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Skeleton - Assembling, Identification & labeling
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INTRODUCTION

 Hippocrates (460-377 B.C.), the "Father of Physic", is regarded as the pioneer in the field of physical anthropology

 

Andreas Vesalius (1514-1564) is a remarkable contributor in the development of physical anthropology. He was a Professor of Anatomy and physician to Charles V and Philip II. His study on the different anatomical features of man and apes did much in bringing revolution in the anatomical studies of those days. The specialty of his study on human anatomy was that he based such study on direct observation and thereby he 'was able to bring many new thoughts and ideas in that line. For this reason Vesalius' services to anatomy have been compared to those of Galileo and Copernicus in the astronomical studies.

 

Then came the year 1707 which was blessed with the birth of a great man who caused an overall change in the line of thinking and thereby brought a revolution in the development of science. He was Linnaeus (1707-1778).The Systema Nature,his immortal work, first saw the light in the year 1737 and in the tenth edition of that book, in 1758, he attempted at the classification of all known living organisms on the basis of the similarities and differences in various features. In the first edition of the book man was included in the class Quadrupedia and the order Anthropomorpha along with the apes and the sloths. In the tenth edition man, apes, lemurs and bats were placed in the order Primate. Man had been divided into Homo sapiens, Homo ferus, americanus europeaus, asiaticus, afer and monstrogus. It was Linnaeus who designated each Living organism by two Latin names (binary nomenclature), one for genus and the other for species. From the days of Linnaeus man has been scientifically known as Homo sapiens.

But it was Lamarck (1744-1829) who came forward boldly with observations on the descent of man from the anthropoid apes. He also pointed out the close resemblances amongst them that were combined with inferiority in bodily and mental capacity.

Johann Fridrich Blumenbach (1752-1840), known as the “father of physical, anthropology," was the real founder of craniology. In his works he attempted to explain human differences on the different grounds. He classified mankind into five varieties, such as the Caucasian, the Mongolian, the Ethiopian, the American, and, the Malay. The study was based on features like hair, colour, and form of the skull. He considered that the form of the skull was of special importance, Blumenbach's classification on the basis of the structure' of norma uerticalis of the three races of mankind - the Mongols (square shape) ; the Negroes (long and laterally compressed) and the Caucasians (intermediate) gained a worldwide recognition. The writing of Blumenbach touched all about the physical aspects of man-skeleton, teeth, hair, skin and internal organs. It was Blumenbach who introduced for the first time the idea of race classification on the basis of measurements, His contribution in this field placed anthropology on a rational basis. In the later period, the anthropologists like Broca, Fowler, Turner and others have followed the path of Blumenbach in the craniological studies.

 

 

Anders Ratzius (1796-1860) brought to light the technique of finding out cranial index and he was the first to classify the crania as dolichocephalic and brachycephalic. In 1840, Ratzius delivered a course of lectures on his theory regarding cranial shapes to the Academy of Science at Stockholm. He tried to correlate the findings of Blumenbach and Camper and thereby arrived at new methods of cranial measurements which were universally accepted. The name of John Grattan (1800-1871) should be remembered here, though he never received his due recognition, for his invention of certain radial measurements on the skull and construction of an ingenious craniometer. 

 

 

The year 1859 is highly remarkable in the history of Anthropology. With the publication of Charles Darwin’s book Origin of species, in the -same year a revolution started in the line of thinking. -But it gave rise to fierce controversies. On the basis of his painstaking researches he put forward the idea that species were not independently created, but they had descended from other species.

