Discovering the Human Skeleton: Anatomy, Functions, and Common Disorders Explored in Detail

Discovering the Human Skeleton: Anatomy, Functions, and Common Disorders Explored in Detail

The skeleton of a newborn child initially consists of more than 300 bones or cartilage, some of which grow together in the course of physical development and thereby become ever more robust and resilient.

An adult human has 206 bones, half in the hands and feet. Joints connect them, give the body stability, and at the same time form protection and framework for all our organs.


The ligaments attached to the periosteum consist primarily of collagen and elastin proteins.

Ligaments are bundles of fibres that run lengthwise or crosswise. They connect the bones by covering the joints, thus giving them stability.

The ligaments also hold internal organs, such as the liver, in the correct position.

Band washers

The intervertebral discs, also known as the intervertebral discs, are cartilage that connects the vertebral bodies. They make up around a quarter of the entire length of the Spine. Each cartilage consists of a fibrous ring and a gelatinous core. At the same time, the fibrous ring is interwoven with the vertebral body and thus strengthens the Spine; the soft, thick core functions as a cushion that absorbs shock and equalizes pressure.

Interestingly, the intervertebral discs temporarily narrow for a day because they are exposed to high levels of stress from daily activities. That’s why people are about two centimetres smaller in the evening than in the morning.

As we age, the intervertebral discs change (water loss), which causes back pain in many people. If this pain occurs at an earlier stage, it may be a displaced disc caused by unfamiliar movements or heavy loads – for example, if someone not used to it suddenly lifts a heavy crate of beer.


The pelvic girdle is a robust and stable ring of bones formed by the two hip bones, the sacrum and the coccyx. It bears the brunt of the body weight and allows us to stay upright. It also protects the pelvic viscera – i.e. the bladder, rectum and internal sex organs.

The arched hipbone is caused by the iliac, ischial and pubic bones growing together, which are initially separate in the embryo. At the lower part of the ilium – similar to the scapula – there is a joint cavity that accommodates the rounded head of the femur. The ileum is connected to the pubic bone in front and the ischium below.

Because the upper space of the pelvis is larger than the lower one, a distinction is made between the large and small pelvis. The female pelvis is generally more significant than the male and thus enables the birth process.


The Thorax has the shape of a cone that tapers upwards and consists of a total of around seventy individual parts. It fulfils two functions: On the one hand, it provides stable protection for the vital organs it covers, and on the other hand, thanks to its movable ribs, it is very elastic and thus enables breathing. The Thorax consists of the thoracic Spine, twelve pairs of ribs and the sternum. The front attachment point of the ribs is the sternum, located in the middle of the chest. Cartilaginous tissue forms the attachment points.

The Thorax protects the intestines, heart and lungs. The most extended pairs of ribs are in the middle area, and the shorter couples further out. Each rib is articulated to the Spine by a head and a small hump.

When it comes to ribs, a distinction is made between real and false pairs of ribs, i.e., those directly or indirectly connected to the breastbone. The first seven pairs of ribs are connected directly to the sternum via cartilaginous processes, the following three pairs only via the cartilaginous costal arch, while the last two pairs of ribs have no connection to the sternum at all. When you breathe, the ribs move up and down, allowing the lungs to expand and contract. Many muscles and ligaments that attach to the ribs also ensure the elasticity and stability of the ribcage.

Thoracic vertebrae

Each of the twelve thoracic vertebrae, which form the centre of the Spine, is connected to a pair of ribs. These vertebrae are less mobile and are, therefore, able to protect the organs in the chest cavity well.

All pairs of ribs, except the two lower (free ribs), connect to the sternum via two articular surfaces at the front.

Real joints

Accurate joints can be divided into the following groups:

Hinge joints only allow movement around one axis (e.g., elbows and knees).< /span>, which allows limited movements in all directions (e.g. carpus and tarsus).Flat joints, in which a ring rotates around a stud (head). They form a particular form of hinge joint.

Stub or wheel joints, with their elliptical shape, allow movement around two axes (e.g. posterior carpal joint). The curved joint surface (thumb) allows saddle joints to move around two axes. Ball joints provide the greatest freedom of movement (e.g., the shoulder joint or the hip joint). 


