The nervous system is generally divided into the central nervous system and the peripheral nervous system. The central nervous system consists of the brain, brainstem, cerebellum, and spinal cord. The peripheral nervous system consists of spinal nerves originating from the spinal cord and the autonomic nervous system.
The brain and spinal cord are located within a bone structure called the cranium and spinal canal, which protects it from impacts. They are enveloped by the meninges, which are three layers of membranes. From outer to inner layers: dura mater, arachnoid mater, and pia mater. The dura mater is a thick, whitish in color, and non-elastic structure. Beneath it lies the arachnoid mater, a thinner, more transparent layer. Below the arachnoid mater is the pia mater, an extremely thin membrane that surrounds all the folds of the brain and spinal cord. Between the dura and arachnoid layers lies the subdural space, and between the arachnoid and pia layers lies the subarachnoid space.
The brain is divided into two main parts: the right and left hemispheres. These hemispheres are connected to each other by special structures in specific locations. The internal structure of the brain consists of gray and white matter. The gray matter forms the outer layer, called the cortex, which is composed of numerous nerve cells (neurons). Thickness of this layer is approximately 2-5 mm. This structure is highly convoluted, consisting of numerous ridges and grooves. Beneath the cortex lies the white matter, which consists of the connecting fibers among neurons.
The right and left hemispheres of the brain are further divided into specific regions (frontal, parietal, temporal, occipital lobes) based on various characteristics. Each region contains specialized centers that perform specific functions and are interconnected with each other (such as speech center, comprehension center, auditory center, visual center, etc.).
Inside the brain, there are small chambers called ventricles, which are interconnected by thin channels. The interior of these cavities is filled with cerebrospinal fluid, the majority of which is produced by specialized structures called choroid plexus within these cavities. Cerebrospinal fluid flows through these channels and reaches the subarachnoid space surrounding the brain and spinal cord, where it is absorbed into the bloodstream via the venous system.
Piriformis syndrome is a neuromuscular condition that occurs when the piriformis muscle, located deep within the hip region, compresses or irritates the sciatic nerve passing nearby. While this muscle performs a critical function by enabling the external rotation of the leg, it exerts pressure on the sciatic nerve—the longest nerve in the body—in cases of […]
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Basic Anatomy of The Spine and Spinal Cord The spine consists of 33 vertebrae. Seven of these bones are cervical vertebrae, 12 are thoracic vertebrae, and 5 are lumbar vertebrae. Five of them are fused to form the sacrum, and 4 are fused to form the coccyx, also known as the tailbone. The function of […]
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Disc Herniation Herniated discs in the neck (cervical), back (lumbar), or more rarely in the mid-back (thoracic) are illness caused by degeneration of structures called discs located between the spinal bones, due to various reasons such as trauma, heavy lifting, excess weight, aging, poor posture, and genetic predisposition. Following the degeneration of the annulus of […]
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Spondylolisthesis (Spinal Slippage) Spondylolisthesis, or spinal displacement (spinal slippage), is the displacement of one or more vertebrae in the spine that are normally aligned, due to various reasons. This displacement can occur forwards, backwards, to the right, or to the left, affecting the neck, back, or lower back. It can occur in a single vertebra […]
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Spinal Stenosis (Narrowing of The Spinal Canal) Spinal stenosis, commonly known as "narrow canal," is a condition characterized by the narrowing of the spinal canal for various reasons, leading to pressure on the spinal cord and the nerves passing through it. This narrowing can occur at any level of the spine, including the neck (cervical), […]
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Spinal Tumors: Symptoms, Diagnostic Methods, and Current Treatment Approaches Spinal tumors are abnormal masses of cells that develop within the spinal canal or the bone structures (vertebrae) that make up the spine. These tumors can originate directly from the spine's own tissues (primary tumors) or occur when cancer from another part of the body (such […]
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Carpal Tunnel Syndrome Carpal tunnel syndrome is a condition that occurs when the median nerve, one of the major nerves in the hand, is compressed and subjected to pressure within a structure called the carpal tunnel at the wrist level, due to various reasons. Causes include repetitive hand and wrist movements (computer use, playing musical […]
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Cubital Tunnel Syndrome Cubital tunnel syndrome is a condition that occurs when the ulnar nerve, one of the three main nerves in the hand, becomes compressed or exposed to pressure at the elbow region. The nerve travels between two bony protrusions on the inner side of our elbow and passes through a structure called the […]
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Thoracic outlet syndrome (TOS) is a complex condition that occurs as a result of the compression of nerves or blood vessels passing through the narrow space between the clavicle (collarbone) and the first rib, known as the thoracic outlet. This narrowing typically results from traumatic injuries, repetitive arm and shoulder movements, postural disorders, or anatomical […]
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Basic Anatomy of Central Nervous System The nervous system is generally divided into the central nervous system and the peripheral nervous system. The central nervous system consists of the brain, brainstem, cerebellum, and spinal cord. The peripheral nervous system consists of spinal nerves originating from the spinal cord and the autonomic nervous system. MENINGES (BRAIN […]
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Brain Tumors The causes of brain tumors are not fully understood, but risk factors include radiation exposure, genetic disorders, a family history of tumors, diseases that affect the immune system, stress, and exposure to various environmental carcinogens. It is thought that brain tumors occur as a result of damage or improper function of specific genes […]
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Pituitary Tumor The pituitary gland is a vital endocrine gland located at the base of the brain in a small bony cavity called the "sella turcica" (Turkish saddle) and is widely known as the body's "conductor of the orchestra." Pituitary tumors are masses that arise from the abnormal and uncontrolled growth of cells within this […]
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Chiari malformation (commonly known as Chiari syndrome) is a structural disorder characterized by the protrusion (herniation) of cerebellar tissue through the opening at the base of the skull (foramen magnum) into the spinal canal. Under normal conditions, the parts of the cerebellum should be located entirely within the skull; however, they are pushed downward due […]
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