Haflinger, 21 years of age. Presented with a mild soft tissue swelling and discharge in the area caudal to the ears. At the clincal examination, a fistolous tract was found and explored in the dorsal cranial neck. Radiographs were taken with a probe inserted. Radiographic examination Radiographic findings
- There are multiple, small (less than 1.5cm in size) amorphous mineral opacities on the soft tissues caudal to the occiput and dorsal to C1. There is a mild new bone proliferation, faint and cloudy, on the occipital protuberance (arrow on the close up image).
- The metallic probe is inserted for approximately 7cm cranioventrally on the mid line, without direct contact to the bony surface.
- An ultrasonographic examination was performed: The assessment of the region was strongly limited from the presence of gas (from exploration) and mineralisations, causing extensive shadowing. The nuchal ligament was interpreted as normal. A fistolous tract could be only partially followed in the direction of the bursa nuchalis.
Close up of the laterolateral view of the nuchal region. The arrows show the periosteal reaction on the caudal aspect of Os occipitalis. Radiographic diagnosis
- Fistolous tract probably involving the bursa nuchalis, suspicious for septic bursitis. Multiple soft tissue mineralisations and periosteal reaction (enthesiophyte formation) on the occiput.
- To assess the exact course of the fistula, a contrast study (fistulogramm) was recommended. It was not performed, the horse was sent directly to surgery.
- In surgery, a septic bursitis of the Bursa nuchalis was confirmed.
Comments
- The ligamentum nuchae extends from ist cranial attachments on the external occipital protuberance to the spinous process of the 3rd ot 4th thoracic vertebra. It is formed by 2 parts, funicular and laminar, both paired. The rope-like funicular part is connected to sheets which comprise the laminar portions. These midline elastic sheets arise from the 2nd through the 7th cervical certebra and insert on the spine of the 2nd and 3rd thoracic vertebrae.
- Bursae are consistently found between the funicular part of the nuchal ligament and the atlas (bursa subligamentosa nuchalis cranialis) and between the nuchal ligament and the 2nd thoracic vertebra (bursa subligamentosa supraspinalis). A 3rd bursa (bursa subligamentosa nuchalis caudalis) is inconsistently found between the nuchal ligament and the spine of the axis.
- Infection of the nuchal and supraspinalis bursae are referred to as poll evil and fistulous whiters.
- The cranial and caudal bursae are a potential space and are therefore not typically identified on ultrasonograms when non diseased or only mildly filled.
- Bursitis have been associated with bacterial growth like Brucella abortus, Streptococcus sp, Staphylococcus sp and Onchocerca cervicalis infection.
- The origin of the bursitis is often unclear if no penetrating wound has been observed or reported.
- Usually, mainly in case of recurrent fistulations, the therapy of choice is surgical debriment.
