Download drawing and description of girdle bones part 1 (clavicle and scapula)

DRAWING AND DESCRIPTION OF
GIRDLE BONES
PART 1 (CLAVICLE AND SCAPULA)
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 one view each. 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 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 labelling the various parts because solid lines may often be confused as a
part of the bone. Then after labelling various parts of the bone you also have to labelled the
various views you have drawn such as anterior view, posterior view, lateral view, inferior view
etc. And after labelling 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.
Systematic Description of Clavicle 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 :
Horizontally located at the root of the neck
Name of bone :
Human clavicle bone (collarbone)
General Description
Pectoral girdle, which is also commonly called shoulder girdle is composed of two different
bones, clavicle and scapula. Clavicle, also known as collar bone is a long bone as it possesses
two ends and a shaft. It looks like an italicized letter f. It is located just at the root of the neck
and in fact is the only bone which is located or situated horizontally in the body.
Anatomical description of various parts
When anatomically examined, clavicle possesses two articulatory extremities called acromial end
and sternal end. The sternal end is quadrangular and articulates with the manubrium of the
sternum. Acromial end is flat and is so called because it articulates with the acromion process of
the scapula. The body of the clavicle is divided into two parts. The lateral one third is flattened
from above downwards and has two borders, the anterior border which is concave, and a convex
posterior border. On the backside there is a prominent projection called deltoid tubercle and
below it there is conoid tubercle. The second part of the body- the middle two third, is convex
forward or concave backward. The cross section of the shaft is somewhat cylindrical in the middle
part, quadrangular in the medial part and flattened at the lateral part.
Identification of Side
For identification of the side it belongs, we have to take into consideration into three important
views i.e. front back, up down, lateral and medial. Considering these points, sternal end should
be medial and acromial end lateral. Most roughnings and irregularities are on the inferior surface.
The conoid tubercle should lie laterally and posteriorly.
Systematic description of scapula 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 flatbone, because it has flat surfaces
Location :
Located on the dorsal or backside of the shoulder.
Name of bone :
Human scapula bone (shoulder blade)
General description
Scapula also commonly called shoulder blade is triangular shaped bone located on the
backside of the shoulder and at the backside of the thorax opposite to the second rib to
seventh rib. Scapula is an endoskeleton as it is located inside the body covered by the
subcutaneous tissue. It is an appendicular flat bone as it is a part of upper extremity having
flat surfaces.
Anatomical description
Its somewhat concave flat surface faces forward at the same time imperfectly medial. It has
three borders, superior border running along the superior edge. Another border starts from
this superior angle and continues up to the inferior angle. This border is called medial or
vertebral border. The other border is lateral or axillary border which in fact is the
anteroposteriorly the thickest border. The scapula has two flat surfaces, one is concave
forward and bit medially called costal surface and the other surface is on the back side
which is convex and called dorsal surface. The dorsal surface has a spine running and
dividing the surface into two parts, one is the upper smaller surface called infra spinous
fossa, whereas, below the spine the larger triangular surface called supra spinous fossa.
Scapula has three angles, first is superior angle formed by superior border and vertebral
border. Second angle is called inferior angle which is formed by vertebral border and lateral
border. The third angle is called lateral angle or glenoid angle.
The scapula has three processes - spine, acromiom process and coracoid process.
The spine is a long projection running along the anatomical length on the backside/dorsal side of
the scapula. Acromiom process is the projection of the spine at the terminal part. It articulates
with the acromial end of the clavicle. Coracoid process – a curved projection which arises from
the upper part of the glenoid cavity is the third process. Just below the coracoid process and
lateral in position there is a articular surface called Glenoid cavity. This glenoid cavity is meant
for articulation with the head of humerus bone so that upper arm can move up and down, front
and back and side to side or freely in any plane.
Identification of Side
When the scapula is oriented in its anatomical position one can easily identify whether it is left
or right by considering the following features.
1. The spine should face backward or should be posterior in position.
2. The Glenoid cavity should face laterally i.e. towards the side of the body
3. Superior angle should be up and inferior angle should be down
CONCLUSION
Why do we draw and describe human bones? The reasons are 1) To identify the bones, 2) To
know its anatomical description, its location, and how it articulates along with other bones and
3) By knowing drawing and description of human bones, we can go for comparative anatomy,
comparison of bones, structure of various parts of bones of human beings as compared to
other animals, mammalian animals and mammalian primates. So as a student of anthropology
it is a must that you all to know how to draw and describe bones.