 

 

But Risley’s view was not supported by the scholars. Crooke made a strong criticism on this point and he was in favour of rejecting that very idea. The Dravidian type of Risley had also not been accepted by Sergi and Deniker. Chanda, in his book The Indo-Aryan Races: a study of the origin of Indo-Aryan People and Institutions (19516) opposed the view of Risley. A. C. Haddon did not agree with the classification put forward by Risley on several points. In his The wanderings of peoples, he stressed that the oldest existing stratum was represented by none but various Pre-Dravidian jungle tribes The Dravidians, according to him, could be distinguished into two separate groups -firstly, the medium-statured, dolichocephalic, mesorrhine group and secondly the dark-skinned, short or medium statured, platyrrbin group. Haddon attempted at the reconstruction of the racial background of India and he divided the country into three main geographical regions with characteristic ethnic elements His classification has based on Physical feature, artefacts, customs, language and folk tales.  He pointed out that the Aryan speaking people first came in this, country in the second millennium B. C. But he did not clear the point as regards the Pre- Dravidian India.

 

Dr. Majumdar did some extensive works on the different groups of people of this sub-continent. He worked among the Ho, Saora, Gond, Bhil and Nuniya caste. In Kolhan he attempted a study on growth of the aboriginal boys. He also made their another study on the height and weight among the different castes and tribes of Gujarat. An anthropometric survey had also been conducted by him in Gujarat which offered a large mass of data on the subject. In this connection, the anthropometric study, conducted in the United Province, P. C. Mahalanobis, D. N. Majumdar and C. R. Rao should be mentioned. They restricted their study among twenty three different castes and tribes. Prof. Mukherjee's work on the body development of Calcutta children should be mentioned here as it is an example of systematic growth study where he has shown how social class plays a dominant role in influencing the development of the sex differentiating characters. Dr. S. S. Sarkar made some original contributions in the field of physical anthropology in. India. His team worked amongst the Kaoars of Kerala and brought an open challenge to Guha's observation on the characteristic Negrito hair amongst the tribal people in question. Sarkar's study on the Race and Race movements in India throws a new light in the study of race in this country. He has attempted to classify the people on the basis of cephalic index and, according to him, India is predominantly a dolichocephalic country. His The Aboriginal Races of India l1954) is considered as a fascinating study which unfolds many new facts in the domain of physical anthropology of tie aboriginal people inhabiting in India.

 

 

 

The bony and cartilaginous framework wich supports the soft tissues and gives a definite form to the body is called the skeleton”.

 

There are more than two handred bones in the adult skeleton. The function of the skeleton include providing a supporting framework for your body, supplying protection for internal organs and acting as a reservoir for essential minerals. By weight, bone tissue is 70% mineral and 30 per cent organic material. It is penetrated by many small nerves and blood vessels. Bone tissue is continually renewed. Because of this it is able to repair  itself following injury and, to a certain extent, bones are able to adapt their forms according to the mechanical strains imposed upon them. Ossification of the bony skeleton begines in about the fifth week of foetal life, and skeleton growth is completed by about 25 years age.

 

The Composition of Bone

 

Bone is a composite material formed an organic and an inorganic (mineral) part. By weight, dry bone is about 70% mineral and 30% organics. The great majority of the organic component is collagen, a protein which forms longs fibres. The small crystals which make up the mineral portion of are embedded in matix of collegen fibres. Bone mineral is chiefly hydroxyapatite, a form of calcium phosphate whose composition approximates to the chemical formula Ca10(PO4)6(OH)2. The mineral component gives bone its rigity, and the organic component lends it a slight ‘give’ or resiliecne which gives it its strenght. The organic part degrades after deaht, which accounts for the rather brittle nature of most archaeological bone. 

 

The functions of the bone are:

 

(a)  To give support to the weight of the body,

(b)  To give the protection to the underlying of soft parts,

(c) To give a definite shape to the body,

(d)  To provide space for muscular attachment ,

(e)  To help in lever action for locomotion.

 

There are more than two hundred separate bones in the adult skeleton. They may be divided into four classes according to theire basic shape and appearance:

  • Long
  • Sort
  • Flat
  • Irregular.

