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.
Sections. Conus medullaris is the cone-shaped end of the spinal cord. It is normally located between the end of the thoracic vertebrae (T12) and the beginning of the lumbar vertebrae (L1), though sometimes the conus medullaris is found between L1 and L2.ections. Conus medullaris is the cone-shaped end of the spinal cord. It is normally located between the end of the thoracic vertebrae (T12) and the beginning of the lumbar vertebrae (L1), though sometimes the conus medullaris is found between L1 and L2.