Osteoarchaeology. A Guide to the Macroscopic Study of Human Skeletal Remains

451 Pages·2017·89.1 MB·English

by  Efthymia Nikita (Auth.)

Dedication
To Dimitris
Osteoarchaeology
A Guide to the Macroscopic Study of Human
Skeletal Remains
Efthymia Nikita
AMSTERDAM lBOSTON lHEIDELBERGlLONDON lNEWYORK lOXFORD lPARIS
SANDIEGO lSANFRANCISCO lSINGAPORE lSYDNEY lTOKYO
AcademicPressisanimprintofElsevier
AcademicPressisanimprint ofElsevier
125LondonWall,LondonEC2Y5AS,UnitedKingdom
525BStreet,Suite1800,SanDiego, CA92101-4495,UnitedStates
50HampshireStreet,5th Floor,Cambridge,MA02139,UnitedStates
TheBoulevard, LangfordLane,Kidlington,OxfordOX51GB,UnitedKingdom
Copyright ©2017Elsevier Inc.Allrightsreserved.
Nopartofthispublication maybereproducedor transmitted inanyformor byanymeans,electronicormechanical, including
photocopying,recording,or anyinformationstorage andretrieval system,without permissioninwritingfrom thepublisher.
Details onhowtoseekpermission, further informationaboutthePublisher’spermissionspoliciesandour arrangements with
organizationssuchasthe CopyrightClearance CenterandtheCopyright LicensingAgency,canbefoundatour website:
www.elsevier.com/permissions.
Thisbookandthe individualcontributionscontainedinitareprotected undercopyright bythePublisher (otherthanas maybe
notedherein).
Notices
Knowledgeandbest practiceinthisfieldareconstantly changing.Asnewresearchandexperiencebroadenour understanding,
changesinresearchmethods,professionalpractices,or medicaltreatmentmay becomenecessary.
Practitionersandresearchersmustalwaysrelyontheirownexperienceandknowledgeinevaluatingandusinganyinformation,
methods,compounds,orexperiments describedherein.In usingsuchinformationor methodstheyshould bemindfuloftheir
ownsafetyandthesafety ofothers,includingpartiesfor whomthey haveaprofessionalresponsibility.
Tothefullestextentof thelaw,neither thePublishernor theauthors,contributors, oreditors, assumeanyliabilityforanyinjury
and/ordamagetopersons orproperty asamatterof productsliability, negligenceorotherwise, orfromanyuseor operationof
anymethods,products,instructions, orideascontained inthematerialherein.
LibraryofCongress Cataloging-in-Publication Data
Acatalogrecordforthisbookisavailablefrom theLibraryofCongress
British LibraryCataloguing-in-Publication Data
Acataloguerecordfor thisbookisavailablefrom theBritishLibrary
ISBN:978-0-12-804021-8
ForinformationonallAcademic Presspublications
visit ourwebsiteathttps://www.elsevier.com/
Publisher: SaraTenney
AcquisitionEditor: ElizabethBrown
EditorialProjectManager:JoslynChaiprasert-Paguio
ProductionProjectManager:LisaJones
Designer:MariaInes Cruz
TypesetbyTNQBooksandJournals
Preface
WhenIreadLarsen’sBioarchaeologyasanundergraduatestudentofarcheology,IknewthatthiswasthespecializationI
wantedtofollow.TheproblemwasthatIhadnoideahowtoperformthefascinatinganalysesdescribedinthecasestudies
thatLarsenpresented.Overthefollowingmonths,moreexcellentbookspileduponmybookshelves.WhiteandFolkens’
Human Osteology, Katzenberg and Saunders’ Biological Anthropology of the Human Skeleton, and Cox and Mays’
Human Osteology in Archeology and Forensic Science are only a few of the most recent titles. Every book gave me an
evenbetterunderstanding ofthepotentialsof human skeletalanalysis butatthe same time it made me realize how much
more there was to learn on a practical level to actually engage in such a study. When I discovered the Buikstra and
UbelakerStandardsforDataCollectionfromHumanSkeletalRemainsitfeltlikeabigbarrierhadbeenfinallylifted,and
indeedtheinformationprovidedbythecontributorsofthisseminalvolumewaspivotalinthecompletionofmyM.Phil.in
BiologicalAnthropology.Nevertheless,giventheadvancesthathadoccurredinthedisciplinesincethedateofpublication
of this volume (1994), important aspects of human skeletal analysis, such as the calculation of cross-sectional geometric
properties of long-bone diaphyses or the performance of geometric morphometric analysis, were missing.
