Nerve Roots Involved in Erb's and Klumpke's Palsy
Erb's palsy (Erb-Duchenne palsy) involves the C5 and C6 nerve roots, while Klumpke's palsy (Klumpke's paralysis) involves the C8 and T1 nerve roots of the brachial plexus.
Erb's Palsy (Erb-Duchenne Palsy)
- Affects the upper trunk of the brachial plexus
- Involves cervical nerve roots C5 and C6 1
- Clinical presentation:
- Arm hangs limply from the shoulder
- Flexion of the wrist and fingers
- Weakness of muscles innervated by C5 and C6 2
- "Waiter's tip" posture (arm adducted and internally rotated, extended elbow, pronated forearm)
- Preserved hand function
Klumpke's Palsy (Klumpke's Paralysis)
- Affects the lower trunk of the brachial plexus
- Involves cervical nerve root C8 and thoracic nerve root T1 3, 4
- Clinical presentation:
- Paralysis of the intrinsic hand muscles
- Weakness of forearm flexors
- "Claw hand" deformity
- May be associated with Horner's syndrome if T1 sympathetic fibers are affected 4
Anatomical Considerations
The brachial plexus is formed from the ventral rami of C5 to T1 nerve roots 5:
- These nerve roots pass between the anterior and middle scalene muscles
- They form trunks that split into anterior and posterior divisions
- The divisions form cords that travel with the subclavian vessels
- Terminal branches form at the lateral margin of the pectoralis minor muscle
Diagnostic Evaluation
- MRI is the mainstay of plexus imaging 5
- Findings may include:
- Meningeal stretch
- Pseudomeningoceles (predictive finding of brachial plexus injury)
- Direct visualization of nerve root avulsion 3
- Electrophysiological testing is essential to complement imaging findings 3
Clinical Pearls
- Erb's palsy has a higher incidence (0.9-2.6 per 1000 live births) 2
- Klumpke's palsy is much rarer
- Recovery rates for Erb's palsy are 80-96%, especially if improvement begins in the first two weeks 2
- Both conditions can occur from obstetrical trauma but may also result from other injuries
- Complete avulsion of all roots (C5-T1) results in a "flail arm" or "flail upper limb" 1
Common Pitfalls
- Relying solely on MRI for diagnosis without clinical and electrophysiological correlation 3
- Delayed referral for surgical intervention when indicated
- Failure to distinguish between different types of brachial plexus injuries
- Overlooking associated conditions like Horner's syndrome in Klumpke's palsy
Understanding the specific nerve root involvement is crucial for proper diagnosis, prognosis assessment, and treatment planning in these brachial plexus injuries.