X-ray of the eye socket

The visual organ consists of the eyeball, its protective parts (the orbit and eyelids) and the appendages of the eye (the lacrimal and motor apparatus). The orbit is shaped like a truncated tetrahedral pyramid. At its apex is an opening for the optic nerve and ophthalmic artery. Attached to the edges of the optic opening are 4 rectus muscles, the superior oblique muscle and the muscle that lifts the upper eyelid. The walls of the orbits are composed of many facial bones and some bones of the cranium. The walls are lined from the inside with periosteum.

The image of the eye sockets is present on plain radiographs of the skull in the frontal, lateral and axial projections. In the image in the frontal projection with the nasochinic position of the head in relation to the film, both eye sockets are visible separately, and the entrance to each of them in the form of a quadrangle with rounded corners is very clearly distinguished. Against the background of the eye socket, a light narrow superior orbital sheath is determined, and under the entrance to the eye socket - a round opening through which the infraorbital nerve exits. In lateral images of the skull, the images of the eye sockets are projected on each other, but it is easy to distinguish the upper and lower walls of the eye socket adjacent to the film. In the axial radiograph, the shadows of the eye sockets are partially superimposed on the maxillary sinuses. The opening of the optic nerve canal (round or oval, diameter up to 0.5-0.6 cm) is not noticeable on plain radiographs; a special image is taken for its study, separately for each side.

An image of the orbits and eyeballs free from overlapping adjacent structures is achieved on linear tomograms and especially on computed tomograms and magnetic resonance tomograms. It can be argued that the visual organ is an ideal object for AT due to the pronounced differences in radiation absorption in the eye tissues, muscles, nerves and vessels (about 30 HU) and retrobulbar fat (-100 HU). Computed tomograms allow obtaining an image of the eyeballs, the vitreous body and the lens in them, the eye membranes (as a summary structure), the optic nerve, the ophthalmic artery and vein, and the eye muscles. For the best display of the optic nerve, a section is made along the line connecting the lower edge of the orbit with the upper edge of the external auditory canal. As for magnetic resonance imaging, it has special advantages: it does not involve X-ray irradiation of the eye, it makes it possible to examine the eye socket in different projections and differentiate blood accumulations from other soft tissue structures.

Ultrasound scanning has opened up new horizons in the study of the morphology of the visual organ. Ultrasound devices used in ophthalmology are equipped with special eye sensors operating at a frequency of 5-15 MHz. They have a minimum "dead zone" - the closest space in front of the piezoelectric plate of the sound probe, within which echo signals are not recorded. These sensors have a high resolution - up to 0.2 OD mm in width and front (in the direction of the ultrasound wave). They allow measurements of various eye structures with an accuracy of up to 0.1 mm and judge the anatomical features of the structure of the biological environments of the eye based on the value of ultrasound attenuation in them.

Ultrasound examination of the eye and orbit can be performed using two methods: the A-method (one-dimensional echography) and the B-method (sonography). In the first case, echo signals corresponding to the reflection of ultrasound from the boundaries of the anatomical environments of the eye are observed on the oscilloscope screen. Each of these boundaries is reflected on the echogram as a peak. Between the individual peaks, an isoline is normally located. Retrobulbar tissues cause signals of varying amplitude and density on the one-dimensional echogram. An image of the acoustic cross-section of the eye is formed on sonograms.

In order to determine the mobility of pathological foci or foreign bodies in the eye, sonography is performed twice: before and after a rapid change in the direction of gaze, or after a change in body position from vertical to horizontal, or after exposure of the foreign body to a magnetic field. Such kinetic echography allows one to determine whether the foci or foreign body are fixed in the anatomical structures of the eye.

Fractures of the walls and edges of the orbit are easily identified using survey and targeted radiographs. A fracture of the lower wall is accompanied by darkening of the maxillary sinus due to hemorrhage into it. If the orbital fissure penetrates the paranasal sinus, air bubbles in the orbit (orbital emphysema) may be detected. In all unclear cases, for example, with narrow cracks in the walls of the orbit, CT helps.

X-ray signs of damage and diseases of the organ of vision