Two regions of the spinal cord are enlarged to accommodate the greater number of nerve cells and connections needed to process information related to the upper and lower limbs (see Figure 1.10B).
What are the 2 widened portions on the spinal cord?
Divided into cervical, thoracic, lumbar and sacral regions – named for the level of the vertebral column from which the spinal nerves emerge. Cord widens at two points along its course: – Cervical enlargement (inferior cervical region) which gives rise to the nerves of the upper extremities.
Why is there a cervical enlargement in the spinal cord?
As the spinal cord is shorter in length than the vertebral column, it extends from the C3 to T1/T2 vertebral levels, its greatest circumference (approximately 38 mm) at the C6 level. The cervical enlargement is a result of the increased volume of motor cells in the ventral horns of the grey matter.
Why do cervical and lumbar enlargements exist?
The reason behind the enlargement of the cervical region is because of the increased neural input and output to the upper limbs. An analogous region in the lower limbs occurs at the lumbar enlargement.
Where does spinal cord end level?
The spinal cord tapers and ends at the level between the first and second lumbar vertebrae in an average adult. The most distal bulbous part of the spinal cord is called the conus medullaris, and its tapering end continues as the filum terminale.
What part of the spinal cord represents an increase in cell body?
The cervical and lumbar regions of the spinal cord show a larger diameter compared to the rest of the regions. The cervical enlargement and lumbar enlargement represent an increased amount of neurons in the gray matter and axons in the white matter that serve the upper limbs and lower limbs, respectively.
At what spinal levels is the lumbosacral enlargement?
Lumbar enlargement comprises the spinal cord segments from L2 to S2, and is found about the vertebral levels T9 to T12.
Which is the widest part of the spinal cord?
It is a long tube about 18 inches (45 cm) in length and around half an inch (1 cm) in diameter at its widest point. At its inferior end, the spinal cord tapers to a point known as the conus medullaris and gives rise to many large nerve fibers known as the cauda equina.
Why are the gray matters of the cervical cord and lumbar cord segments larger?
spinal segments of the cervical and lumbosacral enlargements; such large structures require a massive innervation. of grey matter since they innervate the thoracic and abdominal regions. matter increases at each successive higher spinal segment.
What is the primary purpose of the spinal cord?
The spinal cord is a complex organization of nerve cells responsible for movement and sensation. It carries signals between the brain and the rest of the body.
Which spinal nerves affect which parts of the body?
The nerves of the cervical spine go to the upper chest and arms. The nerves in your thoracic spine go to your chest and abdomen. The nerves of the lumbar spine then reach to your legs, bowel, and bladder. These nerves coordinate and control all the body’s organs and parts, and let you control your muscles.
How many pairs of spinal nerves do humans have?
In total, there are 31 pairs of spinal nerves, grouped regionally by spinal region. More specifically, there are eight cervical nerve pairs (C1-C8), twelve thoracic nerve pairs (T1-T12), five lumbar nerve pairs (L1-L5), and a single coccygeal nerve pair.
What does GREY matter in the spinal cord contain?
The central nervous system is made up of two types of tissue: the grey matter and the white matter. The grey matter is mainly composed of neuronal cell bodies and unmyelinated axons. Axons are the processes that extend from neuronal cell bodies, carrying signals between those bodies.