 

Skull

 

Skull may be divided into

(a)  a cranial part or cranium: forms the brain –box

(b)  a facial part: situated below the front portion of the cranium

The cranial part is constituted by the following bones:

  • Frontal:The region of the forehead or the front of the cranial region
  •  Parietal Two in number. Each one is irregularly quadrilateral in shape. They form the side walls and roof the brainbox.
  • Occipital:The posterior and the interior part of the cranium
  • Ethmoid: The anterior part of base of the cranium, and is cuboidal in shape. It forms the lateral walls and roof of the nasal   cavity, the medial walls of the orbit and the septum of the nose.
  • Sphenoid: In shape it resembles a flying bat. It is placed in front of the temporal bones and the basal portion of the occipital bone, at the skull. It consists of a centrally placed body and two wings – greater and lesser.
  • Temporal: Two in number. They are placed at the base and sides of the skull.

 

 

A temporal bone has five parts- the squamous, petrous, mastoid, tympanic parts and the styloid process.

  • Inferior Nasal Conchae:Two in number. Each forms a curved lamina and is placed horizontally in the lateral walls of the nasal cavity.
  • Nasal bones:Two in number. These are small bones placed side by side immediately below the frontal, forming the bridge of the nose.
  • Lachrymal: Two in number. They are placed near the front part of the medial orbital walls.
  • Vomer: It is a thin bony plate, composed of two fused laminae and is quadrilateral in shape. It is situated in the lower part of the septum of the nose.

 

The bones of the facial part are:

 

  • Maxilla: Two in number. They form the whole of the upper jaw. Each is placed below the orbit forming the floor of the orbit, and also forms the roof of the mouth and the floor and the lateral wall of the nasal cavity. Each maxilla has a body and four processes- frontal, alveolar, zygomatic and palatine.
  • Zygomatic:Two in number. Each being situated in the upper and lateral part of the face, makes prominence of the cheek.
  • Palantine: Two in number. It is placed between the maxilla and the pterygoid process of the sphenoid bone of the posterior aspect of the nasal cavity.
  • Mandible: It forms the lower jaw and is the largest and strongest bone of the face.

The skull as a whole may be looked at from above (norma verticalis), from front ( norma frontalise), from back (norma occipitalis), from below (norma basalis), and from the side (norma lateralis). These different aspects are to be described systematically one by one in time of describing a skull as a whole.

 

Norma vertical:

 

The following features may be noted:

The contour  is more or less oval or sometimes nearly circular.

The sutures, namely (a) coronal- in between the frontal and the two parietal bones (b) the sagittal- in between the two parietal bones (c) the lamboidal between the parietal bones and the occipital bones.

The bones, namely (a) the frontal with its two frontal eminences (b) the two parietals- with parietal tuberosities, one on each bone (c) the occipital- squama of the occipital.

The important landmarks are- (a) the bregma- the meeting place of the coronal and sagittal sutures. (b) the lambda- the junction of the sagittal and lamboidal sutures. (c) the obelion- in between the two parietal foramina. (d) The vertex- the highest point in the median plane.

 

Norma frontalis

 

The following are the some of the important features to be noted on the frontal aspects of the skull.

  • The more or less oval outline, wider above than below.
  • The forehead formed by the frontal bone.
  • The superciliary arch above the orbit,
  • The orbits: Each orbit has medial and lateral walls, a roof, a floor, a base or orbital opening and the apex. The orbital cavity is pyramidal in shape.
  • The nasal aperture- bounded by the maxillae and the nasal bones.
  • The maxilla: The zygomatic process of the maxilla.
  • The supra -orbital foramen and infra orbital foramen.
  • The sutures, e.g. (a) frontal nasal (b) fronto-maxillary (c) fronto- zugal, (d) intra-nasal(e) naso-maxillary (f) intermaxilliary, (g) zygomatico maxillary etc.
  • The land marks e.g. (a) glabelia, (b) nasion, (c) rhinion, (d) nasospinale, (e) prosthion etc.

 

Norma Occipitalis:

 

The outline is roughly pentagonal, being convex above and on each side, and flattened below:

The external occipital protuberance is the most important feature on these aspects. The nuchal lines – the inferior, the superior and the supra or the highest, are also to be noted.

