an adjustable device is designed to apply a traction to streach the
tibia. it is attached to the tibia by rigid pins as illustrated below.
there is a mechanism for lenght adjustable in the centre of the
vertical section.
Draw a free-body diagram for each of the three straight sections of
the device, showing the forces and bending moments to which each is
subjected. Discuss the criteria that you would use to determine the
required dimentions of this device. What are the potential failure
mechanisms? What materials might be appropriate for the manufacture of
this device, and why?
Estimate the mean cross-sectional area of the tibia and, assuming that
its youns?s modulus is 10000 Mpa, calculate the load required to
stretch it by 1mm over a length, L, of 300mm.
Determine appropriate cross-sectional dimensions for the vertical
section of the traction device to enable it to sustain this applied
load.
Review critically the assumptions that you have made in your analysis
of this device.

Apparently an illustration is missing here.  Perhaps you could post
the illustration and provide a link.  For thirty bucks you might even
get an answer.