C

C fibres small, non-myelinated, free nerve endings within skin, and fibres within mixed nerves, carrying afferent pain impulses from high-threshold polymodal nociceptors; C-fibre nerve endings also secrete bradykinins, initiating or perpetuating neurogenic inflammation

cad-cam orthoses; computer-aided design and manufacture of bespoke functional orthoses digitized data (of the dimensions of the neutral cast, modified by computer program to incorporate prescribed postings, expansions and accommodations) is used to mill the orthotic directly from a block of polypropylene (see Table B1)

cadence number of steps per minute during normal gait

cadexomer iodine wound-cleansing agent containing 0.9% w/w iodine on hydrophilic and absorbent microscopic beads; absorbs exudate and removes wound surface debris/bacteria by capillary action

café au lait spots uniformly light-brown, sharply defined, ovoid areas of skin pigmentation, especially of axillary skin, characteristic of neurofibromatosis (see disease, von Recklinghausen’s)

cal (calorie) (1) quantity of energy required to raise temperature of 1 gram of water by 1°C

cal (calorie) (2); kilocalorie (Kcal) quantity of energy required to raise temperature of 1 kg of water by 1°C; unit used to describe food energy values

calamine zinc oxide or zinc carbonate, coloured with ferric oxide; mild topical astringent and soothing agent, as dusting powders, lotions and ointments, for mild inflammation and pruritus (see antipruritic)

calcaneal apophysitis see disease, Sever’s; Table O7

calcaneal eversion calcaneal frontal-plane motion; part of compensation mechanisms characteristic of compensated rearfoot varus, mobile pes cavus and high calcaneal angle of inclination; resultant rearfoot movement against the inner surface of heel cup imposes shear stresses on central lateral soft tissues of rearfoot, contributing to bursa formation and Haglund’s deformity

calcaneal fracture fracture of body of calcaneum due to sudden severe trauma, e.g. falling from a height or road traffic accident (see duck bill fracture)

calcaneal gait severe, non-compensated, whole-foot inversion, with short stepping gait and little forefoot weight-bearing; characterized by excessive wear along lateral side of rear and middle parts of the sole and little/no forefoot wear

calcaneal inclination angle angle subtended by the plane of the plantar aspect of the calcaneum and the support surface, on a lateral radiograph see Figure P2

high calcaneal inclination angle indicates rearfoot varus, restricted subtalar joint movement/supination, pes cavus or talipes equinovarus

low calcaneal inclination angle indicates pes valgus, rearfoot valgus, excess subtalar joint pronation or calcaneovalgus

calcaneal projection bony prominence at posterior superior aspect of calcaneum; functions to lengthen Achilles tendon lever arm, and increase mechanical advantage of posterior superior muscle group during ankle dorsiflexion

calcaneal spur see heel spur

calcaneal step bony prominence of posterior aspect of calcaneum; locally irritant to Achilles tendon (TA) at ankle joint dorsiflexion, causing TA tears, just superior to its insertion into middle one-third of posterior calcaneal surface

calcaneocuboid joint biaxial saddle joint formed by distal articular surface of calcaneum and proximal articular surface of cuboid; part of midtarsal joint complex

calcaneodynia mechanical overuse characterized by heel pain extending distally along entire course of plantar fascia, fascial thickening and nodule formation

calcaneofibular ligament; CFL extra-capsular, cord-like ligament crossing ankle and subtalar joints; originates at distal inferior surface of fibula and inserts into tubercle on lateral aspect of calcaneum, deep to the peroneal tendons; strongly resists calcaneal inversion (see Table A9)

calcaneus; calcaneum; heel bone; os calcis largest bone in the rearfoot, forming the heel, articulating at its superior surface with inferior aspect of the talus, and anteriorly with the posterior aspect of cuboid; plantar aspect gives origin to plantar fascia; middle one-third of posterior facet receives insertion of the deep fibres of tendo Achilles; has two centres of ossification – the primary centre within the body of calcaneum, and secondary centre towards posterior aspect of the calcaneum – that unite at approximately 12 years of age (see Table O5)

calcareous chalky

calciferol vitamin D synthesized within skin under influence of sunlight; see ergocalciferol

calcific tendinosis see insertional Achilles tendinitis

calcification of tissues abnormal deposition of insoluble calcium salts within soft tissues; noted on plain radiograph as irregular, non-corticated and non-trabecular radiopaque areas (see Mönckeberg’s sclerosis)

