Anatomy of the spine Medical ppt Medical ppt .

Anatomy of the spine

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The spine is one of the most important parts of your body. Without it, you could not keep yourself upright or even stand up. It gives your body structure and support. It allows you to move about freely and to bend with flexibility. The spine is also designed to protect your spinal cord.

At BirthThe spine of a newborn is C-shaped, with one curve

At About Six MonthsAs the infant lifts his or her head during the first few months, the neck (cervical) curve and its muscles develop

At About Nine Months As the infant learns to crawl and stand, the lower back (lumbar) curve and its muscles develop. Strong back muscles help give your child the strength and balance to walk and run.

The spine has three major components:

•the spinal column (i.e., bones and discs)•neural elements (i.e., the spinal cord and nerve roots)•supporting structures (e.g., muscles and ligaments)

A. The spinal column

The spinal column consists of individual bones called vertebrae, the building blocks, which provide support for the spine. These vertebrae are connected in the front of the spine by intervertebral discs.

The spinal column consists of:•seven cervical vertebrae (C1–C7) i.e. neck•twelve thoracic vertebrae (T1–T12) i.e. upper back•five lumbar vertebrae (L1–L5) i.e. lower back•five bones (that are joined, or "fused," together in adults) to form the bony sacrum • three to five bones fused together to form the coccyx or tailbone

In general a typical vertebra consists of :

1.large vertebral body in the front2.two strong bony areas called pedicles connecting the vertebral body and the posterior arch3.an arch of bony structures in the back (posterior arch) = (the spinous process). BODY

PEDICLE

transverse process

spinous process

2 special cervical vertebrea:

1.Atlas:

The atlas is the topmost vertebra

The Atlas has no body, and this is due to the fact that the body of the atlas has fused with that of the next vertebra (the Axis)

it has no spinous process, is ring-like, and consists of an anterior and a posterior arch and two lateral masses

2. Axis:

The second cervical vertebra (C2) of the spine is named the axis

The most distinctive

characteristic of this bone is the strong dens which rises perpendicularly from the upper surface of the body.

B. Neural Elements:

The neural elements consist of the spinal cord and nerve roots.

The spinal cord runs from the base of the brain down through the cervical and thoracic spine. Below the L1–L2 level the spinal cord ends, as an array of nerve roots continues, looking somewhat like a horse's tail (cauda equina).

At each vertebral level of the spine there are a pair of nerve roots. These nerves go to supply particular parts of the body.

The intervertebral discs make up one fourth of the spinal column's length. There are no discs between the Atlas (C1), Axis (C2), and Coccyx. Discs are not vascular and therefore depend on the end plates to diffuse needed nutrients

Discs are composed of two parts: a tough outer portion and a soft inner core:

•The outer portion of the disc (annulus fibrosus) composed of concentric sheets of collagen fibers that seal the gelatinous nucleus and evenly distribute pressure and force imposed on the vertebral column.

•The inner core (nucleus pulposus) contains a loose network of fibers suspended in a mucoprotein gel.

The outer portion and inner core of the spinal disc fit together like two concentric cylinders and are interconnected by cartilaginous end-plates

C. the supporting structures:

1.Ligaments

1.Fascia

1.Muscles

1.Nerves

Ligaments:

Ligaments are rope-like bands of tissue that connect bones together. Most ligaments are lined up to keep joints from bending in the wrong way

The most important ones are:

1. Anterior and posterior longitudinal ligaments

2. Ligamentum flavum3. Intervertebral discs

Fascia:

Fascia is similar to ligaments, but fascia is more like a sheet than a rope. The most important of which is the thoracolumbar fascia (TLF) which has the following functions:

As the spinal muscles work, the TLF pulls tightly the low back, keeping the lumbar spine from bending out of the neutral position. It augments the power generated by spinal muscles.

Muscles:

Because of their location toward the center of the body, and because of their importance in spine stability, these key stabilizers are called "core, paraspinal" muscles

Core muscles help grip and hold the spine. They keep each spinal segment from shifting and sliding as you do your activities

Nerves:

•Motor nerves signal the key muscles to grip and hold and to guide and control the spine.

•Sensory nerves transmit sensations such as heat, cold, touch, pressure, and pain. They also give us our sense of position

Absorbs the shocks of walking on hard surfaces More weight can be supported by a curved spine than if it were straightAdditional space for the viscera is provided by the concavities of the thoracic and pelvic regions.Lastly, the S-curvature protects the vertebral column from breakage

What are the functions of the spinal column?

The major functions of the vertebral column are:oProtection of the spinal cord. oProviding stiffening for the body and attachment for the pectoral and pelvic girdle and many other muscles.oProviding motion for the human skeleton.oThe S-curvature enables the vertebral column to absorb the shocks of walking on hard surfaces

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