WALDEN UNIVERSITY BIOMECHANIC_OF_THE_SPINE[1]
The spine
The spine is a complex and functionally significant segment of the human body. Providing the
mechanical linkage between the upper and lower extremities, the spine enables motion in all
three planes, yet still functions as a bony protector of the delicate spinal cord. To many
researchers and clinicians, the lumbar region of the spine is of particular interest because low
back pain is a major medical and socioeconomic problem in modern times.
Structure of the Spine
Vertebral Column
The spine consists of a curved stack of 33 vertebrae divided structurally into five regions.
Proceeding from superior to inferior, there are 7 cervical vertebrae, 12 thoracic vertebrae, 5
lumbar vertebrae, 5 fused sacral vertebrae, and 4 small, fused coccygeal vertebrae. There may be
one extra vertebra or one less, particularly in the lumbar region.
Because of structural differences and the ribs, varying amounts of movement are permitted
between adjacent vertebrae in the cervical, thoracic, and lumbar portions of the spine. Within
these regions, two adjacent vertebrae and the soft tissues between them are known as a motion
segment. The motion segment is considered the functional unit of the spine
,
, Each motion segment contains three joints. The vertebral bodies separated by the intervertebral
discs form a symphysis type of amphiarthrosis.
The right and left facet joints between the superior and inferior articular processes are diarthroses
of the gliding type that are lined with articular cartilage.
Vertebrae
A typical vertebra consists of a body, a hollow ring known as the neural arch, and several bony
processes. The vertebral bodiesserve as the primary weight-bearing components of the spine. The
neural arches and posterior sides of the bodies and intervertebral discs form a protective
passageway for the spinal cord and associated blood vessels known as the vertebral canal. From
the exterior surface of each neural arch, several bony processes protrude. The spinous and
transverse processes serve as outriggers to improve the mechanical advantage of the attached
muscles.
The first two cervical vertebrae are specialized in shape and function. The first cervical vertebra,
known as the atlas, provides a reciprocally shaped receptacle for the condyles of the occiput of
The spine
The spine is a complex and functionally significant segment of the human body. Providing the
mechanical linkage between the upper and lower extremities, the spine enables motion in all
three planes, yet still functions as a bony protector of the delicate spinal cord. To many
researchers and clinicians, the lumbar region of the spine is of particular interest because low
back pain is a major medical and socioeconomic problem in modern times.
Structure of the Spine
Vertebral Column
The spine consists of a curved stack of 33 vertebrae divided structurally into five regions.
Proceeding from superior to inferior, there are 7 cervical vertebrae, 12 thoracic vertebrae, 5
lumbar vertebrae, 5 fused sacral vertebrae, and 4 small, fused coccygeal vertebrae. There may be
one extra vertebra or one less, particularly in the lumbar region.
Because of structural differences and the ribs, varying amounts of movement are permitted
between adjacent vertebrae in the cervical, thoracic, and lumbar portions of the spine. Within
these regions, two adjacent vertebrae and the soft tissues between them are known as a motion
segment. The motion segment is considered the functional unit of the spine
,
, Each motion segment contains three joints. The vertebral bodies separated by the intervertebral
discs form a symphysis type of amphiarthrosis.
The right and left facet joints between the superior and inferior articular processes are diarthroses
of the gliding type that are lined with articular cartilage.
Vertebrae
A typical vertebra consists of a body, a hollow ring known as the neural arch, and several bony
processes. The vertebral bodiesserve as the primary weight-bearing components of the spine. The
neural arches and posterior sides of the bodies and intervertebral discs form a protective
passageway for the spinal cord and associated blood vessels known as the vertebral canal. From
the exterior surface of each neural arch, several bony processes protrude. The spinous and
transverse processes serve as outriggers to improve the mechanical advantage of the attached
muscles.
The first two cervical vertebrae are specialized in shape and function. The first cervical vertebra,
known as the atlas, provides a reciprocally shaped receptacle for the condyles of the occiput of
