High-Yield Exam Mnemonics
- “L1-L2, cord is through” – lumbar puncture is safely done below L2 to avoid cord injury.
Recall: The adult spinal cord ends at the lower border of L1 or upper border of L2 vertebra as the conus medullaris.
- Lateral for Locomotion.
Recall: The lateral corticospinal tract (major motor pathway) descends in the lateral column of white matter.
- Nigra in the MID – Missing It causes parkinsonism.
Recall: Substantia nigra is a pigmented nucleus in the midbrain, part of basal ganglia circuitry, producing dopamine.
- MCA = Makes Contralateral Arm weak.
Recall: The middle cerebral artery supplies the lateral surface including face and arm areas of motor cortex.
- VERMIS in the VERYMIDDLE.
Recall: The vermis is the midline structure connecting the two cerebellar hemispheres.
- Luschka = Lateral; Magendie = Medial.
Recall: Two lateral foramina of Luschka and one median foramen of Magendie allow CSF exit from fourth ventricle.
- FACE has SEVEN letters – CN VII.
Recall: CN VII supplies all muscles of facial expression derived from the second pharyngeal arch.
- Parotid duct → Upper 2nd molar; Submandibular duct → lower teeth.
Recall: Stensen’s duct (parotid duct) opens on a papilla opposite the upper second molar tooth.
- MASseter = MAStication (chewing = closing jaw).
Recall: The masseter is the primary elevator of the mandible, assisted by temporalis and medial pterygoid.
- Cricothyroid is the EXCEPTION – External laryngeal.
Recall: Cricothyroid is supplied by the external laryngeal nerve (branch of superior laryngeal nerve).
- V1 and V2 branches supply nasal sensation.
Recall: General sensation to the nasal septum comes from nasopalatine nerve (from V2) and anterior ethmoidal nerve (from V1).
- Parotid = Pure Serous; SubMANdibular = Mixed; SubLINGual = Mainly Mucous.
Recall: The submandibular gland is mixed seromucous with serous demilunes capping mucous acini, predominantly serous.
- First Pouch = Middle Ear.
Recall: The first pharyngeal pouch forms the tubotympanic recess → middle ear cavity and Eustachian tube.
- SO = Superior Oblique = SO4 (CN IV) – looks down at nose.
Recall: Superior oblique (CN IV) depresses the eye when adducted, abducts, and intorts.
- “Glutamate → GABA” – both start with G.
Recall: GABA is synthesized from glutamate by the enzyme glutamate decarboxylase (GAD), which requires pyridoxal phosphate (vitamin B6).
- Ketones Keep brain alive during starvation.
Recall: During prolonged fasting/starvation, ketone bodies (acetoacetate and β-hydroxybutyrate) become the major alternative fuel for the brain.
- Niemann-Pick = No sPhingomyelinase.
Recall: Niemann-Pick disease (Type A and B) results from sphingomyelinase deficiency, causing sphingomyelin accumulation.
- CSF protein is Low (15-45).
Recall: Normal CSF protein is 15-45 mg/dL, much lower than plasma due to the blood-brain barrier.
- PLA2 at position 2 releases arachidonic acid.
Recall: Phospholipase A2 cleaves arachidonic acid from the sn-2 position of membrane phospholipids, initiating eicosanoid synthesis.
- Purines → Uric acid (PU).
Recall: Humans lack uricase, so uric acid is the final product of purine catabolism.
- Okazaki on the Opposite (lagging) strand.
Recall: Okazaki fragments are short DNA segments synthesized discontinuously on the lagging strand (3′ to 5′ template direction).
- tRNA transports amino acids.
Recall: Transfer RNA (tRNA) carries specific amino acids to the ribosome, matching them to mRNA codons via anticodons. mRNA carries genetic information. rRNA forms ribosomes. snRNA is involved in splicing.
- Denaturation = Dang hot (94-98°C).
Recall: Denaturation occurs at 94-98°C to separate DNA strands.
- Alpha = Big Alpha dogs = Large neurons for large muscle movements.
Recall: Alpha motor neurons are large multipolar cells in the anterior horn with prominent Nissl bodies that directly innervate extrafusal skeletal muscle fibers.
- PICA = Posterior Inferior = Lateral medulla.
Recall: This is lateral medullary syndrome (Wallenberg syndrome) caused by PICA occlusion.
- Nigra’s Compacta Produces Dopamine for Parkinson’s.
Recall: The substantia nigra pars compacta contains dopaminergic neurons that form the nigrostriatal pathway, projecting to the striatum (caudate and putamen).
- Tele = Two cerebral hemispheres; failure = Holoprosencephaly (One brain).
