The Brachial Plexus

Question 1

What makes up the brachial plexus?

Answer 1

The brachial plexus is made up of the VENTRAL RAMI of cervical and thoracic spinal nerves (C5-T1)

Question 2

What nerve makes up the anterior compartment of the arm?

Answer 2

Musculocutaneous Nerve (flexors of elbow joint)

Question 3

What nerve makes up the posterior compartment of the arm?

Answer 3

Radial Nerve (extensors of elbow joint)

Question 4

What nerves make up the anterior compartment of the forearm and hand?

Answer 4

Ulnar and median nerves

Question 5

What nerve makes up the posterior compartment of the forearm and hand?

Answer 5

Radial nerve

Question 6

Sensory deficits of Erb’s Palsy

Answer 6

Lateral aspect of upper limb

Question 7

Motor deficits of Erb’s Palsy

Answer 7

Loss of arm abduction
Loss of elbow flexion
Loss of forearm supination
Weakness of wrist extenion

Question 8

Presentation of Erb’s Palsy

Answer 8

Upper limb is adducted, medially rotated and elbow is extended and wrist is flexed (This is the “waiter’s tip” position)

Question 9

Injuries to Superior Trunk (C5 and C6 Spinal Nerve Roots) can result from:

Answer 9

Excessive, forceful increase in angle between neck and shoulder

Question 10

Injuries to Inferior Trunk (C8 and T1 Spinal Nerve Roots) can occur when:

Answer 10

Limb is suddenly and/or forcefully pulled in a superior direction

Question 11

Sensory deficits of Klumpke’s Palsy

Answer 11

Medial aspect of upper limb (except axilla)

Question 12

Motor deficits of Klumpke’s Palsy

Answer 12

Loss of precision finger movements
Weakness in forearm pronation
Weakness of wrist and finger extension
Weakness of wrist and finger flexion

Question 13

Presentation of Klumpke’s Palsy

Answer 13

Primary clinical sign is “claw-hand”, and there may also be wasting of intrinsic hand muscles. Seen with attempted extension of digits, leaving 4th and 5th digits flexed

Question 14

Causes of Radial Nerve Injuries (C5-T1 spinal nerve roots)

Answer 14

Can occur with mid-shaft fractures of the humerus

Improper use of crutches

Question 15

What are the results of radial nerve injuries?

Answer 15

Extensors compartments affected
“Wrist drop”
Paresthesia and/or pain along course of nerve

Question 16

What’s another name for a radial nerve injury?

Answer 16

Saturday Night Palsy

Question 17

Causes of Axillary Nerve Injury (C5 and C6 Spinal Nerve Roots)

Answer 17

Can occur with fractures to the surgical neck of the humerus or dislocation of the glenohumeral joint.
Improper use of backpack (Quandrangular space syndrom)

Question 18

What are the results of axillary nerve injury

Answer 18

Can result in impaired or lost function of deltoid and teres major
Patient would be unable to fully abduct their arm, and may have a diminished ability to laterally rotate arm.
Paresthesia and/or pain along course of nerve

Question 19

Causes of Long Thoracic Nerve Injuries (C5, C6, C7 spinal nerve roots)

Answer 19

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

Question 20

What are the results of the Long Thoracic Nerve (C5, C6, C7 Spinal Nerve Roots)

Answer 20

Serratus anterior is affected

“Winged scapula”, inability to raise arms past 90 degrees

Question 21

Causes of Ulnar Nerve Injuries (C8, T1, and often C7)

Answer 21

Fracture of medial epicondyle of humerus can damage this nerve.
Fracture of proximal ulna may also result in damage
Slashed wrist (medial side)

Question 22

What are the results of Ulnar Nerve Damage (C8, T1, and often C7)

Answer 22

Damage will involve flexors of wrist, digits, and intrinsic hand muscles
Radial deviation of 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 23

Causes of Median Nerve Injuries (C6-T1 Spinal Nerve Roots)

Answer 23

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)

Question 24

What are the results of Median Nerve Injuries?

Answer 24

Flexors of wrist and digits affected, also intrinsic hand muscles, particularly those that move digit 1
Paresthesia and/or pain along median nerve

Question 25

Names for Median Nerve Injuries

Answer 25

“Pope’s Blessing”

“Ape hand”