The Brachial Plexus Flashcards
What makes up the brachial plexus?
The brachial plexus is made up of the VENTRAL RAMI of cervical and thoracic spinal nerves (C5-T1)
What nerve makes up the anterior compartment of the arm?
Musculocutaneous Nerve (flexors of elbow joint)
What nerve makes up the posterior compartment of the arm?
Radial Nerve (extensors of elbow joint)
What nerves make up the anterior compartment of the forearm and hand?
Ulnar and median nerves
What nerve makes up the posterior compartment of the forearm and hand?
Radial nerve
Sensory deficits of Erb’s Palsy
Lateral aspect of upper limb
Motor deficits of Erb’s Palsy
Loss of arm abduction
Loss of elbow flexion
Loss of forearm supination
Weakness of wrist extenion
Presentation of Erb’s Palsy
Upper limb is adducted, medially rotated and elbow is extended and wrist is flexed (This is the “waiter’s tip” position)
Injuries to Superior Trunk (C5 and C6 Spinal Nerve Roots) can result from:
Excessive, forceful increase in angle between neck and shoulder
Injuries to Inferior Trunk (C8 and T1 Spinal Nerve Roots) can occur when:
Limb is suddenly and/or forcefully pulled in a superior direction
Sensory deficits of Klumpke’s Palsy
Medial aspect of upper limb (except axilla)
Motor deficits of Klumpke’s Palsy
Loss of precision finger movements
Weakness in forearm pronation
Weakness of wrist and finger extension
Weakness of wrist and finger flexion
Presentation of Klumpke’s Palsy
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
Causes of Radial Nerve Injuries (C5-T1 spinal nerve roots)
Can occur with mid-shaft fractures of the humerus
Improper use of crutches
What are the results of radial nerve injuries?
Extensors compartments affected
“Wrist drop”
Paresthesia and/or pain along course of nerve
What’s another name for a radial nerve injury?
Saturday Night Palsy
Causes of Axillary Nerve Injury (C5 and C6 Spinal Nerve Roots)
Can occur with fractures to the surgical neck of the humerus or dislocation of the glenohumeral joint.
Improper use of backpack (Quandrangular space syndrom)
What are the results of axillary nerve injury
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
Causes of Long Thoracic Nerve Injuries (C5, C6, C7 spinal nerve roots)
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
What are the results of the Long Thoracic Nerve (C5, C6, C7 Spinal Nerve Roots)
Serratus anterior is affected
“Winged scapula”, inability to raise arms past 90 degrees
Causes of Ulnar Nerve Injuries (C8, T1, and often C7)
Fracture of medial epicondyle of humerus can damage this nerve.
Fracture of proximal ulna may also result in damage
Slashed wrist (medial side)
What are the results of Ulnar Nerve Damage (C8, T1, and often C7)
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.
Causes of Median Nerve Injuries (C6-T1 Spinal Nerve Roots)
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)
What are the results of Median Nerve Injuries?
Flexors of wrist and digits affected, also intrinsic hand muscles, particularly those that move digit 1
Paresthesia and/or pain along median nerve
Names for Median Nerve Injuries
“Pope’s Blessing”
“Ape hand”
