Spinal column

Cervical rachis

It is composed of seven cervical vertebrae, named by the letter C : of C1 with C7.

The two first are particular and are called the atlas and the axis.

The atlas

The atlas is the first cervical vertebra (C1), and consequently, first vertebra of the rachis.

It is called thus, because it is it which carries the head (by analogy with the Greek god Atlas which carries the world).

It is made up:

of a former arc carrying ahead the former tuber and behind the fovea dentis for the tooth of the axis ;
of a posterior arc;
of two unituberculés transverse processes dug of a foramen: the foramen transversaire which lets pass the vertebral Artère;
of two side masses where are with the higher face articular surfaces for the condyles of the occipital Os , and with the lower face articular surfaces for the axis (2^e cervical vertebra). Behind articular surfaces of the higher face, one finds both furrows of the vertebral artery (a furrow on each side for each artery).

It does not have a body nor of thorny process.

Its foramen vertebral is large and coarsely a round square.

It carries two tubers in its former portion where comes to fit the transverse ligament of the atlas . This ligament delimits two cabins (ventral and dorsal). Ahead, a cabin for the tooth of the axis and behind a cabin for the Spinal-cord.

The axis

The axis is the second cervical vertebra. Its name comes owing to the fact that it defines an axis of rotation for the atlas with its process flank profile (or tooth of the axis ).

It is made up:

of a body on which is fixed, with its higher face, the process flank profile , and with its face a lower articular surface for C3 ;
of two side masses carrying articular surfaces with the atlas with its face higher and C3 than its lower face;
of two unituberculés transverse processes, perforated by the foramen transversaire which lets pass the vertebral Artère;
of a bituberculé thorny process connected to the transverse process by two blades.

The process flank profile (or tooth of the axis ) is a vertical osseous projection located at the higher face of the body of the axis. It comprises with its face a postéro-higher dorsal articular facet articulating itself with the transverse ligament of the atlas , and with its face a antéro-higher ventral articular facet articulating itself with the fovea dentis of the atlas.

This process flank profile is used as pivot for the atlas and contributes to maintain this vertebra in place to protect the Spinal-cord.
At the time of traumatisms (generally at the time of the road accidents, in particular motorbike accidents), it is imperative to make a Radiographie cervical rachis to make sure that there is no Fracture collar of this process flank profile, in which case it is necessary to avoid at all costs a deviation of this osseous projection which could cause a compression of the Spinal-cord involving a Paralysie partial or total, and if compression is rather high, of the respiratory disorders being able to lead to the mort.
For this reason. Only the firemen and doctors are entitled to do it.

The vertebral foramen of the axis is coarsely round, a little less large than that of the atlas, and does not present a characteristic.

Other cervical vertebrae

Vertebrae C3-C4-C5-C6-C7 are in the continuity of the transition operated by the axis.

They are made up:

of an articular body on its higher and lower face with the vertebrae under and overlying. It presents on its supéro-side board two uncus stabilizing the articulation with the overlying vertebra;
of two bituberculés transverse processes (a former tuber and posterior), perforated by the foramen transversaire which lets pass the vertebral artery;
of two side processes articular for the vertebrae under and overlying, separated from the body by the two pedicles;
of a bituberculé thorny process connected to the articular processes by two blades.

The vertebral foramen is triangular (final form of the vertebral foramen for the other vertebrae of the rachis) and lets pass the Spinal-cord.

With the higher face of the transverse processes, one finds a furrow which leaves the body, passes by the pedicle, then finishes oneself by the hole of conjugation . In this furrow, the nervous roots of the spinaux nerves passes.

C6 and C7 are standard cervical vertebrae, with this close which they present some differences.

C6 vertebra

The former tuber of its transverse process is bulkier than those of the other cervical vertebrae. It is called tuber carotidien .

C7 vertebra

C7 is a vertebra of transition between the cervical rachis and the thoracic rachis.

Its thorny process is unituberculé, very long and very behind tilted and in bottom. It represents the postéro-lower limit of the Cou.