calcinosis deposition of nodular foci of calcium salts in various tissues, other than the viscera (see CREST)

calcitonin; thyrocalcitonin hormone (secreted by parafollicular cells of thyroid) reducing plasma calcium (by increasing urinary calcium excretion and reducing osteoclastic bone resorption); used to treat Paget’s disease

calcitriol vitamin D derivative used to treat vitamin D deficiency, postmenopausal osteoporosis and rickets

calcium channel blockers; calcium antagonists agents altering movement of calcium ions into cells; used to reduce myocardial contractility, suppress formation and propagation of electrical impulses with the heart, and reduce vasomotor tone in coronary and systemic vessels; overdose causes nausea and vomiting, hypotension, agitation, confusion, metabolic acidosis, hyperglycaemia and peripheral vasodilatation; e.g. verapamil, nifedipine, amlodipine, diltiazem

calf large muscle mass at the posterior aspect of the lower leg

calf pump see venous pump

calibration standardization of a measuring instrument against a known reference

caliper brace shaped metal rods strapped to a limb, to reduce tendency to contracture, for cases with unequal or absent muscular function, e.g. cerebral palsy, spina bifida, poliomyelitis

calipers jawed calibrated instrument, used to measure distance or diameter

callosity; mechanically induced hyperkeratosis thickening of stratum corneum in response to localized, intermittent, low-grade mechanical trauma, e.g. friction, shear stress, pressure, tension, often associated with lower-limb/foot pathomechanical faults; increased mechanical skin load causes local dermal inflammation, release of growth factors and increased mitosis of overlying epidermal cells, increased epidermal transit rate and imperfect keratinization; immature keratinocytes reach the outer skin surface and fail to desquamate in the normal manner; affected skin areas show increased thickness and inflexibility of stratum corneum, which increases local mechanical trauma, so hyperkeratosis predisposes to further hyperkeratosis formation (i.e. callosity and corn); long-standing dermal inflammation ultimately causes subdermal fibrosis, reducing local shock absorption and increasing tissue stress of overlying epidermis, and further callus formation; mechanical hyperkeratosis is managed by identification and resolution of its cause (i.e. addressing underlying patho-mechanical or dermatological anomalies), sharp debridement or chemical dissolution of accumulated hyperkeratotic plaques, provision of deflecting or antishear padding, and by use of footwear and orthoses that minimize effects of causative trauma

callous relating to bone callus or epidermal callosity

callus hard, bone-like tissue formed between and around ends of fractured bones; part of the healing response of bone

Calmurid keratoplastic and skin-hydrating topical cream (containing 10% urea and 5% lactic acid) applied daily to counteract severe anhidrosis or reduce seed corn reformation

calor heat; one of five cardinal signs of inflammation; causes increased blood flow through inflamed tissues (see inflammation)

calorie unit of heat energy, now replaced in SI notation by the joule (1 joule = 0.24 calories)

Campylobacter a genus of Gram-negative, flagellate bacteria that cause gut infections; a rare trigger of Guillaine-Barré syndrome

campylodactyly characteristic of Dupuytren’s contracture, i.e. permanent flexion of one or both finger interphalangeal joints, most commonly fifth and fourth fingers

canal duct, channel

cancer; Ca any of various types of malignancy, or neoplasm showing signs of malignancy (i.e. local tissue invasion, metastasis formation and recurrence after apparent cure)

Candida albicans microorganism constituent of normal skin and gut flora becoming pathogenic when normal floral balance is disturbed, causing mild skin infections and a range of endogenous disease states (poorly controlled diabetes, patients on immunosuppressant therapies, and those with acquired immunodeficiency syndrome [AIDS] are especially susceptible to severe candidal infections); nail fold C. albicans infection causes chronic paronychia; skin infections are more common in warmer weather, and affect intertriginous areas, e.g. interdigital skin, causing a distinctive yeast odour and maceration (with sloughing of superficial epithelium and exposure of raw-looking dermal tissues) or fissure formation (with local inflammation and pain); candidal infections respond to topical azoles, 1% terbinafine, itraconazole or ketoconazole; 10% povidone-iodine in spirit is effective in the treatment of raw intertriginous infections

candidal onychomycosis chronic Candida albicans infection of proximal nail apparatus secondary to chronic paronychia, with nail plate dystrophy (discoloration, friability and marked ridging); patients with Raynaud’s phenomenon and psoriasis, or those with defective cell-mediated immunity, predispose to candidal onychomycosis; treated by nail plate avulsion and allowing plate regrowth under cover of topical azoles, 1% terbinafine, itraconazole or ketoconazole

candidiasis; candidosis infection with, or disease state caused by, Candida spp.

