The lateral pectoral nerve (LPN) sub serves the proximal two thirds of the pectoralis major muscle. It does not contain cutaneous sensory fibers. Clinical findings of lateral pectoral nerve injury include asymmetry of chest wall associated with atrophy and weakness of the pectoralis major muscle. Mononeuropathy of the lateral pectoral nerve occurs less frequently. In this report we present two cases of progressive atrophy and weakness of the clavicular part of pectoralis major muscle innervated by lateral pectoral nerve.
A twenty-six years old man, who had progressive atrophy of the right clavicular portion of pectoralis major muscle accompanied by pain on the right chest and shoulder for three months, was referred to our neurology outpatient clinic. He was a worker of an automotive plant. He had been working in a leaning position at a narrow place with his right arm stretched out.