Skeletal muscles

Skeletal (striated) muscles are the muscles that move the bones of our body. When a muscles contracts, one of the bones to which it is joined remains virtually stationary as a result of other muscle that hold in the place.

Intervertebral disc.

The vertebra are separated from each other by pads of cartilage, intervertebral discs. These have a though, flexible outer case and a soft, jelly-like centre, and cushion and protect the vertebra.Intervertebral disc act as a shock absorbers to prevent damage from sudden jolts.

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Function

Muscles are responsible for movement. Internal movement involves the contraction and relaxation of muscles that are part of viscera, and external movements is accomplished by the contraction and relaxation of muscles that are attached to the bones.

What is the lower back?

Your lower back is a complex structure of vertebrae, disks, spinal cord and nerves. There are: five bones called lumbar vertebrae, six shock absorbers called disks, spinal cord and nerves, small joints, muscles and ligaments.
This important part of your spine provides you with both mobility and strength. The mobility allows movements such as turning, twisting or bending; and the strength allows you to stand, walk and lift.

Atlas

The first cervical vertebra, the atlas, supports the skull, alowing it free movement.

Normal curves of the spine

The four normal curves of the spine are natural, and they are: Cervical Lordosis, Thoracic Kyphosis, Lumbar Lordosis and Sacral Kyphosis. Function of the spine's natural curves is to help evenly distribute weight loads from daily activities, while providing structural support and stability.

Vagus

Vagus nerve is a cranial nerve, that is, a nerve connected to the brain. It has branches to most of the major organs in the body, including the larynx, throat, windpipe, lungs, heart and most of the digestive system.
Vagus nerve can cause symptoms of a problem within the peripheral or central nervous system. These symptoms could be: numbness in head, back, arms and dizziness.

´Posture´ muscles

Your back is made up of three major muscles: the latisimus dorsi, the erector spinae and the rhomboids (major and minor). These muscles are also known as your ´posture´ muscles.