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tough elastic tissue; mostly converted to bone in adults (同)gristle

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軟骨[組織]

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2018/03/30 06:20:16」(JST)

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The cricoid cartilage /ˌkraɪkɔɪd ˈkɑːrtɪlɪdʒ/, or simply cricoid (from the Greek krikoeides meaning "ring-shaped") or cricoid ring, is the only complete ring of cartilage around the trachea. It forms the back part of the voice box and functions as an attachment site for muscles, cartilages, and ligaments involved in opening and closing the airway and in producing speech.

Structure

The cricoid cartilage sits just inferior to the thyroid cartilage in the neck, at the level of the C6 vertebra, and is joined to it medially by the median cricothyroid ligament and postero-laterally by the cricothyroid joints. Inferior to it are the rings of cartilage around the trachea (which are not continuous – rather they are C-shaped with a gap posteriorly). The cricoid is joined to the first tracheal ring by the cricotracheal ligament, and this can be felt as a more yielding area between the firm thyroid cartilage and firmer cricoid.

It is also anatomically related to the thyroid gland; although the thyroid isthmus is inferior to it, the two lobes of the thyroid extend superiorly on each side of the cricoid as far as the thyroid cartilage above it.

The posterior part of the cricoid is slightly broader than the anterior and lateral parts, and is called the lamina, while the anterior part is the band; this may be the reason for the common comparison made between the cricoid and a signet ring.

Composition

It is made of hyaline cartilage, and so can become calcified or even ossified, particularly in old age.

Function

The function of the cricoid cartilage is to provide attachments for the cricothyroid muscle, posterior cricoarytenoid muscle and lateral cricoarytenoid muscle muscles, cartilages, and ligaments involved in opening and closing the airway and in speech production.

Clinical significance

When intubating a patient under general anesthesia prior to surgery, the anesthesiologist will press on the cricoid cartilage to compress the esophagus behind it so as to prevent gastric reflux from occurring: this is known as the Sellick manoeuvre. The Sellick Manouevre is typically only applied during a Rapid Sequence Induction (RSI), an induction technique reserved for those at high risk of aspiration.

The Sellick maneuver was considered the standard of care during rapid sequence induction for many years.^[1] The American Heart Association still advocates the use of cricoid pressure during resuscitation using a BVM, and during emergent oral endotracheal intubation.^[2] However, recent research increasingly suggests that cricoid pressure may not be as advantageous as once thought. The initial article by Sellick was based on a small sample size at a time when high tidal volumes, head-down positioning, and barbiturate anesthesia were the rule.^[3]

Cricoid pressure may frequently be applied incorrectly.^[4]^[5]^[6]^[7]^[8] Cricoid pressure may frequently displace the esophagus laterally, instead of compressing it as described by Sellick.^[9]^[10] Several studies demonstrate some degree of glottic compression^[11]^[12]^[13] reduction in tidal volume and increase in peak pressures.^[14] Based on the current literature, the widespread recommendation that cricoid pressure be applied during every rapid sequence intubation is quickly falling out of favor.

Gastric reflux could cause aspiration if this is not done considering the general anesthesia can cause relaxation of the gastroesophageal sphincter allowing stomach contents to ascend through the esophagus into the trachea.

A medical procedure known as a cricoidectomy can be performed in which part or all of the cricoid cartilage is removed. This is commonly done to relieve blockages within the trachea.^[15]

Fractures of the cricoid cartilage can be seen after manual strangulation also known as throttling.

Additional images

Cricoid cartilage.
Larynx
The cartilages of the larynx. Posterior view.
Ligaments of the larynx. Posterior view.
Sagittal section of the larynx and upper part of the trachea.
Cricoid cartilage

