GENERAL SCOPE AND USES OF PHYSICAL/BIOLOGICAL ANTHROPOLOGY. Paper No. & Title: B.A./B.Sc. (Honours) 2 dn semester. (Practical)

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1 GENERAL SCOPE AND USES OF PHYSICAL/BIOLOGICAL ANTHROPOLOGY Course name: Physical Anthropology Paper No. & Title: B.A./B.Sc. (Honours) 2 dn semester (Practical) Topic No. & Title: 5/12 (Part-I) Drawing and Description of Limbs Bones: Humerus, Radius and Ulna.

2 Objective: Why do students of physical anthropology need to draw and describe bones? The important aims and objectives of drawing and description of bones are: 1. to know and get acquainted with the anatomical details and features, location and orientation on the skeleton, 2. to understand the functional interpretations of the bones, and 3. to establish phylogenetic as well as evolutionary interpretations of the bones through comparative study of different species. Content & Script of the Programme Introduction: Human skeleton is made up of 206 bones, comprising of 80 in axial part and 126 in appendicular part (64 in upper limb and 62 in lower limb). In the study of physical anthropology, the knowledge of bones and skeleton is a must as it forms a

3 part and parcel of the discipline. Now the question is why we study human skeleton and bones in physical anthropology. The sub discipline physical anthropology is devoted to the study of physical aspect of man. And when we say physical aspect, it covers a very wide spectrum ranging from the unit of living organism to multifaceted inter and intra population physical variation of human species on this globe as well as its relationship, affinities and variations with non human primates. So in physical anthropology we study human bones and skeleton with a view to understand the anatomical details of the bones, its location on the skeleton and functional interpretations as well. At the same time through the study of human bones and skeleton, an evolutionary sequence of different lineages can be established using the techniques of comparative anatomy of bones and skeleton of human and non human primates. Therefore it is of basic necessity for the students of anthropology to learn and know the fundamentals of drawing and description of human bones.

4 Procedures for Drawing and Description of Bones: The basic requirements for drawing a bone include a ruler, a well sharpened pencil, a rubber (eraser) and a drawing sheet of appropriate size corresponding to the size of the note book. Before we directly start drawing the bone, first of all draw the bordering line on the paper where the drawing is to be made. Then, after drawing the borderline, just on the right hand top corner below the borderline you should keep a space for writing the date on which the diagram is drawn. Along with it in the middle portion just below the borderline you have to write the name of the bone. After that you make a virtual division of the drawing sheet, so that the required views of the bones can be drawn proportionately in each division. As for example if you want to represent the anterior, posterior, medial and lateral views of the bone then divide the drawing sheet into four virtual divisions wherein you can draw each one view. Thereafter, you can start drawing in a systematic way. The drawing should be purely free hand drawing. However, it should be proportionate to the original bone. That means it should neither be very large nor very lengthy. You can use slight shading of various parts of the bone like condyles, facets, tuberosities, tubercles, fossa, foramen, ridges, crests

5 etc. so that the same is very clearly and distinctly visible. After drawing, the next step is to label the various parts of the bone. You should as far as possible use dotted lines in labeling the various parts because solid lines may often be confused as a part of the bone. Then after labeling various parts of the bone you also have to labeled the various views you have drawn such as anterior view, posterior view, profile view, inferior view etc. And after labeling provide a space for the teacher s remark and signature at the bottom right or left hand corner just above the border line. For a systematic description of the bone, first of all, you should carefully observe the bone, and identify the type of skeleton, part of skeleton, type of bone by stating reasons, and also anatomical position and location in the skeleton. Then you can start elaborate systematic description of various parts of the bone.

6 Systematic Description of Humerus Bone: Type of skeleton : Endoskeleton as it is found underneath the tissue. Part of skeleton : Appendicular part as it is the bone of upper extremity. Type of bone : A long bone because it possesses two epiphyses (extremities) and a diaphysis (shaft). Location : Vertically located in the upper arm. Name of bone : Human humerus bone (upper arm bone). General description: The humerus is the longest and largest bone of the upper arm of upper extremity. It is divisible into three parts i.e. two extremities (epiphyses) and a shaft (diaphysis) in between. The head, present at the upper end of the bone articulates with the scapula, while the lower end with the radius and ulna bone.

7 Anatomical description: The upper extremity consists of a large hemispherical head joined to the body by a constricted portion called the neck, and two eminences, the greater and lesser tubercles. Circumference of the head is slightly constrictedanatomical neck forming obtuse angle with shaft. The tapering region of the upper end where it meets the shaft is called surgical neck. Greater tubercle, which forms the lateral most point in the shoulder is situated at the lateral side of the upper end, and lesser tubercle is the small blunt eminence anterolateral to the head on the proximal shaft, its upper surface is rounded and marked by three flat facets separated by two ridges. The lesser tubercle is more prominent than greater and it is situated in front of head and directed inward and forward. The two tubercles are separated by a deep bicipital groove. Shaft is the region of the bone which joins upper and lower extremities, The upper half is almost cylindrical and lower half prismatic and flattened below. It has 3 borders and 3 surfaces. Anterior border runs from front of greater tubercle to coronoid depression below. External border starts from

