic dysfunction (definition): Impaired or altered function of related components of the somatic system: skeletal, arthrodial, myofascial structures + their vascular, lymphatic, neural elements.
STAR mnemonic: Sensitivity (tenderness), Tissue texture change, Asymmetry, Restriction of motion — same findings as TART.
Fryette Type I dysfunction: Neutral spine; rotation & sidebending to OPPOSITE sides; a GROUP of vertebrae; often chronic compensatory curve.
Fryette Type II dysfunction: Flexed or extended spine; rotation & sidebending to the SAME side; usually a SINGLE vertebra; often acute (named FRS or ERS).
Fryette's third principle: Initiating motion in one plane reduces the range of motion in the other two planes.
Naming somatic dysfunction: By the direction of FREEST motion (where the segment moves best), not the restriction.
Restrictive barrier: The point in the range of motion where motion is limited by the dysfunction — short of the anatomic barrier.
Physiologic barrier: The limit of active motion the patient can produce voluntarily.
Anatomic barrier: The limit of passive motion set by bone/ligament — beyond it, injury occurs.
Viscerosomatic reflex: Diseased organ → afferent input at its sympathetic level → paraspinal tissue texture change, tenderness, restriction.
Somatovisceral reflex: Somatic (musculoskeletal) input that produces an altered visceral function — the reverse of viscerosomatic.
Chapman's points: Tender, smooth, firm neurolymphatic nodules at predictable anterior/posterior sites; each points to a specific organ.
Facilitation (osteopathic): A spinal segment held at a lowered firing threshold, perpetuating heightened sympathetic output to related tissues.
Heart sympathetic level: T1–T5 — basis of the cardiac viscerosomatic reflex.
Lung sympathetic level: T2–T7 — pulmonary viscerosomatic reflex.
Foregut sympathetic level: T5–T9 (stomach, liver, gallbladder, spleen, proximal duodenum).
Midgut & kidney sympathetic level: T10–T11 (small bowel to proximal colon, kidney, upper ureter).
Hindgut & pelvis sympathetic level: T12–L2 (descending/sigmoid colon, bladder, reproductive organs).
Head & neck sympathetic level: T1–T4 — fibers ascend the chain to the superior cervical ganglion.
Vagus nerve (CN X) territory: Parasympathetic supply to head, neck, thorax, and abdomen to the splenic flexure (proximal 2/3 of transverse colon).
Pelvic splanchnics (S2–S4): Parasympathetic supply to the descending colon, pelvis, bladder, and reproductive organs.
Adrenal medulla innervation: Preganglionic sympathetic fibers synapse directly on chromaffin cells (no postganglionic neuron) — they ARE modified neurons.
Acute vs chronic tissue texture: Acute: warm, boggy, edematous. Chronic: cool, ropy, fibrotic.
Zink common compensatory pattern: Alternating fascial preferences at the 4 transition zones (OA, cervicothoracic, thoracolumbar, lumbosacral): L/R/L/R.
Sacral diagnosis tests: Seated flexion test localizes sacroiliac (sacrum on ilium) dysfunction; standing flexion test localizes iliosacral.
Structure–function tenet: A structural problem can impair function, and altered function can change structure — they are reciprocal.
Muscle energy: DIRECT technique: patient actively contracts against the physician's counterforce; post-isometric relaxation lets the barrier be re-engaged.
Counterstrain: INDIRECT technique: position into ease away from the tender point, hold ~90 seconds, then slowly return to neutral.
Counterstrain return rule: Return the patient to neutral SLOWLY and passively, or the tender point/dysfunction can recur.
HVLA: High-Velocity, Low-Amplitude — DIRECT: a quick, short thrust through the restrictive barrier, often with an audible cavitation.
HVLA 'pop' cause: Cavitation — release of gas from the synovial joint, NOT a bone moving back into place.
HVLA absolute contraindication: Bony instability: e.g., spinal metastasis, fracture, severe osteoporosis, or atlantoaxial instability (Down syndrome, RA).
Myofascial release: Can be DIRECT (load fascia to its barrier) or INDIRECT (move into ease); felt as palpable tissue softening (creep/release).
Cranial osteopathy: Based on the primary respiratory mechanism / cranial rhythmic impulse palpated at the sphenobasilar synchondrosis.
Spencer technique: A sequenced articulatory treatment for the shoulder (glenohumeral joint), patient in lateral recumbent.
Lymphatic pump (thoracic/pedal): Promotes lymph flow; avoid directly over an acute infection site or in fragile patients who cannot tolerate it.
