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Joints of Bones of Trunk

The vertebral column

consists of 24 vertebrae,
the sacrum, and the coccyx.



Joints of the vertebral bodies

Intervertebral discs
between bodies of adjacent vertebrae, composed of:

Nucleus pulposus:

an inner soft, pulpy, highly elastic structure (gelatinous core )

Annulus fibrosus:
an outer fibrous ring consisting of fibrocartilage




Anterior longitudinal ligament

Strong band covering the anterior part of the vertebral bodies and intervertebral discs running from the anterior margin of foramen magnum to the S1~S2.

Maintains stability of the intervertebral disc and prevents hyperextension of the vertebral column.

Posterior longitudinal ligament
Attached to the posterior aspect of the intervertebral discs and posterior edges of the vertebral bodies from C2 vertebra to sacrum
Prevents hyperflexion of the vertebral column and posterior protrusion of the discs

Joints of the vertebral arches

Ligamenta flava ― elastic ligament, unite laminae of adjacent vertebrae, and complete the posterior wall of vertebral canal; tend to prevent hyperflexion of the vertebral column

Interspinal ligament
Supraspinal ligament
Ligamentum nuchae
Intertansverse ligament
Zygapophysial joint


Atlantooccipital joint

Between superior articulating surfaces of atlas and occipital condyles

Supported by membrances and ligaments that join occipital bone and atlas

Action ― nodding of head, lateral tilting of head


Normal Curves of vertebral column




Thoracic cage

Composition

Bones ― consists of twelve thoracic vertebrae, twelve pairs of ribs and costal cartilages, and sternum




General features of thoracic cage

Roughly cone-shape, narrow above and broad below, flattened from before-backwards, longer behind than in front.

Inlet of thorax: bounded by upper border of manubrium, first rib, and vertebra T1

Outlet of thorax: bounded by vertebra T12, 12th and 11th ribs, costal arch and xiphoid process
Infrasternal angle: formed by the costal arch of both side

Intercostal spaces: lie between the ribs


Functions:

protects the organs in the thoracic cavity and upper abdominal cavity;

plays a vital role in the process of breathing.