cannulation introduction of a wide-bore needle into a vein, through which medication can be delivered directly into the circulation

capillary smallest division of the systemic circulation; a vast network of minute vessels (each approximately 10 μm in diameter), whose walls are formed of a single layer of vascular endothelial cells on a basement membrane, across which water and small molecules pass to allow tissue respiration

capillary bed capillaries and their collective fluid volume

capillary fragility proneness to skin bruising with minor trauma, due to loss of normal capillary function

capillary haemangioma see granuloma pyogenicum

capillary refill; capillary bed return measure of capillary bed perfusion; digital pressure is applied to the nail plate or distal pulp of a toe and the time in seconds is noted for the return of normal colour/normal perfusion; colour return should be almost immediate; >5 seconds to regain normal perfusion colour is indicative of tissue ischaemia

capilloscopy capillary blood flow investigation by microscopic examination of skin fold capillaries, e.g. at dorsal proximal nail fold

capitate rounded tip or head

capsaicin chilli derivative; see rubefacients

capsid outer coat of a virus

capsomere subunit of the viral capsid

capsule dense collagenous connective tissue membrane enveloping an organ, joint or benign tumour

capsulitis joint capsule inflammation, joint ligament and tendon sheath engorgement secondary to osteoarthritis or rheumatoid arthritis, or ongoing, low-grade trauma; treated by physical therapies (e.g. rest, local heat, contrast foot baths), non-steroidal anti-inflammatory drug medication and reduction of the causative trauma

capsulorrhaphy suture of a joint capsule to repair a tear (e.g. the first metatarsophalangeal joint capsule to repair a ‘turf toe’) or prevent recurrent joint dislocation

capsulotomy surgical incision through the dorsal capsule of a lesser metatarsophalangeal joint to reduce hyperextension deformity

carbamazepine anticonvulsant agent used to treat epilepsy in some chronic pain states, e.g. painful diabetic neuropathy

carbidopa formulation of dopamine, used to control symptoms of Parkinson’s disease

carbohydrates saccharides C_n(H₂O)_n, e.g. glucose C₆(H₂O)₆, sucrose C₁₂(H₂O)₁₂; some are simple molecules (e.g. monosaccharides), others form complex macromolecules (e.g. glycogen)

carbolic acid phenol

carbon a non-metallic element (C) forming compounds that occur in all living tissues; carbon, liberated by metabolic reactions, unites with oxygen (during tissue respiration) forming carbon dioxide (CO₂)

carbon dioxide laser a form of therapeutic laser light, used to destroy tissue; short-pulse CO₂ laser has been shown to be effective in nail matrisectomy

carbonic anhydrase inhibitors see diuretics

carboxylation the addition of CO₂ to an organic compound to create a carboxyl (–COOH) group

carbuncle a deep-seated pyogenic infection of skin and local soft tissues

carcinogen any cancer-inducing substance

carcinoma any of various types of malignant neoplasm derived from epithelial tissues; characterized by local invasion of adjacent tissues and anaplasia, more commonly affecting the skin and large intestine (in both sexes), the bronchi, prostate and stomach (in men) and the breast and cervix (in women)

cardiac arrest cessation of heart function and circulatory collapse; characterized by unconsciousness, pulselessness, rapid fall of blood pressure and oxygen saturation levels; death is imminent unless effective life support is instigated (see basic life support)

cardiac arrhythmia abnormal heart muscle contraction rates, e.g. atrial fibrillation and ventricular tachycardia

cardiac asthma bronchoconstriction and pulmonary oedema secondary to left ventricular failure

cardiac cycle sequence of events that manifests as the ‘heart beat’ (Table C1)