Still technique: Combines an INDIRECT start (into ease) with a final DIRECT movement through the barrier.
Facilitated positional release (FPR): Indirect: neutral position + compression/torsion to shorten tissue, then move into ease for ~3–5 seconds.
Soft tissue technique: Stretch, kneading, or inhibition of hypertonic muscle — addresses myofascial tissue, not the bony segment directly.
Articulatory technique (LVHA): Low-Velocity, High-Amplitude: repetitive springing through the restrictive barrier to restore range of motion.
Direct vs indirect (rule): Direct = engage the restrictive barrier; Indirect = move away from it, into the position of ease.
Reciprocal inhibition: Contracting a muscle reflexively relaxes its antagonist — the principle some muscle-energy variants use.
Rib raising: Soft-tissue/articulatory technique along the paraspinals thought to normalize sympathetic tone and aid lymphatic flow.
Exhaled (depressed) rib: Rib held DOWN; moves freely on exhalation, restricted on inhalation; treat the KEY rib (the top one of a group).
Inhaled (elevated) rib: Rib held UP; moves freely on inhalation, restricted on exhalation; treat the BOTTOM rib of the group.
OMT selection rule: Technique choice is guided primarily by the patient (acuity, age, frailty, contraindications), not personal preference.
Psoas syndrome treatment: Counterstrain to the psoas/iliacus tender point is a gentle, effective approach when direct techniques aren't tolerated.
Erb–Duchenne palsy: Upper trunk injury (C5–C6): 'waiter's tip' posture — arm adducted, internally rotated, forearm pronated.
Klumpke palsy: Lower trunk injury (C8–T1): claw hand from intrinsic hand muscle paralysis.
Radial nerve injury: Mid-shaft humeral fracture or 'Saturday night palsy' → wrist drop (loss of extensors).
Axillary nerve injury: Surgical-neck humeral fracture / anterior shoulder dislocation → deltoid weakness, lateral shoulder numbness.
Median nerve injury: Carpal tunnel / supracondylar fracture → thenar wasting, loss of thumb opposition.
Ulnar nerve injury: Medial epicondyle or hook of hamate → claw hand, weak grip, sensory loss to digits 4–5.
Common peroneal nerve injury: Fibular neck injury / leg crossing → foot drop (loss of dorsiflexion and eversion).
Horner syndrome: Interruption of the cervical sympathetic chain: ptosis, miosis, anhidrosis (± enophthalmos).
Trigeminal nerve (CN V): Facial sensation (3 divisions) + muscles of mastication; trigeminal neuralgia = brief, electric, lancinating facial pain.
Brachial plexus roots: C5, C6, C7, C8, T1 → trunks, divisions, cords, branches.
Phrenic nerve: C3, C4, C5 — 'keep the diaphragm alive'; supplies the diaphragm.
Recurrent laryngeal nerve: Branch of vagus (CN X); injury → hoarseness; loops under the aortic arch (left) and subclavian (right).
Long thoracic nerve: C5–C7; injury → winged scapula (serratus anterior palsy).
Cremasteric reflex: L1–L2 (genitofemoral nerve); absent reflex is a sign of testicular torsion.
Carpal tunnel contents: Median nerve + 9 flexor tendons (4 FDS, 4 FDP, 1 FPL); compression → median neuropathy.
Pharyngeal (branchial) arch 1: Gives the muscles of mastication, malleus & incus, maxillary/mandibular processes (CN V).
Diaphragm openings: T8 IVC (vena cava), T10 esophagus (+ vagus), T12 aorta (+ thoracic duct, azygos).
Cardiac action potential phase 0: Rapid Na⁺ influx → depolarization (in ventricular myocytes).
Cardiac action potential phase 2: Plateau: Ca²⁺ influx balances K⁺ efflux — sustains contraction.
Cardiac action potential phase 3: Repolarization from K⁺ efflux.
SA node phase 4: Spontaneous diastolic depolarization ('funny' Na⁺ current + Ca²⁺) — sets heart rate.
Resting vagal tone: High parasympathetic tone keeps the heart rate BELOW the SA node's intrinsic rate (~100/min).
Carotid sinus massage: ↑ vagal tone → slows AV conduction; can terminate some supraventricular tachycardias.
Proximal convoluted tubule: Reabsorbs the LARGEST fraction of filtered Na⁺, water, glucose, amino acids, and bicarbonate.
Juxtaglomerular apparatus: Secretes renin in response to ↓ renal perfusion, ↓ NaCl at the macula densa, and sympathetic input.
RAAS cascade: Renin → angiotensin I → (ACE) → angiotensin II → vasoconstriction + aldosterone → Na⁺/water retention.
Inulin clearance: Estimates GFR because inulin is freely filtered and neither reabsorbed nor secreted.
Anion gap: Na⁺ − (Cl⁻ + HCO₃⁻); a high anion gap acidosis points to added acid (DKA, lactate, toxins).
Thiazide + vomiting: Hypokalemic, contraction metabolic alkalosis maintained by volume/chloride depletion + hyperaldosteronism.
