Module 2.4 Spinal Nerves Flashcards
List the 5 types of human spinal nerves.
Humans have 8 pairs of cervical nerves, 12 pairs of thoracic nerves, 5 pairs of lumbar nerves, 5 pairs of sacral nerves, and 1 pair of coccygeal nerves.
Describe the structure of spinal nerves within the vertebral column.
Each spinal nerve emerges from the spinal cord by two short roots: the dorsal root, which contains the axons of afferent neurons, and the ventral root, which contains the axons of efferent neurons. These two roots join just before a spinal nerve leaves the vertebral column.
Describe the structure of spinal nerves after leaving the vertebral column.
Almost immediately after emerging from the vertebral column, a spinal nerve divides into branches called the smaller dorsal ramus and the larger ventral ramus.
Describe a nerve plexus and list the four major body nerve plexuses.
A nerve plexus is a network of interconnecting spinal nerves (ventral rami) carried together to some target location. Major plexuses include the cervical, brachial, lumbar, and sacral plexuses.
What is a dermatome?
A dermatome is a region of skin that carries sensory information through a specific pair of spinal nerves to the spinal cord and up to the brain.
What is the most important nerve of the cervical plexus and what structure does it supply?
The phrenic nerve is the most important nerve of the cervical plexus and supplies both motor and sensory fibers to the diaphragm.
List the five final nerves that come from the Brachial plexus.
Axillary nerve, radial nerve, median nerve, musculocutaneous nerve, and ulnar nerve.
What 3 muscles are served by the axillary nerve?
The axillary nerve supplies the deltoid muscle, the teres minor muscle, and the triceps brachii muscle (long head).
What muscles are served by the radial nerve?
The radial nerve supplies the triceps brachii muscle as well as 12 muscles in the forearm.
What is served by the median nerve?
The median nerve supplies flexor muscles of the forearm and the skin of the first 3 ½ fingers.
What muscles are served by the musculocutaneous nerve?
The musculocutaneous nerve supplies the flexor muscles of the arm: biceps brachii and brachialis.
What muscles are served by the ulnar nerve?
The ulnar nerve supplies part of the flexor muscles of the forearm, wrist, and hand as well as the skin of half the ring finger and pinky finger.
What is the major nerve of the Lumbar plexus?
The femoral nerve is the major nerve of the Lumbar plexus.
What is the major nerve of the sacral plexus and what is unique about this nerve?
The sciatic nerve is the major nerve that comes from the sacral plexus and is the largest nerve in the human body.
What muscles are served by the femoral nerve?
The femoral nerve supplies the hip flexors and knee extensors.
What areas are served by the sciatic nerve?
The sciatic nerve supplies the inferior trunk and posterior surface of the thigh.
True or False: The common tibial nerve travels on the anterior surface of the tibia.
False
What is the function of the dorsal ramus?
Contains nerves that serve the dorsal portions of the trunk including the skin and muscles of the back.
What is the function of the ventral ramus?
Contains nerves that serve the remaining ventral parts of the trunk and the upper and lower limbs.
How is the brachial plexus divided?
Divided into roots (C5-T1), trunks (3), divisions (anterior and posterior), cords (lateral, posterior, and medial), and 5 major branches.
Where does the radial nerve travel?
Follows the posterior surface of the humerus, wraps around to the anterior surface close to the elbow joint, and follows the radial bone in the forearm.
Where does the ulnar nerve travel?
Travels posteriorly behind the medial side of the elbow, then travels along the ulnar side of the forearm.
Where does the musculocutaneous nerve travel?
Along the radial side of the forearm.
How is the lumbar plexus divided?
Roots (T12-L4) divide into anterior and posterior divisions.
What does the lateral femoral cutaneous nerve supply?
Supplies sensory information from the skin of the anterior, lateral, and posterior surfaces of the thigh.
What does the saphenous nerve do?
Receives sensation from the medial surface of the leg.
How is the sacral plexus divided?
Roots (L4-S4) into its 2 branches: the common fibular (peroneal) nerve and the tibial nerve.
How do the peroneal and tibial nerves travel?
The peroneal nerve travels laterally along the fibula and the tibial nerve travels posteriorly along the tibia.