Recall: The telencephalon develops into cerebral hemispheres, cerebral cortex, basal ganglia, hippocampus, and olfactory structures.
- Layer 5 = Pyramids Move (corticospinal motor output).
Recall: Layer V (internal pyramidal layer) contains large pyramidal neurons, including Betz cells in the primary motor cortex.
- SubThalamic = Sudden wild Throwing movements (hemiballismus).
Recall: The subthalamic nucleus (STN) excites the GPi via glutamate in the indirect pathway.
- Granules Go up and Go Parallel to tickle Purkinje dendrites.
Recall: Granule cell axons ascend to the molecular layer and bifurcate to form parallel fibers, which run perpendicular to Purkinje cell dendritic trees.
- Choroid = Pia + Ependyma = Production factory in L, 3rd, and 4th.
Recall: Choroid plexus is present in the lateral ventricles (body and inferior horn), third ventricle (roof), and fourth ventricle (roof).
- Hyperacusis = Hole in the canal (stapedius branch damaged).
Recall: Hyperacusis indicates loss of the stapedius muscle function (nerve to stapedius).
- Lateral pterygoid paralysis = Jaw goes to the Lesion side.
Recall: The lateral pterygoid muscles work together to protrude the mandible and open the mouth.
- Chin to subMental (M for Midline chin).
Recall: The central lower lip and chin drain to submental lymph nodes (below the chin between the anterior bellies of digastric).
- Lateral ligament = Limits going too far forward.
Recall: The upper compartment allows translation (gliding) of the disc-condyle complex on the articular eminence during wide opening and protrusion.
- Marginal Mandibular = Moves the Lower lip down.
Recall: The marginal mandibular branch courses along the lower border of the mandible and supplies muscles of the lower lip including depressor anguli oris, depressor labii inferioris, and mentalis.
- Thyroglossal = Tongue (foramen cecum) Goes down to Trachea.
Recall: The thyroid develops from the foramen cecum at the base of the tongue and descends anterior to the hyoid bone and laryngeal cartilages to reach its final pretracheal position.
- Carotid triangle = SCM, Omohyoid, Digastric = Carotid pulse.
Recall: The carotid triangle is bounded by SCM (posteriorly), superior belly of omohyoid (anteroinferiorly), and posterior belly of digastric (superiorly).
- Accessory = Accesses posterior triangle, Assists SCM and Trapezius.
Recall: The accessory nerve (CN XI) passes through the posterior triangle and supplies sternocleidomastoid (turns head to opposite side) and trapezius (shoulder shrugging and arm elevation).
- Follicular cells Fill follicles with thyroglobulin for T3/T4.
Recall: Thyroid follicles are lined by follicular (principal) cells that synthesize thyroglobulin, which is stored in the colloid.
- Cribriform = CN I holes = Crack them = Smell lost.
Recall: Olfactory nerve fibers (CN I) pass through multiple small foramina in the cribriform plate of the ethmoid bone to reach the nasal cavity.
- Lateral shelves must fuse for Palate; failure = Cleft.
Recall: The secondary palate forms from bilateral lateral palatine shelves (from maxillary prominences) that grow medially, elevate above the tongue, and fuse in the midline with each other and with the primary palate anteriorly.
- Palatoglossus = Palate muscle disguised as tongue muscle = Pharyngeal plexus (vagus).
Recall: Palatoglossus is anatomically a tongue muscle but embryologically develops from pharyngeal arch mesoderm and is supplied by the pharyngeal plexus (CN X and XI, primarily vagus).
- Sublingual = Small ducts along the Sublingual fold.
Recall: The sublingual gland has 8-20 small ducts (ducts of Rivinus) that open along the sublingual fold (plica sublingualis) on the floor of the mouth.
- Vagus leVates the palate (Levator veli palatini).
Recall: The vagus nerve (via pharyngeal plexus) supplies levator veli palatini, which is the main elevator of the soft palate.
- CN III = All muscles except SO4 and LR6; parasympathetics for pupil.
Recall: CN III (oculomotor) supplies all extraocular muscles except superior oblique (IV) and lateral rectus (VI).
- Ciliary contracts → Zonules relax → Lens rounds up for near vision.
Recall: Zonular fibers attach the lens to the ciliary body.
- Outside of TM = Auriculotemporal (V3 touches the eardrum outside).
Recall: The external surface of the tympanic membrane is primarily innervated by the auriculotemporal nerve (V3) with contributions from the auricular branch of vagus (X) and facial nerve (VII).
- PCA = Posterior Cricoarytenoid = Only Abductor. RLN = supplies it.
