rami communicantes

Introduction

Communicating branches that connect each intercostal nerve to the ipsilateral sympathetic trunk.

Sympathetic nerve fibers are distributed through all branches of the intercostal nerves to blood vessels, sweat glands & smooth muscle.

The fibers passing from the ganglion to the spinal nerve are nonmyelinated & are called gray rami communicantes & those passing in the reverse direction are myelinated & are called white rami communicantes.

In addition to the rami communicantes, branches of the intercostal nerve include:

• collateral branches:
  • arise near the angles of the ribs & help to supply the intercostal muscles

• lateral cutaneous branches:
  • arise beyond the angles of the ribs & pierce the internal & external intercostal muscles approximately halfway around the thorax
  • division of the lateral cutaneous branches in turn results in:
    • anterior & posterior branches that supply the skin of the thoracic & abdominal walls

• anterior cutaneous branches:
  • supply the skin on the anterior aspect of the thorax & abdomen
  • after penetrating the muscles & membranes of the intercostal space in the parasternal line, division of the anterior cutaneous branches in turn results in
    • medial & lateral branches

• muscular branches:
  • supply the intercostal, subcostal, transversus thoracis, levatores costarum, & serratus posterior muscles.

More general terms

• peripheral nerve

More specific terms

• gray rami communicantes
• white rami communicantes

Additional terms

• autonomic nervous system
• peripheral nervous system
• sympathetic nervous system