the human skeleton

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					                                The Human Skeleton

         Bone is the major calcified tissue of all vertebrates. It is a dense
     material or matrix in which spidery cells, Osteocytes are embedded.
     The matrix is composed of collagen fibres, crystals of calcium
     phosphate complex and a ground substance or cement containing

          The human skeleton is the solid framework of the body. There are
     two main sub-divisions of the skeleton. The axial skeleton
     including the bones of the head, the neck and the trunk. The
     appendicular skeleton which includes the upper and lower limbs.
(a) Skull
frontal                    parietal - 2            inferior nasal concha - 2
occipital                  temporal - 2            malleus - 2
sphenoid                   maxilla                 incus - 2
ethmoid                    nasal - 2               stapes - 2
vomer                      zycomatic - 2
hyoid                      lacrimal - 2
mandible                   nalate - 2
(b) Vertebral column
cervical - 7 thoracic- 12-13 lumber - 5 sacrum - 1 (5 in sub-adults) coccyx
(c) sternum - 1 - 3 (d) scapula - 2 (e) clavicle - 2

Palmar                 -           toward the palm of the hand

Plantar            -       toward the sole of the foot

      Complete skeleton or isolated bones are received in the laboratory for
the following examinations :

1.   Whether the bones are of human being or not.
2.   Whether the bones belong to one or more individuals.
3.   Whether the bones are of a male or a female.
4.   What could be the age of the person to whom the bones belonged.
5.   Stature of the person to whom the bones belonged.
6.   Whether there is any cut on the bones
7.   If skull is present, whether it belongs to the person in the
          photograph supplied.

      Whether the remains are human or not can be determined by
serological techniques, such as the precipitin test, if the bone is fairly recent
or if soft tissue is present. This is necessary only when the remains are badly
fragmented or incomplete.
     If the relatively intact bone is available, identification depends upon the
experience and knowledge of both human and non-human bones. Sometimes
microscopic examinations of small fragments of long bones determine the
bones to be human or non-human depending upon the presence of sheets of
plexiform structures in non human bones (in cross section).


      Commencing from the eighth week of intra-uterine life onwards upto
eighty years of age series of changes are known to occur in the human
skeleton and the age of an individual can be estimated with a considerable
degree of accuracy from a combined data provided by
     I. Teeth and
     II. Ossification of bones.


           Examination of teeth provides valuable data for the
      determination of age. Teeth are one of the hardest material in nature.
      Teeth preserve well and therefore provides evidence of evolutionary
      changes through time.

           There are two sets of teeth i.e. temporary and permanent.
      Temporary teeth are deciduous or milk teeth and are 20 in number.
      Incisor - 4, Canines - 2, Molars 4 in each jaw.

            Permanent teeth are 32 in number. Incisor - 4, Canines -2,
      Premolars -4 and molars -6 in each Jaw.
      Dental eruption gives a very good indication of age and is summarised in
      the table given below :

Temporary Teeth                                        Permanent Teeth
1.     Small, narrow, light and delicate except Big, broad, heavy and
temporary molars which are longer than permanent strong         except
premolars replacing them                         permanent premolars
                                                 replacing temporary

2. Crowns china-white in colour                        Crowns ivory-white in

3. Junction of the crown with the fang often Junction of the
marked by a ridge                            crown with the fang
                                             not so marked
4. Neck more constricted                     Neck less constricted

5. Edges serrated                            Edges not serrated

6. Anterior teeth vertical                   Anterior teeth
                                             usually incline
                                             somewhat forward.
7. Molars are usually larger. Their          Bicuspids which
   crowns are flat and their roots smaller   replace the
   and also more divergent                   temporary molars are
                                             usually smaller.
                                             Their crowns have
                                             cusps which sharply
                                             differentiate them.
                                             The roots are bigger
                                             and less divergent.
Temporary Teeth              Eruption Time   Complete Root
Central incisors (Lower)     6-8 months      1 year 6 months-2
Central incisors (Upper)     7-9 months      1 yea; 6 months-2
Lateral incisors (Upper)     7-9 months      1 year 6 months-2
Lateral incisors (Lower)     10-12 months    1 year 6 months-2
first molars                 12-14 months    2 ye?r.s-2 year 6
Canines                      17-18 months    2 years 6 months -3
Second molars                20-30 months    3 years

