出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/07/10 21:23:51」(JST)
Bone: Cervical vertebrae or Cervilar | |
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Position of human cervical vertebrae (shown in red). It consists of 7 bones, from top to down, C1, C2, C3, C4, C5, C6 and C7. | |
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A human cervical vertebra | |
Latin | vertebrae cervicales |
Gray's | subject #21 97 |
MeSH | Cervical+vertebrae |
In vertebrates, cervical vertebrae (singular: vertebra) are those vertebrae immediately inferior to the skull.
Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also belong to the trunk, but do not carry ribs. In reptiles, all trunk vertebrae carry ribs and are called dorsal vertebrae.
In many species, though not in mammals, the cervical vertebrae bear ribs. In many other groups, such as lizards and saurischian dinosaurs, the cervical ribs are large; in birds, they are small and completely fused to the vertebrae. The transverse processes of mammals are homologous to the cervical ribs of other amniotes.
In humans, cervical vertebrae are the smallest of the true vertebrae, and can be readily distinguished from those of the thoracic or lumbar regions by the presence of a foramen (hole) in each transverse process, through which passes the vertebral artery.
The remainder of this article focuses upon human anatomy.
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By convention, the cervical vertebrae are numbered, with the first one (C1) located closest to the skull and higher numbered vertebrae (C2-C7) proceeding away from the skull and down the spine. The general characteristics of the third through sixth cervical vertebrae are described here. The first, second, and seventh vertebrae are extraordinary, and are detailed later.
The movement of nodding the head takes place predominantly through flexion and extension at the joint between the atlas and the occipital bone, the atlanto-occipital joint. However, the cervical spine is comparatively mobile, and some component of this movement is due to flexion and extension of the vertebral column itself.
The movement of shaking or rotating the head left and right happens almost entirely at the joint between the atlas and the axis, the atlanto-axial joint. A small amount of rotation of the vertebral column itself contributes to the movement.
Base of Nose and the Hard palate corresponds to C1.
Teeth (when mouth remains closed) correspond to C2.
Mandible and Hyoid bone correspond to C3.
The thyroid cartilage is from C4 to C5.[1]
The cricoid cartilage is from C6 to C7.[1]
Injuries to the cervical spine are common at the level of the second cervical vertebrae, but neurological injury is uncommon.
If it does occur, however, it may cause death or profound disability, including paralysis of the arms, legs, and diaphragm, which leads to respiratory failure.
Common patterns of injury include the odontoid fracture and the hangman's fracture, both of which are often treated with immobilization in a cervical collar or Halo brace.
A common EMS practice is to immobilize a patient's cervical spine to prevent further damage during transport to Medical Aid. This practice has come under review recently as incidence rates of unstable spinal trauma can be as low as 2% in immobilized patients. Canadian studies have developed the Canadian C-Spine Rule (CCR) for physicians to decide who should receive radiological imaging. [2]
Position of cervical vertebrae (shown in red). Animation.
Shape of cervical vertebrae (shown in blue and yellow). Animation.
Cervical vertebrae, lateral view (shown in blue and yellow).
Vertebral column
Vertebral column.
X-Ray of cervical vertebrae.
X-ray of cervical spine in flexion and extension.
First cervical vertebra, or Atlas
Second cervical vertebra, or epistropheus, from above.
Second cervical vertebra, epistropheus, or axis, from the side.
Seventh cervical vertebra.
Posterior atlantoöccipital membrane and atlantoaxial ligament.
Median sagittal section through the occipital bone and first three cervical vertebræ.
Section of the neck at about the level of the sixth cervical vertebra.
Wikimedia Commons has media related to: Cervical vertebrae |
This article incorporates text from a public domain edition of Gray's Anatomy.
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リンク元 | 「頚椎」「cervical vertebra」 |
関連記事 | 「cervical」 |
概念 | 疫学 | 自覚症状 | 他覚症状 | ||||
頚椎症状 | 神経根症状 | 脊髄症 | 神経根症 | 脊髄症 | |||
頚椎椎間板ヘルニア | 椎間板の退行変性に基づく線維輪断裂部からの椎間板組織の脱出。後方正中ヘルニア→脊髄症。後側方のヘルニア→神経根圧迫 | 30-50歳代。男性。中下位頚椎 | 喉頭・頚部から肩甲背部の疼痛、しびれと頚椎運動制限を呈する。通常頚椎の運動時に増悪し、安静にて軽快する。 | 一側の肩甲背部の疼痛、上肢へ放散する疼痛、しびれと感覚障害、脱力、筋萎縮、筋の線維性攣縮などを呈する | 感覚以上は手指、手掌全体に及ぶしびれ感が主体で、体幹、下肢に広がる。運動系では、手指巧緻運動障害を訴える。下肢痙攣麻痺(ぎこちない歩行、階段下降時に手すりが必要、走れない)。進行すると膀胱直腸障害を自覚 | 神経障害部位に一致した上肢の筋力低下、および筋萎縮、感覚障害、腱反射減弱。Spurlingテスト陽性が多い。 | 上肢に障害髄説に一致した腱反射低下、筋力低下。それ以下は錐体路障害による腱反射亢進(Hoffmann反射、Rossolimo徴候、Mendel-Bekhterev反射、膝・足クローヌス陽性)。手指巧緻運動障害。感覚障害は初期に上肢、故知に体幹・下肢に拡大。腹壁反射、睾丸挙筋反射消失。Babinski反射陽性。排尿障害は軽微 |
変形性頚椎症 | 椎間板の退行変性により、椎間板腔の狭小化、椎体近縁の骨硬化・骨棘形成、椎間関節の狭小化などを生じる。これにより、可動域制限、疼痛、こり感などの局所症状を呈した状態 | 中下位頚椎。高齢者ではC3-4椎間。 | 椎間板および椎間関節の変形などによる頚肩部の疼痛、運動制限 | ||||
頚椎症性神経根症 | 変形性頚椎症に加え、神経根症を呈した状態 | 圧迫に伴う神経根刺激症状として、上肢のしびれ、放散痛、感覚異常(後根)がある。 | Jacksonテスト、Spurlingテスト陽性。神経脱落症状としては、感覚鈍麻、脱失および上肢の脱力、筋萎縮筋の線維束攣縮が見られる。 | ||||
頚椎症性脊髄症 | 頚椎症性神経根症に加え、脊髄症を合併した状態。 | 上肢における巧緻運動障害、myelopathy hand、下肢腱反射亢進、病的反射の亢進、痙性歩行障害などの痙性麻痺および神経因性膀胱などが見られる。 | |||||
頚椎後縦靭帯骨化症 | 椎体および椎間板の後面にあり脊柱管の前壁をなす後縦靭帯が肥硬・骨化し、脊髄を緩徐に圧迫して脊髄症状を引き起こす疾患。 | 後縦靭帯骨化:男性4%、女性2%。 | 頚椎可動性の減少、肩こり、頚部痛が見られる。重要な障害は圧迫による脊髄症の麻痺症状である。一般に脊髄症は緩徐に進行する。外傷を契機に急激に悪化する場合もある。受診時に、多くの患者は種子のしびれや巧緻運動障害、下肢の痙性麻痺による歩行障害を呈する。 |
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