Recall: The posterior cricoarytenoid is the ONLY abductor of the vocal cords, supplied by the recurrent laryngeal nerve (RLN).
- PterygopalaTINE fossa = PterygopalaTINE ganglion + SphenoPalaTINE foramen.
Recall: The pterygopalatine fossa communicates with the nasal cavity through the sphenopalatine foramen.
- Lesser occipital = Lateral posterior scalp and behind ear.
Recall: The lesser occipital nerve (C2) ascends along the posterior border of SCM to supply skin behind the ear and posterior scalp.
- Tensor Tympani = Trigeminal (V3); Stapedius = facial (VII); both dampen loud sounds.
Recall: Tensor tympani is supplied by the mandibular nerve (V3) and contracts in response to loud sounds (acoustic reflex) to tense the tympanic membrane and reduce sound transmission, protecting the cochlea from acoustic trauma.
- Ca²⁺ causes “cargo release” at the synapse.
Recall: Arrival of an action potential opens voltage-gated calcium channels in the presynaptic terminal.
- Rest = K⁺ leaks out quietly.
Recall: At rest, neuronal membranes are most permeable to potassium, mainly due to potassium leak channels.
- Pacinian = Pressure; both start with P.
Recall: The Pacinian corpuscle is a classic mechanoreceptor that responds to deep pressure and vibration.
- Schwann shows the “path” for regrowth.
Recall: Schwann cells in the PNS form regeneration tubes and secrete factors that promote axonal regrowth.
- DCML crosses “Delayed” in the medulla.
Recall: The dorsal column fibers ascend ipsilaterally in the spinal cord and cross only in the medulla.
- LMN = Low tone, Less reflex, Loss of bulk.
Recall: Lower motor neuron (LMN) lesions cause fasciculations, flaccid paralysis, hypotonia, hyporeflexia, and muscle atrophy.
- UMN = Up goes tone and reflexes.
Recall: UMN lesions typically cause hyperreflexia, spasticity, increased tone, and extensor plantar response.
- Precentral = movement comes before action.
Recall: The primary motor cortex is located in the precentral gyrus of the frontal lobe, corresponding mainly to Brodmann area 4.
- D1 = Direct = Drive movement.
Recall: Dopamine from the substantia nigra pars compacta facilitates movement overall by stimulating the direct pathway via D1 receptors and inhibiting the indirect pathway via D2 receptors.
- “Vertebra minus 2 equals cord segment in lumbar region.” Option A ignores the vertebral-cord discrepancy. Options C and D represent segments that would be found at lower vertebral levels or within the cauda equina.
Recall: Due to differential growth of the vertebral column and spinal cord, the adult spinal cord terminates at L1-L2 vertebral level (conus medullaris).
- “IX = 9 lives of motor neurons.” Laminae I-II (A) process pain/temperature input. Laminae V-VI (B) are interneuron zones. Lamina VII (C) contains autonomic neurons in thoracolumbar/sacral regions.
Recall: Lamina IX of Rexed contains alpha motor neurons (lower motor neurons) that innervate skeletal muscles.
- “Lateral striates = Charcot’s arteries of hemorrhage.” Medial striates (A) supply caudate head. Anterior choroidal (C) supplies optic tract, hippocampus. Thalamoperforators (D) supply thalamus.
Recall: Lateral striate arteries (lenticulostriate arteries) arise from the M1 segment of the middle cerebral artery and supply the putamen, lateral globus pallidus, and posterior limb of the internal capsule.
- “MMM = Medial Medullary = Motor pyramid + Medial lemniscus + cranial nerve XII.” PICA (A) causes lateral medullary syndrome. Basilar occlusion (D) would cause more extensive brainstem damage.
Recall: Medial medullary syndrome (Dejerine syndrome) results from anterior spinal artery or vertebral artery branch occlusion affecting the pyramid (contralateral hemiplegia), medial lemniscus (contralateral sensory loss), and hypoglossal nerve/nucleus (ipsilateral tongue weakness/atrophy).
- “Climbing fibers CLIMB from Inferior Olive.” Pontine nuclei (A) give rise to mossy fibers via middle cerebellar peduncle. Vestibular nuclei (C) also send mossy fibers. Deep nuclei (D) receive Purkinje cell output.
Recall: Purkinje cells are large flask-shaped neurons in the middle (Purkinje) layer of cerebellar cortex.
- “Huntington’s Hunts GABA neurons in striatum.” Dopaminergic neurons (A) are in substantia nigra. Cholinergic interneurons (C) are relatively spared early. Glutamatergic neurons (D) are not predominant in striatum.