Permanent Teeth              Eruption Time   Complete Root Calcification

First molars        ' '      6-7 years       9-10 years

Central incisors             6-8 years       10 years

Lateral incisors             8-9 years       1 1 years

First bicuspid               9-11 years      12-13 years

Second bicuspid              10-12 years     13-14 years

Canines                      11-12 years     13-15 years

Second molars                12-14 years     '4-16 years
Third Molars(wisdom)          17-25 years         18-25 years
                    Anatomical Descriptive Terms
Crest               a ridge especially surmounting or

                    bordering bone
Spine               a sharp prominence or slender
                    process of bone
Process             a slender point (thorn like)
Tubercle            a small tuberosity
Tuberosity          an elevation or blunt eminence
Trochanter          a marked tuberosity
Sulcus              a liner depression
Groove              same as sulcus
Meatus              tubular opening
Foramen             an opening or hole
Ossification of Skeleton

       The precursor of all the 206 bones of a mature human skeleton
 primarily consist of soft, elastic matrix known as cartilage until upto 7th
 week age of the embryo. Therefore, the process of calcification ' or
 ossification commences in some localised spots which are termed as
 ossification centres. By 15 years of age almost all the centres of
 ossification appear. The following table shows the age range of the
 appearance of ossification centres in different bones :

     Name of the bone             Time of appearance of centres
1.   Thigh (femur)                before birth    9 years 6 months

2.   Upper arm(humerus)           before birth       10 years 6 months

3.   Ankle (tarsals)              before birth       8 years

4.   Shin (tibia)                 before birth       1 1 years

5.   shoulder(scapula)            before birth       19 years

6.   Wrist (carpals)              6 months           12 years

7.   forearm(radius)              7 months           4 years

8.   Palm(metacarpals)            10 months          3 years

9.   Finger(Phalanges)            1 1 months         5 years

10 Toe (        " )               1 1 months         5 years
1    Foot(Metatarsals)       2 years 5 years 6 1 1 years
     Forearm(ulna)           months 10 years 14 10 years
     Hip(Innominate)         years                      19 years
     Collar (Clavicle)                              16 years
14                                  Fusion of epiphyses

       The process of union of epiphyses is divided into four stages viz.
  a)     No union
  b)    Commencement of union
  c)     Recent union
  d)     Complete union

           In the first stage the external margins of the diaphysis (main shaft) and epiphyses are
           separate and well defined. In the second stage, there is occasional bridging over of the
           margins. In the third stage of recent union, a fine line of demarcation exists between
           the two margins. In the fourth stage of complete union, the line usually disappears.
           The following table shows the age order of post natal union of epiphyses.
                     w          •                       • >   .<
                     Union of Epiphyses
13 - 14 years        The lateral ipicondyle of the humerus unites with the
                     trochlea and capitulum.

14 - 15 years        Proximal epiphyses of radius.

15 - 16 years        Epiphysis of second phalanges of hand fuses,
                     epiphysis of calcaneum joins the bone, the
                     triradiate cartilage of acetabulum fuses, the
                     coracoid unites to the scapula, the olecranon unites to
                     the ulna.
16 - 18 years     All epiphyses at elbow (except medial condyle), head
                  of fiimur and lower end of tibia joins the respective
                  shafts. In females, the epiphyses at the elbow join their
                  respective shafts by 13 - 14 years.
18 -20 years      All epiphyses at wrist, knee, crest of ilium, lateral end of
                  the clavicle unites. The acromion unites to
20 -21 years      Articular facets of the ribs unite.