It is easily palpable under the skin: while going down along the nape of the neck, it is the first large projection under the skin.

It is with this height that the bump of bison is formed, which is a form of Cellulite.

Dorsal rachis or vertebral rachis

It is composed of twelve thoracic or dorsal vertebrae, named by the letters T or D : of T1 with T12, or D1 with D12.
It makes following the cervical rachis and precedes the lumbar rachis.

The dorsal rachis form a posterior curve called kyphosis .

The rachis lombal or lumbar rachis

It is composed of five vertebrae lombales (lumbar), named by the letter L : of L1 with L5.
the lumbar rachis form a former curve called lordosis .

It makes following the dorsal rachis and precedes the crowned rachis.

Crowned rachis or sacrum

The crowned rachis or Sacrum are also called sacral rachis or sacrum . The five crowned vertebrae are welded at the adulthood, and form nothing any more but one osseous block called sacrum .

It is composed of five crowned or sacral vertebrae, named by the letter S : of S1 with S5.

It makes following the rachis lombal and precedes the rachis coccygien.

It is tilted approximately 45 degrees behind.

It forms the posterior part of the Pelvis and solidity ensures some thus.

The transverse processes, because of this welding, are not any more distinguished and form an osseous blade on the two sides, they are the wings of the sacrum .

It is the same for the thorny processes which do not form any more but of small bumps to the posterior face of the sacrum.

The higher articular surface of the first crowned vertebra S1 forms the head of the sacrum , which is articulated with the last lumbar vertebra, L5.

On the edges of the sacrum, in the upper part, one finds an articular surface with the iliaque Os (bone coxal), it is the auricular articular face (because it has a form of Oreille). It is turned backwards and is in connection with its counterpart of the iliaque Os to form the sacro-iliaque articulation (synovial articulation, reinforced by ligaments sacro-iliaques former, posterior and interosseux). This articulation allows only very few movements and transmits the weight top of the body to the articulations of the Hanche when the person is held upright.

On the faces former and posterior, four sacral pairs of foramens let pass the ventral and dorsal branches of the spinaux Nerfs.

With the proximale part (lower) of the sacrum, one finds the articulation sacro-coccygienne , which articulates it with the coccyx. It is a cartilagineuse articulation not allowing almost any movement.

The rachis coccygien

It is more known under the name of coccyx . The coccyx is an osseous vestige. It corresponds to the tail of the mammals.

It is composed of four or five vertebrae coccygiennes welded between them. Contrary to the others, they are not named by a letter.

It makes following the sacrum and constitutes the lower end of the rachis. It is buckled ahead.

It is not of great interest in Anatomie, nor in medicine in general, if it is not that it is often the seat of pains at the time of a violent shock on the posterior one or even of fractures.

Intervertebral articulations

Anatomical description

Each vertebra is articulated with the vertebra known and subjacent (except the atlas which articulates with the occipital condyles and of course the vertebrae coccygiennes).

The vertebrae are linked by three articulations:

the intervertebral Disc linking the plates of two vertebrae.
two posterior articulations inter apophysaires, where the higher articular apophyses of a vertebra are articulated with the lower articular apophyses of the overlying vertebra.

Solidity is ensured by:

the Ligament S vertebral commun runs former and posterior,
ligaments inter thorn-bush,
yellow ligaments,
the ligaments interapophysaire,
antagonistic rachidian muscles of the movements,
capsules of the posterior articulations apophysaires.

Vertebral articular mobility

The movement S of the rachis are possible thanks to the existence of an articular system complex, the rachidian articular segment , functional unit consisted:

the disco music-somatic complex disco music-corporéal or,
posterior articulations inter apophysaires,
intervertebral ligaments and muscles vertebral.

This articular segment allows the movements in a plan, whose amplitude is very variable according to the vertebral stage considered:

sagittal (inflection extension);
frontal (lateralities);
transverse (rotation in the axis of the rachis).

