Download THORACIC VERTEBRAE

General features of vertebrae & curvatures of vertebral
column
Vertebral Column (Spine)
• Collection of vertebrae
• Forms the central axis
• Supports skull
• Gives attachment to
–
Thoracic cage by ribs
–
Upper limb by pectoral girdle
–
Lower limb by pelvic girdle
• Flexible due to various joints b/w vertebrae
• Contains spinal cord in its cavity
Vertebral Column (Spine)
• Made up of five regions
– Cervical
– Thoracic (Dorsal)
– Lumbar
– Sacral
– Coccygeal
Spinal Curvatures
• Primary curvature
– Anterior flexion in fetus
– Persist in adults in
•
Thoracic,
•
Sacral &
•
Coccygeal
• Secondary curvatures
– Anterior convexity (Lordosis) in adults
– Develop in
•
Cervical &
•
Lumbar
Relation of
Nerve Roots
Vertebral
Spinal Cord &
with
column
General Characteristics of a Vertebra
Vertebra consists of two essential parts:
•
an anterior segment, the body
•
a posterior part, the vertebral or neural arch
•
these two together enclose a foramen, the vertebral foramen.
•
vertebral foramina constitute a canal for the protection of the
spinal cord
Vertebral body
• More or less cylindrical in shape.
• Its upper and lower surfaces are flattened and
rough
• Give attachment to the intervertebral
fibrocartilages
•
convex from side to side
•
concave from above downward
• Anterior surface presents a few small apertures, for the
passage of nutrient vessels
• On the posterior surface is a single large, irregular aperture for the exit
of the basi-vertebral veins from the body of the vertebra.
Intervertebral discs
(or intervertebral fibrocartilage)
• Lie between adjacent vertebrae in the spine.
• Each disc forms a cartilaginous joint to allow slight movement of the
vertebrae, and acts as a ligament to hold the vertebrae
together.
The vertebral arch
 Consists of a pair of pedicles and a pair of laminæ
 Supports seven processes
•
Four articular
•
Two transverse
•
one spinous.
PEDICLES
• Two short, thick processes,
•
project backward, one on either side,
• project from the upper part of the body, at the junction
of its posterior and lateral surfaces.
• Concavities above and below the pedicles are named
the vertebral notches
INTERVERTEBRAL FORAMINA
• When the vertebrae are articulated, the superior and inferior
notches of each contiguous pair of bones form the intervertebral
foramina
• through it spinal nerve leaves the vertebral
canal as ventral and dorsal rami
LAMINAE
• Two broad plates directed backward and medially
from the pedicles.
•
fuse in the midline posteriorly, and so complete the
posterior boundary of the vertebral foramen.
• Their upper borders and the lower parts of their
anterior surfaces are rough for the attachment of the
ligamenta flava
PROCESSES
• Single Spinous Process
• Paired Transverse Processes
• Paired Superior Articular Processes
• Paired Inferior Articular Processes
.
SPINOUS PROCESS
• Is directed backward and downward from the
junction of the laminæ
•
serves for the attachment of muscles (which are
extensors of vertebral column)and ligaments.
ARTICULAR PROCESSES
• Two superior and two inferior, spring from the
junctions of the pedicles and laminæ.
• The superior project upward, and their superior
articular facets backwardare directed more or less
•
The inferior project downward, and their
inferior articular facets look more or less
forward.
• The articular surfaces are coated with hyaline cartilage.
TRANSVERSE PROCESSES
• Two in number
•
project one at either side from the point where
the lamina joins the pedicle, between the superior
and inferior articular processes.
•
serve for the attachment of ligaments &
muscles( that cause lateral bending and rotation
of vertebral column)
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