Recall: Huntington’s disease causes selective degeneration of GABAergic medium spiny neurons in the striatum, particularly those of the indirect pathway projecting to the external globus pallidus.
- “Lateral pterygoid: Lateral deviation to OPPOSITE side; paralysis deviates TOWARD lesion.” Other muscles (A, C, D) elevate or assist but don’t cause this specific deviation pattern.
Recall: The lateral pterygoid muscle protrudes the jaw and deviates it to the opposite side.
- “Wharton’s duct Welcomes saliva at the caruncle.” Option A describes the parotid duct opening. Option C is adjacent to the sublingual gland openings. Option D is the embryological site of thyroid descent.
Recall: The submandibular duct (Wharton’s duct) opens at the sublingual caruncle (papilla), a small elevation on the floor of the mouth lateral to the frenulum of the tongue.
- “Canaliculi = Canals for serous secretion through mucous maze.” Gap junctions (A) allow ionic communication. Tight junctions (C) seal cells together. Striated ducts (D) modify saliva composition later.
Recall: Serous demilunes are crescent-shaped serous cells at the periphery of mucous acini in mixed salivary glands.
- “Frey = Facial sweating from misdirected parotid parasympathetics.” Sympathetic fibers (A) normally supply sweat glands. Facial nerve (C) is motor to face muscles. Great auricular nerve (D) is purely sensory.
Recall: Frey syndrome occurs when postganglionic parasympathetic secretomotor fibers from the auriculotemporal nerve (intended for parotid gland) aberrantly reinnervate sweat glands in facial skin during regeneration.
- “Geniculate = Zoster’s Gate for facial paralysis with ear vesicles.” Gasserian ganglion (A) causes trigeminal zoster. Otic (C) and pterygopalatine (D) ganglia are parasympathetic relay stations.
Recall: Ramsay Hunt syndrome (herpes zoster oticus) involves reactivation of varicella-zoster virus in the geniculate ganglion of the facial nerve.
- “RLN = Recurrent = Returns to larynx = vocal cord movement.” External SLN (A) affects voice pitch. Internal SLN (B) is sensory above cords. Ansa cervicalis (D) supplies infrahyoid muscles.
Recall: The recurrent laryngeal nerve supplies all intrinsic laryngeal muscles except cricothyroid and carries sensory innervation below the vocal cords.
- “VAN between scalenes: Vein (Anterior to anterior scalene), Artery and Nerves (between scalenes).” The subclavian vein passes anterior to anterior scalene.
Recall: The subclavian artery and brachial plexus trunks pass through the scalene triangle (interscalene triangle) between the anterior scalene anteriorly and middle scalene posteriorly, with the first rib inferiorly.
- “Second is Most common and located at Sternocleidomastoid.” First cleft (A) causes external auditory canal anomalies. Third and fourth pouch (C, D) anomalies present more medially/inferiorly.
Recall: Second branchial cleft cysts (most common type) present along the anterior border of the sternocleidomastoid muscle, typically between the external and internal carotid arteries.
- “Left RLN = Loops under Left Aortic arch.” The ligamentum arteriosum (D) is a landmark near the loop but not the structure looped around. Right subclavian (B) is for the right RLN.
Recall: The left recurrent laryngeal nerve loops under the aortic arch (lateral to the ligamentum arteriosum), then ascends in the tracheoesophageal groove.
- “Lateral tongue = Submandibular; Tip = Submental.” Submental (A) drains the tongue tip. Upper deep cervical (C) is secondary. Retropharyngeal (D) receives posterior wall and nasopharynx drainage.
Recall: The lateral border of the tongue (anterior two-thirds) drains primarily to the ipsilateral submandibular lymph nodes, which then drain to deep cervical nodes.
- “Medical (diabetes) = Middle of nerve = pupil spared; Surgical (aneurysm) = Superficial fibers = pupil involved.” Options C and D don’t match the clinical picture of oculomotor palsy.
Recall: Diabetic oculomotor palsy is characterized by pupil-sparing (normal pupil reactions) because microvascular ischemia affects the central nerve fibers while sparing the peripheral parasympathetic pupillary fibers.
- “RPE = Recycles Photopigments and Eats outer segments.” Outer nuclear layer (A) contains photoreceptor cell bodies. Choroid (C) provides blood supply. Inner nuclear layer (D) contains bipolar cells.
Recall: The retinal pigment epithelium (RPE) is a single layer of pigmented cells adjacent to photoreceptor outer segments.
- “Acoustic neuroma = Vestibular Schwannoma (VS); starts Vestibular, presents with Cochlear symptoms.” Spiral ganglion (C) contains the primary auditory neurons.
