The spinal cord has two main descending tracts: the anterior and the posterior. Each of these tracts contains fibers that carry information to and from the lumbar and cervical regions. Each descending tract consists of ascending and descending tracts. Incorrect labels include the fibers that enter the axon terminals of the laminae II. Therefore, correct labels are those that include the dorsal ganglion and the ventral thalamic.
The spinal cord is made up of two parts, the lumbar column and the brain. The two parts are joined in the center of the spinal column. The lumbar column has four segments and connects the vertebrae. The lumbar segment is the largest of the three. The thoracic segment consists of six segments, which are called vertices. The upper portion of the thoracic vertebra is the occipital nucleus, while the femur is situated at the distal end of the forearm.
The spinal cord is segmented. The 31 pairs of nerves that exit the cord are called segments. These segments are separated into eight cervical levels, twelve thoracic segments, five lumbar levels, and one sacral segment. The eighth branch exits the spinal cord between the C7 and T1 vertebra. These root systems connect the lumbar and thoracic regions.
The ventral roots of the spinal cord are called ventral root fibers. These rootlets are formed from discrete segments of the spinal cord. They contain motor nerve axons that innervate intrafusal and extrafusal muscle fibers. Preganglionic fibers from visceral neurons innervate visceral organs. Axons of the dorsal roots form the axon of the spinal nerve.
The spine is covered by three layers: the pia mater and the dura mater. Each layer is covered by three types of nerves. The different types of nerves are numbered based on where they exit the spinal canal. The first two sections are dorsal and the second is sacral. Each section of the spinal cord is located at the vertebral level of the sacrum.
The two lateral and ventral gray horns surround the spinal cord. The arachnoid horn contains the fourth ventricle. The lateral region is an extension of the cerebral artery. The lumbar and sacral horns are the two major divisions of root cells. Similarly, the arachnoids of the cord are the two major components of the axons of the cranial nerve.
The vertebrae and the spinal cord are part of the central nervous system. The lumbar and the cervical arteries are the two other types. The posterior and the anterior auricular arteries are not connected to the brain. The iliac artery is connected to the arachnoid artery and to the brain. The radicular arteries supply the lower levels of the spinal cord.
The anterior and posterior spinal arteries are narrowed and form an anastomotic network with the radicular arteries. The radicular artery supplies the most lower levels of the spinal cord. There are six to eight pairs of these arteries. They are connected to the sacral artery. They are encased within the lumbar artery. These anatomical features of the cervical and thoracic arteries are not always visible.
The spinal cord is made up of two parts called the anterior and the posterior vertebral arteries. The anastomotic arteries are the two primary arteries in the spinal cord. They are positioned in the anterior and posterior lumbar arteries and attach to the axons of the vertebrae. The axons of the ventral lumbar artery are connected to the other parts of the spine.
The spinal cord has two arteries: the anterior and the posterior. Both of these arteries supply the corticospinal and other areas of the spinal cord. The anterior lumbar artery is the smallest of these arteries. The nerves in the rexed laminas III are larger and are connected to the axons of the ipsilateral lumbar artery.