4 - Brachial Plexus

C7

Although the middle trunk does not give off nerves, it is a continuation of what spinal root?

Lateral cord

The musculocutaneous nerve is a branch off of what cord?

C5,6,7

The musculocutaneous nerve is made up of spinal nerve fibers from what segment(s)?

C5 - T1

The radial nerve comes off of spinal cord segments ____________

Root

A cluster of rootlets is called a __________

Spinal nerve

A cluster of roots makes up a ____________

Median

A formation of the union of the lateral and medial cords, the _____________ nerve innervates the anterior forearm muscles.

Loss of sensation on the lateral aspect of the deltoid Loss of muscle innervation to the deltoid, teres major, biceps, brachialis, and brachioradialis

A patient with Erbs Palsy, a superior brachial plexus injury, will have what loss of sensation and muscle innervation?

C5,6

A superior brachial plexus injury involves what spinal nerve segments?

Superior brachial plexus injury = Waiters Tip Syndrome Inferior brachial plexus injury = Claw hand

A superior brachial plexus injury results in a ___________, an inferior brachial plexus injury results in a ___________.

C8,T1

An inferior brachial plexus injury involves what spinal nerve segments?

C8 and T1

An inferior brachial plexus injury involves which spinal cord segments?

As a muscular and cutaneous nerve, the musculocutaneous nerve innervates the anterior arm (biceps, brachialis, and coracobrachialis) in the anterior arm and the lateral skin sensation in the forearm.

As a muscular and cutaneous nerve, the ___________________ innervates ________________ in the anterior arm and ____________________ in the forearm.

Superior brachial plexus injury due to micro injuries to the superior trunk of the brachial plexus

Backpacker's palsy is a __________ brachial plexus injury due to a __________________________

5

How many terminal branches are in the brachial plexus?

The fracture likely occurred at the distal and of the humerus. The flexors, or anterior forearm muscles, would lack innervation.

If your patient has a median nerve injury due to a fracture, where did the fracture occur? What muscles would lack innervation?

Anesthetic solution for the upper limb should be injected between the posterior side of the sternocleidomastoid and the clavicle. Going too deep can cause pneumothorax

In administering an anesthetic solution, where should it be injected? Why is the location so important?

The cords

In looking at a cadaver's brachial plexus, what is the first part we are able to see below the clavicle?

5 roots, 3 trunks, 6 divisions, 3 cords, 5 branches

In the brachial plexus, there are ____ roots, ___ trunks, ____ divisions, ____ cords, and ____ branches.

Klumpke's syndrome is an inferior brachial plexus injury resulting in the sudden upward pull of the arm.

Klumpke's syndrome is a _____________ which is caused by the ______________. Results in clawhand.

Axillary artery

Starting at the cord region, the brachial plexus wraps around the _______________

1. Subclavian nerve 2. Suprascapular nerve

The Superior trunk is the only trunk that gives off nerve(s). What nerve(s) does the superior trunk give out?

Root region, innervates supraspinatus, infraspinatus, and glenoid joint

The Suprascapular nerve is an extension off of the spinal nerves C4, 5, 6 from the ___________ region of the brachial plexus, innervating __________________.

C5,6

The Upper subscapular nerve is made up of what spinal nerve segments?

Medial cord; Medial cutaneous nerve of the arm and medial cutaneous nerve of the forearm

The _______ cord of the brachial plexus has 3 branches off of it, one being the median pectoral nerve. What are the other two?

Lateral cord -- Lateral Pectoral nerve

The ________ cord has 1 nerve branch off of it, the ___________________.

Acute brachial plexus neuritis

The ________ is a neurological disorder with an unknown cause, but presents with severe pain around the shoulder.

Posterior cord

The ____________ cord is a union of the posterior divisions of all three trunks

Radial nerve innervates anterior arm and forearm muscles, also known as flexors

The _______________ innervates the anterior muscles of the arm and forearm, which are also known as _______________

The ulnar nerve innervates the hand, except the three thenar muscles and the 1&2nd lumbricles.

The _______________ nerve is the main nerve in the hand. It innervates all the hand muscles except three and a half. What are the three

Musculocutaneous nerve

The _________________ is the only branch coming off of the lateral cord

Medial cutaneous nerve of arm

The __________________ supplies the skin medial side of the arm and the superior side of the forearm

Medial cutaneous nerve of forearm

The __________________ supplies the skin on the medial side of the forearm

Anterior region of the upper limb (flexors) Posterior region of the upper limb (extensors)

The anterior division of the brachial plexus mainly innervates ___________________, thus flexor muscles while the posterior division mainly innervates _______________, thus extensor muscles

Flexors

The anterior forearm muscles are __________

Posterior cord

The axillary nerve is a branch off of what cord?

Innervates: Deltoid, teres minor, and skin over deltoid Spinal segments C5-6

The axillary nerve, innervates the _____________ and has fibers from _________ spinal segments.

Motor, Sensory, and Autonomic (sympathetic)

The brachial plexus carries 3 types of nerve fibers. What are they?