Of the anatomical points the inion is very important.

The sutures are: (a) occipitomastoid. (b) parietomastoid (c) lamboid.

 

 

Norma Basalis:

 

 It can be divided into an interior part, a middle part and posterior part.

The anterior part is formed by the palatine process of the maxillae and the horizontal plates of the palatine bones.

The following are the important features in the part:

  • Intermaxillary suture,
  • Interpalatine suture
  • Palate- maxillary suture
  • Incisive fossa,
  • Lateral incisive foramina,
  • Median incisive foramina,
  • Greater palatine foramina,
  • Lesser incisive foramina,
  • Tubercle of the palatine bone,
  • Palatine crest,
  • Posterior nasal spine,
  • Alveolar process

 

The middles part lies posterior to the anterior part of the norma basalis extending up to an arbitrary line drawn transversely through the anterior margin of the foramen magnum: the important features to be noted are – (a) pharyngeal tubercle, (b) pterygoid lamina and pterygoid fossa, medial and lateral pterygoid lamina and pterygoid hamulus, (c) foramen ovale, (d) foramen spinoum, (e) foramen lacirum (f)carotid canal, (g) tympoanic part of temporal bone.

The posterior part is formed by the rest of the norma balasis. The important features are (a) foramen magnum, (b) occipital condyle, (c)  condyler fossa, (d) jugular foramen, (e)styloid process (f) mastoid process, etc.

 

 

Norma Lateralis:

 

The noteworthy features are:

    (a)  Temporal line,

    (b)  Temporal fossa,

    (c)  Zygomatic arch,

    (d)  Pterion,

    (e)   External auditory meatus,

    (f)   Squama of the temporal ,

    (g)  Mastoid portion of the temporal bone,

    (h)  Mastoid process,

    (i)    Styloid process,

    (j)  Infratemporal fossa’

    (k) Pterygopalatine fossa, etc.

The important sutures are: (a)squamosal, (b) sphenotemporal, (c) spheno – frontal, (d) zygomatico-temporal, etc.

 

 

Dentition:

 

Two sets of teeth make their appearance at different periods of life of a man. The first set, known as the deciduous or milk teeth, is temporary and begins  to erupt during the first one year. The other set called the permanent teeth, begins to replace the first set from about the sixth year.

The deciduous set consists of 20 teeth of which 4 incisors, 2 canines and 4 molars are found in each of the upper and lower jaw.

The permanent teeth are 32 in number. The dental formula is

Molar premolar canine incisor incisor canine premolar molar

Upper jaw 3 2 1 2 2 1 2 3 Lower jaw 3

 

Each tooth presents three different Parts, viz:

    (a)  The crown: the projected portion beyond the gum.

    (b)  The root: portion that lies embedded in the sockets of the maxilla or mandible.

    (c)  The neck: the constricted portion between the root and the crown.

 

  • Incisors:they form the front teeth in each dental arch. The crown is chisel- shaped. An incisor bears only one root.
  • Canine: the crown is large and conical. The root is usually single.
  • Premolars:The present two pyramidal cusps or tubercles, one lingual and other labial, the two being separated by a groove. The root is usually single.
  • Molars:
    • Upper molars – the crown of the first, second and third molars present 4, either 3 or 4 and 3 cups respectively. Each molar has 3 roots.
    • Lower molars; the first molar presents 5 cups while the second and third have 4 or 5 cups. Each lower molar possesses 3 roots. 
  • Hyoid Bone: The hyoid bone is U – shaped. It is placed in the ventral floor of the pharynx below the base of the tongue, in front of the epiglottis.

 

Vertebral Column

 

 The vertebral column is made up of a series of independent, irregular bones, called the vertebrae, intervened by fibro – cartilaginous discs, termed the intervertebral discs. The vertebrae are   firmly connected to one another in such a manner that very little movement is possible between adjacent bones. The vertebral column supports the weight of the body and transmits it to the pelvis and lower extremities. It also protects the spinal cord and its membranes.

