*4.1.2 Operating procedure on the ultrasound machine*

**Pairing and orientation of ultrasound image and sensor.** Coordination of needle and sensor movements, verification of the resulting image and orientation in the tissues of the body are developed over time. With the necessary experience, no problems in the orientation of the image will arise. For beginners, determining the coincidence of the sides of the sensor and the image on the monitor is an elementary but mandatory rule to get started. To do this, different simple methods are used: palpation of tissues, tapping on the edge of the working surface of the sensor, and positioning the label on the basis of the sensor.

**Work with instrument settings.** The skill of working with the parameters of the device also plays an important role. If for examining of some muscles (quadriceps femoris), special settings are not required, and then when scanning some other – the quality of the settings can affect the effectiveness of the injection. Additional image adjustment may require the location of the long extensors of the thumb and toes, the posterior tibial muscle, as well as the study of the muscles of the foot.

There are several basic settings for ultrasound imaging. Depending on the instrument, adjustments can be made manually or partially automatically.

The main adjustment parameters include:

1. Imaging modes:

• B-mode – the main imaging mode in which anatomical tissues and organs are displayed in real time.

	- Muscles of the shoulder girdle-up to 4 cm.
	- Shoulder muscles-up to 4–6 cm.
	- Upper third of the forearm 3.3–4 cm.
	- The middle and lower third of the forearm-3.3 cm.
	- Muscles of the hand-up to 2 cm.

In addition to the basic adjustments, there are additional ones that can be used to change the power of the ultrasonic wave, improve the quality and overview of the image, change its profile, remove image interference, etc.
