Question

Signet ring cartilage of larynx is
A. Cricoid
B. Arytenoid
C. Thyroid
D. All of the above

Answer 1

Hint: Larynx is generally called a glottis or voice box. It is a way for air passage. It has a pharynx above and a trachea below. It extends from the fourth vertebral level to the sixth vertebral level. It plays a crucial role in breathing and speech. It has three important functions, namely control of the airflow during the breathing process, protection of the air passage and production of sound for the speech.

Complete answer
Option A Cricoid: At the inferior part of the larynx, the cricoid cartilage is present, which is a ring of hyaline cartilage. It is the only complete ring of cartilage present around the trachea. It possesses the shape of a signet ring. It has a broad portion posterior to the airway (lamina of cricoid cartilage) and a narrow portion rounding anteriorly (arch of cricoid cartilage). The word cricoid means ring-shaped, which refers to the signet-ring resemblance of cricoid cartilage.
Option A is correct
Option B Arytenoid: Arytenoid cartilages are two in number and shaped like three-sided pyramids. They lie at the posterior aspect of the larynx. Since they are not ring-shaped, the option is wrong.
Hence, Option B is not correct
Option C Thyroid: Thyroid cartilage is present in front of the larynx and above the thyroid gland. It is shield-shaped. So the option is not wrong.
So, Option C is not correct
Option D All of the above: As options B and C are not correct, this option is irrelevant.
Option D is not correct

Therefore, Option A is the correct answer.

Note:
Larynx contains a framework of cartilage with surrounding soft tissue. Larynx is a point at which the aerodigestive tract gets splitted into two separate pathways. Through one pathway, the inspired air travels via the trachea or windpipe into the lungs. Through the second pathway, the swallowed food from the mouth enters the oesophagus and passes into the stomach.