Common Carotid Artery: The common carotid artery is a key aortic trunk in the head and neck region. It originates from the innominate artery on the right and immediately from the aortic arch on the left. Both common carotids pass behind the styloids before ascending along the sides of the trachea and larynx, reaching the level of the superior margin of the thyroid cartilage to become the internal and external carotid arteries. When bleeding in the head and neck area, the common carotid artery is compressed for temporary hemostasis.

Anatomical Structure of Common Carotid Artery:

1. Common Carotid Artery:

On each side, one originates from the brachiocephalic trunk, and the other immediately from the aortic arch. After passing the left and right styloids, they ascend along the sides of the trachea and larynx, reaching the superior margin of the thyroid cartilage to become the internal carotid artery and external carotid artery. There are no branches along this trunk. In front of the common carotid artery, it is covered by the neck muscles and the subhyoid muscle group below. The upper segment is located within the carotid triangle, superficially placed, where the heartbeat of the aorta can be felt. It is adjacent to the esophagus, trachea, larynx, and thyroid cyst. On both sides, it is close to the internal jugular vein, and there is a sympathetic nerve behind them. The common carotid artery, internal jugular vein, and sympathetic nerve are enclosed within the common carotid sheath, with the hypoglossal nerve loop and branches crossing in front of the sheath.

The line connecting the center of the head of the fibula with the center of the line from the angle of the mandible to the mastoid process is the epidermal projection of the common carotid artery and the external carotid artery.

During the rise of the common carotid artery, the height ratio of the annular cartilage (center of the neck muscle circumference) passes in front of the transverse process of the sixth cervical vertebra. In cases of bleeding inside the face, neck, and head, the common carotid artery can be pressed backward against the transverse process of the sixth cervical vertebra to achieve the temporary effect of blood rescue.

At the point where the common carotid artery divides into the internal carotid artery and the external carotid artery, there are two key structures. The carotid sinus, which is slightly enlarged at the start and end of the internal carotid artery, is called the carotid sinus. The wall is thick and contains many sensory nerve endings from the glossopharyngeal nerve, forming a pressure receptor, whose function is similar to that of the aortic arch pressure receptor. The other key structure is the common carotid body (common carotid globus), a flat oval body composed of squamous epithelial cells. Located behind the bifurcation of the common carotid artery, it is attached to the posterior inner wall by connective tissue. It contains many sensory nerve endings from the glossopharyngeal nerve, forming a chemical receptor, whose function is similar to that of the pulmonary artery body (globus).

2. Neck:

When examining the neonatal neck, one hand can support the upper back and allow the head to relax and extend to expose the neck.

Neonates have a relatively short neck, located in the middle, with easy movement (but not yet able to stand straight), without dimples, wounds, or lumps; there is no resistance when bending the neck, except when crying and fussing.

Neonatal neck deformity: Short neck is commonly seen in congenital fusion of the cervical and lumbar vertebral bodies, cretinism, mucopolysaccharidosis; the characteristic of pterygium colli is excessive skin from the sides and back of the neck reaching the middle of the shoulder; supplementary torticollis is common in congenital torticollis, with the cause often being trauma to the fetal neck muscles in the uterine cavity, and in a very few cases, due to birth trauma. Examination shows that the neck muscles on the affected side are short and thick, and if not prominent, the patient’s head position can be corrected to show the prominence of the scapular end of the affected side of the neck muscle.

Neonatal neck mass: The most common cause of neck mass is neck muscle abscess, often caused by birth trauma, which can be felt on one side or in the middle of the neck muscle, with a diameter of 2-4 cm, a localized and firm fusiform mass, moves with the muscle, often with mild tenderness, and all other symptoms are normal; congenital neck hydrocele is also a common hard mass in infancy, located in the upper neck, soft and translucent. The supplementary central neck mass is thyroid cyst, thyroglossal cyst, and goiter, the latter often being the result of treatment with thyroid cyst medication for thyroid cyst disease in mothers. Auscultation of the lungs at the site of the thyroid cyst may reveal abnormal sounds. In these two situations, neonates may have transiently elevated thyroid hormone levels.