C5 - T1

The brachial plexus is the nerve plexus for what spinal nerves?

Ventral rami of C5-T1

The brachial plexus nerves are all _______________ of the spinal region _______________

Brachial plexus -- anterior and middle Long thoracic -- middle and posterior

The brachial plexus travels between the _______________ scalene muscles whereas the long thoracic travels between the _____________ scalene muscles.

C5

The dorsal scapular nerve has fibers from which spinal level?

The ventral rami from C5 - T1

The five roots are composed of _________

C5,6,7

The lateral pectoral nerve is made of spinal nerves from what segment(s)?

C5,6,7

The long thoracic nerve has fibers from which spinal level?

C6, 7; Teres major and the inferior portion of the subscapularis muscle

The lower subscapular nerve is made up of spinal nerves from _________ and innervates which muscles?

C8, T1

The medial cutaneous nerve of the arm and forearm are made up of what spinal segment?

C8, T1

The medial pectoral nerve is made up of what spinal segment?

C5 - T1

The median nerve comes off of what spinal cord segments?

3; Upper & lower subscapular nerves, and Thoracodorsal nerve

The posterior cord gives rise to how many spinal nerves? What are they?

Posterior cord

The radial nerve is a branch off of what cord?

3 total nerves come off of the root region of the brachial plexus. 1. Dorsal Scapular Nerve 2. Phrenic Nerve 3. Long Thoracic Nerve

The roots region gives out ____ nerves. What are these nerves?

3 cords; Lateral, Posterior, Medial

There are ____ cords in the brachial plexus, named ________________

6

There are ____ divisions in the brachial plexus

3 trunks; Superior, Middle and Inferior

There are a total of _____ trunks in the brachial plexus, named _______________________.

C6,7; Latissimus Dorsi

Thoracodorsal nerve has nerve fibers from ________ spinal segment and innervates the ___________

Roots, Trunks, Divisions, Cords, Branches

What are the 5 sections of the brachial plexus?

The trunks, divisions, and cords may vary, however the terminal branches are uniform throughout.

What is the extent of variation in the brachial plexus?

Pectoralis major and pectoralis minor

What muscle does the medial pectoral nerve innervate?

The subscapularis

What muscle(s) does the upper subscapular nerve innervate?

Rootlet

When a spinal nerve first exits the spinal cord, it is called a ___________

The long thoracic runs between the posterior and middle scalene muscles. It innervates the serratus anterior

Where does the long thoracic nerve travel, and which muscle(s) does it innervate?

The rhomboids and the levator scapulae

Which muscle(s) does the dorsal scapular nerve innervate?

Diaphragm

Which muscle(s) does the phrenic nerve innervate?

Test spinal segments C5,6 Effects -- skin sensation on top of the deltoid along with abduction issues

You suspect nerve damage to the axillary nerve in your patient. What spinal segments can you test to confirm your suspicion? What effects do you see in your patient signaling a axillary nerve injury?

Spinal segments - C5,6,7 Effects -- Anterior arm paralysis and loss of skin sensation on the lateral forearm

You suspect nerve damage to the musculocutaneous nerve in your patient. What spinal segments can you test to confirm your suspicion? What effects do you see in your patient signaling a musculocutaneous nerve injury?

The patient fractured their humerus at the radial groove. They will not have innervation to the anterior forearm muscles, thus will have complications with flexing their arm and forearm

Your patient fractured their _____________, which led to radial nerve and deep arm vessel damage. What muscles will not receive innervation due to this fracture?

The brachial plexus is formed at C6-T2 rather than C5-T1

Your patient has a postfixed brachial plexus. What does this mean?

The brachial plexus is formed at C4-C8 rather than C5-T1

Your patient has a prefixed brachial plexus. What does that mean?

Erbs Palsy, "waiter's tip position"

_________________ is a superior brachial plexus injury due to excessive separation between the head and neck region. Clinically, what does this look like?

Dorsal Ramus and Ventral Ramus

_______________________ are branches off of the spinal cord

C3,4,5

The phrenic nerve has fibers from which spinal level?

C8 and T1

The Inferior trunk is a union of what two spinal roots?

Hyperabduction of the arm

Compression of the brachial plexus can be caused by a cervical rib or ____________

C8 and T1

The ulnar nerve comes off of spinal cord segments ____________

An individual with backpacker's palsy may experience sensory deficits in the distribution of the musculocutaneous and radial nerve. Also may cause muscle spasms.

What are clinical consequences of backpacker's palsy?

The roots region is located between the anterior and middle scalene muscles, meaning that if the scalene muscles are "bulky", they compress on the brachial plexus root region, causing pain and discomfort. If the humerus is in maximum abduction for a long period of time, the scalene muscles and clavicle can compress on the brachial plexus, causing similar symptoms

What are some considerations and conditions associated with the roots region of the brachial plexus?

Pectoralis major (and minor)

What muscle does the lateral pectoral nerve innervate?