A typical vertebra consists of a body and a vertebral arch. These two enclose a foramen, termed the vertebral foramen through which the spinal cord a pair of pedicles and of laminae. It has a spinous process, two transverse processes and four articular processes.

They can be grouped under the names of:

              Cervical:they are seven in number. They are the smallest of the moveable vertebrae.

              Thoracic:Twelve in number.

              Lumber:5 in number

              Sacral:the 5 sacral vertebrae fuse with one another to form a lorge, triangular bone, called the sacrum.

 

Coccygeal or Caudal:

 

 The rudimentary vertebrae of this region form a small triangular bone by fusion. The number of vertebrae is 4, but it may be 5 or even 3.

When looked at the lateral side, the vertebral column presents 4 curves, namely, cervical, thoracic, lumber and pelvic.These 4 curves make the vertebral column S – shaped as the cervical curve is convex forwards, the thoracic one is concave forwards, and the lumber is convex forwards, while the pelvic curve is again concave forwards. 

 

 

Ribs

 

 The thoracic region contains 12 ribs on each side. Of each series of 12 the upper seven are directly connected with the sternum by cartilages. They are called true or sterna ribs, the reminder are false or asternal. The cartilages of the 8th, 9th, 10th ribs are joined each to the cartilages of the one immediately above. The anterior ends of the remaining 2 are free and they are called floating ribs.

The sternum is a long, flat bone, composed of several parts, of which the first piece is the longest and is termed the manubrium. The succeeding piece is called the body and the last one termed the xyphoid process.The sternum is placed in the front wall of the chest.

 

 

The Upper Limb

 

 Scapula: It is a large, flat bone situated on the postero – lateral aspects of the chest wall, connected with sternum by the clavicle and articulating with the humerus.

Side identification: (a) the glenoid cavity lies on the lateral aspects of the bone, (b) the bone tapers down towards the interior side, (c) the anterior surface is convex.

Clavicle: Lying on the anterior side almost horizontally at the root of the neck the clavicle articulates with the sternum on one hand and with the acromian process of the scapula on the other.

 

 

Humerus:

 

 It is the bone of the upper arm. It articulates with the scapula above and with the bones of the forearm below. The bone comprises expanded upper and lower extremities and a long shaft which is less cylindrical. The upper end presents the head, the greater and lesser tuberosities, the neck and the bicipital groove. The shaft possesses three borders, viz medial, anterior, and lateral and three surfaces, viz., posterior, antero – lateral and antero – media. The transversely expanded lower end comprise a pulley- shaped articular surface, termed the trochlea and a convex articular surface, termed the capitulum. It also presents medial epicondyle, lateral epicondyle, olecranon fossa, coronoid fossa and radial fossa.

Side identification:  (a) The rounded head is placed at the upper end of the bone,

                               (b) the head faces medially,

                               (c) the olecranon fossa lies on the posterior side of the bone.

 

 

Radius:

 

 It is the lateral bone of the forearm. The bones have two extremities and a shaft. The upper end presents a disc – shaped interosseous, anterior and posterior and three surfaces, anterior, posterior and lateral. The lower end comprises the styloid process on the lateral surface. The inferior surface of the lower end has a medial and a lateral (triangular) articular area for articulation with the wrist bones.

Side identification: (a) The lower end is much wider than the upper end, (b) the shaft is concave forwards in its lower part, (c) the ulnar notch is on the medial side.

 

 

Ulna:

 

It is the medial bone of the forearm. It has a shaft, an upper end and a lower end or head. The upper end presents a deep notch; the trochlear notch; a beakshaped structure – the olecranon process; at the uppermost part of the bone – the coronoid process and the radial notch. The shaft has 3 borders, interesseous, posterior and medial and 3 surfaces, anterior, posterior and medial. The lower end or head is slightly enlarged and has a smooth articular surface and a prominent styloid process.