The current book attempts to provide the practical guidance required so that the reader can perform a thorough
macroscopicstudyofhumanskeletalremainsstartingfromboneidentificationandprogressingtoadvancedanalyses,such
as biodistance estimation. Microscopic, biomolecular, and biochemical methods have intentionally been omitted despite
theirprominentroleinosteoarchaeologicalresearch.Thereasonwasthattheaimofthisbookistopresentmethodsthatthe
readercanuseonhisorherownwithoutanyparticularlyspecializedequipmentrequired.Severalotherbooksdiscussthe
use of such specialized techniques in detail.
Beforethestructureofthebookisoutlined,abriefclarificationonterminologyisinneed.Thereiscurrentlynosingle
universally agreed-upon term to describe the study of human skeletal remains from archaeological contexts. The term
bioarchaeologyisfrequently adoptedfor thispurpose;however, bydefinition thisterm coversallremains ofabiological
nature, not solely human skeletal material. Similarly, osteoarchaeology is another common term used to denote human
skeletalanalysis,butagain,bydefinitionthistermalsocoversthestudyofanimalskeletalremains.Owingtothelackofa
generally accepted term, osteoarchaeology isusedin the current book torefer exclusively to thestudy ofhuman skeletal
material, acknowledging the limitations of this choice.
Thisbookisstructuredinninechapters.Chapter1presentstheadulthumanskeletonandprovidesidentificationtipsfor
each bone and tooth, and Chapter 2 outlines the main taphonomic factors that affect the preservation of human skeletal
remains. Chapter 3 describes methods for assessing the sex and ancestry of an individual based on various skeletal ele-
ments. The methods presentedaremostlydesignedfor adult material because sexand ancestry assessmentinjuveniles is
problematic for reasons explained in the relevant sections. However, brief mention is also made of methods for sex and
ancestry assessment in subadults. Age estimation standards for adults and juveniles are given in Chapter 4. Chapter 5
focuses on biodistance analysis by means of metric and nonmetric traits. Descriptions of cranial measurements and
landmarksareprovided,alongwithdefinitionsofcranialanddentalnonmetrictraits.Anumberofappendicesdescribein
detailthestepstobefollowed,fromdatacollectiontopreprocessingandtheactualcalculationofbiodistances.Chapter6
outlines the utility of growth pattern studies. In this context, methods for stature and body mass estimation are also
provided, along with an appendix illustrating postcranial measurements. Chapter 7 presents skeletal markers of activity,
namely cross-sectional geometric properties of long-bone diaphyses, entheseal changes, and dental wear. Instructions for
how to calculate cross-sectional geometric properties using a nondestructive method are provided, as well as recording
protocolsforenthesealchanges.Withregardtodentalwear,bothordinalscoringschemesandamethodforcalculatingthe
areaofexposeddentinearedescribed.Chapter8brieflypresentsthemainpathologicalconditionsthatmaybeidentifiedon
humanskeletalremains.Consideringthelargenumberofexcellenttextbooksonpaleopathology,thefocusofthischapter
is on listing the lesions commonly associated with pathological conditions that frequently affect the skeleton. Finally,
Chapter 9 offers step-by-step instructions for the statistical analysis of human osteological data using SPSS and,
ix
x Preface
secondarily,Excel.Descriptiveandinferentialstatisticsarepresentedandnumerouscasestudiesaregiventocoversimple
tests but also more advanced multivariate analyses.
The emphasis in all chapters is on the practical implementation of each method, which resulted in a very limited
referencetobackgroundtheoreticalinformationorpublishedcasestudies.Thiswasanecessarycompromisebutthereader
may find ample information regarding the context of useof each described method inalready publishedosteology books
and scientific papers. Note that even though there is limited reference to published case studies, case studies based on
artificial and actual data sets are used throughout this book to demonstrate the steps of data acquisition, processing, and
results interpretation.
