In the occurrence of traumatic disorders, exogenous pathogenic factors are very important, but such inner factors as age, physique and local anatomic structure are also closely related to it.

Age:  
There are different predilection sites and incidence of trauma in persons with different ages. For example, in the case of fall with the hip first touching the ground and the same external force, fracture of neck of femur often occurs in old people, seldom in young people. Children are subject to fracture because of their delicate bones. But their fractures are often incomplete because of their thicker and flexible periosteum. The injury of epiphysis often occurs in young people who are in their growth and developmental periods and whose epiphyses are not occlusal. People in the prime of life seldom get fracture when falling, for their tendons and bones are strong.
      
Physique:  
The strength of physique is closely related to the occurrence of trauma. Young and vigorous people with abundance of qi and blood, rich kidney essence and strong tendons and bones seldom suffer from trauma. Old and weak people with deficiency of qi and blood, asthenia of the liver and kidney and osteoporosis are susceptible to trauma. For example, when falling on a level ground with the hip first touching the ground, they may also get fracture of neck of femur or intertrochanteric fracture even the external force is small.

Anatomic structures:  
Trauma is related to the anatomic structures to a certain extent. Transmitting force acting on a bone usually causes fracture in the junction between compact bone and spongy bone. For example, the part 2 to 3 cm away from the lower end of radius is the junction of compact bone and spongy bone, it is subject to fracture when the palm touches the ground in a fall. The clavicular fracture often occurs in the junction of the two arcuations without protection of ligaments. Take occult cleft spine of S1 as another example, because there is no spinous process, the supraspinal and interspinal ligaments are short of their attachments, thus the stability of lumbosacral joint decreases, the weak part is susceptible to trauma.
     
Occupation:
The occurrence of trauma is to a certain degree related to occupation. For example, mechanical workers without necessary safety devices are subject to the trauma of hand. Workers constantly bending over or shouldering heavy load are subject to chronic lumbar strain. Athletes, acrobats and Gongfu actors are subject to various sport injuries. And middle-aged people constantly bending over the desk are subject to cervical spondylopathy.