The cricothyroid is the soft indentation in the neck located directly below the Adam's apple. It gets its name because it is sandwiched between the cricoid cartilage and the thyroid cartilage. This indentation is made up of the the cricothyroid muscle and the cricothyroid ligament. The cricothyroid and conus elasticus combine to make the cricoarytenoid articulation, the full joint that connects the cricoid and thyroid cartilages.
The cricothyroid muscle and ligament are important to the way a person's voice sounds. The muscle is used to create tension in the vocal folds, which is one of the factors that affects pitch. The ligament is what holds the cricoid cartilage and thyroid cartilage together; it is a thin, white membrane with a good amount of elasticity. As the muscle flexes and membrane stretches and contracts, a person's voice will rise up and down the scale. Exercising the this muscle will help a person's vocal range and cricothyroid exercises are used in study of vocology, which is the science of the fitness of the human voice.
The most common medical procedure involving the cricothyroid is a cricothyrotomy. A cricothyrotomy is commonly confused with a tracheotomy. Both are procedures in which a hole is cut in a person's throat and a tube is inserted that allows him to breathe.
To perform a cricothyrotomy, a hole is cut in the throat below the thyroid cartilage, through the cricothyroid ligament. A tube is then placed into the hole, and a ventilation bag is used to allow the patient to breathe. Emergency cricothyrotomies have been featured on many television shows, where objects like a straw and an eyedropper have been used as breathing tubes; this is extremely dangerous and not recommended, however.
A tracheotomy differs from a cricothyrotomy in that it is performed by cutting the hole between the tracheal rings, which are farther down the throat, below the cricoid cartilage. This is a much sturdier procedure, but takes longer to perform. A tracheotomy may be used in cases where long-term mechanical ventilation is needed; a cricothyrotomy is usually only intended to be a temporary measure.
Finding the cricothyroid is easy for most people. Men can push in with a finger just below the Adam's apple; there will be an indention between the Adam's apple and the hard cartilage below it. The indentation is the cricothyroid ligament. In women, both pieces of cartilage are still present, just a little harder to find.