Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Wounds, Accidents, Medical TreatmentSlide 24Rickets – dietary causeGrowth Arrest LinesEnamel HypoplasiaSlide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42THE HUMAN SKELETONCan reveal basic information about the individualand about the populationThe first two things you want to know about anyindividual skeleton are:AGE and SEXSexing a skeletonDepends on sexual dimorphismNot possible until secondary sexualcharacteristics develop, or untilafter pubertySexing a skeletonMALESFEMALESGenerally are more robust, larger, more heavily muscledThe more muscle, thedenser the bone andmore prominent muscleattachmentsGenerally are more gracile,smaller, less heavilymuscled(Whitehead et al. 2005:255)Two adult mandibles from sameEskimo site, Greenland, CanadafemalemaleMale more robustFemale more gracile(France 1998:90)Skull -- 2nd best area to use todetermine sex of skeletonbrow ridge(supraorbitalridge)chinmastoid processMaleFemaleBrow ridges more prominent in malesChin is more square in malesFemale skull smaller, smoother, and more gracileNuchal crest (a muscle attachment point) larger on malesMastoid processes larger in malesnuchal crestchin squaremastoid process larger in malenuchal crestlarger in male(Bass 1987:82)Pelvis -- best area for determining sex MaleFemalepubisiliumsciatic notch(France 1998:90)Male FemaleMale pelvis narrower, female is broader(in female, ilia flare out more), resulting in: Female have longer pubic portion and subpubic angle is greater Sciatic notch wide in female, narrow in maleAging a skeletonCan get a pretty good age for young,but from about 25-30 years onward,estimation of age depends almostentirely on degenerative changes1. Tooth eruption2. Epiphyseal closure3. Skull suture closure4. Pubic symphasis roughnessAge Estimation -- tooth eruption(Steele & Bramblett 1988:103)Cross-section of 6-year-old child’s mandible,showing developing but unerupted permanent teethHumans have deciduous and permanent teeththat tend to erupt at known agesDeciduous teeth -- 20 of them erupt between 7-24 months of age; 2-6 years the roots ossifyPermanent teeth erupt between 6-18 years of age; the third molar may never erupt, or erupt lateTooth wear is NOT reliable for aging --depends on diet, use of teeth as tools(Whitehead et al. 2005:257)Age estimation -- epiphyseal closureA child has 300 bones, yet an adult has only 206Long bones grow in three sections: diaphysis (shaft) [plural: diaphyses] epiphyses (two ends) [singular: epiphysis]When growth is complete, the cartilaginous disks ossifyWe know when this happens (when the epiphyses unite with the diaphysis) because the cartilaginous disks ossified)Age estimation -- epiphyseal closureAdult femur NewbornOssification centers ina subadult femurepiphysisdiaphysis(bone shaft)epiphysisAn adult human has 206 bonesDuring the first 16-18 years of life, wemore than triple in lengthThis growth takes place between theepiphysis (end of bone) and thediaphysis (shaft of bone)When the epiphysis unites with thediaphysis, growth stopsPremature union results in dwarfism;Failure of union results in gigantismepiphysisdiaphysisGrowth plate18-2315-2223-2816-2319-2512-1613-1817-2014-1818-2514-1917-2216-2014-18Years for epiphysealunion(France 1998:96)Skull Sutures•Human babies are born with 300 bones•Infant’s head has fontanelles •Fontanelles fill in with bone•Where bone meets, form suturesAge estimation: skull suture closureJust as long bones grow, so does the skullThe plates eventually join together, and withage the sutures between the plates smooth outBut skull suture closure is not considered very reliable:From the outside of the skull, if all sutures are completely open, the individual is less than 84 years of age If all sutures arecompletely closed, the individual is 36 or olderAge estimation: pubic symphysisThis is where the two pelvic bones join in the frontTen age phases of changes established,based on how rugged or smooth the surface isMale: younger olderSUMMARYFirst two things you want to know about a skeleton:AGE:* Dental eruption (teeth erupt at known ages)* Epiphyseal closure (diaphyses/epiphyses unite)* Pubic symphysis (change in roughness)* Cranial suture closure (least exact)SEX:* Pelvis (female wide, male narrow)* Skull (male bigger brow ridge, muscle attachments, more square chin)* Males generally more robust, females gracileWhat else can we learn from a skeleton?StatureInjuries that affect bonesCause of death (maybe)Diseases (maybe)General health and nutritionDietCultural practicesGenetic relationshipReconstruct face (maybe)What else can we learn from a skeleton?Stature (height: from length of long bones)Injuries, and whether you lived to heal or not(Whitehead et al. 2005:246)Wounds, Accidents, Medical Treatment •Fractures, dislocations, and amputations revealed in bones•Trephining –Prehistoric surgery–Large holes cut into skullCause of death if it affected bonesDiseases that affect bonesGeneral health and nutrition(Whitehead et al. 2005:247)Rickets – dietary causeGrowth Arrest Lines•AKA Harris lines•Lengthwise growth of child’s long bones halted during periods of malnutrition•When nutrition restored, bones recommence growing•Interruption marked by horizontal lines at ends of long bonesEnamel Hypoplasia•Buds of adult teeth susceptible to health and nutrition problems of early childhood•Permanently scarred from malnutrition•Presence of growth lines and/or enamel: hypoplasia provides direct evidence of dietary problemsDiet You are what you eat!The isotopes you ingest become partof your bonesC12, C13, C14 heavy carbon isotopesC14 is unstable, used for datingC12 and C13 are stable, used to tell about your dietDIETPlants have different photosynthetic pathways,resulting in different isotopes of carbonFor example, maize is a tropical plant thatproduces C13, whereas wheat is a temperateplant that produces C12If you ate wheat but no maize, or maize butno wheat, we could tell from the ratio ofC12 to C13 in your bonesDietOther isotopes and elements are also used to tell about diet:Heavy nitrogen (N) isotopes ratio of C to N speaks to
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