The most common lesion of vertebral bodies and discs is ventral, ventrolateral, or lateral bony proliferation (often called vertebral spondylosis); it is mainly found in the midthoracic area (mostly between T11 and T13) but can also be seen in the lumbar area. They can be found on asymptomatic horses but can also be responsible for acute pain or chronic back stiffness. Spondylosis is a rare cause of back pain; in one survey, only 3.4% of 670 horses with back pain demonstrated this abnormality. Congenital abnormalities with vertebral body deformation (triangular or trapezoidal shape) are rare and usually found in the thoracic vertebrae. Vertebral body osteomyelitis, leading to neurologic signs, can be seen in the thoracolumbar spine in foals. Vertebral body fractures occur in horses that have had severe trauma or falls, particularly in racehorses in jumping races. Complete or partial paraplegia results from damage to the spinal cord. The prognosis is usually grave.