Respiratory acidosis compensation: Kidneys retain bicarbonate over days (chronic COPD).
Alpha-1 receptor effect: Vascular smooth muscle contraction → vasoconstriction, ↑ blood pressure.
Beta-1 receptor effect: ↑ heart rate, ↑ contractility, ↑ renin release.
Beta-2 receptor effect: Bronchodilation, vasodilation in skeletal muscle, uterine relaxation.
Acetylcholine at autonomic ganglia: Acts on NICOTINIC receptors (all preganglionic fibers are cholinergic).
Frank–Starling law: ↑ ventricular filling (preload) → ↑ stroke volume, up to a physiologic limit.
Excitation–contraction coupling: Dihydropyridine receptor (T-tubule) triggers the ryanodine receptor to release Ca²⁺ from the SR.
Rate-limiting step of glycolysis: Phosphofructokinase-1 (PFK-1) — the committed step.
Net yield of glycolysis: Per glucose: 2 ATP + 2 NADH + 2 pyruvate (in the cytoplasm).
Krebs cycle yield (one turn): 3 NADH, 1 FADH₂, 1 GTP, and 2 CO₂ released.
Citrate formation: Acetyl-CoA (2 carbons) condenses with oxaloacetate (4 carbons) to form citrate (6 carbons).
Oxidative phosphorylation: NADH/FADH₂ donate electrons to the ETC; the proton gradient drives ATP synthase — most cellular ATP.
Michaelis constant (Km): Substrate concentration at ½ Vmax; LOW Km = HIGH affinity.
Competitive inhibitor: ↑ apparent Km, Vmax UNCHANGED (overcome by more substrate).
Non-competitive inhibitor: ↓ Vmax, Km UNCHANGED.
Lineweaver–Burk plot: Double-reciprocal (1/V vs 1/[S]); x-intercept = −1/Km, y-intercept = 1/Vmax.
Pyruvate kinase deficiency: Impairs the last ATP step of glycolysis → hemolytic anemia (RBCs rely on glycolysis).
Rate-limiting enzyme of TCA cycle: Isocitrate dehydrogenase.
Philadelphia chromosome: t(9;22) BCR-ABL fusion → constitutive tyrosine kinase; chronic myeloid leukemia.
Cori cycle: Lactate from muscle → liver → gluconeogenesis → glucose back to muscle.
Enzyme & temperature: Rate rises with temperature only until the enzyme denatures, then falls sharply.
Spindle assembly checkpoint: At metaphase→anaphase: ensures all chromosomes are attached to the spindle before separation.
Gram-positive cell wall: Thick peptidoglycan; retains crystal violet → stains PURPLE.
Gram-negative cell wall: Thin peptidoglycan + outer membrane with LPS (endotoxin); stains PINK with safranin.
Catalase test: Staphylococcus (catalase +) vs Streptococcus (catalase −).
Coagulase test: S. aureus (coagulase +) vs S. epidermidis / S. saprophyticus (coagulase −).
Alpha vs beta hemolysis: Alpha = partial (green, e.g. S. pneumoniae, viridans); beta = complete clearing (e.g. S. pyogenes).
Listeria monocytogenes: Gram-positive rod with tumbling motility; grows at cold temperatures; risky in pregnancy/neonates.
Pseudomonas aeruginosa: Gram-negative, oxidase +, blue-green pigment; resistant; treat with antipseudomonal beta-lactams.
Strep mutans: Gram-positive, catalase-negative, alpha-hemolytic; causes dental caries and subacute endocarditis.
Endotoxin (LPS): Lipid A of gram-negative outer membrane; triggers fever, hypotension, and septic shock.
Type I hypersensitivity: Immediate, IgE-mediated: anaphylaxis, allergies, atopy, allergic asthma.
Type II hypersensitivity: Antibody (IgG/IgM) vs cell-surface antigen: autoimmune hemolytic anemia, Goodpasture.
Type III hypersensitivity: Immune complexes deposit: serum sickness, Arthus reaction, SLE.
Type IV hypersensitivity: Delayed, T-cell mediated (no antibody): PPD/TB test, contact dermatitis, graft rejection.
ACID mnemonic: Hypersensitivity: Anaphylactic (I), Cytotoxic (II), Immune complex (III), Delayed (IV).
C3a and C5a: Anaphylatoxins; C5a is also a potent neutrophil chemoattractant.
Allergen immunotherapy: Gradual desensitization shifts response from IgE toward IgG and induces tolerance.
Second allergen exposure: More severe because memory IgE is already bound to mast cells (sensitized).
Coombs (antiglobulin) test: Detects antibodies on or against red blood cells (direct = on RBCs; indirect = in serum).
Apoptosis: Programmed, ATP-dependent death of single cells WITHOUT inflammation; membrane stays intact.
Necrosis: Unregulated death of groups of cells that DOES incite inflammation; membranes rupture.
Five cardinal signs of inflammation: Rubor (redness), calor (heat), tumor (swelling), dolor (pain), functio laesa (loss of function).
Acute inflammation cell: Neutrophils predominate; short-lived.
Chronic inflammation cells: Lymphocytes, plasma cells, macrophages; tissue destruction + repair (fibrosis, angiogenesis).
Defining feature of malignancy: Metastasis — spread to a distant, non-adjacent site.
