Table of Contents
What are Spinal Nerves? Functions of the Spinal Nerves:
There are 31 pairs of spinal nerves, which branch out from the spinal cord and provide nerve impulses to the body’s muscles and organs. The spinal nerves are responsible for sensations such as touch, pain, and temperature, as well as controlling muscle movement.
Spinal Cord and Nerves Anatomy
The spinal cord is a long, thin bundle of nerve tissue that extends from the base of the brain down the back. It is covered by three thin membranes called the meninges. The spinal cord contains bundles of nerve fibers that carry messages between the brain and the rest of the body. These messages control the movement of muscles and the sensations felt in the skin.
The spinal cord is divided into four sections:
Cervical spinal cord: This section is located in the neck and contains the nerves that control the muscles of the neck and arms.
Thoracic spinal cord: This section is located in the chest and contains the nerves that control the muscles of the chest and upper back.
Lumbar spinal cord: This section is located in the lower back and contains the nerves that control the muscles of the lower back and legs.
Sacral spinal cord: This section is located in the pelvis and contains the nerves that control the muscles of the hips and legs.
The spinal cord is connected to the brain at the base of the brain by the spinal cord stem. The spinal cord stem contains the highest concentration of nerve cells in the spinal cord. It controls many of the automatic functions of the body, such as breathing and heart rate.
Location of the Spinal Nerves
The spinal cord is a long, thin, white cord that runs down the middle of the back. The spinal cord is a bundle of nerves that carries messages between the brain and the rest of the body. The spinal cord is protected by the spine, a series of bones called vertebrae. The spinal cord ends at the bottom of the spinal column.
There are 31 pairs of spinal nerves. Each spinal nerve arises from a specific segment of the spinal cord. The spinal nerves run down the back and branch out to the rest of the body.
Cervical Plexus:
The cervical plexus is a network of nerve fibers that originate from the spinal cord in the neck and supply the head and neck region. The cervical plexus consists of the anterior and posterior divisions, which are divided into cervical and suboccipital plexuses.
The cervical plexus provides motor and sensory innervation to the muscles and skin of the head and neck, as well as the thyroid and parathyroid glands. The cervical plexus also provides autonomic innervation to the blood vessels and glands of the head and neck.
Brachial Plexus:
The brachial plexus is a network of nerves that originates in the spinal cord in the neck and supplies the shoulder, arm, and hand. The brachial plexus is formed by the union of the four ventral roots of the spinal cord. These roots merge to form three trunks (anterior, middle, and posterior), which in turn divide into five divisions (superior, middle, inferior, lateral, and medial). The medial and lateral divisions each supply a half of the hand. The divisions of the brachial plexus are named for the muscles they innervate:
• The superior division innervates the deltoid and the teres minor muscles.
• The middle division innervates the biceps brachii, the brachialis, and the coracobrachialis muscles.
• The inferior division innervates the triceps brachii muscle.
• The anterior division innervates the pectoralis major and the anterior deltoid muscles.
• The posterior division innervates the latissimus dorsi and the posterior deltoid muscles.
Lumbar Plexus:
The lumbar plexus is a network of nerves that originate from the lower spinal cord and innervate the lower extremities. The lumbar plexus is formed by the ventral rami of the L1-L4 spinal nerves. These nerves travel through the lumbar canal in the vertebral column and exit through the intervertebral foramina.
The lumbar plexus provides motor and sensory innervation to the muscles and skin of the lower extremities. The lumbar plexus also supplies autonomic fibers to the organs of the pelvis and lower abdomen.
Sacral Plexus:
This is a network of nerves that originate in the lower back and run through the pelvis. The sacral plexus provides nerve signals to the muscles of the pelvic floor and the lower extremities.
Coccygeal Plexus:
The coccygeal plexus is a network of nerves that originate in the lower lumbar and sacral spinal cord and innervate the skin and muscles of the coccyx and perineum.
The coccygeal plexus provides sensation and innervation to the skin and muscles of the coccyx and perineum. It consists of the following nerves:
-The dorsal nerve of the coccyx
-The ventral nerve of the coccyx
-The perineal nerve
-The inferior rectal nerve
-The pudendal nerve
Sensory Function:
The sensory function of the eye is to detect light and allow the perception of images. The retina is a layer of tissue in the back of the eye that contains light-sensitive cells. These cells convert light into electrical signals that are sent to the brain, where they are interpreted as images.
Autonomic Functions:
1. heart rate
2. blood pressure
3. digestion
4. sweating
5. urination
6. sexual arousal
Motor Functions:
The shoulder muscles are responsible for shoulder movement. The shoulder muscles are the deltoid muscles, the pectoral muscles, and the latissimus dorsi muscles. The deltoid muscles are responsible for moving the arm up and down. The pectoral muscles are responsible for moving the arm forward and backward. The latissimus dorsi muscles are responsible for moving the arm sideways.