The differences in amplitude are due to the vertebral anatomical differences in particular:

with the sagittal slope of the articular apophyses;
with the sagittal slope of the thorny apophyses;
with the difference in thickness of the intervertebral disc;
with the articulation with other elements (head, rib cage);
with the type of convexity (before or back) of the stage.

Reports/ratios

The spinal column is obviously not insulated in the organization, it is even the pillar and present for this reason of many relationship with the surrounding structures.

Blood-vessels

In addition to the vascularization itself of the rachis, there is the passage of vessels in or in the vicinity direct of the column.

the vertebral Artery

It is a branch of the artery subclavière (subclavian), and goes up in the channel formed by the superposition of the foramens transversaires (channel transversaire) on the level of the cervical rachis. It engages in general in this channel on the level of C6, but can enter there in C7 or much higher (sometimes, it crosses only three or four vertebrae). On the level of the atlas, it is curved with right angle and penetrates in the brain by the foramen magnum. There, it joined the other vertebral artery, forming the Tronc basilaire and takes part in the arterial circle of the brain (the Polygone of Willis).

the thoracic aorta (then abdominal aorta)

It is the continuity of the Aorte and goes down along the thoracic rachis to its former wall. It is shifted on the left compared to the axis of the column and thus allows, for example, to direct towards a medical image. To the level of the lumbar rachis, it gives both common iliaques arteries.

the former radicular Artery of Adamkiewicz

The aéro-digestive axis

It is the unit formed by the esophagus and the Larynx then the Trachée. It begins compared to C4 and is continued until T4 (where the trachea is divided into two bronchi). It is median , i.e. it walks on right in front of the vertebral bodies.

Muscles

The rachis are an important zone of muscular insertions. Indeed, it is used as anchoring with the muscles of the posture and, on the level of the neck, it receives a good part of the muscles céphalogyres , which drive the head.

Principal Muscle S having insertions on the spinal column:

cervical Rachis

Muscle small right posterior of the head
Muscle musculus rectus abdominis posterior of the head
Muscle small right former of the head
Muscle musculus rectus abdominis former of the head
Muscle obliques higher of the head
Muscle obliques lower of the head
Muscle longissimus of the head (musculus longissimus capitis)
Muscle longissimus of the neck
Muscle semi-thorn-bush of the head (large complexus)
Splénius
Trapezius muscle
long Muscle of the head
long Muscle of neck
scalene Muscles

thoracic Rachis

large Muscle dorsal
Trapezius muscle

and all the interépineux muscles (between the thorny processes), then all other muscles of the posture.

The pathology of the rachis

It has a repercussion doubles on:

statics: deformations
contents of the rachidian channel: spinal-cord above L1, roots of the tail of horse in lower part, with constitution of central nervous system disorders.

The attacks of the rachis are classified better according to an analytical mode, that is to say according to the type of affection:

traumatic: the inflammatory accidents
: had with inflammatory diseases (inflammatory rheumatisms), primarily spondylarthrite ankylosante or rheumatic polyarthritis
metabolic: fractures due to the Osteoporosis or anomalies of the infectious Osteomalacia
: had with infections of the vertebral bodies (spondylites, rare), discs (discites) or of both (spondylodiscites, frequent)
tumoral: had with primitive or secondary tumors (metastases)
degenerative: the malformatives Osteoarthritis and its derivatives
: congenital
idiopathic: what does not have etiology determined in the actual position of knowledge but among them, the Scoliose S idiopathic, most frequent

See too

Rachis:

Reports/ratios:

Other meanings of the word Rachis
Classification set of themes of the neurosciences

External bonds

http://www.fondationcotrel.org: Site, information and contact of the Foundation Cotrel < http://fr.wikipedia.org/wiki/Yves_Cotrel/ > for research in rachidian Pathology, created by Dr. Yves Cotrel under the aegis of the Institute of France.
Voir a detailed diagram of the spinal column
Another diagram detailed
the medullary casualty is not a victim like the others, the General practitioner n°2115, May 4th 2001
has photographic guide to prehospital spinal care

Fiu-vro: Sälgruuts Simple: Vertebral column

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