Plastic model of the spinal cord

Muscle and bone pain

”It’s muscular”, we often say when muscles hurt.

Unless it is ordinary muscle stiffness, the cause is unlikely to be found in the muscles themselves, even though some muscles are too tight and others too weak. How does this muscle pain come into being?

Muscles keep us erect and make us move. They are attached to the bones. Humans are vertebrates. The spinal column goes from head to “tail”. It consists of a long chain of vertebras like pearls on a string or building blocks of bone tissue.

Between these vertebral bones, we have flexible cushions. These are called spinal plates or spinal discs. Inside the cushions there is a jelly-like shock-absorbing pulp, called the nucleus. The nucleus is kept in place by a capsule of connective tissue, which is full of pain sensors. The capsule can feel very painful. At the front and the back of the vertebras and plates, there are longitudinal ligaments keeping it all in line. The spinal column is bent like a waved line and is very flexible.

If a spinal disc is over-exerted, it may crack and some of the nucleus may leak out. The material leaking out has a very irritating effect on nerve tissue. It causes an inflammatory reaction that can imitate the pain we feel when nerves are crushed. This pain feels as if it sits in those body parts where the nerves originate. Crack formations in the capsule may cause the nucleus to dry out, and the spinal disc becomes stiff and flat.

Vertebras also have direct contact with each other. The contact faces are flexible joints. When a spinal disc becomes flat, wear and tear of the joints, increases, and gradually, arthritis, a degenerative joint disease, develops. The joint’s cartilage breaks, and bone outgrowths develop. These may become so large that they leave little space for the nerves, which become irritated or squeezed with body movement.

The most common pain from the spinal cord originates from the disc capsule and the intervertebral joints.

Capsule pain most often sits in the middle above the neck vertebras or in the back or as a girdle across the neck or the back. When we bend forward, pressure on the plates increases and pain increases. If we stay too long without moving, the plate becomes stiff and it is painful to start movements. People with disc pain should thus move as lightly as possible, and change their position often.

Intervertebral joints sit on both sides. Joint pain is felt mostly on the sides of the vertebras and lengthwise. It increases when we rotate the neck or back. If we bend and rotate simultaneously, we may get an acute crick in the neck or in the back.

Pain signals through the nerves from joints and discs in the spinal column have an effect in the nervous system, which tells the muscles to tauten automatically. It takes place independent of will or mind.

With injuries and illness, spinal discs and ligaments can be strained. Joints between the vertebras can loosen, and muscles must worker harder to keep things together. Muscles contain sensors registering its pressure. This is necessary in order to adjust a muscle’s contraction appropriately. Sensors also tell us in what position our body parts are.

When pain or loose joints cause muscles to tighten automatically, we loose our sense of the position of our body or body parts. Our control of the muscles gets confused, and we may suddenly drop things or fall. Or we may have cramp-like muscle contractions.

Movements and balance loose their natural harmony and elegance. Tight muscles can put such a strain on spinal discs and joints that pain increases. This again leads to stronger muscle reflexes and even greater sensation error. Tight muscles can put a strain on muscle attachments and ligaments, which will start hurting.

It gets even worse if sensitization of the pain sensation system develops in addition. Everything then hurts even more, muscles get tighter, muscle control gets more disturbed and a vicious circle develops where it all just gets worse. This condition is often called fibromyalgia.

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