A colloquial term for internal derangement of the knee joint, characterized by pain or instability, locking, and weakness. It is usually the result of a torn internal cartilage, a fracture of the tibial spine, or an injury to the collateral or cruciate ligaments.
The brainstem is the region of the brain that connects the cerebrum with the spinal cord. It consists of the midbrain, medulla oblongata, and the pons. Motor and sensory neurons travel through the brainstem allowing for the relay of signals between the brain and the spinal cord. Most cranial nerves are also located in the brainstem.
The cerebral cortex is entirely composed of gray matter and the cerebellum also contains some deep-seated masses of it. The spinal cord has a central core of gray matter surrounded by white matter; in cross section, its gray matter is shaped approximately like the letter H. Called also substantia grisea and gray substance.