8 back part of greater tubercle to external condyle, prominent at the lower end where it forms lateral supracondylar ridge, The medial border forms the medial lip of the intertubucular sulcus. Anterolatral surface is between anterior and lateral border. A little above the middle there is deltoid tuberosity. Antero-medial surface is between anterior and medial border, and posterior surface- between medial and lateral this surface is somewhat twisted. The lower extremity consists of 2 epicondyles, 2 processes (trochlea and capitulum), and 3 fossae (radial fossa, coronoid fossa, and olecranon fossa). Structurally, it is antero posteriorly flattened, has articulatory and non articulatory part. Capitulum and trochlea are the articulatory parts. Capitulum articulates with head of radius, trochlea articulates with trochlear notch of ulna. Non articular parts are- 2 condyles, 3 fossa coronoid, radial and olacranon, 2 supracondylar ridges- medial and lateral. Side identification: 1. The upper end having head should lie superior in position, while the lower expanded end should be inferior in position. 2. The head should direct medially and backward.

9 The coronoid fossa present at the distal end should be anterior and olecranon fossa posterior in position. Systematic Description of Radius Bone: Type of skeleton : Endoskeleton as it is found underneath the tissue. Part of skeleton : Appendicular part as it is the bone of upper extremity. Type of bone : A long bone because it possesses two epiphyses (extremities) and a diaphysis (shaft). Location : arm. Vertically located in the outer side of lower Name of bone : arm). Human radius bone (outer bone of lower

10 General description: Radius (the outer bone of fore arm) :- The radius, situated on the lateral side of the ulna, is the shortest bone of the three long bones of the arms of upper extremity. Its upper end is small, and forms only a small part of the elbow-joint; but its lower end is large, and forms the chief part of the wrist-joint. It is a long bone with its body prismatic in form and slightly curved longitudinally. Anatomical description: The upper extremity (proximal extremity) presents a head, neck, and tuberosity. The head is of a cylindrical form, and on its upper surface is a shallow cup or fovea for articulation with the capitulum of the humerus. The head is smooth and disk shaped with a superior concave articular surface (articular fovea) which articulates with the capitulum of humerus. The medial side of the disk shaped head is a broad articular surface where it articulates with the radial notch of the ulna. The head is supported on a round, smooth, and constricted portion called the neck. Beneath the neck, on the

11 medial side, is an eminence, the radial tuberosity; its surface is divided into a posterior, rough portion for the insertion of the tendon of the biceps brachii, and an anterior, smooth portion, on which a bursa is interposed between the tendon and the bone. The Body or Shaft is prismoid in form, narrower above than below, and slightly curved, so as to be convex lateralward. It has three borders and three surfaces. The three borders are : anterior border, which extends from anterior margin of radial tuberosity to the styloid process; posterior border which is clearly defined only in its middle 1/3 and medial border which extends from the radial tuberosity to the posterior margin of the ulnar notch. The three surfaces of the shaft of radius are : anterior, posterior and lateral surface. The widest part of the radius bone is the lower end. It has 5 surfaces a thick anterior surface, posterior surface with 4 grooves, medial surface occupied by the ulnar notch, lateral surface which is prolonged downwards into the styloid process and inferior surface which bears a lateral triangular area for the scaphoid.

12 Side identification 1. The proximal end is cap like, while the distal end is widest part of the radius. 2. The shaft should be convex laterally and concave forward in anatomical position 3. Radial tuberosity should be medial in position. Systematic Description of Ulna Bone: Type of skeleton : Endoskeleton as it is found underneath the tissue Part of skeleton : Appendicular part as it is the bone of upper extremity Type of bone : A long bone because it possesses two epiphyses (extremities) and a diaphysis (shaft). Location : arm Vertically located in the inner side of lower Name of bone : arm) Human ulna bone (inner bone of lower

13 General description: Ulna (inner bone of fore arm.):- The ulna is a long bone, prismatic in form, placed at the medial side of the forearm, parallel with the radius. It is divisible into a body and two extremities. Its upper extremity is of great thickness and strength. It forms a large part of the elbow-joint; the bone diminishes in size from above downward, its lower extremity being very small, and excluded from the wrist-joint by the interposition of an articular disk. Anatomical description: Upper Extremity is a curved olecranon process, undersurface of olecranon has a greater sigmoid cavity, Below olecranon is coronoid process with lesser sigmoid cavity above. Olecranon fossa of humerus receives the olacranon process of ulna in flexed position. Upper end of ulna also has two notchs trochlear notch which articulates with the trochlea of humerus, and ulnar notch which articulates with head of ulna.

14 Shaft is prismatic in form and curved from behind and forward, it has three borders i.e. anterior, posterior, medial and three surfaces- anterior, posterior and medial surface. The lower extremity of the ulna is small, and possesses two eminences; a head which is lateral, larger and rounded articular eminence, the medial is narrower and more projecting, is a non-articular eminence called the styloid process. Side identification: 1. The upper end of ulna having hook like olecranon process should be superior in position 2. Greater sigmoid cavity should be anterior in position. 3. The lateral border of the shaft should be sharp and crest like. 4. The styloid process present at the distal end should be medial in position.