Benign vs malignant: Benign: well-differentiated, slow, encapsulated, no metastasis. Malignant: poorly differentiated, invasive, metastasizes.
Carcinoma spread: Epithelial origin; spreads FIRST via lymphatics.
Sarcoma spread: Mesenchymal origin; spreads FIRST hematogenously.
Transudate vs exudate: Transudate: low protein (↑ hydrostatic / ↓ oncotic). Exudate: high protein/cells (inflammation, ↑ permeability).
Granuloma: Organized collection of activated macrophages (epithelioid) — type IV reaction (TB, sarcoid, fungi).
Caseous necrosis: Cheese-like; classic for tuberculosis.
Hypertrophy vs hyperplasia: Hypertrophy = bigger cells; hyperplasia = more cells.
Metaplasia: Reversible change of one mature cell type to another (e.g., Barrett esophagus: squamous → columnar).
Functio laesa: Loss of function — the fifth cardinal sign of inflammation.
Bethanechol: Muscarinic agonist; treats postoperative urinary retention and neurogenic bladder (stimulates the bladder).
Class I antiarrhythmics: Na⁺ channel blockers (quinidine, lidocaine, flecainide).
Class II antiarrhythmics: Beta-blockers (metoprolol) — rate control + post-MI mortality benefit.
Class III antiarrhythmics: K⁺ channel blockers (amiodarone, sotalol) — prolong repolarization.
Class IV antiarrhythmics: Non-dihydropyridine Ca²⁺ channel blockers (verapamil, diltiazem) — rate control in atrial fibrillation.
Dobutamine: Beta-1 agonist; ↑ contractility in acute decompensated heart failure.
Norepinephrine receptor profile: Strong alpha + beta-1; weak beta-2 → vasoconstriction with some inotropy (first-line in septic shock).
Statins: Competitively inhibit HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis.
Probenecid + penicillin: Probenecid blocks renal tubular secretion of penicillin → higher, longer-lasting blood levels.
First-order elimination: Constant FRACTION removed per unit time; rate ∝ concentration; constant half-life (most drugs).
Zero-order elimination: Constant AMOUNT removed per unit time (saturated): ethanol, phenytoin, high-dose aspirin.
Half-life: Time for concentration to fall by half; only constant/meaningful in first-order kinetics.
Digoxin use: Rate control in atrial fibrillation and inotropy in heart failure; narrow therapeutic index.
Carbamazepine: First-line for trigeminal neuralgia; blocks voltage-gated Na⁺ channels.
Cholinergic crisis: Excess cholinesterase inhibitor → SLUDGE (salivation, lacrimation, urination, defecation, GI, emesis) + muscle weakness.
Epinephrine + antihistamine in anaphylaxis: Epinephrine reverses the life-threat (airway/BP); antihistamines treat the milder histamine symptoms.
Sensitivity: Proportion WITH disease who test positive (true-positive rate); a negative SENSitive test rules OUT (SnNout).
Specificity: Proportion WITHOUT disease who test negative (true-negative rate); a positive SPecific test rules IN (SpPin).
Positive predictive value: Of those who test positive, the proportion who truly have disease; FALLS as prevalence falls.
Negative predictive value: Of those who test negative, the proportion who are truly disease-free; RISES as prevalence falls.
Likelihood ratios: Independent of prevalence; LR+ > 10 strongly rules in, LR− < 0.1 strongly rules out.
Relative risk (RR): Risk in exposed ÷ risk in unexposed; used in cohort studies. RR = 1 means no association.
Odds ratio (OR): Used in case-control studies; approximates RR when the disease is rare.
Number needed to treat: NNT = 1 ÷ absolute risk reduction; how many to treat to prevent one outcome.
Type I error: Rejecting a true null hypothesis (a false positive); its probability is alpha.
Type II error: Failing to reject a false null (a false negative); its probability is beta; power = 1 − beta.
p-value: Probability of seeing the data (or more extreme) if the null were true; < 0.05 is conventionally significant.
Confidence interval: If it crosses the null value (1 for RR/OR, 0 for a difference), the result is not significant.
Confounding control: Randomization, restriction, matching (design) and stratification/multivariable analysis (analysis).
Cohort vs case-control: Cohort follows exposure → outcome (incidence, RR); case-control starts from outcome → exposure (OR).
Informed consent: A patient with capacity voluntarily agrees after disclosure of risks, benefits, and alternatives.
Incidence vs prevalence: Incidence = NEW cases over time; prevalence = ALL existing cases at a point in time.
Sphenobasilar synchondrosis (SBS): The cranial articulation between the sphenoid and occiput; central to the cranial concept and cranial strain patterns.
