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•Vertebral column consists of a number of separate
irregular bones called VERTEBRAE
•Forms the central axis of the body.
Protects spinal cord.
Supports and transmits body weight.
Provides attachment to axial muscles.
Provides movement of the trunk.
• Vertebrae are named according to region in which they lie.
• There are 33 vertebrae but only 31 spinal nerves.
Vertebrae Number Spinal Nerve Number
Cervical 7 Cervical 8
Thoracic 12 Thoracic 12
Lumbar 5 Lumbar 5
Sacral 5 Sacral 5
Coccygeal 4 Coccygeal 1
• In adults, 5 sacral vertebrae fuse together to form ‘sacrum’ 4 coccygeal
vertebrae fuse together to form ‘coccyx’.
Characteristics of a vertebrae:
• A typical vertebrae has two parts:
1. Body- anterior or ventral part.
2. Arch-posterior or dorsal part (also called neural arch).
• Vertebral foramen: lies between the body and arch.
• Vertebrae are placed one above the other with intervertebral discs between
them and forms a vertebral canal(spinal canal) which lodges the spinal cord
with its meninges and blood vessels.
1. Body of vertebrae:
• It is nearly cylindrical in shape, the size and shape varying in vertebrae of different regions.
• It possesses 6 surfaces: Upper, Lower, Anterior, Posterior and two Lateral.
i. Upper and Lower surfaces – Rough and provide attachment to intervertebral discs.
ii. Anterior surface – convex fom side to side; concave from above downwards; it also bears
few small openings for passage of veins.
iii. Posterior surface – flat from above downwards; slightly concave side to side; it also bears
one or more large openings of exit of basi-vertebral vein and a no of small foramina for
iv. Lateral surface – continuous with anterior surface and has the same features.
• Bodies of vertebrae lie one above another separated by intervertebral disc and form the
2. Vertebral (neural) arch:
• The vertebral arch consists of:
I. A pair of pedicles.
II. A pair of lamina.
III. Seven processes:
o Spinous ---- one
o Articular ---- four
o Transverse --- two
The arch is connected to the body by pedicles.
• Short, thick processes pass backward from the junction of lateral and posterior surfaces of
• Possess 2 surfaces and 4 borders.
Medial---forms lateral boundary of vertebral column.
Lateral---free and rough.
Anterior—united with the body.
Posterior—united with the lamina.
Superior---concave which forms superior vertebral notch.
Inferior---concave which forms inferior vertebral notch.
Intervertebral foramen: When two vertebrae articulate with each other the inferior vertebral
notch of the vertebrae above together with the superior vertebral notch of the vertebrae
below form the intervertebral foramen.
Transmits: Spinal nerves and vessels.
• Broad plates of bone lying behind and medial to pedicles.
• They fuse behind in the median plane into the spinous process.
• They form posterior boundary of vertebral foramen.
A. Spinous process----
Passes backwards and downwards from the junction of the two laminae.
Shape and size varies in vertebrae of different regions.
Gives attachment to muscles and ligaments.
B. Articular process:
4 in number, 2 superior and 2 inferior.
Arise from the junction of pedicles and laminae.
Superior articular process:
i. Project upwards from the junction of laminae and pedicles.
ii. Articular surface faces more or less backwards.
iii. Articulate with inferior articular processes of the vertebrae.
Inferior articular process:
i. Project downwards.
ii. Articular surface faces more or less forwards.
iii. Articulate with superior articular processes of the vertebrae below.
C. Transverse processes:
• 2 in number.
• Project laterally from the junction of pedicle and lamina.
• In thoracic region they articulate with ribs.
The most important distinguishing feature of vertebrae of different regions
Cervical: Presence of a foramen in the transverse process, called Foramen
Thoracic: Presence of costal facets on the body
Lumbar: No foramen transversariumand no costal facets on the body.