Table C1 The cardiac cycle

cardiac glycoside positive inotrope drug which increases force of cardiac contraction and reduces atrioventricular node conductivity; used to control atrial fibrillation, e.g. digoxin

cardinal planes of the body frontal (coronal), sagittal (median) and horizontal (transverse) planes of the body, each of which is oriented on the three planes of space

cardiopulmonary resuscitation; CPR maintenance of circulation of oxygenated blood to the brain during cardiac arrest, by closed chest massage ± assisted respiration (see basic life support; external chest message)

cardiotachography diagnosis of loss of heart rate variability, characteristic of autonomic neuropathy; record of change in heart rate (beats per minute) during deep inspiration and exhalation (normal = 10-beat increase on inspiration), or between heart rate at rest and immediately after standing upright (normal = >12-beat increase on standing) (see autonomic neuropathy; manoeuvre Valsalva’s)

cardiotoxicity drug-induced suppression of heart muscle or its conduction system, e.g. local anaesthetic overdose

cardiovascular accident; CVA collapse and possible death due to sudden-onset cardiac disease, e.g. heart attack, myocardial infarction

cardiovascular effects of local anaesthetics relative or actual toxic (overdose) levels of local anaesthetics causing decreased myocardial activity, reduced cardiac output and blood pressure

cardioversion restoration of normal sinus heart rhythm by administration of electrical shock (see defibrillation)

carotene plant or animal-derived yellow-red pigments; vitamin A precursors

carotenosis cutis carotene deposition within skin, causing yellow discoloration

carotid pulse neck pulse palpable just medial to belly of the sternomastoid muscle at the level of larynx; magnitude of the carotid pulse reflects strength of cardiac muscle contraction

carotid sinus dilatation at the bifurcation of the common carotid artery; its walls contain baroreceptor nerve endings sensitive to blood pressure; baroreceptor stimulation triggers bradycardia, general vasodilatation and resultant fall in blood pressure

carpal tunnel space deep to flexor surface of the wrist, through which median nerve and flexor tendons pass

carpal tunnel syndrome see syndrome, carpal tunnel

carpopedal spasm spasmodic flexion of wrists/fingers and dorsiflexion of the ankles and plantarflexion of the toes in association with hyperventilation, calcium deprivation (parathyroid disease) and tetany

carrier individual with asymptomatic contagious infection, forming a source of disease without showing any signs of that disease, e.g. carriers of Staphylococcus aureus, hepatitis B, hepatitis C and human immunodeficiency virus (HIV)

cartilage specialized avascular connective tissue formed of chondrocytes (cells) and interstitial substance (matrix) in a chondromucoid ground substance; lubricated and protected from injury by the hydrostatic mechanism (high-speed movement or under high load) or the boundary surface phenomenon (moving slowly or under low load)

caseation coagulation necrosis characteristic of tuberculous lesions

cast plaster of Paris positive model of a foot; a direct (negative) mould of the foot is made with the foot maintained in the neutral position, and subsequently filled with liquid plaster of Paris that is allowed to set to create model identical to the foot (see Bivalve cast, Negative casting, Table N1)

casted diabetic insoles see insole

casted foot orthoses rigid or semirigid orthoses made to a neutral foot cast (subsequently modified by the addition of expansions and intrinsic posts to control pathomechanical anomalies within the foot and lower limb); see insole

casting box compressible plastic foam (similar to that used for flower arranging) within a box, onto whose surface the weight-bearing foot is placed; the clinician adjusts the rearfoot to produce a near-neutral impression of the plantar contours of the foot in the foam, to create a negative mould from which a positive plaster cast can be made

catabolism metabolic processes breaking down complex compounds into simpler forms, and release of energy (opposite: anabolism)

catalyst agent accelerating a chemical reaction but not used up, nor permanently changed, by that reaction; most enzymes are catalysts

cataract loss of lens transparency; a cause of blindness in diabetes

catecholamines adrenaline (epinephrine) and noradrenaline (norepinephrine)

cation positively charged ion, attracted to a negatively charged cathode

cationic detergents see detergents

caudal distal end of the spine (opposite: rostral)

cauda equina bundle of paired spinal nerve roots extending from the distal tip of the spinal cord and traversing the subarachnoid space within the vertebral canal; begins at level of first lumbar vertebra (L1)

caudate nucleus see basal ganglia

causalgia see syndrome, complex regional pain, type 2

caustic strong inorganic acid or alkali, or organic acid (e.g. phenol) applied to soft tissue, e.g. verruca or nail matrix, to cause controlled destruction of that area of tissue; different caustics exert different actions on tissues: silver nitrate forms insoluble chlorides (i.e. creating a barrier to further tissue penetration), nitric acid precipitates albumen (i.e. forming a barrier to further tissue penetration), pyrogallol acts as a reducing agent (i.e. penetrating deep into tissues, and continuing to act for some weeks after the initial application), mono and trichloroacetic acids hydrolyse tissues (soften and penetrate proteins); Table C2 and see Table K1