In functional terms, the elbow joint consists of three joints, as three bones are movably connected. The interaction of a hinge joint and a ball joint causes the bending and extension of the forearm. In addition, there is the tenon joint, which enables forearm-hand rotation.

The elbow is a protruding part of the elbow bone. This hinge joint means that the forearm cannot be bent back.


The growth areas of bones are called epiphyses. They each begin at the ends of the long bones. The bone grows by – put < an i=5>– calcified: Calcium salts spread from the bone shaft to the limitations and thus stabilize the bone. This growth process also explains why, in rare cases, there are always particularly tall or short people:

While physically “normal” ” humans only grow until they are about twenty years old, the epiphyses of tall people are still active beyond this stage. Conversely, people of short stature grow only half as fast as other children. In any case, the growth hormones determine a person’s height and are to blame for fast or slow bone growth.

The diaphysis refers to the bone shaft, which forms the middle part of the long bones. The calcium salts required for bone formation are deposited here.

When the bone is fully grown, bone marrow and trabeculae develop in its shaft. These form a sponge-like filling material that makes the bone extremely stable without making it heavy. Incidentally, this support system served as a model for constructing the Eiffel Tower in Paris!


The foot skeleton comprises seven tarsal bones, five metatarsals, and fourteen toe bones. A curve-like recess can be seen in the middle when a healthy foot is cast on flat ground.

The unique arrangement of the tarsal bones creates two arches: the longitudinal arch on the inside of the foot between the toes and heel and the transverse arch in the foot Area of ​​the metatarsal bone between the inner and outer edge of the foot.

This means the foot can elastically absorb the body pressure that occurs when running, for example. With every standard step, An adult’s foot must withstand around 450 kilograms of force. Wide, flat bands above the ankle support the foot so it cannot bend to the side.

The seven tarsal bones are the calcaneus, talar, scaphoid, and cuboid bones and the inner, outer, and middle sphenoid bones.


Joints are the connection points between the bones that make our body mobile. The joint surfaces are covered by smooth cartilage, which makes them slippery. Larger joints also contain a slimy fluid that reduces contact surface friction and increases mobility.

Humans have a total of over a hundred joints. There are two main groups:

Connective tissue or bony joints: These joints can hardly or not be moved at all. The bone sutures in the skull and the pelvis are examples of this.

Accurate joints: The actual joints enable a range of motion that varies depending on the type of joint. For example, you can turn your head in different directions, while your knee can only be bent and extended. That’s why the accurate joints are further divided into subgroups that are differentiated according to their degree of mobility.

Cervical vertebrae

The upper two of the seven cervical vertebrae differ from the remaining vertebrae in their shape. The first vertebra (Atlas) is shaped like a ring and supports the head. The second cervical vertebra (axis), which has a tooth (dens), forms a joint with the atlas. The atlas ring rotates around the axial tooth when the head is turned sideways. The seven cervical vertebrae allow the head maximum mobility.


Twenty-seven bones make up the entire hand. The carpus consists of eight: scaphoid, lunate, pea bone, capitate, large and small polygonal bone, hook bone and triangular bone.

The five metacarpal bones are connected to these bones, forming a slight arch via joints.

Each of the fingers, except the thumb, consists of three bones. The thumb, which has only two joints, is connected to the carpal bone by a saddle joint. Thanks to this joint, the thumb can face the other fingers. This means the hand can grasp larger objects and has more strength.


The knee is the largest and most complex joint in the human body. It is a hinge joint that connects the femur with the shinbone and the fibula.

Eight joint bodies work together here and, in addition to bending and stretching the lower leg, enable rotational movements around its longitudinal axis. However, this is only possible when the leg is bent.

The curved kneecap (patella) protects the front of the knee joint. Inside this joint, a cartilage cushion absorbs the stress caused by the meeting of the femur and shinbone.


