Nerve
Intercostal nerves
Segmental nerves supplying the chest and abdominal walls
High-yield
In the main bundle, the nerve lies below the artery and vein. T4 near the nipple and T10 near the umbilicus are approximate dermatome landmarks, with overlap and individual variation.
Overview
Thoracic anterior rami T1–T11 form the intercostal nerves. They supply muscles and sensation in the trunk; the lower nerves continue beyond the rib cage into the abdominal wall. T12 travels below the last rib as the subcostal nerve.
Reference facts
- Root value
- Thoracic anterior rami T1–T11; T12 forms the subcostal nerve
- Course
- Cross the rib spaces mainly between internal and innermost intercostals, near the costal groove
- Motor
- Intercostal muscles; lower thoracic branches also supply abdominal-wall muscles
- Sensory
- Segmental trunk skin and relevant parietal pleura; lower branches also carry abdominal-wall and parietal peritoneal sensation
Clinical correlation
Thoracic shingles or injury to an intercostal nerve can produce band-like pain or altered sensation. The distribution helps localize a possible nerve problem but does not exclude other causes of chest pain.
Frequently asked questions
What are the roots of the intercostal nerves?
Thoracic anterior rami T1–T11; T12 forms the subcostal nerve.
What muscles do the intercostal nerves supply?
Intercostal muscles; lower thoracic branches also supply abdominal-wall muscles.
What is the sensory distribution of the intercostal nerves?
Segmental trunk skin and relevant parietal pleura; lower branches also carry abdominal-wall and parietal peritoneal sensation.
What is the course of the intercostal nerves?
Cross the rib spaces mainly between internal and innermost intercostals, near the costal groove.