Brachial Plexus Lecture

Question 1

Fill in the Blank:

The brachial plexus is made up of the ___ ____ of cervical and thoracic spinal nerves (C5-T1).

Answer 1

VENTRAL RAMI

Question 2

True or False:

The nerves of the anterior division of the brachial plexus innervate only flexion muscles.

Answer 2

True

Question 3

Out of the root, trunk, divisions, cords, and branches, which are supraclavicular and which are infraclavicular?

Answer 3

Supraclavicular

• roots
• trunks

Infraclavicular

• divisions
• cords
• branches (nerves)

Question 4

Which cervical ventral rami does the dorsal scapular nerve come off of?

Answer 4

C5

Question 5

Which cervical ventral rami does the roots for the long thoracic nerve come from?

Answer 5

C5-C7

Question 6

Which nerves come off the upper trunk of the brachial plexus?

Answer 6

• nerve to subclavius
• suprascapular nerve

Question 7

Which cords come off the anterior divisions of the brachial plexus?

Answer 7

• lateral cord
• medial cord

Question 8

Which cord comes off the posterior division of the brachial plexus?

Answer 8

• posterior cord

Question 9

Which nerve comes off the lateral cord?

Answer 9

lateral pectoral nerve

Question 10

Which nerves come off of the medial cord of the brachial plexus?

Answer 10

• medial pectoral nerve
• medial brachial cutaneous nerve
• medial antebrachial cutaneous nerve

Question 11

Which nerves come off the posterior cord of the brachial plexus?

Answer 11

• upper subscapular nerve
• lower subscapular nerve
• thoracodorsal nerve

Question 12

What are the two terminal (named nerves) branches that come from the posterior compartment?

Answer 12

• radial nerve
• axillary nerve

Question 13

What are the three terminal (names nerves) branches that come off the anterior compartment?

Answer 13

• musculocutaneous nerve
• median nerve
• ulnar nerve

Question 14

For the arm(brachium), what divides the anterior and posterior compartments?

Answer 14

medial and lateral intermuscular septa

Question 15

Which nerve (flexors of elbow joint) is found in the anterior compartment of the arm (brachium)?

Answer 15

musculocutaneous nerve

Question 16

Which nerve (extensors of elbow joint) is found in the posterior compartment of the arm (brachium)?

Answer 16

radial nerve

Question 17

Which two nerves are found in the anterior compartment of the forearm (antebrachium)?

Answer 17

• ulnar nerve
• median nerve

Question 18

Which nerve is found in the posterior compartment of the forearm (antebrachium)?

Answer 18

radial nerve

Question 19

What condition can be caused by an injury to the superior trunk (C5 and C6 spinal nerve roots) of the branchial plexus? Most typically a result from excessive, forceful increase in angle between the neck and shoulder.

Answer 19

Erb’s Palsy

Question 20

What are the sensory deficits of Erb’s Palsy?

Answer 20

lateral aspect of upper limb

Question 21

What are the motor deficits seen with Erb’s Palsy?

Answer 21

Motor Deficits:

• loss of arm abduction
• loss of elbow flexion
• loss of forearm supination
• weakness of wrist extension

Question 22

How does a patient typicaly present with Erb’s Palsy?

Answer 22

• upper limb is adducted
• upper limb is medially rotated
• elbow is extended
• wrist is flexed

** “waiter’s tip” position **

Question 23

What is the condition that results to an injury to the inferior trunk (C8 and T1 spinal nerve roots) of the brachial plexus?This typically can occur when the limb is suddenly and/or forcefully pulled in a superior direction.

Answer 23

Klumpke’s Palsy

Question 24

What sensory deficits are seen in a patient with Klumpke’s Palsy?

Answer 24

medial aspect of upper limb (except axilla)

Question 25

What motor deficits are typically seen in a patient with Klumpke's Palsy?

Answer 25

Motor Deficits: * loss of precision finger movements * weakness in forearm pronation * weakness of wrist and finger extension * weakness of wrist and finger flexion

Question 26

How does a patient with Klumpke's Palsy typically present in the clinic?

Answer 26

Primary clinical sign is "claw-hand". There may also be wasting of intrinsic hand muscles. Seen with attempted EXTENSION of digits, leaving 4th and 5th digits flexed.

Question 27

What are the results to an injury to the radial nerve (C5-T1 spinal nerve roots) of the brachial plexus?

Answer 27

* can occur with mid-shaft fractures of the humerus * improper use of crutches * extensors compartments affected * "wrist drop" * "Saturday Night Palsy" (nerve gets pinched due to certain sleep position resulting in loss of ability to extend wrist and digits) * paresthesia and/or pain along course of nerve

Question 28

What are the results of an injury to the axillary nerve (C5 and C6 spinal neve roots) of the brachial plexus?

Answer 28

* can occur with ractures to the surgical neck of the humerus or dislocation of the glenohumeral joint * improper use of backpack (quadrangular space syndrome; can also involve compression of posterior circumflex humeral artery) * can result in impaired or lost function of deltoid and teres minor * patient would be unable to fully abduct their arm, and may have a diminished ability to laterally rotate arm * paresthesia and/or pain with along course of nerve

Question 29

What are the results if an injury to the long thoracic nerve (C5, C6, C7 spinal nerve roots) of the brachial plexus occurs?

Answer 29

* this nerve can be damaged during surgical removal of lymph nodes or other tissues in the axillary region * penetrating trauma to the axillary region can also damage this nerve * serratus anterior is affected * "winged scapula", inability to raise arms past 90 degrees

Question 30

What is the result of an injury that occurs to the ulnar nerve (C8, T1, and ofter C7) of the brachial plexus?

Answer 30

* fracture of medial epicondyle of humerus can damage this nerve. * fracture of proximal ulna may also result in damage * slashed wrist (medial side) * damage will involve flexors of wrist, digits, and intrinsic hand muscles * radial deviation at wrist joint, loss of ab- and adduction of fingers, weak wrist flexion and some loss of flexion of digits * losses depend on where nerve is damaged

Question 31

What are the results of an injury to the median nerve (C6-T1 spinal nerve roots) of the brachial plexus?

Answer 31

* can be injured by fracture of the humerus above the condyles, slashing of the wrist, or by inflammation or irritation in the carpal tunnel (Carpal Tunnel Syndrome) * flexors of wrist and digits affected, also intrinsic hand muscles, particularly those that move digit 1 (thumb) * "Pope's Blessing" (when making a fist, unable to flex second and third digits). Seen with attempted FLEXION of digits, where 2nd and 3rd digits are left extended * "Ape Hand" (thenar eminence atrophy and loss and thenar opposition) * paresthesia and/or pain along median nerve