X-ray anatomy of the skull

The entire skull, both the cerebral and facial, is visible on lateral X-rays. The contours of the cranial vault are represented on the X-ray by a double line of compact bone substance. The clearer and smoother outer line corresponds to the outer plate of the cranial vault bones. The inner line of varying thickness represents the inner plate. The narrow "cleared" strip (darker in the image) between them is the spongy substance. In the anterior sections of the vault, the narrow strip of "cleared" (diploe) turns into a sharp expansion of an oval or triangular shape, corresponding to the frontal sinus. Behind, the outer contour of the cranial vault ends in a more or less pronounced external occipital protuberance. Inside of it, there is a thickening of the cruciate eminence with a small depression, corresponding to the groove of the transverse sinus.

Against the background of the cranial bones, lighter lines of the cerebral eminences and darker areas of various shapes ("enlightenment") - finger-like depressions - are visible. The coronal and lambdoid sutures are visible against the background of the cranial vault bones. The occipito-mastoid suture is visible as a downward continuation of the lambdoid suture. Other sutures of the cranial bones are weakly defined or not visible at all in the lateral projection image. The sutures should be distinguished from the wavy dark stripes at the site of the diploic veins and meningeal arteries. Within the base of the skull, intense shadows of the petrous parts of the temporal bones are distinguished, overlapping each other. In front of them is the body of the sphenoid bone with the sella turcica, the walls of which have clear contours. In the thickness of the body of the bone, under the sella turcica, there is an extensive dark spot of the sphenoid sinus.

Behind the sella turcica, a slope begins in the form of a line that goes to the anterior edge of the large (occipital) foramen. Behind the pyramids of the temporal bones, the enlightenment of the mastoid process cells and the wide "enlightened" (dark) groove of the sigmoid sinus are visible.

In the facial skull area, the eye sockets are defined as a cone, the base of which is directed forward, and the apex is directed backward. The eye sockets are superimposed with a pattern of ethmoid labyrinth cells. In front of the eye sockets, the contours of the nasal bones are visible, the base of which is directed upward and backward, and the apex is directed downward and forward. The nasal cavity is superimposed on the eye sockets and the maxillary sinuses located below the eye sockets, which have the appearance of a dark area of a quadrangular or irregular shape on the radiograph. Against the background of this quadrangle, one can distinguish the shadows of the nasal turbinates as elongated semi-oval stripes, and between them are the nasal passages. Below the superimposed images of the nasal cavity and maxillary sinuses, a horizontally located light strip (shadow) is visible, designating the bones of the hard palate. Below and in front of it are the alveolar process of the maxilla and the upper teeth. The contours of the overlapping right and left halves of the lower jaw and the teeth are clearly visible on the lateral radiograph. A darker strip of the mandibular canal can be traced against the background of the body and the lower part of the branch. The contours of the vault can be traced on the radiograph in the anterior projection; the pattern of the frontal bone is superimposed on the pattern of the occipital bone. The contours of the eye sockets are clearly defined, and between them and slightly below lies the nasal cavity, divided by the nasal septum. Intense shadows of the pyramids of the temporal bones are superimposed on the lower parts of the eye sockets on the side of the nasal cavity. The body of the sphenoid bone with the sphenoid sinus, the cells of the ethmoid bone and the contours of the nasal turbinates are projected onto the upper part of the nasal cavity between the eye sockets. Dark areas ("clearances") corresponding to the maxillary sinuses stand out on the sides of the nasal cavity, under the eye sockets. In the lower part of the facial skull, the upper and lower teeth and the lower jaw with its right and left branches are visible.