Comprehensive Preclinical Medical Review

Essential high-yield vocabulary flashcards spanning anatomy, human physiology, histology, biochemistry, and research fundamentals.

Eversion

Movement that turns the sole of the foot outward, away from the anatomical midline.

Distal

Anatomical directional term indicating a position farther away from the trunk attachment, used primarily for limbs.

Brachialis

The muscle that functions as the prime mover of elbow flexion.

Gomphosis

A fibrous peg-and-socket joint, exemplified by a tooth anchored in its alveolar socket.

Bankart Lesion

A tear of the anteroinferior glenoid labrum resulting from recurrent anterior shoulder dislocations.

Quadrangular Space Syndrome

Compression of the axillary nerve and posterior circumflex humeral vessels within the quadrangular space, presenting with posterior shoulder pain and deltoid/teres minor weakness.

Erb Palsy

Injury to the upper trunk of the brachial plexus ($C5\text{--}C6$) commonly caused by shoulder dystocia, presenting in a classic "waiter's tip" posture with the arm adducted and medially rotated and the elbow extended.

Klumpke Palsy

Injury to the lower trunk of the brachial plexus ($C8\text{--}T1$) resulting from excessive arm elevation or traction during birth, affecting the intrinsic hand muscles and producing a claw hand deformity.

Bicipital Aponeurosis

A fibrous band in the roof of the cubital fossa that covers and protects the underlying brachial artery and median nerve during venipuncture of the median cubital vein.

Froment Sign

A clinical diagnostic sign of ulnar nerve palsy where weakness of the adductor pollicis forces compensatory flexion of the thumb interphalangeal joint via the flexor pollicis longus when pinching paper.

Saturday Night Palsy

Radial nerve injury occurring within the radial groove of the humerus, causing wrist drop and finger drop while sparing triceps-mediated elbow extension.

Dupuytren Contracture

Progressive fibrous thickening and shortening of the palmar aponeurosis that leads to fixed flexion contractures of the fingers, predominantly affecting the metacarpophalangeal joint of the ring finger.

Nursemaid Elbow

A pulled elbow subluxation seen in young children where sudden longitudinal traction causes the radial head to slip out from the annular ligament.

Trendelenburg Sign

Pelvic drop toward the unsupported leg when standing on one limb, demonstrating weakness or paralysis of the gluteus medius and gluteus minimus muscles on the weight-bearing side.

Iliofemoral Ligament

An inverted Y-shaped band running from the anterior inferior iliac spine to the intertrochanteric line; recognized as the strongest ligament in the human body, functioning to resist hip hyperextension during standing.

Pes Anserinus

The conjoined tendinous insertion onto the superior medial surface of the tibia formed by the sartorius, gracilis, and semitendinosus muscles.

Baker Cyst

A posteromedial fluid-filled distension behind the knee originating from the gastrocnemius-semimembranosus bursa, whose rupture can clinically mimic deep vein thrombosis.

Popliteus

A posterior leg muscle that unlocks the fully extended knee joint by laterally rotating the femur on the tibia.

Unhappy Triad

A severe knee injury complex consisting of concurrent tears of the anterior cruciate ligament (ACL), medial collateral ligament (MCL), and medial meniscus.

Lachman Test

A diagnostic physical exam maneuver for anterior cruciate ligament integrity characterized by excessive anterior displacement of the tibia when stressed at $20^\text{--}30^\text{o}$ of knee flexion.

Aquaporin

A specialized membrane-spanning channel protein responsible for facilitating the rapid movement of water across the cell membrane.

Chronaxie

The minimum duration an electrical current of double the rheobasic intensity must flow to elicit an excitation threshold in an excitable tissue; inversely related to excitability.

Rheobase

The minimum electrical current intensity of indefinite duration required to stimulate an excitable nerve or muscle membrane.

Saltatory Conduction

The rapid, energy-efficient propagation of an action potential along a myelinated axon, occurring via localized depolarization jumps from one node of Ranvier to the next.

Myasthenia Gravis

An autoimmune neuromuscular disorder featuring circulating antibodies against skeletal muscle nicotinic acetylcholine receptors ($N_M$), resulting in receptor loss, fluctuating weakness, and easy fatigability.

