Nervous System Disease Anatomy
To better understand neurological disease, it helps to understand the anatomy of the brain and nervous system.
The nervous system is composed of the brain, spinal cord, peripheral nerves, and autonomic nervous system.
The brain is well protected by:
- The scalp
- The skull
- The dura
- A tough 3-layer sheath that surrounds the brain and spinal cord
- Layers include the dura mater (strongest layer), arachnoid mater (middle layer), and pia mater (closest to the brain)
The brain is a complicated structure containing many parts. These include:
- The cerebrum:
- Made up of two cerebral hemispheres that are connected in the middle
- It is the largest part of the brain
- Each area of the cerebrum performs an important function, such as language or movement
- Higher thought (cognition) comes from the frontal cortex (front portion of the cerebrum)
- Outside of the cerebrum are blood vessels
- There are fluid-filled cavities and channels inside the brain
- The cerebellum:
- The brainstem and pituitary gland:
- Responsible for involuntary functions such as breathing, body temperature, and blood pressure regulation
- Pituitary gland is the "master gland" that controls other endocrine glands in the body, such as the thyroid and adrenal glands
- The cranial nerves:
- Twelve large nerves exit the bottom of the brain to supply function to the senses such as hearing, vision, and taste
- The cerebral blood vessels:
The blood supply to the brain is divided into two main parts:
- Anterior cerebral circulation:
- Posterior cerebral circulation:
- Carotid artery branches shown on arteriogram
- Cerebral arteries viewed in cross-section through middle of brain
- Cerebral arteries viewed from bottom of brain
- Cerebral arteries on enhanced CT scan
- Cerebral arteries on arteriogram
Spinal Cord Anatomy
- Bones of the cervical, thoracic and lumbar spine
- Front view of the spine and spinal cord
- Cross sectional view
- The conus medullaris is the end of the spinal cord in the back.
- The spinal cord ends in the lumbar spine at the level of L1 to L2
- The cauda equina is a bundle of nerves at the bottom of the spinal cord.
- Nerves of the cauda equina supply the bladder, rectum, perineum, and legs.