Left rotation and dorsoventral collapse of the trachea on an adult Dartmoor cross‐gelding: Imaging diagnosis.

Summary: A 9‐year‐old Dartmoor cross‐gelding was referred for investigation and treatment of exercise intolerance, cough and abnormal respiratory noise. Endoscopic examination revealed the presence of left 90‐degree rotation and dorsoventral collapse of the entire cervical trachea. Although the tracheal collapse was not obvious on laterolateral radiographs, these showed the abnormal presence of tracheal cartilages along with the dorsal and ventral limits of the trachea. Oblique radiographs showed partial tracheal collapse in the caudal aspect of the neck. Ultrasound examination revealed the presence of tracheal cartilages on the right side of the neck, dorsal tracheal ligament along with the left side of the neck and the junction between tracheal cartilage and dorsal tracheal ligament coursing over the ventral aspect of the neck. This report highlights the value of detailed examination of standard and non‐standard radiographic and ultrasound imaging of the trachea to achieve correct diagnosis of tracheal collapse when associated with tracheal rotation. [ABSTRACT FROM AUTHOR]