APMLE Part I flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Tarsal tunnel contents

The tibial nerve, posterior tibial artery and veins, and the tendons of tibialis posterior, flexor digitorum longus, and flexor hallucis longus pass behind the medial malleolus beneath the flexor retinaculum.

Dorsalis pedis pulse site

Palpated on the dorsum of the foot between the extensor hallucis longus and extensor digitorum longus tendons, lateral to the first metatarsal; it continues the anterior tibial artery.

Deep fibular nerve

A branch of the common fibular nerve supplying the anterior compartment muscles and sensation from the first dorsal web space; injury produces foot drop with a steppage gait.

Lower limb rotation embryology

During the eighth week the lower limb bud rotates medially about 90 degrees, bringing extensor muscles anteriorly and placing the great toe on the medial side.

Rate-limiting enzyme of glycolysis

Phosphofructokinase-1 converts fructose-6-phosphate to fructose-1,6-bisphosphate; it is activated by AMP and fructose-2,6-bisphosphate and inhibited by ATP and citrate.

G6PD deficiency consequence

Reduced NADPH production lowers reduced glutathione, causing oxidative damage, Heinz body formation, and episodic hemolysis after infection or exposure to sulfa drugs, fava beans, or primaquine.

Vitamin C in collagen synthesis

Ascorbate is required for hydroxylation of proline and lysine in procollagen; deficiency yields weak collagen, causing scurvy with bleeding gums, perifollicular hemorrhage, and poor wound healing.

Windlass mechanism

Dorsiflexion of the hallux during late stance tightens the plantar fascia around the first metatarsal head, elevating the medial arch and inverting the rearfoot to stiffen the foot.

Subtalar joint pronation

Pronation is triplanar dorsiflexion, eversion, and abduction about an oblique axis; it unlocks the midfoot for shock absorption during the loading response.

Neutral position of subtalar joint

The position in which the foot is neither pronated nor supinated, with the plantar forefoot perpendicular to the rearfoot; clinicians use it as the reference for casting orthoses.

Coagulase test

Coagulase positivity distinguishes Staphylococcus aureus from other staphylococci; S. aureus converts fibrinogen to fibrin and is the most common cause of skin and soft tissue infection.

MRSA resistance mechanism

Methicillin resistance arises from the mecA gene, which encodes penicillin-binding protein 2a, a transpeptidase with low affinity for all beta-lactam antibiotics.

IgM characteristics

IgM is a pentameric antibody produced first in a primary immune response, strongly activates the classical complement pathway, and does not cross the placenta.

Clostridium perfringens alpha toxin

A lecithinase that lyses cell membranes and causes myonecrosis and gas gangrene; such infections follow deep contaminated wounds and require urgent debridement plus penicillin.

Caseous necrosis

A form of necrosis with a cheesy, friable, eosinophilic center surrounded by granulomatous inflammation, classically seen in tuberculosis and histoplasmosis with complete loss of tissue architecture.

Chronic osteomyelitis features

Chronic bone infection shows necrotic devitalized bone (sequestrum) surrounded by reactive new bone (involucrum), with lymphocytes, plasma cells, and fibrosis; biofilm makes eradication difficult.

Gout crystal identification

Monosodium urate crystals are needle-shaped and negatively birefringent under polarized light, whereas calcium pyrophosphate dihydrate crystals are rhomboid and positively birefringent.

Vancomycin mechanism

A glycopeptide that binds the D-Ala-D-Ala terminus of peptidoglycan precursors, blocking cell wall elongation; used for MRSA with nephrotoxicity requiring serum level monitoring.

Aspirin platelet effect

Aspirin irreversibly acetylates cyclooxygenase-1 in platelets, blocking thromboxane A2 production; the antiplatelet effect lasts the platelet lifespan of about 7 to 10 days.

N-acetylcysteine antidote

It replenishes hepatic glutathione and binds the toxic metabolite NAPQI, preventing hepatocyte necrosis after acetaminophen overdose; it is most effective within 8 to 10 hours.

Bohr effect

Increased carbon dioxide, hydrogen ion concentration, temperature, and 2,3-bisphosphoglycerate shift the oxyhemoglobin dissociation curve rightward, lowering hemoglobin oxygen affinity and enhancing tissue oxygen unloading.

Glomerular filtration rate formula

GFR equals the filtration coefficient times net filtration pressure, calculated as glomerular capillary pressure minus Bowman space pressure minus oncotic pressure of glomerular plasma.

ADH action

Antidiuretic hormone binds V2 receptors on collecting duct principal cells, raising cyclic AMP and inserting aquaporin-2 channels apically to reabsorb water and concentrate urine.

Wagner ulcer classification

Grades diabetic foot ulcers from 0 (intact skin with deformity) through 5 (whole-foot gangrene), with higher grades indicating deeper wounds, osteomyelitis, or gangrene.

Charcot neuroarthropathy

Noninfective progressive destruction of weight-bearing foot joints in neuropathy, presenting as a warm, swollen, erythematous foot; treated with immobilization and offloading to prevent rocker-bottom deformity.

Plantar fasciitis presentation

Medial heel pain maximal with the first steps after rising and tenderness at the medial calcaneal tubercle; associated with limited ankle dorsiflexion and treated with stretching, orthoses, and night splints.

Mulder sign

A palpable painful click elicited by squeezing the metatarsal heads laterally in a patient with Morton neuroma of the third interdigital space as the neuroma displaces between metatarsals.

Transtheoretical stages of change

Precontemplation, contemplation, preparation, action, and maintenance; relapse is common and patients may cycle through stages, so counseling should match the current stage.

Transference

The patient unconsciously redirects feelings and expectations from past important relationships onto the clinician, potentially distorting the therapeutic alliance and requiring recognition and address.

Sensitivity versus specificity

Sensitivity is the proportion of true positives detected among all diseased persons; specificity is the proportion of true negatives among all healthy persons.

Informed consent elements

Valid consent requires patient decision-making capacity, disclosure of risks, benefits, and alternatives, comprehension of that information, and voluntariness free of coercion.

HIPAA minimum necessary

The privacy rule permits disclosure of protected health information for treatment, payment, and operations but requires that only the minimum necessary information be shared.