The number and size of the synovial bursae in donkey vary accord ing to the type of work of the animals. The light worker animals have two small subcutaneous supraspinous bursae located on two spines of any of the vertebrae of the caudal half of the throracic region. The hard worker animals have 2-8 subcutaneous supraspinous bursae located on the spines of the cranial thoracic region. More over there is a slight degree of connection between the adjacent bursae in some cases.
In draft donkeys the subcutaneous bursae are located on the spines of the sacral and cranial thoracic regions, their number is relatively smaller than those of the hard worker but they are longer and more extended than those of the light worker animals.