The supporting pillars of our body

What are bones?

Bones are the rigid structural elements that make up the human skeleton. In adults, this framework typically comprises around 206 individual bones. They are particularly numerous in the hands and feet, where many small bones provide mobility and fine motor control. The exact number can vary, however, as some bones fuse over the course of life. In newborns the count is significantly higher, up to around 300.

For the musculoskeletal system to work, bones are connected to one another by joints. Muscles, tendons and ligaments add further stability and keep them in place. At the same time, bones are embedded in a network of blood vessels and nerves, which provide nutrients and enable signal transmission.

Bones come in different shapes depending on their size, form and function. There are long bones, such as those in the arms and legs, flat bones like the skull plates or the shoulder blade, and short, cuboid bones in the hands and feet. In addition there are irregularly shaped bones such as the vertebrae, sesamoid bones like the kneecap, and air-filled bones in parts of the skull.

How are bones built?

The structure of a bone is complex and consists of several layers and components that together ensure its strength, elasticity and function. On the outside lies a thin but sensitive periosteum, richly supplied with nerve fibres and blood vessels. This layer is important not only for nourishing the bone but also makes it pain-sensitive when it is stressed without protection.

Beneath this is the compact cortical layer (Substantia compacta), which makes the bone firm and resilient. Its thickness varies depending on the type and load of the bone. Inside is the sponge-like spongiosa. This network of fine bony struts (trabeculae) is arranged so that it provides the bone with high stability despite its low weight. In the cavities of the spongiosa lies the bone marrow, which fulfils various tasks.

Bone marrow exists in two forms: red marrow, which is responsible for producing blood cells, and yellow marrow, which consists mainly of fatty tissue. While red marrow predominates in childhood, it gradually converts to yellow fatty marrow during life. In adults, red marrow remains only in specific areas such as the sternum, the ribs or the pelvis.

In addition, bones are traversed by blood vessels and nerves that supply nutrients and oxygen. In long tubular bones such as the femur or the humerus, the shaft also contains a central medullary cavity that holds red or yellow marrow depending on age. This shows that bones are not a rigid substance but a living, dynamic structure.

Why are bones important?

Bones are essential to the human body because they provide shape and support and serve as a stable framework. Without their load-bearing capacity, standing upright and controlled movement would not be possible. At the same time they have an important protective function, shielding sensitive organs such as the heart, lungs or brain from external forces. Bones also play a key role in the musculoskeletal system, as muscles and tendons attach to them and thereby enable controlled movement.

Moreover, bones are closely involved in vital metabolic processes. For example, bone marrow produces blood cells responsible for oxygen transport, immune defence and blood clotting. Bones also act as a store for minerals such as calcium and phosphorus, which can be released into the bloodstream when needed to support numerous bodily functions.

Which vitamins and nutrients do bones need?

Various vitamins and minerals are indispensable for bone health and strength. Foremost is calcium, stored in bone tissue and providing rigidity. If calcium in the blood is low, the body can draw on its bone reserves. Magnesium is equally important because it helps incorporate calcium and strengthens bone structure. Zinc and copper additionally contribute to bone formation and support enzymatic processes necessary for regeneration.

Among vitamins, vitamin D plays a key role by regulating calcium absorption and utilisation. Vitamin K is also crucial, as it ensures that calcium is actually deposited in bone. Vitamin C, in turn, promotes collagen formation, a fundamental component of bone tissue. The B vitamins – particularly B6, B12 and folate – influence bone cell metabolism and blood formation and thus help maintain a stable bone system.

What problems can affect bones?

Bones can be affected by a variety of diseases and disorders that impair their stability and load-bearing capacity. Some conditions cause the bone to lose strength and to give way more easily, such as rickets in children or osteomalacia in adults. Both result from impaired mineralisation and lead to skeletal deformities.

Osteogenesis imperfecta (brittle bone disease) is another genetic condition that makes bones particularly susceptible to fractures. Collagen formation is disturbed, so bones are unusually fragile and often fracture under relatively low stress.

Additionally, bones can be affected by infections, tumours or malformations. Tumours may develop directly in the bone or reach it via metastases. Fractures caused by accidents or congenital malformations can also significantly limit bone function.

What is osteoporosis?

Osteoporosis is characterised by a progressive loss of bone substance, making bones less stable. The bones become porous and prone to fractures, which is why the disease is commonly referred to as bone loss. It affects the whole skeletal system and can occur anywhere in the body, but is most common in the spine, the hip and the femur.

The diagnosis is usually made by measuring bone density. A T-score is calculated to indicate how much the bone substance deviates from a healthy reference value. The lower the score, the more advanced the disease. A precursor to osteoporosis is osteopenia, which already shows reduced bone density but is not yet as pronounced.

Typical signs include a decline in bone mass, changes in internal bone structure and an increased risk of fractures. The insidious aspect of this disease is its slow progression: it often goes unnoticed until a fracture occurs, frequently triggered by minor stress or even with no apparent cause. Such spontaneous fractures are a hallmark of advanced osteoporosis.

What you can do yourself for strong bones: helpful tips

• Ensure a regular calcium intake. Drink a glass of milk daily or choose calcium-fortified plant milk alternatives, eat yoghurt and hard cheese, or opt for calcium-rich mineral water. This helps you reach the recommended daily dose of 1,000 mg more easily.
• Complement your diet with foods rich in vitamin K. Green vegetables such as kale, spinach or broccoli, as well as sauerkraut, help the body deposit calcium into bone. Osteoblasts build bone substance while osteoclasts resorb it – a natural process that maintains skeletal stability.
• Eat protein-rich foods. Protein is important not only for muscle building but also for bone substance. Regularly include fish, legumes, eggs or tofu in your diet.
• Don't forget magnesium, as this mineral supports bone metabolism. Choose nuts, wholegrain products or legumes to meet your needs.
• Reduce strongly acid-forming foods. Too much meat, refined flour products or soft drinks can disturb the acid–base balance and leach minerals from bone. Instead, favour vegetables and fresh fruit as alkaline counterparts.
• Get regular sunlight. Spend 10 to 20 minutes outdoors daily, exposing arms and face to the sun and temporarily foregoing sunscreen. In winter months, taking vitamin D supplements can be sensible. Discuss the correct dosage with your GP.
• Include weight-bearing activities in everyday life. Walk more often, take the stairs or cycle. These activities directly affect bone metabolism and stimulate bone cells to increase activity.
• Use targeted strength exercises. Perform exercises like wall presses or pelvic lifts regularly. Even a few repetitions daily stimulate bone formation.
• Incorporate jumping movements. Impact sports such as running, dancing or ball sports are more effective for building bone than pure swimming or cycling.
• Avoid nicotine. Smoking impairs blood flow to bone tissue, can affect the supply of blood cells and thus increases the risk of fractures, especially with osteoporosis.
• Maintain a healthy body weight. Underweight can lead to hormonal and nutrient deficiencies, while overweight places excessive strain on bones and joints. An ideal BMI is between 20 and 25.
• Use aids if necessary. Non-slip mats, orthotic insoles or braces can reduce strain in osteoporosis and prevent falls. Especially with injuries or pain, it is crucial to act early.
• Keep track of your bone health with medical checks. Regular bone density measurements help to identify risks early. Particularly stable structures like the skull bones show how important solid bones are for overall health.

The skeletal system is a true masterpiece of nature: it is resilient, dynamic and indispensable. Preserving it is the foundation for an active and healthy life.