caustic soda see sodium hydroxide

cautery device used to cut, scarify or destroy tissue, by application of energy (heat, laser or an electric current)

cavitation formation of micro-sized bubbles or cavities within gas-containing tissue fluids during application of therapeutic ultrasound

cavus foot see pes, and Box P2

CE mark logo awarded by the Medical Devices Agency (MDA) denoting that the device manufacturer has been appropriately registered under EEC Directive 93/42 (Box C1)

cell cytoplasm, containing a nucleus and a variety of organelles, enclosed within a membrane envelop

cell receptors; cell membrane receptors protein structures within cell membranes, activated by ligands (i.e. drugs, enzymes, biochemicals or hormones) to cause a cell membrane or intracellular effect; receptor numbers rise and fall in response to local needs and demand, e.g. receptor upregulation occurs when ligand-driven demand increases, and vice versa

cell respiration oxidization of intracellular fuels, causing release of energy and formation of water and carbon dioxide

cell structure common intracellular features (nucleus, cytoplasm, cell membrane) and organelles (endoplasmic reticulum, lysosomes, mitochondria, microtubules, Golgi apparatus) which facilitate specialist function (see Table O3)

cell wall bimolecular lipid membrane that envelops the cell; contains receptors and pores through which small molecules can diffuse and larger molecules can be transported in and out of the cell

cellular response that part of the inflammatory response mediated by cells, e.g. monocytes (polymorphonuclearcytes) and macrophages

cellulitis hot, tender area of spreading skin erythema, with associated general malaise and pyrexia, due to a streptococcal infection

central nervous system; CNS brain and spinal cord

central nervous system (CNS) effects of local anaesthetics (LAs) relative or actual toxic (overdose) levels of local anaesthetics include initial excitement, euphoria and talkativeness, numbness of the tongue and perioral tissues, light-headedness, dizziness, tinnitus and difficulty with visual focus, progressing to slurring of speech, shivering, facial/hand/foot twitches, drowsiness and fleeting unconsciousness, to generalized tonic/clonic convulsions, respiratory depression and ultimately death; toxic effects are dose-dependent

centre group of nerve cells governing a specific function

centre of gravity; CG point within a body through which gravitational force acts; each body segment has an individual CG, but the overall CG of the static human body lies just superior to the navel, with the line of gravitational force directed downwards between the medial malleoli and just anterior to the ankle joint (through talonavicular joint); thus the erect body is stable; CG position changes continuously in relation to body movements; forward body motion is initiated when the CG is projected forward and the line of gravitational force falls beyond the body outline

centre of pressure; CP point within the base of support through which the full ground reaction force acts

centripetal direction of force pulling an object towards its axis of rotation

centromere primary constriction of a chromosome dividing it into two arms

cephalexin broad-spectrum antimicrobial derived from cephalosporin

cephaloridine broad-spectrum antimicrobial derived from cephalosporin

cephalosporins broad-spectrum antibiotics used to treat septicaemia; 10% of penicillin-sensitive individuals are also sensitive to cephalosporins; e.g. cefalexin (first-generation cephalosporin), cefotaxime (second-generation), ceftazidime (third-generation)

cerebellar ataxia see ataxia

cerebellar gait ataxic gait (Table C3 and see Table G1)

Table C3 Characteristic symptoms of unilateral cerebellar lesions

cerebellar lesions – Table C4

Table C4 Characteristic limb effects of cerebellar lesions

cerebellum posterior part of brain formed of right and left hemispheres united by the vermis; located superior to the pons and medulla and inferior to the posterior area of the cerebrum; it coordinates voluntary motor activity via afferent input (from proprioceptive organs in joints and muscles, the corticospinal system, basal ganglia, vestibular and olivary nuclei) and efferent output to the red nuclei, the vestibular nuclei, the basal ganglia and the corticospinal system; lateral lobe of each cerebellar hemisphere coordinates movement of ipsilateral limbs; vermis coordinates maintenance of axial (midline) posture and balance; any interruption to normal cerebellar function or its connections is characterized by impaired coordination of voluntary movement

cerebral haemorrhage bleeding within the cerebrum (cerebral hemispheres), secondary to head injury, ruptured cerebral aneurysm or weakened cerebral vessels secondary to severe atherosclerosis and hypertension; causing local and increasing pressure on brain tissue