Recall: Vestibular schwannoma (acoustic neuroma) arises from Schwann cells of the vestibular division of CN VIII, most commonly at the internal acoustic meatus.
- “Nucleus aMbiguus = Motor to pharynx/larynx Muscles.” Dorsal motor nucleus (B) is parasympathetic. Nucleus solitarius (C) receives visceral afferents and taste.
Recall: The nucleus ambiguus contains branchial motor neurons that supply the pharyngeal muscles (via CN IX and X) and laryngeal muscles (via CN X).
- “EAAT glutamate for breakfast” – EAATs consume glutamate to clear it.
Recall: Ketamine antagonizes NMDA receptors that bind glutamate, the major excitatory neurotransmitter.
- SAM the Methylator comes from Methionine.
Recall: COMT (catechol-O-methyltransferase) converts catecholamines to metanephrines using S-adenosylmethionine (SAM) as the methyl donor.
- NAA = Neurons Acetylate for Axon wrapping (myelin).
Recall: N-acetylaspartate (NAA) is synthesized in neurons and transported to oligodendrocytes, where aspartoacylase releases acetate for myelin lipid synthesis.
- Astrocytes are Lactate factories for hungry Neurons.
Recall: The astrocyte-neuron lactate shuttle (ANLS) describes how astrocytes perform glycolysis, producing lactate via lactate dehydrogenase.
- PC donates its head to Ceramide → Sphingomyelin + DAG.
Recall: Sphingomyelin synthase transfers phosphocholine from phosphatidylcholine to ceramide, producing sphingomyelin and diacylglycerol.
- Fabry’s Fiery pain = DRG neuron Fat accumulation.
Recall: In Fabry disease, globotriaosylceramide (Gb3/GL-3) accumulates in dorsal root ganglion neurons, causing small fiber neuropathy and characteristic burning pain (acroparesthesias).
- Choroid Plexus = Epithelium Produces and Protects CSF.
Recall: The blood-CSF barrier at the choroid plexus is formed by choroid plexus epithelial cells connected by tight junctions.
- Carbonic Anhydrase Creates Bicarbonate for CSF secretion.
Recall: Carbonic anhydrase generates H⁺ and HCO₃⁻ from CO₂ and H₂O in choroid plexus epithelium.
- PGE keeps the duct opEn.
Recall: Prostaglandin E2 (PGE2) maintains ductus arteriosus patency in utero.
- PAM lets Cas9 PAM-per the DNA with cuts.
Recall: The protospacer adjacent motif (PAM) is a short sequence (NGG for SpCas9) immediately downstream of the target DNA sequence.
- AAV stays As An episomal Visitor–safe, stable, non-integrating.
Recall: AAV vectors primarily exist as episomal (extrachromosomal) DNA in transduced cells, providing stable long-term expression in non-dividing cells without insertional mutagenesis risk.
- HGPRT: Hypoxanthine/Guanine + PRPP → Purine nucleoTides.
Recall: HGPRT transfers the phosphoribosyl group from PRPP (phosphoribosyl pyrophosphate) to free purine bases (hypoxanthine or guanine), producing IMP or GMP respectively.
- THF Transfers Formyl, methenyl, and methylene–all one-carbons.
Recall: THF carries one-carbon units in various oxidation states: formyl (CHO) and methenyl groups are essential for de novo purine synthesis (carbons 2 and 8 of purine ring).
- Dam Methylation Marks the old strand–new strand gets nicked.
Recall: In *E. coli*, the parental strand is marked by N6-methyladenine at GATC sequences (Dam methylation), while the newly synthesized strand is transiently unmethylated.
- Erythromycin Exits–blocks the tunnel Exit.
Recall: Erythromycin binds the 23S rRNA of the 50S subunit near the peptide exit tunnel, blocking elongation of the nascent peptide chain and causing premature dissociation.
- Aminoglycosides at A-site cause Amino acid mistakes.
Recall: Aminoglycosides bind the 30S ribosomal subunit (specifically 16S rRNA), causing misreading of mRNA and incorporation of incorrect amino acids.
- Exon-Exon primers Exclude genomic DNA–no intron product.
Recall: Primers spanning exon-exon junctions will only amplify spliced mRNA (cDNA), not genomic DNA containing introns.
- Overlap Extension = mutations Extend through the product.
Recall: Overlap extension PCR uses primers containing the mutation to generate overlapping fragments that are combined in a subsequent PCR reaction.
- Ammonia + α-KG → Glutamate → Glutamine: Glutamatergic system overwhelmed.
Recall: Hyperammonemia depletes α-ketoglutarate (consumed forming glutamate, then glutamine) from the TCA cycle in astrocytes.