References

^ Salem MR, Sellick BA, Elam JO. The historical background of cricoid pressure in anesthesia and resuscitation. Anesth Analg 1974;53(2):230-232.
^ American Heart Association (2006). Textbook of Advanced Cardiac Life Support. Dallas, TX: American Heart Association.
^ Maltby, J. M., & Berialt, M. T. (2002). Science, pseudoscience and Sellick. Canadian Journal of Anesthesia, 49(5), 443-447
^ Escott MEA, Owen H, Strahan AD, Plummer JL. Cricoid pressure training: how useful are descriptions of force? Anaesth Intensive Care 2003;31:388-391
^ Owen H, Follows V, Reynolds KJ, Burgess G, Plummer J. Learning to apply effective cricoid pressure using a part task trainer. Anaesthesia 2002;57(11):1098-1101
^ Walton S, Pearce A. Auditing the application of cricoid pressure. Anaesthesia 2000;55:1028-1029
^ Koziol CA, Cuddleford JD, Moos DD. Assessing the force generated with the application of cricoid pressure. AORN J 2000;72:1018-1030
^ Meek T, Gittins N, Duggan JE. Cricoid pressure: knowledge and performance amongst anaesthetic assistants. Anaesthesia 1999;54(1):59-62.
^ Smith, K. J., Dobranowski, J., Yip, G., Dauphin, A., & Choi, P. T. (2003). Cricoid pressure displaces the esophagus: an observational study using magnetic resonance imaging. Anesthesiology, 99(1), 60-64;
^ Smith, K. J., Ladak, S., Choi, Pt L., & Dobranowski, J. (2002). The cricoid cartilage and the oesophagus are not aligned in close to half of adult patients. Canadian Journal of Anesthesia, 49(5), 503-507.
^ Palmer, JHM, Ball, D.R. The effect of cricoids pressure on the cricoids cartilage and vocal cords: An endoscopic study in anaesthetized patients. Anaesthesia (2000): 55; 260-287
^ Hartsilver, E. L., Vanner, R. G. Airway obstruction with cricoids pressure. Anesthesia (2000): 55: 208-211
^ Haslam, N., Parker, L., and Duggan, J.E. Effect of cricoid pressure on the view at laryngoscopy. Anesthesia (2005): 60: 41-47
^ Hocking, G., Roberts, F.L., Thew, M.E. Airway obstruction with cricoids pressure and lateral tilt. Anesthesia (2001), 56; 825-828
^ Michihiko Sonea1; Tsutomu Nakashimaa1; Noriyuki Yanagita (1995) "Laryngotracheal separation under local anaesthesia for intractable salivary aspiration: cricoidectomy with fibrin glue support" The Journal of Laryngology & Otology:Cambridge University Press

External links

Illustration at nda.ox.ac.uk
Anatomy figure: 32:04-06 at Human Anatomy Online, SUNY Downstate Medical Center - "Skeleton of the larynx."
lesson11 at The Anatomy Lesson by Wesley Norman (Georgetown University) (larynxsagsect)

UpToDate Contents

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1. 成人における嗄声hoarseness in adults [show details]
…prominent in men. The cricoid cartilage, which lies below the thyroid cartilage and above the entrance to the trachea, is the only complete ring of the laryngeal skeleton. The cricoid cartilage encloses the subglottic …
2. 緊急時の輪状甲状靭帯（軟骨間膜）切開emergency cricothyrotomy cricothyroidotomy [show details]
…surgical cricothyrotomy can damage the cricoid cartilage of young children. Since the tracheal cartilages are C-shaped, soft, and pliable in a child, the cricoid cartilage is the only circumferential support …
3. 頭頸部肉腫head and neck sarcomas [show details]
…most common sarcoma developing in the larynx, with 75 percent of tumors originating in the cricoid cartilage . Men are affected three times more often than women . Chondrosarcomas are classified according…
4. Scalp block and cervical plexus block techniquesscalp block and cervical plexus block techniques [show details]
… Palpate the bony C6 transverse process (ie, the Chassaignac tubercle) at the level of the cricoid cartilage by applying digital pressure in a posteromedial direction. Draw a line from the mastoid process…
5. 小児における嗄声：評価hoarseness in children evaluation [show details]
…to the cricoid cartilage and has the narrowest diameter in infants and children. The larynx is formed by the articulation of the thyroid and cricoid cartilages The ring-shaped cricoid cartilage is the …

English Journal

Idiopathic subglottic stenosis: a familial predisposition.

Dumoulin E, Stather DR, Gelfand G, Maranda B, Maceachern P, Tremblay A.SourceDepartment of Medicine, University of Sherbrooke, Sherbrooke, Quebec. Electronic address: elaine.dumoulin@usherbrooke.ca.
The Annals of thoracic surgery.Ann Thorac Surg.2013 Mar;95(3):1084-6. doi: 10.1016/j.athoracsur.2012.07.076.
Idiopathic subglottic stenosis is a narrowing of the trachea at the level of the cricoid cartilage of unknown etiology. It is a rare condition for which the real incidence has never been established owing to the difficulty of making the diagnosis. Although there is a female preponderance, no familia
PMID 23438539

The effects of botulinum toxin injections into the cricopharyngeus muscle of patients with cricopharyngeus dysfunction associated with pharyngo-laryngeal weakness.