Asitstitlesuggests,thisbookhasbeenwrittenprimarilyforosteoarchaeologists.Nevertheless,forensicanthropologists
are also expected to find most sections of it useful. Specifically, the methods described in Chapters 1e4 are practically
identicaltothoseusedinforensiccontexts.Similarly,thestatureandbodymassestimationmethodsdescribedinChapter6
areamongthemainapproachesusedintheidentificationofunknownindividuals,alongwithsex,age,andancestry.Finally,
althoughthetraumasectioninChapter8isbrief,itmaybeusefulintheforensicanalysisofthemannerofdeathofanin-
dividual.Theremainingchaptersandsectionsarealsopotentiallyusefulinthestudyofforensicmaterialbutmoremarginally.
Tofacilitatetheuseofthemethodsdescribedinthisbook,aseriesofmacrosisprovidedinthecompanionwebsiteof
this book, available on http://textbooks.elsevier.com/web/Manuals.aspx?isbn=9780128040218. The most important
ofthesemaybeusedfor(1)thecalculationofthenumberofindividualsincommingledassemblages;(2)thepretreatment
ofcraniallandmarksandnonmetrictraitsforthecalculationofbiodistances;(3)theactualcalculationofbiodistancesbased
on continuous, ordinal, and binary data; (4) the estimation of sex, age, stature, and body mass; (5) the generation of
artificial data sets; and (6) statistical analysis.
This book would not have been completed without numerous people who, directly or indirectly, contributed to its
creation. First of all, I would like to thank my editor, Elizabeth Brown, for believing in this book and supporting its
publicationdespitemyratheryoungacademicage.Similarly,JoslynChaiprasert-PaguioandLisaJonesofferedimportant
help with practical issues toward the final stages of the submission and publication. I would also like to express my
gratitudetootherpersonnelatElsevierwithwhomIneverhaddirectcontactandwhocontributedtotheproductionofthis
book. Furthermore, I would particularly like to thank the four reviewers of my book proposal, namely Dr. Elizabeth
DiGangi, Dr. Megan Moore, Dr. Christina Papageorgopoulou, and Dr. Jay Stock, for approving it as well as for their
valuablecomments.Inaddition,Iwouldliketoacknowledgethecontributions ofDr.CharlotteHenderson,OliviaJones,
Ria Kiorpe, Anna Lagia, Effrossyni Michopoulou, Dr. Marin Pilloud, and Dr. Emma Pomeroy in reviewing various
chaptersbeforemyfinalsubmissionandprovidingusefulsuggestionsfortheirimprovement.Mymother,MalamatiNikita,
patiently proofread all chapters, and Dr. Victoria Ling also proofread a few of the chapters in their early stages of
preparationandkindlysent mecertainpublicationsthatIcould notaccess inGreece.Finally,myfather,ProfessorPanos
Nikitas, provided valuable guidance during the creation of the macros given as online material.
Unless otherwise specified, all photographs were obtained by the author from the Athens Collection, housed at the
DivisionofAnimalandHumanPhysiology,DepartmentofBiology,NationalandKapodistrianUniversityofAthens.Iam
deeplygratefultoProfessorEfstratiosValakosforgrantingmepermissiontousethismaterialforthecurrentpublication,
as well as to Professor Sotiris Manolis, Dr. Costas Eliopoulos, and Anna Lagia for setting up this important collection.
Image processing was sort of a family business, as my father and sister, Margarita, spent endless hours preparing the
illustrations ofeachchapter.Moreover,ProfessorDavidMattinglykindlyprovidedmeaphoto fromhispersonal records
forthetaphonomychapter,andFranceCastinggavemepermissiontousephotosItookoftheirSucheyeBrookscastsfree
of charge. Similarly, I am grateful to Dr. Chris Dudar for allowing the use of screenshots of the Osteoware software and
Professor Dennis Slice for permitting the use of screenshots of Morpheus et al. Finally, the Leicester Arts and Museums
Service, and Laura Hadland in particular, generously allowed me to use photographs I had obtained from material from
Medieval Leicester, without which the paleopathology chapter would have been notably poorer.
My Ph.D. supervisor, Dr. Marta Lahr, and all my colleagues and tutors at the Leverhulme Center for Human
EvolutionaryStudies,UniversityofCambridge,playedamajorroleinshapingmyresearchinterestsandwayofthinking.
