Bursitis and tendinitis are both common conditions that cause swelling around muscles and bones. They occur most often in the shoulder, elbow, wrist, hip, knee, or ankle. A bursa is a small, fluid-filled sac that acts as a cushion between a bone and other moving body parts such as muscles, tendons, or skin.
In higher vertebrates, such as reptiles, birds and mammals, there are 12 pairs of cranial nerves. Lower vertebrates, such as fish and amphibians, have 10 pairs of cranial nerves. Continue Reading.
Central Nervous System (CNS). The Central Nervous System is composed of the brain and spinal cord. The brain has 12 cranial nerves. The spinal cord, which originates immediately below the brain stem, extends to the first lumbar vertebra (L1).Beyond L1 the spinal cord becomes the cauda equina (see below).he Central Nervous System is composed of the brain and spinal cord. The brain has 12 cranial nerves. The spinal cord, which originates immediately below the brain stem, extends to the first lumbar vertebra (L1). Beyond L1 the spinal cord becomes the cauda equina (see below).