Abstract
A variety of surgical specialties use different abdominal wall incisions to access the abdominal cavity. A thorough understanding of the anatomy, distribution, communication and course of these nerves are essential for surgeons. Anatomical knowledge remains limited. The anatomic relationships to other landmarks such as bone structures, ligaments, and muscles are important in prevention of peri-operative complications such as abdominal muscle weakness, flank bulge, and incisional hernias. Imaging modalities do not provide many details about abdominal wall nerves.
The goal of this study is to provide a better understanding of the directions, course, communications, and branches of abdominal muscle wall nerves in order to minimize the risk of nerve injury.
Four frozen-preserved cadavers with no abdominal wall scars visible were dissected layer by layer. The ninth, tenth, eleventh, and twelfth intercostal nerves were dissected from the midline to the posterior axillary line.
The ninth, tenth, eleventh, and twelfth thoracolumbar nerves run in the same plane, between the internal oblique muscle and the transverse muscle, with varying directions and course. The T9 intercostal nerve has a horizontal course between the muscles, whereas the T10 and T11 and T12 have an oblique course toward the midline. Eleventh intercostal nerve, and twelfth subcostal nerves are bigger compared to the other nerves, with several communications and branches.
The anatomy of nerves in abdominal muscles appears to be more complex and variable. Eleventh intercostal nerve and twelfth subcostal nerves appear to have larger contribution to the abdominal wall muscle innervation. They have a complex and variable network of communication. Preserving these nerves during surgical incisions, operation, and closure could help in the prevention of postoperative abdominal wall complications.