21 -22 years      The ischial tuberosity fuses in females.
              Inner epiphyses of clavicle fuses, basi-occiput fuses
22    years23 with the basi-sphenoid. Sacral vertebrae start uniting
              with one another from below upwards. Complete union
years 25 - 26 of vertebral bodies of sacrum.

26 27 years      Medical epiphyses of clavicle unites completely.
                 Sternal end of clavicle unites.

     Age Changes in Pubic Symphvsis

         The pubic symphysis is formed by the meeting of the right and left innominate bones at
    the midline in front. This is the best area for age determination in young adults after
    closure of the various epiphyses is completed until about the age of 45 years. Ageing is
    done by comparison of the face of the pubic symphysis for males than females due to less
    regular change and more rapid degeneration in females.
18 - 19 years       Surface rugged, having horizontal ridges separated by
                    well marked grooves.
20 -21 years         Grooves becoming filled with new formation of
                     finely textured bone.

22 - 24 years        Formation of dorsal plateau, fusion of ossific
                     nodules, dorsal margin gradually become defined.

25 - 26 years        Great increase of the ventral bevelled area.

27 - 30 years        Dorsal margin becoming increasingly clear and well

                   Completion of oval outline of face, ventral rampart
30 - 35 years 35 - completely formed. Face and ventral aspect change
                   from granular texture to fine grained or dense bone.
39 years 39 - 44 Face smooth.

45 - 50 years        Formation of 'rim'dorsal, margin lipped.

50 - 60 years        Surface showing erosion with breaking down of
                     anterior margin.

60 - 70 years        Surface irregularly eroded.
       Estimation of age by closure of cranial sutures

             Sutures are the irregular serrated lines joining the different bones of the vault of skull.
       Age estimation after 30 years depending upon the obliteration of the cranial sutures.
       However, fusion between basi-occiput and basi sphenoid is complete by 18 - 22 years. The
       closure of the suture is first seen on the inner and then on the outer surface. The closure
       starts with sagittal, coronoid, lambdoid, parietomastoid and spheno - parietal.
Age                     Closure of Suture
25 - 30 years           Sagittal suture close to parietal formina showing signs
                        of partial obliteration; coronal suture shows some
                        obliteration close to spenoid.

30 - 35 years           Sagittal suture mostly obliterated; lambdoidal suture
                        starts closing near lambda.

35 - 40 years           Lambdoidal closure spreading beyond lambda on
                        either side; marked obliteration in more portions of
                        coronal suture.

40 - 45 years           Coronal completely obliterated.

45 - 50 years           Lambdoidal completely closed at lambda.

50 - 60 years           Lambdoidal on either side of lambda completely

60 - 70 years           Masto-occipital and parieto-mastoid are closed.

70 - 80 years           Spheno-parietal closed.

80 years or above        Temporals united with parietal.


          Sex is usually one of the easiest determinations made from skeletal material and one of
   the most reliable if the essential parts of the skeleton are present and in good condition. Most of
   the criteria for determining sex pertains to the pelvis and the skull, although the round of ball
   joints also provide very reliable means of determining sex.

         The following are the principle points of differentiation in skeleton:

Male                                    Female
1. Skeleton comparatively bigger and 1. Skeleton comparatively smaller
stouter.                             and slender.

2. Muscular ridges, depression and 2. Muscular ridges, depression and
process is more prominent.         process is less prominent.

3. Shaft of the long bones relatively 3. Shaft of the long bones relatively
rough and the articular surfaces and smooth and the articular surfaces and
ends larger.                          ends small.
        As the female moves from puberty into adulthood her skull retains much of the
   gracility and smoothness characteristic of the prepubertal period, whereas the male's
   skull during this period becomes less gracile, relatively larger and much rougher in the areas
   of muscular insertions. The resulting differences are most noticeable
  in the orbital borders, supra orbital ridges, mastoid processes, occipital crest and chin.
Male                                   Female
1. Bigger, heavier and much more 1. Smaller, lighter and much less
rugged.                          rugged.

