3-Vertebral column

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Vertebral column: 

Vertebral column P. Simoonga BSc Hb . Unza

Vertebral column: 

Vertebral column Central bony pillar of the body It supports the skull, pectoral girdle, upper limbs & the thoracic cage & by the pelvic girdle transmits body wt to the lower limb Within its cavity lies the spinal cord, the roots of the spinal nerves & the covering meninges , to which the vertebral column gives great protection

Composition: 

Composition 33 vertebrae 7 cervical 12 thoracic 5 lumbar 5 sacral (fused to form the sacrum) 4 coccygeal ( the lower 3 are commonly fused) It is a flexible structure Made up of pads of fibrocartilage-intervertebral disc The intervertebral dics form ¼ the length of column

General characteristics: 

General characteristics A typical vertebra consist of the : round body anteriorly Vertebral arch posteriorly Vertebral foramen The vertebral arch consist of : A pair of cylindrical pedicles- which form the sides of the arch A pair of laminae - which complete the arch posteriorly

PowerPoint Presentation: 

The vertebral arch gives rise to the 7 processes: 1 spinous 2 transverse 4 articular The spinous process or the spine is directed posteriorly from the junction of the 2 laminae The transverse process are directed laterally from the junction of the laminae & the pedicles

PowerPoint Presentation: 

The articular surfaces are vertically arranged & consists of 2 superior & 2 inferior processes. Arise from the junction of the laminae & the pedicles The 2 superior articular processes of 1 vertebral arch articulate with the 2 inferior articular processes of the arch above, forming 1 synovial joints The pedicles are notched on their upper & lower borders forming the superior & inferior vertebral notches.

PowerPoint Presentation: 

On each side, the superior notch of 1 vertebra& the inferior notch of the adjacent vertebra together form an intervertebtral foramen- transmits spinal nerves & blood vessels

Characteristics of a typical cervical vertebra: 

Characteristics of a typical cervical vertebra The transverse process posses a foramen transversarium - for passage of the vertebral artery & veins (vertebral artery passes through C1-C6, NOT C7) The spines are small & bifid( divided ) The vertebral foramen is large & triangular The superior articular processes have facets that face backwards & upwards: the inferior processes have facets that face downwards & forward. The body is small & broad from side to side

Characteristics of atypical cervical vertebra: 

Characteristics of atypical cervical vertebra 1 st , 2 nd , 7 th are atypical The 1 st cervical vertebra or ATLAS Does not posses a body Does not have a spinous process Has an anterior & posterior arch Has a lateral mass on the each side with articular surfaces on its upper surface for articulation with the occipital condylar ( atlanto -occipital joints) Articular surfaces on its lower surface for articulation with the AXIS ( atlanto -axial joint)

PowerPoint Presentation: 

The 2 nd cervical vertebra or AXIS Has a peg like odontoid process that projects from the superior surface of the body The 7 th cervical vertebra or VERTEBRA PROMINENS Is so named becoz it has the longest spinous process The spinous process is not bifid The transverse process is large The foramen tranversarium is small & transmits the vertebral vein or veins

Characteristics of thoracic typical vertebra: 

Characteristics of thoracic typical vertebra Body is medium sized & heart shaped Vertebral foramen is small & circular Spines are long & inclined downward Costal facets are present on the side of the bodies for articulation with the head of the ribs. Costal facets are present on the transverse processes for articulation with the tubercles of the ribs (T11& T12 have no facets on the transverse processes)

Atypical thoracic vertebra: 

Atypical thoracic vertebra 1 st , 9 th , 10 th , 11 th and 12 th are atypical. 1 st thoracic vertebra Body resembles that of a cervical vertebra Spine is thick, long and nearly horizontal. The superior vertebral notches are well marked as in cervical vertebrae. 9 th thoracic vertebra - The body has only the superior costal demifacets . The inferior are absent. 10 th thoracic vertebra - Has a single complete superior costal facet on each side.

Atypical thoracic vertebra: 

Atypical thoracic vertebra 11 th thoracic vertebra Body has a single large costal facet on each side. transverse process is small and has no articular facet 12 th thoracic vertebra The shape of the body, pedicles, transverse processes and spine are similar to the lumbar vertebra. Body bears a single costal facet on each side. Transverse process is small and has no facet but has superior, inferior and lateral tubercles. Inferior articular facets are lumbar in type, they are everted and directed laterally.

Characteristics of lumbar typical vertebra: 

Characteristics of lumbar typical vertebra A typical lumbar vertebra has: Body is large & shaped like a kidney The pedicles are short, strong & directed backward Laminae are short, thick and broad. The vertebral foramina are triangular The transverse process are long & slender Spinous processes are short, flat & quadragular & projected backward. Articular surfaces of superior articular processes face medially and those of the inferior face laterally.

PowerPoint Presentation: 

Note: lumbar vertebrae have no facets for articulation with the ribs & no foramina in the transverse processes. Only the 5 th lumbar is atypical because: Transverse processes are thick, short and pyramidal in shape. The spine is small, short and rounded at the tip. The body is the largest of the lumbar vertebra. The pedicles are directed backwards and laterally.

Sacrum: 

Sacrum Consits of 5 rudimentary vertebrae fused together to form a wedged shaped bone- concave anteriorly The upper border articulates with the 5 th lumbar & the lower border with the coccyx Laterally articulates with the 2 hip bones- sacroiliac joint Sacral promontary Vertebral foramina are present & form the sacral canal Sacral hitus : 5 th sacral nerve, pair of coccygeal nerves, filum terminale .

PowerPoint Presentation: 

Sacral canal- anterior & posterior roots of the sacral & coccygeal spinal nerves, filum teminale & fibrofatty material Foramina- 4 on each side for passage of the anterior & posterior rami of the upper 4 sacral nerves. COCCYX Consists of 4 vertebrae fussed together to form a single, triangular bone.

Important variations: 

Important variations The # of the cervical vertebrae is constant but the 7 th may possesses a cervical rib The thoracic vertebrae may be increased by addition of the 1 st lumbar vertebrae which may have a rib The 5 th lumbar may incorporated into the sacrum The 1 st sacral vertebra may remain partially or incompletely separated from the sacrum & resemble the 6 th lumbar The coccyx may have 3 or 5