cerebral hemisphere large mass of the telencephalon either side of the midline, consisting of paired cerebral cortices and their fibre systems together with the corpus striatum

cerebral palsy chronic disorder of motor function, with associated impaired mental ability in 60% of cases; becomes evident during second year of life, but present since, or before, birth; associated with birth injury, premature birth or perinatal brain anoxia; presents as upper motor neurone lesion of variable severity (depending on cause) affecting pyramidal tracts and/or extrapyramidal tract function, with loss of motor control and characteristic limb effects (Tables C5 and C6; see mixed cerebral palsy)

Table C5 Effects of spastic cerebral palsy in the lower limb

Table C6 Types and effects of cerebral palsy (CP)

cerebrospinal fluid fluid surrounding the brain and spinal cord

cerebrovascular accident; CVA; stroke rapidly developing focal dysfunction of brain tissue persisting for longer than 24 hours, commonly caused by interruption of normal blood supply to brain or spinal cord (e.g. infarction), exacerbated by atherosclerosis and thrombus formation; 1:3 of those affected by CVA are aged less than 65 years; patients with diabetes mellitus are especially prone to CVA; CVA effects vary widely, and presenting features depend on extent and location of central nervous system damage; third most common cause of death in the UK: 20% die within 1 month of CVA and 50% of survivors show permanent change in physical capability, speech and language, cognitive or emotional function; cause of major mobility impairment, e.g. hemiplegia, with footdrop and circumductory gait; surviving CVA cases are likely to be on lifelong anticoagulant therapy, e.g. warfarin or aspirin

cerebrum cerebral hemispheres

cervical ligament ligament of the subtalar joint; runs obliquely upwards and medially from the anterior superior aspect of calcaneum to lateral aspect of neck of talus; it becomes taut during foot inversion; helps control subtalar joint supination

cetrimide bacteriostatic antiseptic and surfactant quaternary ammonium compound; active against a narrow spectrum of Gram-positive bacteria; non-effective against Pseudomonas, fungi and spore forms; may be combined with chlorhexidine (0.015% chlorhexidine and 0.15% cetrimide, e.g. Tisept); cytotoxic; not routinely used to cleanse ulcers

Chaddock reflex see response, Chaddock

chairside appliances orthotic devices manufactured within the clinical environment, e.g. adapted preformed moulded insoles (pads or wedges affixed to a manufactured simple insole); silicone orthodigita; splints made from low-temperature thermoplastic materials (Hexalite, Aquaplast and Polyform) moulded (and remoulded) directly to the foot (material is immersed for 54–60 seconds in water at 65–70°C, after which it remains workable for up to 5 minutes; setting is accelerated by immersion in iced water)

Charcot foot gross midfoot deformity secondary to distal autonomic and/or sensory neuropathy; early-stage symptoms include swelling and mild inflammation, and possible discomfort; differential diagnosis should exclude osteomyelitis; see Charcot neuroarthropathy

Charcot–Marie–Tooth (CMT) disease see disease, Charcot–Marie–Tooth

Charcot neuroarthropathy; Charcot joint disease; neuropathic osteoarthropathy gross distortion of weight-bearing joints secondary to long-term sensory and autonomic neuropathy, abnormal inflammatory and healing responses; early immobilization for a minimum of 12 weeks is essential to minimize joint distortion; typical of diabetes mellitus and tabes dorsalis (syphilis)

Table C7 Classification of Charcot neuroarthropathy

Table C8 Clinical features of hypertrophic Charcot joint disease

Charcot restraint orthotic walker; CROW custom-made boot incorporating a total contact cast; worn after initial oedema has subsided, allowing the patient to remain weight-bearing during the natural course of the disease yet minimizing trauma to the affected area (Figure C1)

Figure C1 Charcot restraint orthotic walker (CROW).