Cranial flexion phase: Midline bones (sphenoid, occiput) flex; paired bones externally rotate; the body widens and shortens.
Primary respiratory mechanism: The 5 components: CNS motility, CSF fluctuation, dural membrane mobility, cranial bone motion, and involuntary sacral motion.
Forward sacral torsion: Named by axis: e.g., left-on-left; treat with muscle energy, often patient in Sims (lateral) position.
Backward sacral torsion: e.g., left-on-right; differs from a forward torsion in the seated flexion test side and the deep sulcus location.
Type I curve trigger: A neutral group curve often arises to compensate for a Type II dysfunction or a structural asymmetry (e.g., short leg).
Otitis media Chapman's point: Anterior Chapman's point classically maps to upper-respiratory/ear congestion problems.
Appendix Chapman's point: Anterior Chapman's point near the tip of the right 12th rib is associated with the appendix.
Posterior Chapman's points: Generally found in the paravertebral region (near the transverse processes/spinous processes).
Tissue texture change examples: Bogginess, ropiness, edema, temperature change, increased/decreased moisture — the 'T' of TART.
Asymmetry in somatic dysfunction: Positional asymmetry of related parts of the musculoskeletal system (the 'A' of TART).
Restriction of motion: Limited or asymmetric range of motion of a segment (the 'R' of TART).
Neurological model goal: Address autonomic balance and reduce nociception/facilitation.
Respiratory–circulatory model goal: Maintain the flow of body fluids — lymph, blood, and cerebrospinal fluid.
Metabolic–energy model goal: Optimize energy expenditure and support immune and metabolic function.
Behavioral model goal: Address mind–body, psychosocial, and lifestyle contributors to health.
Femoral triangle (NAVEL): Lateral → medial: femoral Nerve, Artery, Vein, Empty space, Lymphatics.
Rotator cuff (SITS): Supraspinatus, Infraspinatus, Teres minor, Subscapularis.
Cauda equina syndrome: Compression below the conus: saddle anesthesia, bowel/bladder dysfunction, lower-limb weakness — a surgical emergency.
Sciatic nerve roots: L4–S3; the largest nerve; divides into tibial and common peroneal nerves.
Cranial nerve VII (facial): Motor to muscles of facial expression; lesion → ipsilateral facial droop (Bell palsy spares the forehead if central).
Cranial nerve X (vagus): Parasympathetic to thoracic/abdominal viscera; motor to pharynx/larynx; sensory from the same.
Suprascapular nerve: From the upper trunk; injury weakens supraspinatus (abduction initiation) and infraspinatus (external rotation).
Thoracic duct: Drains lymph from most of the body into the left subclavian/internal jugular junction; enters thorax via the aortic hiatus (T12).
Coronary artery dominance: ~85% right-dominant: the posterior descending artery arises from the right coronary artery.
Hemoglobin–oxygen curve right shift: ↑ CO₂, ↑ temperature, ↑ 2,3-BPG, ↓ pH (Bohr effect) → easier O₂ unloading to tissues.
Hemoglobin–oxygen curve left shift: ↓ CO₂, ↓ temperature, ↓ 2,3-BPG, ↑ pH, fetal hemoglobin → tighter O₂ binding.
Aldosterone action: Distal nephron: reabsorb Na⁺/water, secrete K⁺ and H⁺.
ADH (vasopressin) action: Inserts aquaporins in the collecting duct → water reabsorption; from the posterior pituitary.
Loop of Henle (thick ascending): Reabsorbs Na⁺/K⁺/2Cl⁻ (the loop-diuretic target); impermeable to water.
Starling forces (edema): ↑ capillary hydrostatic pressure or ↓ plasma oncotic pressure (low albumin) → net filtration → edema.
Compliance of the lung: Change in volume per change in pressure; ↓ in fibrosis, ↑ in emphysema.
Insulin effect on potassium: Drives K⁺ INTO cells (used to treat hyperkalemia, given with glucose).
Baroreceptor reflex: ↑ BP stretches carotid sinus → ↑ vagal tone, ↓ sympathetic → ↓ HR and ↓ BP.
Countercurrent multiplier: The loop of Henle establishes the medullary osmotic gradient that lets the kidney concentrate urine.
Gluconeogenesis key enzymes: Pyruvate carboxylase, PEP carboxykinase, fructose-1,6-bisphosphatase, glucose-6-phosphatase.
Pentose phosphate pathway: Makes NADPH (biosynthesis, antioxidant) and ribose-5-phosphate (nucleotides); rate-limiting = G6PD.
G6PD deficiency: ↓ NADPH → oxidative hemolysis (Heinz bodies, bite cells) after infection, fava beans, or oxidant drugs.
Beta-oxidation: Breaks fatty acids into acetyl-CoA in mitochondria; carnitine shuttles long-chain fatty acids in.
