SEARCH RESULTS FOR: Brachial-Plexus-Injury

Brachial Plexus Injury

**See corresponding Calgary Guide slide Legend: Brachial Plexus Injury: Pathophysiology and clinical findings High impact collision (ex. motorcycle accidents, sports) Fetal complications during labor & delivery** (ex. shoulder dystocia) Author: Merry Faye Graff Reviewers: Taylor Krawec Emily J. Doucette Jean K. Mah* *Indicates MD at time of publication Upward traction of arm with forced widening of scapulohumeral angle (lower brachial plexus injured first) Downward traction of arm with forced widening of shoulder-neck angle (upper brachial plexus injured first) Surgical trauma Direct trauma (i.e. gunshot wound, penetrating injuries) Pancoast tumour** Nerves are stretched or torn Nerves are severed or crushed Brachial Plexus Injury Damage to brachial plexus nerves that may cause weakness, decreased sensation or loss of movement in the shoulder, arm or hand Injury or compression demyelinates nerves without causing axonal injury (neuropraxia) Injury demyelinates nerves & severs axons (axonotmesis) Injury completely transects nerves (neurotmesis) Demyelination slows & disrupts nerve signal conduction Basal lamina tubes (axon scaffolds) are preserved Basal lamina tubes are severed Nerves are torn proximal to attachment at spine (post-ganglionic rupture) Nerve roots are torn from spinal cord (pre-ganglionic avulsion) ↓ Efferent signals (motor) ↓ Afferent signals (sensory) Inflammatory mediators sensitize primary afferent neurons Abnormal ectopic firing of nerves at or near nerve lesion Neuroma (benign growth or thickening of nerve tissue at lesion) during healing Breakdown of axon(s) & myelin distal to nerve lesion (Wallerian degeneration) Connection to central nervous system (CNS) lost Muscle weakness or loss of function in affected myotomes Paresthesia (numbness or tingling) in affected dermatomes Hyperalgesia (extreme sensitivity to touch) Neuropathic pain (burning, stabbing, electric-like pain) Neuroma blocks distal nerve conduction No conduction in affected nerves or nerve roots Repeated pain signals sensitize CNS Afferent signals are not transduced Efferent signals are not transduced Paravertebral sympathetic chain is disrupted (if C8 & T1 involved) Central sensitization Numbness Paralysis Horner’s syndrome** Shortening & hardening of muscles & tendons ↓ Muscle use Widespread pain Allodynia (normal touch perceived as painful) Contractures Muscle atrophy Note: Specific signs & symptoms vary based on nerves affected. Complications Published May 14, 2025 on www.thecalgaryguide.com Pathophysiology Mechanism Sign/Symptom/Lab Finding