cheater Akin procedure Akin medial basal wedge-closing osteotomy to proximal phalanx of hallux, without preoperative great-toe deformity; part of surgical metatarsus primus varus reduction, to achieve normal postoperative first-ray alignment

cheilectomy; chilectomy excision of joint margin bony irregularities to increase range of available joint movement and prevent joint movement pain, e.g. reduction of medial or dorsal bony eminence at first metatarsal head during surgical correction of hallux abductovalgus/rigidus

cheiropodopompholyx intense itching, dyshidrosis/hyperhidrosis and vesiculation (sago-sized blisters) of foot and hand skin due to allergic or id reaction; associated with fungal infection in atopic patients; treated with potassium permanganate soaks (to combat dyshidrosis) and topical steroid creams (to reduce inflammation)

chelation removal of ions so that they are unavailable to participate in biological reactions; tea chelates dietary iron (Fe²⁺), preventing its absorption; excessive tea drinking can exacerbate tendency to iron-deficiency anaemia, especially in the elderly

chemical burns local skin destruction by strong organic and inorganic acids and alkalis; tissue destruction is minimized by copious postcontact irrigation with water, or a neutralizing agent, e.g. bicarbonate of soda solution for acids, dilute vinegar for alkalis, glycerin for organic acids (e.g. phenol)

chemical cautery topical application of strong caustics to destroy skin cells or neoplasms, e.g. verrucae; the stronger the caustic, the greater the degree of tissue destruction caused; cauterizing chemicals include monochloroacetic acid, pyrogallic acid, potassium hydroxide, 40–70% salicylic acid, >25% silver nitrate (Table C9)

Table C9 Factors that should be considered in the use of chemical cauterizing agents to destroy verrucae

chemical disinfection destruction of microorganisms by chemical agents whose effectiveness is determined by concentration (manufacturers’ dilution guidelines must be followed exactly to ensure effectiveness), shelf-life (solutions must be used within a finite time after being made up), local environment (e.g. hard water, traces of contaminants [detergents, soap, organic or body tissue, cork, cellulose/cotton wool within the solution]) may all decrease disinfectant effectiveness (Table C10)

Table C10 Types of chemical disinfectant agents

chemoreceptors cells, or groups of cell membrane molecules, which initiate nerve action potentials

chemotaxis attraction of inflammatory cells (neutrophils, macrophages) to sites of actual or potential tissue trauma, mediated by the local release of trigger chemicals (exogenous substances [from infecting microorganisms] and endogenous acute inflammatory response compounds [complement factors, clotting factors, histamine, kinins, prostaglandins, leukotrienes, cytokines, and platelet-activating factor])

chemotherapy treatment of disease by chemical substances or drugs, e.g. antimetabolic agents to inhibit inflammation, or rapidly dividing cells

cherry angioma small, circumscribed haemangioma

chevron transpositional osteot-omy see Austin osteotomy

chief complaint; CC primary subjective symptom reported by the patient

chigoe; chigger flea; sand flea; jigger; Tunga penetrans tiny soil-dwelling tropical insect; the female burrows through plantar and webspace skin or under toenails to feed and lay eggs; infestation causes tungiasis, i.e. formation of haemorrhagic/ulcerated nodules 3–4 weeks after initial infection; differential diagnosis includes verruca pedis and amelanotic melanoma; treated by lesion curettage, cryotherapy or minute dissection to remove insect and all eggs

chilblain; perniosis cold-induced skin lesion characterized by marked inflammation, affecting peripheral tissues (fingers, toes, heel, lower legs, nose, tips of ears) especially in areas of skin exposed to cold draughts, in susceptible people; presents in four phases (Table C11); treatment is tailored to the phase of presentation; patients at risk of chilblain are advised to keep feet and legs warm (wear soft, multilayered leg clothing, roomy shoes with thermal insoles), avoid draughts and never immerse cold feet in hot water; systemic beta-blockers should be avoided, especially in winter

Table C11 Characteristic stages and treatments of chilblain

childhood osteomalacia see rickets

Chinese foot binding practice of binding feet of female babies from birth so that the plantar aspects of toes contacted the plantar midfoot or heel; linear foot growth was unaffected, but overall foot profile appeared tiny; the girl/woman was unable to walk for more than a few footsteps; a long-outlawed practice

