Terminology in anatomy General information on the systems Kaan Yücel M.D., Ph.D. 13. 15.September. 2011Thursday 20. September. 2011 Tuesday
Terminology in anatomy It is importantformedicalpersonneltohave a soundknowledgeandunderstanding of thebasicanatomicterms. Withtheaid of a medicaldictionary, youwillfindthatunderstandinganatomicterminologygreatlyassistsyou in thelearningprocess. Theaccurateuse of anatomictermsbymedicalpersonnelenablesthemtocommunicatewiththeircolleaguesbothnationallyandinternationally. Withoutanatomicterms, onecannotaccuratelydiscussorrecordtheabnormalfunctions of joints, theactions of muscles, thealteration of position of organs, ortheexactlocation of swellingsortumors.
Theaccurateuse of anatomictermsbymedicalpersonnelenablesthemtocommunicatewiththeircolleaguesbothnationallyandinternationally. Withoutanatomicterms, onecannotaccuratelydiscussorrecordtheabnormalfunctions of joints, theactions of muscles, thealteration of position of organs, ortheexactlocation of swellingsortumors.
Anatomical terms are descriptive terms standardized in an international reference guide, TerminologiaAnatomica (TA). These terms, in English or Latin, are used worldwide. Colloquial terminology is used by—and to communicate with—lay people. Eponyms are often used in clinical settings but are not recommended because they do not provide anatomical context and are not standardized.
Many anatomical terms have both Latin and Greek equivalents, although some of these are used in English only as roots. Thus the tongue is lingua (L.) and glossa (Gk), and these are the basis of such terms as lingual artery and glossopharyngeal nerve.
Variousadjectives, arranged as pairs of opposites, describetherelationship of parts of the body orcomparetheposition of twostructuresrelativetoeachother. Anatomicaldirectionaltermsarebased on the body in theanatomicalposition. Fouranatomicalplanesdividethe body, andsectionsdividetheplanesintovisuallyusefulanddescriptiveparts.
TermsRelatedtoPosition Alldescriptions of thehuman body arebased on theanatomicposition. Thevariousparts of the body arethendescribed in relationtocertainimaginaryplanes.
MedianSagittalPlane This is a verticalplanepassingthroughthecenter of the body, dividing it intoequalrightandlefthalves. .
CoronalPlanes Imaginaryverticalplanes at rightanglestothemedianplane. Horizontal, orTransverse,orAxialPlanes At rightanglestoboththemedianandthecoronalplanes.
Anatomicaltermsarespecificforcomparisonsmade in theanatomicalposition, orwithreferencetotheanatomicalplanes: • Superiorrefersto a structurethat is nearerthevertex, thetopmostpoint of thecranium (Mediev. L., skull). • Cranialrelatestothecraniumand is a usefuldirectionalterm, meaningtowardtheheadorcranium. • Inferiorrefersto a structurethat is situatednearerthe sole of thefoot. • Caudal (L. cauda, tail) is a usefuldirectionaltermthatmeanstowardthefeetortailregion, represented in humansbythecoccyx (tail bone), thesmall bone at theinferior (caudal) end of thevertebralcolumn.
Posterior(dorsal) denotesthebacksurface of the body ornearertotheback. • Anterior (ventral) denotesthefrontsurface of the body. • Rostral is oftenusedinstead of anteriorwhendescribingparts of thebrain; it meanstowardtherostrum (L. forbeak); • Todescribetherelationship of twostructures, one is saidto be anteriororposteriortotheotherinsofar as it is closertotheanteriororposterior body surface.
Medialis usedtoindicatethat a structure is nearertothemedianplane of the body. Forexample, the 5th digit of thehand (littlefinger) is medialtotheotherdigits. • Lateralstipulatesthat a structure is fartherawayfromthemedianplane. The 1st digit of thehand (thumb) is lateraltotheotherdigits. • Dorsumusuallyreferstothesuperioraspect of anypartthatprotrudesanteriorlyfromthe body, such as thedorsum of thetongue, nose, penis, orfoot
Combinedtermsdescribeintermediatepositionalarrangements: inferomedialmeansnearertothefeetandmedianplane—forexample, theanteriorparts of theribsruninferomedially; superolateralmeansnearertotheheadandfartherfromthemedianplane.
Otherterms of relationshipandcomparisonsareindependent of theanatomicalpositionortheanatomicalplanes, relatingprimarilytothebody'ssurfaceoritscentralcore: • Superficial,intermediate, anddeep (Lat. Profundus, profunda) describetheposition of structuresrelativetothesurface of the body ortherelationship of onestructuretoanotherunderlyingoroverlyingstructure.
Externalmeansoutside of orfartherfromthecenter of an organ orcavity, whileinternalmeans inside orclosertothecenter, independent of direction.
Proximalanddistalareusedwhencontrastingpositionsnearertoorfartherfromtheattachment of a limborthecentralaspect of a linearstructure (origin in general), respectively. Forexample, thearm is proximaltotheforearmandthehand is distaltotheforearm.
Terms of Laterality Pairedstructureshavingrightandleftmembers (e.g., thekidneys) arebilateral, whereasthoseoccurring on onesideonly (e.g., thespleen) areunilateral. Somethingoccurring on thesameside of the body as anotherstructure is ipsilateral. Contralateralmeansoccurring on theoppositeside of thebody relativetoanotherstructure.