The same applies to my colleagues in Greece, primarily Dr. Sevi Triantaphyllou, Professor Kostas Kotsakis, and all
membersoftheFitchLaboratoryattheBritishSchoolatAthens.Ifeelveryluckytohaveworkedwithallofthem.Finally,
I would like to thank my employers and colleagues at the Cyprus Institute for being particularly supportive during the
preparation of this book.
Onamorepersonallevel,IwouldliketothankmydearfriendandcolleagueAnitaRadiniforgrantingmeaccesstoa
rich collection of skeletal material from Leicester and permitting the publication of selected photographs from the
Southwellmaterial.MyfriendEleftheriaBousakispentseveralhourstranslatingMartin’s(1928)definitionsofpostcranial
measurementsfromGermantoEnglish,whichwasquiteanadmirabletask!Finally,myfamilyandfriendshavesupported
Preface xi
meineverystepofthisendeavor.Atthispoint,specialthanksmustbeaddressedtomyhusbandforhisendlesspatience
and encouragement at all times.
Iamhopingthatthisbookwillcomplementexistingtextbooksusedinupper-levelundergraduateandgraduatecourses
on osteoarchaeology, human osteology, and, to some extent, forensic anthropology. The book is also addressed to pro-
fessionalosteologists.Itmustbestressedthatthemethodspresentedherearebynomeanstheonlywaytoapproacheach
research question. Various recording protocols, data processing methods, and statistical tests may provide equally valid
results. Themethodsdescribed here arethose thatIhavehadtheopportunitytoapply myself andfound toperform well.
However, they are aimed at acting as a starting point and equipping the reader with a basic understanding required for a
thorough human skeletal study so that he or she subsequently feels confident enough to experiment with different tech-
niques.Everyefforthasbeenmadetoavoidmistakesandpresentanupdatedreviewoftheliterature.Giventhevolumeof
thisbook,itisinevitablethatsomemajorpublicationwillhavebeenmissed,andsomeerrorsmusthavefoundtheirwayin.
IapologizeinadvanceandIwouldbeverygratefulifyoucouldcontactmedirectlytopointoutanymistakesoromissions
or share suggestions for the future improvement of this book.
Chapter 1
The Human Skeleton
Chapter Outline
1.1 BoneFunction 2 1.8 Teeth 54
1.2 BoneClassification 2 1.8.1 ToothTypesandDentalNumberingSystems 54
1.3 BoneStructure 3 1.8.2 DentalDirectionalTerms 56
1.3.1 GrossAnatomy 3 1.8.3 ToothAnatomyandComposition 56
1.3.2 MicroscopicAnatomy 4 1.8.4 ToothFormationandDevelopment 57
1.4 BoneCompositionandCells 4 1.8.5 ToothIdentification 58
1.5 BoneGrowthandDevelopment 5 1.8.5.1 DiscriminationBetweenDeciduousand
1.6 PlanesofReferenceandDirectionalTerms 5 PermanentTeeth 58
1.7 BoneIdentification 6 1.8.5.2 IdentificationofIncisors 59
1.7.1 AxialSkeleton 6 1.8.5.3 IdentificationofCanines 60
1.7.1.1 Skull 6 1.8.5.4 IdentificationofPremolars 61
1.7.1.2 HyoidandSpine 16 1.8.5.5 IdentificationofMolars 63
1.7.1.3 ThoracicCage 26 References 64
1.7.2 AppendicularSkeleton 27 SuggestedReadings 64
1.7.2.1 ShoulderGirdle 27 Appendices 66
1.7.2.2 PelvicGirdle 31 Appendix1.I:BoneInventory 66
1.7.2.3 ArmandLegBones 33 Appendix1.II:ToothInventory 69
1.7.2.4 HandandFootBones 40 Appendix1.III:BoneandToothInventoryUsingOsteoware 69
Chapter Objectives
By the end of this chapter, the reader will be able to:
l understandthefunction,structure,andcompositionofthehumanskeleton;
l useproperterminologytodescribeskeletalanatomy;
l definethetermsoforientationforthehumanskeleton;
l identifythemajorbonesoftheadulthumanskeletonincompleteandfragmentarystates;and
l identifyallpermanentmaxillaryandmandibularteeth.
