Dens is a bony projection on the second cervical vertebra (C2), also called the axis. It forms a key pivot point that allows the head and the first cervical vertebra (C1) to rotate. Dens is commonly discussed in neck anatomy, trauma (fractures), and upper-cervical stability. It is also a central landmark on cervical spine imaging such as X-ray, CT, and MRI.

The Internal Carotid Artery is a major artery that carries oxygen-rich blood to the brain. It runs up the neck and enters the skull to supply key brain regions. Clinicians often discuss it when evaluating stroke risk and neurologic symptoms. It is commonly assessed with vascular exams and imaging tests of the neck and brain vessels.

The Odontoid process is a tooth-like bony projection on the second cervical vertebra (C2), also called the axis. It sits high in the neck, just below the skull, and helps the head rotate side to side. Clinicians often refer to it as the “dens,” and it is a key landmark on cervical spine imaging. It is commonly discussed in neck trauma, instability, arthritis, and certain congenital spine conditions.

The Carotid Artery is a major blood vessel in the neck that carries oxygen-rich blood to the brain. Most people have a right and left Carotid Artery system, each branching into internal and external vessels. Clinicians commonly reference it when evaluating stroke risk, neurologic symptoms, or vascular disease. It is also a frequent target of noninvasive imaging such as ultrasound.

The Atlantoaxial joint is the joint complex between the first and second cervical vertebrae (C1 and C2) at the top of the neck. It is the main structure that allows the head and neck to rotate side to side. Clinicians discuss it when evaluating neck pain, headache patterns, instability, or upper cervical spinal cord symptoms. It is also a key focus in cervical spine imaging, injections, and some stabilization surgeries.

Inferior Vena Cava is the body’s largest vein that carries blood from the lower half of the body back to the heart. It runs through the abdomen and enters the right side of the heart (the right atrium). Clinicians often refer to it in imaging, ultrasound exams, and procedures involving venous access. It is also central to discussions about blood clots and venous return (blood flowing back to the heart).

The Superior Vena Cava is a large vein that returns blood from the upper body to the heart. It carries oxygen-poor blood from the head, neck, arms, and upper chest into the right atrium. Clinicians reference it often in imaging, central venous access, cardiac devices, and evaluation of chest symptoms. It also matters in conditions that block venous flow, such as Superior Vena Cava obstruction (often discussed as “SVC syndrome”).

The Atlanto-occipital joint is the connection between the base of the skull and the first cervical vertebra (C1, the atlas). It helps you nod your head “yes” and keeps the head balanced on the neck. Clinicians refer to it when evaluating upper-neck pain, headache patterns, and craniocervical stability. It is also a key landmark in imaging and in some diagnostic or surgical decision-making.

The Coccyx is the small, tail-like bone at the very bottom of the spine. It sits below the sacrum and forms part of the pelvic ring. In everyday language, it is often called the “tailbone.” Clinically, it is discussed in back pain, pelvic pain, and sitting-related pain evaluations.

Pulmonary Veins are blood vessels that carry oxygen-rich blood from the lungs to the heart. They connect the lungs to the left atrium, which is the heart’s receiving chamber on the left side. Clinicians refer to Pulmonary Veins in heart rhythm care, imaging reports, and congenital heart evaluations. They are also discussed when symptoms suggest lung-to-heart blood flow problems.