Spinal Nerves Flashcards
How many pairs of cervical spinal nerves are there?
8
How many pairs of thoracic spinal nerves are there?
12
How many pairs of lumbar spinal nerves are there?
5
How many pairs of sacral spinal nerves are there?
4 or 5
How many pairs of coccygeal spinal nerves are there?
1
Do the cervical spinal nerves exit superior or inferior to the vertebrae they are named for?
Superiorly
With exception of the cervical spinal nerves, do spinal nerves exit superiorly or inferiorly to the vertebrae for which they are named?
Inferiorly
Are the coccygeal spinal nerves present in all humans?
No, they may be absent.
Define what a plexus is…
It is a network of nerves.
When nerves exit the spinal nerve rami, do they go directly to the body structure they supply?
No, they join up with other axons from anterior rami of adjacent nerves to form plexus.
Intercostal nerves form plexus; true or false?
False, when the intercostal nerves (T1-12) exit the anterior rami, they run along the ribs or within the intercostal muscles.
What are the majors nerve of the cervical plexus?
The phrenic nerrves.
What do the phrenic nerves innervate?
The diaphragm.
What are the major nerves of the brachial plexus?
The musculocutaneous, the radial, the axillary, the median, and the ulnar nerves.
How are the brachial plexus divided?
From the midline outward: Roots, Trunks, Divisions, Cords, Branches.
To help you remember: Robert Taylor Drinks Coffee Black! ;D
Where does the suprascapular nerve arise from?
The superior trunk of the brachial plexus.
Injury to the suprascapular nerves can affect what structures?
Supraspinatous muscle and infrasinpatous muscle.
Damage to the suprascapular will affect the infraspinatus muscle if what way?
Loss of lateral rotation of humerus - Waiter’s tip.
Damage to the suprascapular nerve will do what to the supraspinatus muscle?
Loss of ability to initiate abduction of the arm.
Where does the axillary nerve arise from?
Posterior cord of the brachial plexus.
What does the axillary nerve innervate?
Deltoid, teres minor, glenohumeral joint.
Injury to the axillary via injury to the surgical nneck of humerus, shoulder dislocation or compression can result in what?
Atrophy of the shoulder muscles.
IE your shoulder muscles will be droopy!
From where does the radial nerve originate?
Posterior cord; Brachial plexus.
What does the radial nerve innervate?
Posterior compartment muscles of arm and forearm.
What are the symptoms of radial nerve damage?
“wrist drop.”
weak or no extension of the wrist.
Where does the musulocutaneous nerve arise?
Lateral cord of the brachial plexus.
What does the musculocutaneous nerve innervate?
coracobrachialis, biceps brachii, and brachialis muscle.
Though injury is uncommon, what would the symptoms of musculocutaneous nerve damage?
Weak flexion of GH joint.
Where does the median nerve arise?
Medial cord & lateral cord of brachial plexus
What does the median nerve innervate?
the anterior compartment of the forearm.
What happens if the median nerve is damaged?
Flexion loss in proximal interphalangeal joints of digits 1-3. Weakened flexion of digits 4-5.
What happens to the medial nerve in carpal tunnel syndrome?
compression of the median nerve as it passed though the carpal tunnel.
What are the symptoms of carpal tunnel syndrome?
paresthesia, anesthesia, and hypoesthedia in the digits.
Where does the ulnar nerve arise from?
medial cord of brachial plexus
What does the ulnar nerve innervate?
flexor carpi ulnaris, and the ulnar half of flexor digitorum produnfus
Where is the ulnar nerve commonly injured?
in the elbow (posterior to medial epicondyle) and at the wrist (nedial side, wraps around the hook of the hamate.)
Ulnar damage results in what?
Metacarpophalangeal joint hyperextension and interphalangeal joints are flexed. results in “claw hand”.
Where does the long thoracic nerve originate?
C5, C6, C7
What does the long thoracic nerve innervate?
serratus anterior
What does damage to the long thoracic nerve result in?
paralysis of the serratus anterior muscle. and the scapula cannot be held in place aka “winged scapula”.
True or false: the lumbosacral plexus is actually comprised of 2 seaparate plexus.
True.
The lumbosacral plexus is comprised of two separate plexuses, what are they?
the lumbar plexus and the sacral plexus.
The largest branch of the lumbar plexus?
The femoral nerve.
The femoral nerve has multiple branches. Name the branches.
Cutaneous branches and muscular branches.
The cutaneous branches of the femoral nerve supply what structures?
the skin over the thigh
the muscular branches of yhe femoral nerve innervate what muscles?
iliacus, pectineus, sartorious, and quadricep femoris.
What are the actions of quadricep femoris?
Flexes hip and extends knee.
When symptoms are present when the femoral nerve is damaged?
weak flexion of thigh, weak extension of knee.
What activity is difficult when the femoral nerve is damaged?
climbing stairs.
What are the major nerves of the Sacral plexus?
Superior gluteal nerve, Sciatic nerve, and the Pudenal nerve.
What does the superior gluteal nerve innervate?
gluteus medius, gluteus minimus, and tensor fascia latae.
What happens when the superior gluteal nerve is damaged?
Pelvic drop on the side of the elevated leg when the patient stands on one leg and elevates the other – also known as Trendelenburg Sign
What is the largest nerve of the body?
The sciatic nerve
The sciaic nerve is comprised of 2 different nerves, what are they?
Tibial Nerve and common peroneal nerve.
How to you locate the sciatic nerve using surface anatomy land marks…
Superiorly, half way between the posterior superior iliac spine and the ischial tuberosity. Inferiorily, halfway between the ischial tuberosity and the greater trochanter.
In males, what does the pudendal nerve innervate?
the dorsal nerve of the penis, skin and glans of penis
in females, what does the pudenal nerve innervate?
clitoris, labia major, labia minora, lower vagina.