This chapter outlines the function, structure, and composition of the human skeleton; presents basic anatomical termi-
nology;andoffersimagesandbriefdescriptionsforallskeletalelementsandthepermanentdentition.Theemphasisison
adultskeletalremainsbecausethejuvenileskeletonchangesdrasticallyduringgrowthandtheconsequentanatomicaland
morphological alterations are not possible to describe in a single chapter. The reader may consult the books given as
suggestedreadingsattheendofthischapterforresourcesonjuvenileosteologyaswellasforadditionalinformationonthe
topics presented in the current chapter.
1
Osteoarchaeology.http://dx.doi.org/10.1016/B978-0-12-804021-8.00001-2
Copyright©2017ElsevierInc.Allrightsreserved.
2 Osteoarchaeology
1.1 BONE FUNCTION
Thehumanskeletonperformsmultiplefunctions.Itsupportsthebodyandenablesmotion,whilecertainskeletalelements
protect internal vital organs; for instance, cranial bones offer protection to the brain. In addition, the skeleton stores: (1)
minerals,suchascalciumandphosphorus;(2)blood-formingcells,astheredbonemarrowproducesredbloodcells,white
bloodcells,andplateletsviaaprocessknownashematopoiesis;and(3)energyviathefat(lipids)storedintheyellowbone
marrow.
1.2 BONE CLASSIFICATION
Theadultskeleton(Fig.1.2.1)typicallyconsistsof206bones,though thisnumbermaydifferslightlyamong individuals
owing to genetic factors. At birth, the skeleton has many more bones (over 270) but during adolescence many separate
elements gradually fuse together.
FIGURE1.2.1 Three-dimensionalmodelof thehumanskeleton.Note:Thehyoidisnot visibleinthisfigure;thecorrespondingarrowdenotesits
location.
Based on their shape, human bones are divided into long, short, flat, and irregular bones. Long bones are elongated
elements,astheirnamesuggests,andconsistofatubularshaftterminatinginanarticularareaateachend.Suchbonesare
found in the upper and lower limbs (clavicle, humerus, radius, ulnaefemur, tibia, fibula). Their main functions include
supportingtheweightofthebodyandenablingmovement.Notethatsomeauthorsplacethemetacarpalsandmetatarsals
alsointhelongbonecategoryonthegroundsthattheirlengthisgreaterthantheirwidth.Inshortbonesalldimensionsare
almostequalandtheirsomewhatcubicshapeprovidesthemwithcompactness.Suchbonesarefoundmostlyinthehands
and feet (carpals, tarsals). Flat bones are flat, thin, and broad elements. As such, they provide extensive areas for muscle
attachmentandprotectvitalorgans.Thiscategoryincludesmostcranialbones(e.g.,frontal,occipital,parietals),aswellas
the scapulae, os coxae, ribs, and sternum. Finally, as their name suggests, irregular bones have a complex morphology,
which serves various functions. The elements of the spine (vertebrae, sacrum, coccyx) and certain cranial elements
(e.g., sphenoid) belong in this category.
Accordingtotheirlocationintheskeleton,bonesareclassifiedintoaxialandappendicular.The axialskeleton has80
bones and includes the skull, hyoid, vertebrae, sacrum, coccyx, ribs, and sternum. The appendicular skeleton consists of
126bones,whicharethelongbonesofthearmsandlegs,patellae,handandfootbones,clavicles,scapulae,andoscoxae
(Fig. 1.2.2).
TheHuman Skeleton Chapter | 1 3
FIGURE1.2.2 Axialandappendicularskeleton.
Two special categories of bones, which differ substantially in number between individuals, are sesamoid bones and
sutural bones. Sesamoid bones are very small-sized and found within tendons. Their function is to protect tendons from
excessive mechanical stress. Sutural bones are small-sized and found within the cranial sutures, that is, the joints that
connect cranial bones.
Details onhowtoidentifyeachboneandtootharegiven inthefollowingsections. Appendix1.Ipresentsarecording
spreadsheetfortheadulthumanskeletonandAppendix1.IIprovidesarecordingspreadsheetforthepermanentdentition.
Finally,Appendix1.IIIpresentstheboneandtoothinventoriesimplementedinOsteoware,afreesoftwareprogramforthe
standardized recording of human skeletal remains, designed and provided by the Smithsonian Institution.
1.3 BONE STRUCTURE
1.3.1 Gross Anatomy
Atypicallongboneconsistsof(1)adiaphysis,theshaftofthebone;(2)twoepiphyses,theextremitiesofthebone;and(3)
twometaphyses,theareasthatliebetweenthediaphysisandeachoftheepiphyses(Fig.1.3.1).Theepiphysesareinitially
FIGURE1.3.1 Longbonestructure.
