The central organ of the nervous system, located in the cranial vault and responsible for complex functions such as thinking, perception, emotions, memory, speech, as well as control over many life processes. The brain is divided into several main structural parts: Cerebral hemispheres Diencephalon Cerebellum Brainstem Interesting fact: The human brain contains approximately 86 billion neurons.

A key part of the central nervous system, running in the spinal canal from the base of the skull to the lumbar region. It serves as the main conductor of information between the brain and the body, and also participates in reflexes. The spinal cord consists of 31 pairs of spinal nerves that pass through the spaces between the vertebrae. It is divided into cervical, thoracic, lumbar, sacral, and coccygeal sections. Its center contains a central canal filled with cerebrospinal fluid, which provides nourishment and protection. Interesting fact: The human spinal cord reaches a length of about 45 cm in adults.

These are nerves that run between the ribs of the thoracic cage, branches of the thoracic spinal nerves. They transmit sensory, motor, and autonomic information from the thoracic cavity and its walls. Intercostal nerves are formed from the anterior branches of the thoracic spinal nerves and run in the intercostal spaces along with arteries and veins. Interesting fact: Intercostal nerves are often pinched or irritated, which can cause chest pain.

The sciatic nerve, or sciatic plexus, is the largest nerve in the human body. This nerve begins in the lumbar-sacral region of the spine and runs through the gluteal muscles, along the back of the thigh, and down to the lower leg and foot. Interesting fact: Inflammation of the sciatic nerve causes a condition known as sciatica, which can cause severe leg pain.

The median nerve, or nervus medianus, is one of the key nerves of the forearm and hand, originating from the brachial plexus (fibers C5-C8 and T1). It runs along the arm, through the wrist into the carpal tunnel, and ends in the fingers. The median nerve performs important motor and sensory functions. Interesting fact: Compression of the median nerve in the wrist leads to a condition known as carpal tunnel syndrome.

The femoral nerve, or femoralis, is one of the main nerves of the lower limbs, originating from the lumbar plexus (branches L2, L3, L4). It runs through the pelvic area and the front of the thigh, innervating most of the muscles in this area, including the quadriceps femoris, which is responsible for extending the knee. Interesting fact: The femoral nerve is one of the largest nerves in the lumbar plexus.

The ankle nerve, or tibial nerve, a branch of the sciatic nerve, innervates the back of the lower leg and foot. It runs along the back of the leg, reaches the foot, and branches to the toes. It controls the muscles responsible for flexing the foot and toes and transmits sensory information from the back of the leg and foot. Interesting fact: The ankle nerve plays a key role in the sensitivity and movement of the foot and lower leg.