In ultrasound, the sound waves are almost completely reflected by bone and air, meaning that sonography is primarily used to visualise soft tissue structures such as tendons, ligaments, vessels and internal organs. However, the surface of bones can also be examined with high resolution. X-rays and ultrasound are therefore two complementary procedures.
The special methods of Doppler sonography and colour Doppler sonography provide additional information about the direction, speed and strength of blood flow in the heart and blood vessels. These procedures are primarily used in cardiac examinations.

Both a modern ultrasound device and an experienced vet who is familiar with the region in question are crucial for a high-quality ultrasound examination. The preparation of the patient also plays an important role: the horse must be able to stand still so that an accurate examination and diagnostically usable images are possible. As the animals are in an unfamiliar environment in the clinic and are therefore often more restless than in their own stables, most horses are sedated for the examination. The area to be examined is clipped, cleaned and rubbed with ultrasound gel in order to optimise the coupling between the transducer and the skin. We have several high-performance ultrasound devices with different transducers available for the different areas of application.

Areas of application of sonography in horses:
The areas of application of sonography are diverse and have developed considerably in the horse in recent years. The constantly improving technology and increasing expertise enable examinations in many areas of equine medicine.

Sonography of the tendons and ligaments:
Ultrasound examination of the flexor tendons is one of the most important examinations in equine orthopaedics. The high-resolution transducer allows even very small defects in the tendons to be diagnosed. The precise localisation and assessment of the defect not only enables individual therapy plans to be drawn up, but also targeted treatment. For example, regeneration-promoting medication can be injected directly into the defect under ultrasound guidance. The healing process can be monitored by a follow-up examination every six to eight weeks and the exercise programme can be adjusted.

Sonography of joints:
When examining joints, X-ray examinations are usually the main focus. In many cases, a supplementary ultrasound examination provides valuable additional information. The joint capsule, collateral ligaments, menisci and sometimes even cartilage sections can be visualised using ultrasound. For example, an ultrasound examination of the knee joint is now an integral part of the detailed examination of this joint. Ultrasound also helps us to precisely localise bone fragments that are visible on X-rays before surgical procedures.

Ultrasound-guided injections:
Under ultrasound guidance, injection needles can be inserted precisely into diseased or difficult-to-access tissue, such as tendon defects or facet joints in the cervical spine. This method also enables targeted needle biopsies, for example from the liver.

Sonography for acute injuries:
Ultrasound can be used to determine which structures (joints/tendon sheaths) are affected. Foreign bodies such as wood splinters, which are not visible on an X-ray, can also be detected using ultrasound.

Use in foal medicine:
It is hard to imagine foal medicine without the use of ultrasound. As a rectal examination is not possible in the case of colic, the ultrasound examination provides an insight into the abdominal cavity and gives an indication of a possible cause. The visualisation of internal organs such as the internal umbilical structures, intestines, kidneys and bladder, as well as fluid in the abdominal cavity, for example in the event of a bladder rupture, helps to make a diagnosis. Ultrasound also enables early diagnosis of pneumonia and monitoring of the healing process.

Gynaecological ultrasound:
In gynaecological ultrasound, the probe is inserted rectally, allowing the ovaries and uterus to be visualised. The examination is primarily used to determine the cycle status, in particular to determine the optimum time for insemination and to recognise early pregnancies. Changes or abnormalities in the ovaries and uterus can also be visualised in this way.

Ultrasound of the lungs:
Healthy lungs are filled with air, so that only the smooth surface is usually visible as a white line on ultrasound. In the case of pneumonia, however, certain areas of the lungs are no longer ventilated and can be easily visualised. Accumulations of fluid in the chest cavity (pleural effusion) can also be recognised using sonography.

Echocardiography (cardiac ultrasound):
During echocardiography, the heart chambers, the heart muscle and the heart valves are examined. Both the size of the heart chambers and the movement patterns of the heart muscle can be precisely assessed. With the Doppler examination, the flow at the individual heart valves can be visualised and thus heart valve defects can be assessed (see heart examination).

Sonography of the abdomen:
The ultrasound examination of the abdomen includes the liver, spleen, kidneys, bladder and parts of the intestine. In some cases, it can also provide valuable information when examining colic.

Sonography of the eye:
If the lens or the cornea are cloudy, the inside of the eye can no longer be seen. In these cases, the posterior segments of the eye can still be assessed using ultrasound.

Examination of neck/neck/back:
Suspected diseases in the neck area usually involve changes in the soft tissue, which is why ultrasound is the preferred diagnostic procedure. The assessment of the facet joints in the cervical spine is only possible to a limited extent using ultrasound. In such cases, X-ray examinations in conjunction with scintigraphy are the preferred method. Treatment of the facet joints by local injection can only be carried out under sonographic control due to the narrow joint spaces.
The muscles, ligaments and small vertebral joints of the lumbar spine can be visualised in the area of the back. However, the sacroiliac joint can only be visualised in a very limited area.

Examination of the pelvis:
Examination of the pelvis in horses is often challenging and in some cases only possible under general anaesthetic. Ultrasound is less invasive and offers the possibility of visualising parts of the hip joint, the bone surface of the pelvis and, for example, pelvic fractures with a penetration depth of up to 30 cm. The posterior section of the sacroiliac joint can be examined using rectal ultrasound.

Examination of vessels:
Visualisation of thromboses in the neck veins or leg arteries. It is used to diagnose vascular constrictions or occlusions.