4 Osteoarchaeology
separated from the diaphysis, as the metaphyses contain a growth plate (or epiphyseal plate), consisting of hyaline
cartilage,whichallowslongitudinalbonegrowth.Onceanindividualreachesadulthoodandgrowthceases,thiscartilageis
ossified and forms the epiphyseal line. The surface of the epiphyses that articulates with neighboring skeletal elements is
covered with a thin layer of hyaline cartilage (articular cartilage) during life. The external bone surfaces that have no
articularcartilagearecoveredbytheperiosteum.Theperiosteumenablesbonegrowthinthickness,protectsandnourishes
the osseous tissues, facilitates fracture repair, and allows the attachment of ligaments and tendons. It attaches to the un-
derlyingosseoustissuesbymeansofthickcollagenfibers,calledSharpey’sfibers.Intheinteriorofthelongbonesliesthe
medullarycavity,which,duringlife,containsyellowbonemarrow.Thewallsofthiscavityarecoveredbytheendosteum,
a membrane that contains bone-forming cells.
Short,flat,andirregularboneshavearathersimplerstructure,consistingoftrabecularbonecoveredbycorticalbone(seeSection
1.3.2fordefinitionsofthetrabecularandcorticalbone).ThegrossstructureofaflatboneisshownschematicallyinFig.1.3.2.
FIGURE1.3.2 Flatbonestructure.
1.3.2 Microscopic Anatomy
Histologically, bone tissue may be woven (immature) or lamellar (mature). During periods of skeletal growth or when
certain pathological conditions have afflicted the skeleton, such as during fracture healing, the bone tissue produced
consists of irregularly shaped collagen bundles with a random orientation. This type of bone is called woven or primary
bone. Woven bone provides a means of responding rapidly to growth, disease, or mechanical loading; however, its
disorganizedstructuremakesitineffectiveinofferinglong-termstructuralsupport.Incontrast,matureorlamellarboneis
formed in later childhood and during adulthood, and it consists of mineral crystals and collagen fibers that form layers
called lamellae. Lamellar bone gradually replaces woven bone.
Lamellarbonehastwostructuraltypes,cortical(orcompact)boneandtrabecular(orcancellous)bone.Corticalboneis
denseandliesunderneaththeperiosteum.Notethatthecorticalbonefoundinthejointsiscoveredbycartilageduringlife
and it is called subchondral bone. Its structural units are osteons, which consist of concentric layers of compact bone,
lamellae,organizedaroundacentralcanal,aHaversiancanal,containingbloodvesselsandnervefibers.Trabecularbone
isfoundattheepiphysesoflongbonesandintheinteriorofallotherbones.Itconsistsofthinbonyspicules,trabeculae,
each of which is composed of a few layers of lamellae. The trabeculae are arranged irregularly, forming a honeycomb
structure.Becauseofthisstructure,trabecularbonehasminimalweightbutatthesametimeprovidesgreatstrengthtothe
skeleton. During life, the spaces within the trabecular network contain hematopoietic red marrow.
1.4 BONE COMPOSITION AND CELLS
Bone tissue consists of inorganic (w70%) and organic (w30%) components. The principal inorganic component is hy-
droxyapatite, Ca (PO ) (OH) , a mineral composed of calcium phosphate. Collagen fibers are the main organic
10 4 6 2
component, along with noncollagenous proteins. The inorganic component makes the skeleton strong, whereas collagen
offers elasticity.
Asa living tissue, thehuman skeleton goesthrough aconstantprocessofboneresorption(releasingofcalciumand
phosphate from mineralized bone) and deposition (use of calcium and phosphate to form new bone). This process is
controlled by the main bone cells: osteogenic cells, osteoclasts, osteoblasts, osteocytes, and bone-lining cells. Osteo-
genic (or osteoprogenitor) cells derive from mesenchymal stem cells in bone marrow. These cells evolve into pre-
osteoblasts, which subsequently give rise to mature osteoblasts. In the marrow of growing individuals, the number of
osteogenic cells is high, but the number or potential of such cells to form mature osteoblasts declines with age. Os-
teoclasts are large, multinucleated cells, whose primary function is to resorb bone tissue by releasing lysosomal