The compact material of a human bone is twice as hard as granite and no less tensile than cast iron. Nevertheless, it doesn’t weigh much: the human skeleton only makes up around twelve per cent of the total body weight. The bones of a fifty-kilogram human weigh only about six kilograms. Bones are living substances: cell tissue. Calcium is stored in this connective tissue, giving the bones high strength to protect and stabilize the vital body organs.

The individual components of the bone are water (approx. 25 per cent), organic Substances (mainly the protein ostium) and finally, inorganic minerals: calcium, phosphorus, magnesium and small amounts of iron, potassium, sodium, chlorine and fluorine.

Every bone has four components:

The compact bone mass from which the thick outer layer of bone is formed. It surrounds the inner core of bone trabeculae and is particularly pronounced in the middle of a bone to protect it from deformation. The periosteum forms the outermost covering around the compact bone mass.

Small bone trabeculae inside the bone. They form a spongy filling material that makes the bone extremely stable without making it heavy. Incidentally, this support system served as a model for constructing the Eiffel Tower in Paris!

The periosteum surrounds the complex bone cortex from the outside. It contains special cells called osteoblasts, from which new bone cells form. These contribute to the growth and regeneration of bones.

The bone marrow is stored in the cavities of the large bones. All blood cells are born in the bone marrow – up to five billion daily. The fatty tissue forms red blood cells (erythrocytes) for oxygen transport, blood platelets (thrombocytes) for clotting and various white blood cells (leukocytes) for the immune system

Bone shapes

Bones have different shapes – depending on their functions. They are divided into: 

 Long bones (for example, femur) are all bones that have a hollow shaft in which the bone marrow is located. The ends of a long bone are the extremities. The part in between is called the corpus. Apart from the fingers and toes, all long bones have two joint ends covered with cartilage.

Short, compact bones are interspersed with bone trabeculae (cancellous bone). A> are steering points for tendons. The most prominent sesamoid bone is the patella. Sesamoid bones contain cavities filled with air and mucous membranes. This includes, for example, the upper jaw. Air-containing bones (such as the bones of the facial skull) are neither tubular nor flat or short bones. Irregularly shaped bones (scapula, skull) serve to protect internal organs or as the attachment of larger muscle groups. They contain a considerable amount of red bone marrow and bone trabeculae.

Flat bones

Bone marrow

The bone marrow, which is stored in the medullary cavity of the bone, produces, among other things, red blood cells.

The endosteum lines the bone marrow cavity. This is a connective tissue membrane that is similar to the periosteum but is much thinner. The marrow is red in children, while it essentially takes on a yellow colour in adults.

The red bone marrow needs iron to produce red blood cells. Iron deficiency is, therefore, the leading cause of anaemia, also known as “anaemia” called. It is primarily noticeable through chronic fatigue.


Cartilage (cartilage) is a smooth, avascular tissue that covers joints and skeletal areas. They must be elastic and, at the same time, stable so that shocks can be absorbed. The cartilage functions as a protective cushion. The embryonic skeleton still consists entirely of cartilage, which becomes bone through calcium deposition.

Depending on the requirements, the cartilage has different compositions. They get their nutrients from the surrounding tissue, the perichondrium, which gradually turns into cartilage tissue.

There are three types of cartilage:

The hyaline cartilage is transparent and shimmers bluish-white like milk glass. It is characterized by high elasticity and pressure resistance. At the ends of the joints, it acts like a cushion that absorbs shocks. The smoothness of the cartilage surface enables the joint bodies to move against each other with little friction.

The fibrocartilage has a high proportion of collagen and interwoven fibre bundles, which make it stable and elastic at the same time. Among other things, the intervertebral discs between the vertebrae are made of fibrocartilage. Each forms a fibrous ring with a gelatinous core that absorbs shocks and vibrations. Bones and ligaments are also firmly connected by fibrocartilage.

The elastic cartilage, like fibrocartilage, has collagen and yellowish elastic fibres. It is contained in the larynx, pinna, ear canal and ear trumpet.

Sacrum and coccyx

Five sacral vertebrae ensure the upper body has a firm foundation and does not collapse unsteadily. Located between the lumbar vertebrae and the coccyx, they are firmly attached to the pelvis and stabilize the torso.