Woisard-Bassols V, Alshehri S, Simonetta-Moreau M.SourceVoice and Deglutition Unit, Otorhinolaryngology and Head and Neck Surgery Department, TSA30030 University Hospital of Rangueil-Larrey, 31059, Toulouse Cedex 09, France, woisard.v@chu-toulouse.fr.
European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery.Eur Arch Otorhinolaryngol.2013 Mar;270(3):805-15. doi: 10.1007/s00405-012-2114-4. Epub 2012 Aug 4.
This prospective, open study was carried out in order to assess changes in the swallowing and dietary status after injection of Botulinum toxin A (BoNT-A) into the upper esophageal sphincter (UES) in a series of patients with cricopharyngeus (CP) muscle dysfunction associated with pharyngo-laryngeal
PMID 22865104

Japanese Journal

カニューレ刺激による気管狭窄に対し鹿野式声門閉鎖術を施行した症例

清野由輩,鹿野真人,細野浩史,大原卓哉,古木省吾,山下拓
頭頸部外科 28(3), 301-306, 2019
症例は33歳男性。25歳時に服毒自殺を図り，四肢麻痺を呈し，気管切開を施行された。著明な気管孔肉芽と，気管カニューレの先端の刺激による気管狭窄を来し，誤嚥による肺炎が頻回に見られた。始めに鹿野式の声門閉鎖術と輪状軟骨鉗除による気管孔形成術を施行した。手術後気管カニューレが不要で，吸引回数も減少し，気管狭窄の悪化を防ぐことができた。8年ぶりに経口摂取を再開した。現在気管内ステントの留置を検討している …
NAID 130007632083

音声機能の温存が求められた進行頸部食道癌症例に対する治療経験

益田宗幸,本郷貴大,池辺正彦,福島淳一,力丸文秀,藤賢史,森田勝,檜垣雄一郎,藤也寸志
日本気管食道科学会会報 69(6), 364-369, 2018
<p>進行した高位頸部食道癌症例に対して喉頭温存手術を行う場合には，臨床的因子のみならず，患者背景も考慮にいれた総合的な判断が求められる。今回われわれは，複雑な因子を抱えた症例の治療を行い，発声機能を温存できた症例を経験したので報告する。症例は20歳代前半の女性で以下のような問題点を認めていた。①引きこもり状態であるが声楽科を目指しており歌うことだけが人生の希望，②身長162 cm，体 …
NAID 130007550209

声門下狭窄症例の気道確保における体外循環 ECMO の使用経験

白倉真之,渡邊健一,橋本光,本藏陽平,石田英一,野村和弘,香取幸夫
日本耳鼻咽喉科学会会報 121(11), 1395-1400, 2018
<p>　緊急時の気道確保は, 気管挿管, あるいは気管切開術や輪状甲状靭帯切開といった手術手技により行われる. しかし高度の気道狭窄例では, 挿管困難や, 術中に気道狭窄が進行して換気困難となる危険性があり, 慎重な対応と習熟した手技が求められる. 今回, 診断未確定の高度な声門下狭窄症に対する気道確保時に, 体外循環である ECMO (Extracorporeal Membrane …
NAID 130007534830

Related Pictures

★リンクテーブル★

リンク元	「輪状軟骨」「annular cartilage」「cartilago cricoidea」

「輪状軟骨」

Cricoid cartilage
	Anterolateral view of head and neck (cricoid cartilage labeled at center left)
	Antero-lateral view of the ligaments of the larynx (cricoid cartilage visible near bottom center)
Details
Precursor	4th and 6th branchial arch
Identifiers
Latin	Cartilago cricoidea
MeSH	D003413
TA	A06.2.03.001
FMA	9615
	Anatomical terminology [edit on Wikidata]

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英: cricoid cartilage (Z), annular cartilage
ラ: cartilago cricoidea
関: 軟骨、輪状甲状靭帯、気管、喉頭軟骨

筋の付着

臨床関連

Henry Gray (1825-1861). Anatomy of the Human Body. 1918.
Henry Gray (1825-1861). Anatomy of the Human Body. 1918.

「annular cartilage」

　　[★]

輪状軟骨

関: cartilago cricoidea、cricoid cartilage

「cartilago cricoidea」

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