Cricoid Cartilage - signet ring with band facing anteriorly (band is only around 4mm, back can be up to 30). The posterior part of the ring is the lamina (the signet) and the anterior part is the arch. It is the only complete ring of cartilage for the airway. Its the strongest ring of cartilage. On each side of the lateral surface there is an articulaion for the cricothyroid joint. On the upper surfcae there is an articular facet for articulation with the base of the arytenoid cartilage.
Thyroid Gland attached to cricoid via lateral thyroid ligaments.
From the 6th arch, its nerve is the recurrent laryngeal!
Subglottic Stenosis may result from an ellipitally shaped hyoid cricoid membrane.
- The hypo (laryngopharynx) extends from the hyoid cartilage to the inferior border of the cricoid cartilage.
- The inferior border of the criocoid cartilage is at c6, demarcated by the carotid tubercle.
- Marks the beginning of the oesophagus.
- The subglottic larynx extends from the lower boundary of the glottis to the lower margin of the cricoid cartilage.
- The middle cervical ganglion, usually small and occasionally absent, lies on the anterior aspect of the inferior thyroid artery at the level of the cricoid cartilage and the transverse process of the C6 vertebra
cricopharynxgeus muscle (outer coat of oesagpheal muscle, acts as the upper esophageal sphincter)
cricotracheal ligament inferiorly
cricothyroid membrane superiorly.
3 Muscles attach - cricothyroid, posterior cricoaretenoid, Lateral cricoarytenoid. (+cricopharyngeus (does not form raphe).
Dense connective tissue attaches the fibrous capsule of the thyroid gland to the cricoid cartilage
Synovial joint with inferior cornu of the thyroid cartilage
Synovial joint with the artenoid cartilage, on lateral superior aspect.
The ideal incision for a thyroidectomy and neck dissection should run at the level of cricoid cartilage.
The two superior parathyroid glands are usually at the level of the inferior border of the cricoid cartilage