Terms of Movement • Varioustermsdescribemovements of thelimbsandotherparts of the body. • Mostmovementsaredefined in relationshiptotheanatomicalposition, withmovementsoccurringwithin, andaroundaxesalignedwith, specificanatomicalplanes. • Whilemostmovementsoccur at jointswheretwoormorebonesorcartilagesarticulatewithoneanother, severalnon-skeletalstructuresexhibitmovement (e.g., tongue, lips, eyelids).
Terms of movementmayalso be considered in pairs of oppositingmovements: Flexionandextensionmovementsgenerallyoccur in sagittalplanesaround a transverseaxis.
Flexionindicatesbendingordecreasingtheanglebetweenthebonesorparts of the body. Formostjoints (e.g., elbow), flexioninvolvesmovement in an anteriordirection, but it is occasionallyposterior, as in thecase of thekneejoint. • Lateralflexionis a movement of thetrunk in thecoronalplane.
Extensionindicatesstraighteningorincreasingtheanglebetweenthebonesorparts of the body. Extensionusuallyoccurs in a posteriordirection. • Thekneejoint, rotated 180° tootherjoints, is exceptional in thatflexion of thekneeinvolvesposteriormovementandextensioninvolvesanteriormovement.
Dorsiflexiondescribesflexion at theanklejoint, as occurswhenwalkinguphillor lifting thefront of thefootandtoesofftheground. • Plantarflexionbendsthefootandtoestowardtheground, as whenstanding on yourtoes.
Abductionandadductionmovementsgenerallyoccur in a frontalplanearound an anteroposterioraxis. • Exceptforthedigits, abductionmeansmovingawayfromthemedianplane (e.g., whenmoving an upperlimblaterallyawayfromtheside of the body) andadductionmeansmovingtoward it.
Circumduction is a circularmovementthatinvolvessequentialflexion, abduction, extension, andadductionin such a waythatthedistalend of thepartmoves in a circle. • Circumductioncan occur at anyjoint at whichalltheabove-mentionedmovementsarepossible (e.g., theshoulderandhipjoints).
Rotationinvolvesturningorrevolving a part of the body arounditslongitudinalaxis, such as turningone'sheadtofacesideways. • Medialrotation (internalrotation) bringstheanteriorsurface of a limbclosertothemedianplane, whereaslateralrotation (externalrotation) takestheanteriorsurfaceawayfromthemedianplane.
Pronationrotatestheradiusmediallysothatthepalm of thehandfacesposteriorlyanditsdorsumfacesanteriorly. Whentheelbowjoint is flexed, pronationmovesthehandsothatthepalmfacesinferiorly (e.g., placingthepalmsflat on a table). • Supination is theoppositerotationalmovement, rotatingtheradiuslaterallyanduncrossing it fromtheulna, returningthepronatedforearmtotheanatomicalposition. Whentheelbowjoint is flexed, supinationmovesthehandsothatthepalmfacessuperiorly.
Eversionmovesthe sole of thefootawayfromthemedianplane, turningthe sole laterally. • Inversionmovesthe sole of thefoottowardthemedianplane (facingthe sole medially).
Oppositionis themovementbywhichthepad of the 1st digit (thumb) is broughttoanotherdigitpad. Thismovement is usedtopinch, button a shirt, and lift a teacupbythehandle. • Repositiondescribesthemovement of the 1st digitfromtheposition of oppositionbacktoitsanatomicalposition.l
Protrusion is a movementanteriorly (forward) as in protrudingthemandible (chin), lips, ortongue. • Retrusion is a movementposteriorly (backward), as in retrudingthemandible, lips, ortongue.
Elevationraisesormoves a partsuperiorly, as in elevatingtheshoulderswhenshrugging. • Depressionlowersormoves a partinferiorly, as in depressingtheshoulderswhenstanding at ease.
Protractionandretractionareusedmostcommonlyforanterolateralandposteromedialmovements of thescapula on thethoracicwall, causingtheshoulderregiontomoveanteriorlyandposteriorly.
General considerations • on thesystems
The skin (L. integumentum, a covering) is the body's largest organ, consists of the epidermis, a superficial cellular layer, and the dermis, a deep connective tissue layer.
The skeleton is composed of cartilages and bones. • The skeletal system may be divided into two functional parts: • Axialskeleton • Bones of the head • Bones of the neck • Bones of thetrunk • Appendicularskeleton • Bones of the limbs
Joints Joints (articulations) are unions or junctions between two or more bones or rigid parts of the skeleton. Joints exhibit a variety of forms and functions. Some joints have no movement, such as the epiphysial plates between the epiphysis and diaphysis of a growing long bone; others allow only slight movement, such as teeth within their sockets; and some are freely movable, such as the glenohumeral (shoulder) joint.
Classification of Joints Three classes of joints are described based on the manner or type of material by which the articulating bones are united.
Synovial joints: The bones are united by a joint (articular) capsule (composed of an outer fibrous layer lined by a serous synovial membrane) spanning and enclosing an articular cavity. The joint cavity of a synovial joint, like the knee, is a potential space that contains a small amount of lubricating synovial fluid, secreted by the synovial membrane. Inside the capsule, articular cartilage covers the articulating surfaces of the bones; all other internal surfaces are covered by synovial membrane.