Isometric Contraction

A type of muscle activation in which tension increases while muscle length remains constant, resulting in zero external mechanical work performed.

Phosphagen System

The anaerobic intramuscular energy system utilizing stored ATP and creatine phosphate, supplying maximal contraction energy for approximately $10\text{--}15\,\text{s}$.

Oxygen Debt

The post-exercise elevation in oxygen consumption necessary to clear accumulated lactic acid and regenerate baseline stores of ATP, creatine phosphate, and oxy-myoglobin.

Starling's Law of Muscle

Physiological principle stating that, within physiologic limits, the greater the initial resting length of a muscle fibre, the greater the force of its subsequent contraction.

Treppe

The staircase phenomenon characterized by a progressive rise in the twitch force of a rested muscle stimulated at low frequency, mediated by persistently high free intracellular $Ca^{2+}$.

Horner Syndrome

A neurological condition caused by interruption of the cervical sympathetic outflow ($T1\text{--}T2$), characterized by ipsilateral pupillary miosis, ptosis, and facial anhidrosis with warm, flushed skin.

Glycocalyx

A carbohydrate-rich cell coat composed of membrane glycoproteins and glycolipids that functions in cellular recognition, adhesion, and immunological specificity.

Peroxisome

A single-membrane organelle possessing catalase and oxidases that executes the $\beta$-oxidation of very-long-chain fatty acids and detoxifies hydrogen peroxide.

Tay–Sachs Disease

A fatal lysosomal storage disorder caused by a genetic deficiency in hexosaminidase A, leading to pathological accumulation of GM2 gangliosides and neuronal degeneration.

I-Cell Disease

A lysosomal enzyme targeting defect caused by deficiency of phosphotransferase, failing to add mannose-6-phosphate tags and causing lysosomal enzymes to be misrouted outside the cell.

Kartagener Syndrome

A genetic condition characterized by defective ciliary dynein arms, leading to immotile respiratory cilia and sperm flagella, recurrent sinopulmonary infections, and infertility.

Epithelial Metaplasia

The reversible reprogramming and replacement of one adult differentiated epithelial cell type into another differentiated epithelial cell type in response to chronic environmental injury.

Holocrine Secretion

A mode of exocrine secretion where the whole cell undergoes apoptosis and is discharged along with its secretory product, exemplified by sebaceous glands.

Zonula Occludens

Tight intercellular junctions composed of transmembrane claudins and occludins that fuse adjoining plasma membranes to seal off the paracellular pathway.

Endomysium

The innermost layer of delicate loose connective tissue, composed predominantly of reticular fibres, that envelopes each individual muscle fibre.

Dystrophin

A cytoskeletal structural protein that anchors the internal actin filament cytoskeleton of a muscle fibre to the surrounding extracellular matrix; absent or defective in Duchenne muscular dystrophy.

Howship Lacunae

Superficial resorption bays or hollowed depressions on the bone surface where multinucleated osteoclasts reside and degrade bone matrix.

Volkmann Canals

Transverse vascular channels in compact bone that connect individual Haversian canals to each other and to the periosteum and marrow cavity.

Zwitterion

A dipolar ion species bearing separate positively and negatively charged groups while maintaining an overall net electrical charge of zero, as seen with amino acids at $\text{pH } 7$.

Peptide Bond

A rigid, planar covalent amide linkage with partial double-bond character formed between the $\alpha$-carboxyl group of one amino acid and the $\alpha$-amino group of another.

Holoenzyme

A complete, catalytically active enzyme system composed of an apoenzyme (protein component) assembled with its non-protein cofactor or coenzyme.

Michaelis Constant ($K_m$)

The specific substrate concentration at which the rate of an enzymatic reaction is half of its maximum velocity ($\frac{1}{2}V_{\max}$), serving as an inverse indicator of enzyme affinity.

Competitive Inhibitor

A reversible regulatory substance that binds to the free enzyme's active catalytic site, raising the apparent $K_m$ while leaving $V_{\max}$ unaltered.

Fundamental Research

Experimental or theoretical work undertaken primarily to acquire foundational knowledge and insights into underlying natural phenomena without direct practical or commercial applications.

Re-cycler Plagiarism

An ethical violation where a researcher or student resubmits their own previously submitted work or assignments without authorization or proper citation.