Computed tomography of the neck is normal

Normal anatomy

The radiologist quickly runs into the limits of the resolution of CT (and perhaps his or her knowledge of anatomy) when attempting to identify each neck muscle. Individual muscles are of little clinical significance.

Sections of the neck usually begin at the base of the skull and continue caudally to the superior thoracic aperture. Sections that include the head therefore include images of the maxillary sinuses, nasal cavity, and pharynx. Behind the pharynx are the long muscles of the head and neck, which continue downward (caudally).

The spread of the inflammatory process within the fascial spaces of the neck is limited by the boundaries of the fascia. The different layers of the fascia of the neck are presented on the next page.

Even more caudally, the following neck muscles become visible under the trapezius muscle: the semispinalis and longissimus capitis muscles are located medially, and the splenius capitis muscles are located somewhat lateral. The parotid gland, located cranially and posteriorly to the submandibular gland, is immediately behind the angle of the lower jaw. The pharynx is surrounded by a ring of Waldeyer's tonsils. The structures of the lower floor of the oral cavity are located in layers under the tongue: the genioglossus muscle runs in the cranial-caudal direction, and the geniohyoid muscle and the anterior belly of the digastric muscle are somewhat lateral. The thin subcutaneous muscle of the neck is located superficially.

Interfascial spaces of the neck

If the source of infection or inflammation is located above the sternum or in the pretracheal space between the superficial fascia and the posterior plate of the pretracheal fascia, the spread of the lesion to the mediastinum is impossible because both fasciae are attached to the sternum. Starting from the parotid gland, a similar barrier consisting of a sagittal leaflet separates the retropharyngeal space from the parapharyngeal space. If inflammation occurs somewhat behind, between the pretracheal and prevertebral fasciae, the process may spread downwards (caudally) to the mediastinum.

Atherosclerotic plaques often form in the area of the bifurcation of the common carotid artery, which may be complicated by thrombus formation. Note the position of the cricoid and arytenoid cartilages in relation to the glottis. In the example shown, after the introduction of a contrast agent, not only the internal, external and anterior jugular veins are enhanced, but also the vertebral arteries in the transverse openings of the cervical vertebrae. Degenerative changes or disc herniations can narrow the spinal canal containing the spinal cord. Two lobes of the thyroid gland are adjacent to the trachea on the right and left, having a smooth contour and uniform (homogeneous) parenchyma.

Due to the iodine content, the thyroid gland has a higher density compared to the surrounding muscles both before and after the introduction of CS). Beginning doctors sometimes confuse the esophagus, located posterior (dorsal) to the trachea, with enlarged lymph nodes or a tumor. In doubtful cases, comparison with other sections will help. A small area of low-density air usually appears in the lumen of the esophagus on one of the sections. As a rule, in patients with neck and chest trauma, the examination is carried out with arms raised above the head, which reduces the number of artifacts formed due to the overlap of bones. Therefore, the muscles of the pectoral girdle and shoulder joints are visible in an unusual position.

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