The Effect of Poorly Designed School Furniture on Children's Head and Scapulae Postures

weight

measured in kilograms

height

measured in centimetres

Body mass index (BMI)

It was calculated as the ratio of the subject's height (in meter) and weight (in kilogram) i.e. BMI= Weight/ Height2

anthropometric measurement for child

The anthropometric measurement for child were measured in mm by Auto CAD analysis for recorded photographs from sitting position.it include:1) elbow seat height: Measured with the elbow flexed at 90°, as the vertical distance from the bottom of the tip of the elbow to the student's seated surface, 2) shoulder height: Measured as the vertical distance from the top of the shoulder at the acromion process to the student's sitting surface,3) upper limb length: Difference between the elbow height and shoulder height.

anthropometric measurement for school furniture

The furniture dimensions were measured in mm by Auto CAD analysis for recorded photographs from sitting position.it include: 1) seat height: Measured as a distance from the floor to the highest point on the front of the seat, 2) seat depth: Measured from the back of the sitting surface of the seat to its front,3) backrest height: The vertical distance from the desk seat to the top edge of backrest, 4)desk- seat height: The vertical distance from the seat to the top of the front edge of the desk and 5) under surface of desk height: The vertical distance from the floor to the bottom of the front edge of the shelf under the writing surface..

Correlation between educational furniture dimensions and the user body dimensions

the percentage of compatibility for the ergonomics design of school furniture were tested by using the following equations: Equation (1): Seat height to popliteal height (N +2) cos 30°≤ SH < (N + 2) cos 5° Where SH is seat height and N is popliteal height). Equation (2): Seat depth to the popliteal-buttock length 80%M≤ SD < 95%M Where SD is seat depth and M is popliteal-buttock length. Equation (3): Backrest height:60% H≤ BH < 80% H Where BH is backrest height and H is shoulder height (scapula height). the previous equations represent the correlation between arthopemeteric measurements for the child (the user) and anthropometric measurement for school furniture.The percentage of matching and dis-matching school furniture calculated.

Head postures (angles)

Auto CAD program (version 2013) used to determine head postures (angles). 1) Head flexion angle: Line of canthus to tragus with respect to vertical (measured from vertical above intersect). 2) Neck flexion angle : Line of tragus to C7 with respect to vertical (measured from vertical above intersect)

scapular postures (displacement and elevation).

Auto CAD program (version 2013) used to determine scapular postures (displacement and elevation in mm). 1) Scapula displacement: Horizontal distance between markers at C7 and the anterior border of the acromion (measured in mm), 2)Scapula elevation: Vertical distance between markers at C7 and the anterior border of the acromion.