Chirocaine see levobupivacaine

chlorambucil drug used to treat chronic lymphocytic leukaemia, non-Hodgkin’s lymphoma and Hodgkin’s disease; it may predispose to opportunistic infection, e.g. tinea pedis

chlorhexidine; Savlon; Hydrex 0.05% chlorhexidine (acetate or gluconate) in industrial methylated spirit (IMS) or water; powerful topical antiseptic effective against a wide range of skin flora, but non-effective against mycobacteria, Pseudomonas or spore forms; incompatible with soap; used for skin cleansing (allow to evaporate to dry for 5 minutes after application); 4% chlorhexidine gluconate in solution (Hibitane) is used as a preoperative surgical scrub

chloroquine antimalarial drug used to treat recalcitrant rheumatoid arthritis and mild systemic lupus erythematosus (note: contraindicated in psoriatic arthropathy)

chlorpromazine antipsychotic agent (Largactil) with antiadrenergic and anticholinergic actions; shows a wide range of adverse effects (e.g. extrapyramidal symptoms [drug-induced parkinsonism, dystonia, akathisia, tardive dyskinesia], hypotension, altered temperature regulation [hypothermia; hyperthermia], insomnia, agitation, convulsions); also used to control neuropathic and chronic pain states

chlorpropamide long-acting sulphonylurea (oral hypoglycaemic) agent; used to treat younger non-obese patients with type 2 diabetes; also used to treat diabetes insipidus (sensitizes renal tubules to antidiuretic hormone)

cholecalciferol vitamin D₃

cholesterol most abundant naturally occurring steroid; raised blood cholesterol levels link strongly to atheroma formation and vascular disease (normal values = 3.5–6.5 mmol/L; ideally < 5.2 mmol/L)

cholesterolosis disturbed lipid metabolism characterized by cholesterol deposition within subcuticular tissues, e.g. isolated fatty lump (lipoma) overlying Achilles tendon

cholinergic acetylcholine-secreting nerve endings (e.g. presynaptic autonomic and postsynaptic parasympathetic nerve endings), or an agent mimicking acetylcholine release

cholinesterases enzymes liberated by synapses, or parasympathetic postganglionic fibres that break down acetylcholine, to free up synaptic acetylcholine receptor sites, allowing transmission of a further impulse across the synapse

chondral modelling phenomenon the rate of bone formation from hyaline cartilage (i.e. articular cartilage, epiphyseal plates, tendon and ligament insertions, apophyseal plates, endplates within symphyses and sesamoids) is directly proportional to exerted and imposed load (see Table B6)

chondrification conversion to cartilage

chrondritis inflammation of cartilage

chondroblast cartilage-forming cell

chondroblastoma uncommon, painful or asymptomatic benign bone lesion of knee, talus and calcaneum, presenting on radiograph as a clearly defined round or oval bone lesion with a sclerotic border (see Table B5)

chondrocalcinosis cartilage calcification

articular chondrocalcinosis deposition of crystalline calcium hypophosphate within synovial fluid, articular cartilage and adjacent soft tissues; characterized by acute, gout-like pain, inflammation and swelling

chondrodystrophy developmental disturbance of the cartilaginous anlage of long bone epiphyses; bone growth arrest; e.g. as in achondroplasia

chondroma benign cartilage neoplasm

chondromalacia inflammatory degeneration of cartilage; e.g. inflamed medial sesamoid secondary to misalignment or ongoing synovitis; the sesamoid no longer glides with flexor hallucis brevis tendon at the first metatarsophalangeal joint, but is immobilized by fibrous tissue formation, causing hallux limitus

chondromalacia patellae retropatellar cartilage degeneration and damage, secondary to patellar tracking disorders; characterized by patellar misalignment and recurrent subluxation; exacerbating factors include increased Q angle, vastus medialis weakness, lower-limb malalignments, increased tibial torsion and excessive foot pronation (see Table K2); presents as deep anterior-knee pain, soft-tissue (knee) and synovial fluid effusion, and weakness of vastus medialis; severe cases show positive patellofemoral ‘grinding’ test (see test, Clarke’s); axial radiographs show osteophyte formation; treatment includes non-steroidal anti-inflammatory drugs, patella-stabilizing splints, RICE(P), ultrasound, antipronatory insoles, activity modification, specific quadriceps exercises and iliotibial band stretches; arthroscopic debridement of deep surface of patella may be indicated, and surgical release and realignment of vastus medialis may be required

chondro-osteodystrophy genetic disorders of bone and cartilage (e.g. Morquio syndrome and similar conditions) leading to abnormal growth

chondrosarcoma malignant neoplasm of cartilage, arising near ends of long bones, talus or calcaneum; presenting in older adults and only rarely in children; characterized by dull pain and swelling, bone matrix calcification, endosteal scalloping, local cortical thinning and expansion and soft-tissue involvement; difficult to diagnose from radiographs (see Table B5)

chorea irregular, spasmodic, involuntary movements of limbs or facial muscles

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