Urea cycle purpose: Converts toxic ammonia to urea for excretion; defects cause hyperammonemia.
Autosomal dominant pattern: Vertical transmission, each child 50% risk, both sexes affected (e.g., Marfan, Huntington).
Autosomal recessive pattern: Often skips generations; 25% risk with two carriers; consanguinity raises risk (e.g., cystic fibrosis).
X-linked recessive pattern: Males mostly affected, no male-to-male transmission (e.g., hemophilia, Duchenne).
Glycogen storage: von Gierke: Type I (glucose-6-phosphatase deficiency) → severe fasting hypoglycemia, hepatomegaly, lactic acidosis.
Collagen synthesis & vitamin C: Vitamin C is needed for hydroxylation of proline/lysine; deficiency = scurvy (poor wound healing, bleeding gums).
Obligate intracellular bacteria: Rickettsia, Chlamydia ('stay inside when it's Really Cold').
Spore-forming bacteria: Bacillus and Clostridium (gram-positive rods).
Exotoxin vs endotoxin: Exotoxin: secreted protein, often gram-positive, specific effects. Endotoxin: LPS in gram-negative wall, septic shock.
Tuberculosis (acid-fast): Mycobacterium tuberculosis; apical disease, caseating granulomas; treat with RIPE.
Encapsulated organisms: S. pneumoniae, H. influenzae, N. meningitidis — dangerous in asplenic patients; need opsonization.
Herpesviruses (latency): DNA viruses that establish latency (HSV in sensory ganglia, VZV in dorsal root ganglia).
Innate vs adaptive immunity: Innate: fast, non-specific (neutrophils, macrophages, complement). Adaptive: slower, specific, memory (T and B cells).
MHC class I vs II: Class I (all nucleated cells) presents to CD8 T cells; class II (APCs) presents to CD4 T cells.
Th1 vs Th2: Th1 (IFN-γ): intracellular pathogens, macrophage activation. Th2 (IL-4/5): humoral, parasites, allergy.
Live attenuated vaccine: Strong, lasting immunity but contraindicated in pregnancy and immunocompromised (e.g., MMR, varicella).
Selective IgA deficiency: Most common primary immunodeficiency; recurrent sinopulmonary/GI infections; anaphylaxis risk with blood products.
Coagulative necrosis: Architecture preserved (ghost cells); ischemic infarcts of most solid organs.
Liquefactive necrosis: Tissue digested to liquid; brain infarcts and abscesses.
Fat necrosis: Saponification; classic in acute pancreatitis (elevated lipase).
Fibrinoid necrosis: Vessel-wall necrosis; malignant hypertension, vasculitis.
Amyloidosis: Misfolded protein deposits; apple-green birefringence with Congo red under polarized light.
Granulomatous diseases: TB, sarcoidosis, fungal infections, Crohn disease, cat-scratch — type IV reaction.
Dystrophic vs metastatic calcification: Dystrophic: in damaged tissue, normal calcium. Metastatic: in normal tissue, high serum calcium.
Hyperplasia (example): Benign prostatic hyperplasia, endometrial hyperplasia — increased cell NUMBER.
Reversible vs irreversible cell injury: Reversible: cell swelling, blebbing. Irreversible: mitochondrial damage, membrane rupture, Ca²⁺ influx.
Free radical injury: Reactive oxygen species damage lipids, proteins, DNA; defended by superoxide dismutase, catalase, glutathione.
ACE inhibitors: Block angiotensin II formation; ↓ BP, renoprotective; side effects: cough, hyperkalemia, angioedema; avoid in pregnancy.
Beta-blocker effects: ↓ HR, ↓ contractility, ↓ renin; post-MI and heart-failure mortality benefit; caution in asthma (β2).
Loop diuretics: Block Na⁺/K⁺/2Cl⁻ in thick ascending limb (furosemide); ototoxicity, hypokalemia.
Thiazide diuretics: Block Na⁺/Cl⁻ in distal tubule; hypokalemia, hyponatremia, hyperglycemia, hyperuricemia, hypercalcemia.
Warfarin: Inhibits vitamin K epoxide reductase (factors II, VII, IX, X); monitor PT/INR; many interactions.
Heparin: Activates antithrombin III; monitor aPTT; reversed by protamine; risk of HIT.
Aminoglycosides: Bind 30S ribosome (bactericidal); nephrotoxic and ototoxic (e.g., gentamicin).
Beta-lactam mechanism: Inhibit cell-wall synthesis (penicillin-binding proteins); penicillins, cephalosporins, carbapenems.
Acetaminophen toxicity: Depletes glutathione → NAPQI hepatotoxicity; antidote is N-acetylcysteine.
Opioid overdose: Respiratory depression + pinpoint pupils; reverse with naloxone.
SSRIs: First-line for depression/anxiety; risk of serotonin syndrome (autonomic instability, clonus, agitation).
Corticosteroid adverse effects: Hyperglycemia, osteoporosis, immunosuppression, Cushingoid features, adrenal suppression with abrupt withdrawal.
Fagan nomogram: Combines pretest probability with a likelihood ratio to read off the post-test probability.
