What is Cricoid Cartilage?

The cricoid cartilage refers to the ring-like structure present at the bottom section of the larynx. It also is considered as the topmost section of the trachea. It plays a major role in a variety of important bodily functions. Also popularly known as the voice box, the cricoid cartilage gives a certain prominence to the larynx in men and hence is also called the Adam’s apple.

The work cricoid is derived from the Greek work ‘krikoeides’ meaning ring-shaped, thereby synonymous with the circular structure and shape of the cartilage.

Anatomy of the Cricoid Cartilage

• The elastic tissue or the cricoid cartilage occurs at the base of the larynx and forms the primary element in the laryngeal structure as it offers connection functions to the muscles and ligaments that work together to facilitate glottis functionality. In simple terms, the cricoid cartilage can be referred to as the structure that forms the lower and back portions of the wall of the larynx.
• The cricoid cartilage is made up of hyaline which is another kind of cartilage. This is why the structure is prone to calcification or ossification, particularly when people begin aging.
• Location and Structure: The cricoid cartilage is regarded as the largest cartilage occurring in the larynx or throat. It is located just below the thyroid cartilage present in the neck. In humans, the cricoid cartilage is located in the 6^th level or stage of the cervical vertebra. The cricoid cartilage is connected to the medial part of the thyroid cartilage via the median cricothyroid ligament, wherein the cricothyroid joints connect posteolaterally. Below this are found the cartilaginous rings which surround the trachea. These circular cartilages occur in a non-continuous manner are shaped like the letter C. They also feature a space or a gap in their back section which facilitates the passage of food across the esophagus. The cricoid ligament and the first tracheal ring are connected together by the cricotracheal ligament. This connection can be felt between the thyroid and cricoid cartilages.
  • As compared to the front and lateral sections, the back portion of the cricoid cartilage is slightly wider and is referred to as the lamina. The front section is known as the arch or the band. This is why people usually make comparisons between the cartilage ring and the signet.
  • The cricoid cartilage tissue has anatomical linkage with the thyroid gland. The thyroid isthmus is located just below the tissue. The two lobes of the gland tend to extend on both sides of the cricoid cartilage and continue to do so till such area where the thyroid cartilage is placed above it.

Functions of the cricoid cartilage

• The main function of the cricoid cartilage is to connect different ligaments, muscles, and cartilages that are essential to the opening and closing of the airways. The cartilage also plays an important role in the creation of speech.
• It may be noted that the cricoid consists of very firm and tough connective tissue. It acts as a covering across the borders or tips of the different bone joints. This is what enables it to play a part in articulation as well as facilitate the smooth motion of the joints. However, the cartilage is not as strong or firm as the bones. It is one of the components or parts of the body that is partially or completely flexible.
• When an individual experiences intense respiratory or breathing problems and when varied options do not help better the airways condition, then doctors may insert a hollow needle into the cricoid cartilage to allow and improve the respiratory processes. This method of treatment is known as Emergency Airway Puncture or cricothyrotomy.

Clinical significance of the cricoid cartilage

Before performing a surgery on an individual placed under general anesthesia, an anesthesiologist will typically press on the cricoid cartilage while introducing a cannula or a tube. This process exerts pressure on the esophagus present at the back of the cartilage and squeezes it thereby preventing the chances of gastric reflux occurrence. The process is medically referred to as the ‘Sellick Maneuver.’

The Sellick Maneuver was considered for several years as the standard care measure to be followed during ‘rapid sequence induction.’ Many medical experts still suggest application of pressure on the cricoid cartilage when performing Emergent Oral Endotracheal Intubation as well as when carrying out resuscitation via the use of a BVM. However, recent studies have found that application of pressure in the area of the cricoid may not be as beneficial as was believed to be.

Experts are also of the opinion that application of pressure on the cricoid may be done in an incorrect manner on numerous occasions. Such incorrect application of pressure can trigger the lateral movement of the esophagus instead of direct compression as suggested in the Sellick Maneuver.

Many studies carried out by researchers have found that incorrect application of pressure on the cricoid cartilage can lead to mild or moderate compression or constriction of the glottis, which is the larynx’s vocal appendage, which in turn can cause reduction of tidal volume and elevation in peak pressures. These recent findings is what has caused the once widely used procedure of cricoid pressure application to become redundant when performing rapid sequence intubation procedure.

Sometimes, doctors may perform a cricoidectomy, a medical procedure marked by full or partial removal of the cricoid cartilage from the throat. It is often carried out by surgeons so as to alleviate any kind of obstruction or blockages within the trachea, which in turn can occur due to calcification of ossification of the hyaline cartilage situated inside the cricoid. Hardening of hyaline can occur due to tracheal blockages or increased age. Affected people are most likely to experience pain in the throat area.

Cricoid and thyroid cartilage fractures are the most common forms of laryngeal cartilage fractures. The fractures are usually caused due to physical trauma or injury to the area. Affected individuals may experience swelling or inflammation of the larynx, or hemorrhage. Airway blockages and speech problems are some of the associated health complications of cricoid cartilage fractures.