2. Cranial capacity almost 10% more. 2. Cranial capacity almost 10%

3. Frontal sinuses more developed.       3. Frontal sinuses less developed.

4. Fronto-nasal angulation distinct.     4. Fronto-nasal angulation not

5. Glabella, supra-orbital ridges 5. Less pronounced.
zygomatic arch, mastoid process
occipital protuberance, occipital
condyles and muscle attachment more

6. Orbital opening comparatively big 6. Orbital opening comparatively
and rectangular.                     small and rounded.

7. Facial bones more massive and         7. Facial bones less massive and
not delicate in texture.                 delicate in texture.

1 . Mean breadth of first cervical 1 . Mean breadth of first cervical
vertebra 83 mm.                    vertebra 72 mm.
2. Lumbar lordosis less marked. 2. Lumbar lordosis more marked.


1 . Lower jaw more massive.            1. Lower jaw less massive.
2. Chin(symphysis menti) square.       2. Chin(symphysis menti) pointed
                                       or rounded.
3. Symphyseal height more.             3. Symphyseal height less.
4. Ramus more broad.                   4. Ramus less broad.
5. Angle region everted.               5. Angle region not everted.
1. Thoracic cage longer and            1. Thoracic cage shorter and
narrower.                             wider.
2. The ribs have a lesser             2. The ribs have a greater
curvature and are less oblique.       curvature and are more oblique.
3. The body of the sternum is         3. The body of the sternum is
bigger and generally more than        shorter and generally less than
twice the length of the manu-         twice the length of the manu-
brium.                                brium.
4. The upper border of the            4. The upper border of the
sternum is generally on the level     sternum is generally on level with
with the lower 'part of the body of   the lower part of the body of the
the second thoracic vertebra.         third thoracic vertebra.


     The pelvis ^affords the best marked and most reliable characteristics for determination of
sex. The female pelvis is shallow, wider, smoother and less massive than the male pelvis. The illia in
the female bones are less sloped, their posterior borders are more rounded, the anterior
superior iliac spines are more widely separated and the greater sciatic notches are much wider
forming almost a right angle than in the male.

Characteristics          Male                      Female
l.Bodyofpubis            Triangular shaped         Quadrangular shaped
2. Sub-pubic arch        V-shaped (i.e.            Approaching U shape
                         narrow)                   (i.e. broader)
3. Symphysis             High                      Low (less deep)
4. Obturator             Large, Ovoid              Smaller more
foramina                                           triangular
5. Acetabula             Large, wide               Smaller, narrow
6. Greater sciatic       Rather close, deep        Wider and shallow or
notch                    angle less than 76        more than 76 degree
                         degree                    nearer to right angle
7. Ilia bones            High, more upright        Lower, more flaring
                                                   in upper portion i.e.
                                                   ilia are less sloped
8. Sacro-iliae         Large                       Smaller
9. Pre-auricular sulci Usually absent              Commonly present
                                                   and well marked
10. Ischial tuberosity   Inverted                  Everted

Male                                  Female
1 . Long and narrow 2. Uniform        Short and wide Sharply curved
curvature along its whole length 3.   forward in its lower half The
The articular surfaces extend over    articular surface extend over two to
two and a half to three elongated     two and a half segment
bodies 4. The sacral index is 1 12    Sacral index is 116

         (Sacral index is calculated by multiplying the breadth of the base by 100 and dividing it
          by anterior length.)

1 . The neck of the femur forms        The neck of the femur forms
an obtuse angle.                       almost a right angle with its
2. Vertical diameter of the head is    Vertical diameter of the head is
more than 47 mm.                       less than 45 mm
3. More inclined.                      Less inclined.


1. Vertical diameter of head is Vertical diameter of head is less
more than 45. 5 mm             than 41. 5 mm

Superimposition Technique

    It is possible to compare the photograph of skull of the deceased with the photograph of the
deceased to prove that the skull of the deceased fits within the contours of the face of the deceased.

