• A 1-day-old boy is noted by his parent that his arm is in an abnormal position. The boy was born to a 27-year-old woman at 38 weeks gestation via spontaneous vaginal delivery. The birth was complicated by shoulder dystocia. On physical exam, the newborn's right arm is adducted and internally rotated with forearm extension. The hand and wrist movements are preserved in the affected arm. (Erb palsy secondary to C5-C6 injury)
Brachial Plexus Lesions
Lesion Location
Etiology Clinical Presentation
Erb palsy
  • C5-C6 roots
    • negatively affects the deltoid and biceps brachii muscle
  • C7 can occasionally be involved
  • Trauma leading to separation of the head and neck
    • e.g., lateral neck traction during birth delivery
traction on neck
during delivery

  • "Waiters tip"
    • internal rotation, adduction, and extension of the arm
      • if C7 is involved there will be flexion of the wrist and fingers
  • Atrophy and weakness of the
    • deltoid
    • biceps brachii
Klumpke palsy
  • C8-T1 roots
    • negatively affects the intrinsic muscles of the hand
  • Upward force exerted on the arm when 
    • delivering a newborn
    • grabbing a tree branch in an attempt to prevent a fall
  • "Claw hand"
    • extension at the metacarpophalangeal (MCP) joints and flexion at the distal interphalangeal (DIP) and PIP joints
      • secondary to impaired function of the lumbricals of the hand
Thoracic outlet syndrome
  • Compression of neurovascular structures in the thoracic outlet
    • classically involved C8-T1
  • Pancoast tumor 
  • Cervical rib
  • Neurogenic thoracic outlet syndrome
    • pain, numbness, and weakness in the affected nerves worsened when elevating the arms above the head (e.g., brushing hair)
Winged scapula 
  • Long thoracic nerve
    • negatively affects the serratus anterior muscle
  • Injury to the long thoracic nerve
    • neuralgic amyotrophy
    • direct trauma to the shoulder or lateral chest wall (e.g., playing football)
    • surgery
      • breast surgery with axillary lymph node dissection
  • Projecting of the affected scapula while the patient presses against the wall

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