The coccyx is a relic of our most distant ancestors, who still had a tail. In humans, the three to four fused vertebral remains are non-functional.

lumbar vertebra

The five lumbar vertebrae allow us to bend or rotate our body in different directions. This ability can be particularly well observed in artistic gymnasts, which shows how resilient the body is.

The lumbar vertebrae, which have the most significant weight when standing or walking, are all Whirl’s largest and most powerful. They lie below the thoracic vertebrae and above the sacral vertebrae.

upper arm

The long humerus opens into a rounded head at the top, which fits into the socket of the shoulder blade and, together with it, forms the shoulder joint. At the elbow joint, it is connected to the two forearm bones, the ulna and the radius.

The humerus enjoys a bad reputation as the so-called “musical bone”: If you hit your elbow violently – and the nerves running there – you could sing in pain.

Upper limbs

The shoulder, upper and forearm, elbow and hand are among the upper limbs.


The longest and heaviest of all human bones is the femur, which supports the upper body’s weight.

For a 1.80-meter-tall person, it is around 50 centimetres long, so it is more than a quarter of the standing height.

Its head is embedded in the hip bone’s socket, while the kneecap’s articular surface is at the lower end. The connection point between the thigh, shinbone and fibula lies in this.


If you feel a newborn’s skull, you will notice soft spots, also called fontanelles, gaps filled with connective tissue. The 22 bones of the small, elastic skull are only firmly connected by bone sutures sometime after birth. This ossification process takes place in the first three years of life.

The fully grown skull bone forms a stable capsule around the brain and higher sensory organs. A distinction is made between the areas of the braincase and those of the facial skull.

shoulder girdle

The shoulder girdle is composed of the posterior scapula and the anterior clavicle.

Scapula: Into the flat, triangular scapula, which, together with the pan-like depression, is built into the collarbone, which forms the shoulder girdle. It joins with the rounded head of the humerus to form the shoulder joint. This joint gives the arm much movement freedom but can also dislocate easily.

The clavicle is a long, light arcuate bone. It lies directly under the skin and, as the front part of the shoulder girdle, forms a palpable border between the neck and chest. Along with the radius, this bone in the body breaks most often.

Skeletal structure

The individual parts of the skeleton are the skull, Spine, and arm skeleton, with the bones of the arms and the hands and the long bones of the arms and legs forming the body. Spineheart and brain. While the skull and Thorax envelop and support delicate organs, the Feet and the legs and leg skeleton with the bones of the Thorax


The two forearm bones, ulna and radius, are connected to the upper arm via the elbow joint.

The radius is connected to the ulna at both ends. In addition, it has contact with the wrist of the hand via two very mobile wrists.

Statistically, fractures in the forearm area are the most common in humans.

Lower limbs

The lower limbs are the pelvis, thigh, knee, lower leg, and foot.

lower leg

The shinbone runs along the front of the lower leg. It flows into the inner ankle at the bottom and is much stronger than the thin fibula that ends with the outer ankle.

The fibula is connected to the tibia and the ankle bone. It is located between the inner and outer malleolus and the talus bone.


The Spine shape, curved like an S, gives the body the support it needs to walk upright and gives it a high degree of elasticity. As the body axis, it supports the head, ribs and upper limbs. A rough distinction is made between a movable and an immovable part of the Spine: the upper part is movable (i.e. cervical, thoracic and lumbar Spine). At the same time, the sacrum and coccyx remain rigid in their position. The Spine forms the channel for the delicate spinal cord, which connects the brain with the peripheral nervous system.

Structure of the Spine

Intervertebral discs connect 32-33 Vertebrae. They make up about a quarter of the total length of the Spine. These elastic shock absorbers combine with the vertebral bodies to form a flexible column that extends from the neck to the bottom of the back. Muscles and ligaments also connect the vertebrae and, in this way, make the Spine flexible.

The entire Spine consists of seven cervical vertebrae, twelve thoracic vertebrae, five lumbar vertebrae, and five sacral vertebrae, and the coccyx comprises three to four coccyx vertebrae.

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