      The photograph of the face of the deceased is enlarged to the same size as that of the
skull. Diapositive transparencies of the photograph are made. Various landmarks such as :
Zygion, Ectoconchion, Glabella, Gonion, Orbitale, Maxillofrontale, Euryon, Nasion, Vomer,
Zygomatic arch, Gnathion, Subnasion are marked on the skull as well as on the transparency of the
photograph. The skull is made to stand on a craniophore in front of the camera, 'Linhoff and is
viewed through the ground glass and a diapositive photograph of the skull is taken. The
transparencies of the photograph and the transparency of the skull are superimposed to determine
if the landmarks tally in contour of the face and the skull. All the land-marks and the general
contour of the face with that of the skull match if photo and skull represent one and the same
      The comparison of the two is more effective if the subject is smiling and exposing several
teeth in the original photograph.

Electronic Skull Identification Device

    In this technique life size face photograph and the skull of the deceased are fixed on two
separate stands. The CCTV system consists of two video cameras, three video monitors, a
video mixer and synchronising generator. One video camera is focused on the skull and the
other video camera is focused on the photograph. Measuring scales are attached on both stands
so that images brought on to the mixing monitor to confirm their actual sizes.

     The image of the life size skull and photograph are seen on their respective video monitors and
then superimposed one over the other on a video monitor of 21" screen with the help of a video
mixer. Video mixer which is an electronic special effects generator makes it possible to scrutinise
the facial view of the skull and face juxtapositioned with the skull on one half and the face on
the other half on the vertical, horizontal and oblique views.

     The superimposed image is scrutinised for agreement, if any of the several land marks and
contours marked on the photographs as well as on the skull which may show matching or otherwise.
Determination of the human(fetal) or animal origin of skeletal remains

     For the determination of the human or animal origin, the cranial bones prove to be the most
suitable. The skull bones of human fetus are thin, standing apart and not fused by sutures. The
cranial bones of animals are considerably smaller in relation to the whole skeleton than are the
human bones. A feature particularly conspicuous of the animal skeleton is the smaller brain case
and fusion of the cranial bones by sutures or their complete ossification.

     Differentiation between animal and human bones is easy if the bone ends are intact, as the
human bones recognised by their characteristic disphyases. In human foetus only the diaphyseal
part of the bone is present and the epiphysis never fuses with the diaphysis. Bones of animal origin
show a solid bony fusion between diaphysis and epiphysis.

     Similarly, shoulder blade and pelvic bones of human differ from animal bones. The essential
differences between them is that the bones of the animal origin are always limited by bony fusion.


    Stature can be determined with fair accuracy by any of several methods, all based on the
assumptions that there is a constant relationship between long bone length and total stature. The
probable stature of the deceased is estimated by applying certain formulae to the length of the long
bones. Length of long bones is measured using osteometric board. Estimation of stature from long
bones of lower limbs are more accurate than those of the upper limb. Usually femur, tibia, humerus
and radius are used. Formulae of Trotter and Gleser are to be adopted. Formulae of Karl Peerson
are now considered obsolete. A single long bone of lower limb can provide remarkably
    reliable evidence of stature. The most useful of the Trotter and Gleser equations are given in the
    table. For each equation read :

   Estimated stature(cm) = Factor x bone length (cm)
                         + factor + standard error of estimation) Table

                   Male                Female              tiale
1.30(Fem+Tib) +63.29+2.99              1.39(Fem+Tib)       +53.20+3.55

2.38 Fern          +61.41+3.27         2.47 Fern           +54.10+3.72
2.68 Fib           +71.78+3.29         2.93 Fib            +59.61+3.57
2.52 Tib           +78.62+3.37         2.90 Tib            +61.53+3.66
3.08 Hum           +70.45+4.05         3.36 Hum            +57.97+4.45
3.78 Rad           +79.01+4.32         4.74 Rad            +54.93+4.24
3.70 Ulna          +74.05+4.32         4.27 Ulna           +57.76+4.30