ROC curve / AUC: Plots sensitivity vs (1 − specificity); a larger area under the curve = better overall test discrimination.
Randomized controlled trial: Gold standard for causation; randomization controls confounding; blinding reduces bias.
Lead-time bias: Earlier detection by screening that lengthens apparent survival without changing the outcome.
Recall bias: Differential accuracy of memory between cases and controls — a classic case-control study flaw.
Selection bias: Non-representative sampling distorts the association (e.g., Berkson, healthy-worker effect).
Statistical power: 1 − beta; increased by a larger sample, larger effect size, or lower variability.
Meta-analysis: Statistically pools results of multiple studies to increase power and precision.
Absolute risk reduction: Control event rate − treatment event rate; NNT = 1 ÷ ARR.
Confidentiality & HIPAA: Protect patient health information; disclose only with consent or a recognized exception (e.g., reportable disease, imminent harm).
Patient autonomy: A competent patient's right to accept or refuse treatment — the basis of informed consent and refusal.
Beneficence vs non-maleficence: Beneficence: act in the patient's best interest. Non-maleficence: 'first, do no harm.'
Muscle energy steps: Diagnose, engage the restrictive barrier, patient contracts ~3–5 s against counterforce, relax, re-engage the new barrier; repeat 3–5×.
Counterstrain anterior tender point: Anterior tender points are generally treated with FLEXION (and fine-tuning of rotation/sidebending) into ease.
Counterstrain posterior tender point: Posterior tender points are generally treated with EXTENSION into the position of ease.
HVLA cervical contraindication: Vertebrobasilar insufficiency and Down syndrome (atlantoaxial instability) are contraindications to cervical HVLA.
Indirect technique principle: Move toward the position of ease (away from the barrier) to allow the dysfunction to release.
Spencer technique position: Patient lateral recumbent, affected shoulder up; physician moves the shoulder through a set sequence of motions.
Thoracic pump precaution: Avoid the lymphatic pump directly over an area of acute infection or a fracture.
Still technique sequence: Start indirect (into ease), add a compressive/distractive force, then carry the segment through the barrier (direct finish).
Rib 1 exhalation dysfunction: First rib held down (exhaled); restricted on inhalation — often involves the anterior/middle scalene.
Key rib (group of ribs): In a group dysfunction, treat the KEY rib: the TOP rib of an exhaled group, the BOTTOM rib of an inhaled group.
Compensated vs uncompensated Zink: Compensated: fascial preferences ALTERNATE at the transition zones; uncompensated: they do not (suggests trauma/pathology).
Somatic dysfunction acuity by reflex: A primary dysfunction is the cause; a secondary (reflex) dysfunction follows from visceral or other input.
Phrenic nerve referred pain: Diaphragmatic irritation refers to the shoulder (C3–C5 shared dermatome) — e.g., subphrenic abscess, ruptured spleen.
Dermatome landmarks: T4 nipple, T10 umbilicus, L1 inguinal region — quick localization of a spinal level.
Anatomic snuffbox: Tenderness suggests a scaphoid fracture (risk of avascular necrosis); contents include the radial artery.
Renal blood flow: Afferent arteriole → glomerulus → efferent arteriole; angiotensin II preferentially constricts the EFFERENT arteriole.
Surfactant: Produced by type II pneumocytes; lowers alveolar surface tension; deficiency → neonatal respiratory distress syndrome.
Penicillin allergy cross-reactivity: Cross-reactivity with cephalosporins is low (especially later generations); avoid all beta-lactams only in severe (anaphylactic) reactions.
Nitrates: Venodilation → ↓ preload; relieve angina; tolerance develops without a nitrate-free interval.
Calcium channel blockers (DHP): Dihydropyridines (amlodipine) act on vascular smooth muscle → vasodilation, peripheral edema.
Spirochetes: Treponema (syphilis), Borrelia (Lyme), Leptospira; thin, spiral organisms.
Anaerobes: Clostridium, Bacteroides, Actinomyces; foul-smelling, abscess-forming; often below the diaphragm.
Apoptosis pathways: Intrinsic (mitochondrial, cytochrome c) and extrinsic (death-receptor, Fas/FasL) — both converge on caspases.
Edema mechanisms: ↑ hydrostatic pressure, ↓ oncotic pressure (low albumin), ↑ capillary permeability, or lymphatic obstruction.
Hypersensitivity II vs III: Type II: antibody binds a FIXED tissue antigen. Type III: antibody binds a SOLUBLE antigen, forming circulating complexes.

