Diagram of the layers within Earth's atmosphere. Troposphere. The troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). This part of the atmosphere is the most dense.Almost all weather is in this region. Stratosphere. The stratosphere starts just above the troposphere and extends to 50 kilometers (31 miles) high.he troposphere starts at the Earth's surface and extends 8 to 14.5 kilometers high (5 to 9 miles). This part of the atmosphere is the most dense. Almost all weather is in this region.
conus. n, pl-ni. 1. (Anatomy) anatomy zoology any of several cone-shaped structures, such as the conus medullaris, the lower end of the spinal cord. 2. (Zoology) anatomy zoology any of several cone-shaped structures, such as the conus medullaris, the lower end of the spinal cord. continental United States.
Conus medullaris syndrome is a collection of signs and symptoms associated with injury to the conus medullaris. It typically causes back pain and bowel and bladder dysfunction but weakness and sensory loss is uncommon.t occurs near lumbar vertebral levels 1 (L1) and 2 (L2), occasionally lower. The upper end of the conus medullaris is usually not well defined. After the spinal cord tapers out, the spinal nerves continue to branch out diagonally, forming the cauda equina.