Side identification: (a) The upper end is thick and hook- like, (b) the trochlear notch is directed forwards, (c) the lateral border is thin and a sharp crest.

 

 

Skeleton of hand:

 

 The skeleton of the hand comprises 27 bones arranged in 3 groups –

(1) The Carpus is the proximal part consisting of eight small irregular bones arranged in 2 rows, proximal and distal. The bones of the proximal row from the lateral to the medial side are (a) scaphoid, (b) lunate, (c) triquetral, (d) pisiform; the bones of the distal row are (e) trapezium, (f) trapezoid, (g) capitates and (h) hamate.

(2) The Metacarpus: They are 5 in number. Each is a miniature long bone, comprising a shaft, a proximal base and a distal head.

(3) The Phalanges: Each finger has 3 phalanges except the thumb which has only 2. Thus the phalanges are 14 in number. Each possesses a shaft, a head and a base. 

 

 

The Lower Limb

 

  • Hip bone:

    It is large, irregular bone comprising 3 parts, namely, the ilium, the ischium, and the pubis. The ilium is the expanded, fan – shaped upper part. It includes the upper part of the acetbulum. The part of the bone below and behind along with the lower part of the acetabulum is termed the ischium. The pubis forms the rest of the bone. The ilium and the ischium enclose a large foramen termed the obturator foramen.

    Side identification: (a) the iliac crest forms the upper border of the bone, (b) the acetabulum lies on the laterl surface, (c)the obturator foramen is placed  below and in front of the acetabulum.

  •  

  • Femur

    The femur or thigh bone is the largest and strongest bone of the skeleton. The bone articulates with acetabulum of hip- bone above and with the tibia below. It consists of a shaft, an upper end a lower end.

    The upper end includes a head, a neck, and two trochanters – greater and lesser. It presents trochanteric crest, trochantric fossa and quadrate tubercle. The posterior border of the middle – third of the shaft is formed by a rough ridge, termed the linea aspera. The posterior surface of the lower third presents a flattened triangular area termed the popliteal shows a spiral line. The lower end bears two condyles, a medial and a lateral and an inter- condyler notch which separates the two condyles; lateral epicondyle; medial epicondyle; patellar surface, tibial surface etc.

    Side identification: (a) the rounded head is the upper end (b) the is placed medially, (c) the shaft shows a forward convexity.

  •  

  • Patella

      The patella bone is placed in front of the knee joint. It is somewhat triangular in shape with rounded margins and an apex directing downwards.

  •  

  • Tibia

    The tibia is the medial and larger of the two leg bones. It has an expanded upper end or head bearing two condyles, medial and lateral, the tubercle of the tibia, the intercondyler area and the intercondyler eminence. The shaft, which is triangular in across – section presents medial, lateral and posterior surface and anterior, interosseous and medial borders. The anterior border formed a sharp crest, termed the ‘shin’. The lateral border of the lower end is formed by a notch, termed the flbular notch. The projected short process of the lower end is called the medial malleolus.

    Side identification: (a) The upper end is much larger than the lower end, (b) the medial malleolus lies on the medial side; (c) the anterior border is the most prominent of the 3 borders.

  • Fibula

    The fibula is very slender and is the lateral bone of the leg. The has an upper end or head, a shaft and a lower end which formas lateral malleolus.

 

 

Skeleton of the foot:

 

The skeleton of the foot consists of 3 sets of bones, namely, the tarsus, the metatarsus and the phalanges.

The Tarsus comprises 7 bones. They are the talus and the calcanneum on the proximal row; the 3 cuneiforms (medial, intermediate and lateral) and the cuboid on the distal row; and the navicular which is placed between the talus and the medial 3 bones of the distal row.

The metatarsusal bones are 5 in number. Each bone presents a head, a shaft and a base.As in the hand, the Phalanges are 3 in number the toes other than the big toe where the number is two.

 

 

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