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By Career EmployerUpdated Sep 12, 2026

250+ free COMLEX Level 1 flashcards — 4 ways to study

COMLEX Level 1 Flashcard of the DayNew daily

The classic card. Do you know this one?

Click Study Flashcards above to open the flashcard hub — hundreds of COMLEX Level 1 cards you can flip, match, type, or quiz yourself on. Every card is drawn from the foundational biomedical sciences and the osteopathic principles the NBOME tests, so you study exactly what COMLEX Level 1 measures.^[1] Pair them with our free practice questions and study guide.

COMLEX Level 1 Flashcard Study Modes

Flip mode lets you read a front, recall the answer, and check yourself card by card. Type mode shows the definition and asks you to spell the term back, so a front like Viscerosomatic reflex has to come from memory. Match runs a timed term-to-definition pairing game, and Quiz turns the same cards into multiple-choice questions for quick retrieval checks.

Free COMLEX Level 1 flashcards from Career Employer — active recall for the NBOME osteopathic licensing exam

Why Flashcards Work for COMLEX Level 1

Osteopathic Principles & OMM is the biggest block at 51 cards, and it drills the structural diagnosis vocabulary that shows up throughout COMLEX Level 1. You get the diagnostic mnemonics TART and STAR mnemonic, the barrier set including Anatomic barrier, Restrictive barrier, and Physiologic barrier, plus reflex and screening terms such as Chapman’s points and Viscerosomatic reflex.

Microbiology & Immunology brings 32 cards covering organism groups and bench tests, with fronts like Spirochetes, Catalase test, and the immune split in Th1 vs Th2. Physiology adds 31 cards on regulation and renal-cardiac mechanics, including Anion gap, RAAS cascade, and Inulin clearance, so you can attach numbers and pathways to the right concept quickly.

Pharmacology holds 31 cards on drug classes and core kinetics, from Heparin and Warfarin to Half-life and Dobutamine. OMT Techniques covers 29 cards of hands-on modality definitions, including Muscle energy, Counterstrain, and the card that asks about HVLA ’pop’ cause, which pairs directly with the barrier language from the principles domain.

Anatomy & Embryology gives you 29 cards on nerves, landmarks, and classic lesions, including Phrenic nerve, Klumpke palsy, and Anatomic snuffbox. Biostatistics & Competencies adds 28 cards on test characteristics and study design, with Sensitivity, Specificity, and Fagan nomogram among the fronts you will see repeatedly in vignette interpretation.

Pathology rounds out injury and repair language across 27 cards, including Apoptosis, Granuloma, and Fat necrosis. Biochemistry & Genetics closes with 25 cards on metabolic pathways and enzyme behavior, such as Cori cycle, G6PD deficiency, and Lineweaver–Burk plot, which reward repeated short passes rather than one long sitting.

Pair that with spacing — short sessions across several days rather than one cram — and you retain more in less time.

That matters on COMLEX, where rule-based facts like the sympathetic levels (T1–L2), the four tenets, Fryette’s principles, and the OMT technique definitions must be instantly available. Used alongside our practice questions and study guide, flashcards turn review time into measurable progress.

COMLEX Level 1 Flashcards by Topic

The cards are organized by the disciplines you study and the osteopathic content. Most of the exam is foundational science (Application of Knowledge, ~60%), so weight your time there — but make the OMM cards guaranteed points, since they are pure recall:^[1]

COMLEX Level 1 flashcard topics and where they sit in the blueprint
Flashcard topic	Blueprint location
Anatomy & Embryology	Application of Knowledge (~60%)
Physiology	Application of Knowledge
Biochemistry & Genetics	Application of Knowledge
Microbiology & Immunology	Application of Knowledge
Pathology	Application of Knowledge
Pharmacology	Application of Knowledge
Osteopathic Principles & OMM	OPP/OMT — Competency Domain 1 (~12%)
OMT techniques & procedural skills	Osteopathic Patient Care (~6%)
Biostatistics & evidence-based medicine	Practice-Based Learning (~4%)

The osteopathic domains together are roughly 18% of the exam — the content with no equivalent on the USMLE Step 1. Because those facts are rule-based, they are some of the most reliable points you can bank.

How to Get the Most Out of These Flashcards

Start with the osteopathic core. Osteopathic Principles & OMM is the largest domain at 51 cards, and its barrier and reflex language feeds directly into the 29 OMT Techniques cards.
Type-drill the terms you blur together. Force exact recall on Restrictive barrier and Physiologic barrier, since recognizing them in Flip mode is easier than producing the difference under pressure.
Use Match for lookalike lab and test terms. Pairing fronts such as Catalase test and Coagulase test against their definitions quickly exposes which microbiology distinctions you only half know.
Move to the practice test once recall holds. When Quiz mode on a domain stops surprising you, shift to full vignette questions and use the study guide to fill whatever gaps appear.
Keep a rotating cadence. With 283 cards, work one domain per session and re-shuffle older domains in, so Pathology and Biochemistry & Genetics do not go cold while you grind OMM.

COMLEX Level 1 Flashcards FAQ

Hundreds of free COMLEX Level 1 flashcards, spanning the foundational biomedical sciences (anatomy, physiology, biochemistry, microbiology, pathology, pharmacology) and the osteopathic principles and OMM that the NBOME tests. They're free with no account required.

References

1.National Board of Osteopathic Medical Examiners (NBOME). “COMLEX-USA Level 1 — Blueprint & Competencies.” nbome.org. ↑
2.American Osteopathic Association (AOA). “What Is Osteopathic Medicine?.” osteopathic.org. ↑
3.U.S. National Library of Medicine (MedlinePlus). “Autonomic Nervous System.” medlineplus.gov. ↑
4.National Institutes of Health (NIH). “Biochemistry, Citric Acid Cycle.” ncbi.nlm.nih.gov. ↑

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