Abstract: Objective　To proceed the anatomical research on the ligaments in the exit regions of the T1~12 intervertebral foramina and to discuss its possible clinical significance.   Methods    Two hundred and forty T1~12 intervertebral foramina from 10 adult cadavers were dissected and observed. All the ligaments that appeared were identified. The number, morphology, distribution, starting and ending position and the adjacency of the ligaments were observed and recorded. The length, width and thickness of each ligament were measured by vernier calipers.    Results    564 extra-foramina ligaments were found in 229 intervertebral foramina, while there were no ligaments in the remaining 11 intervertebral foramina. The occurrence rate of extra-foramina ligaments was 95.42%. There were two types of ligaments: radiating ligaments accounting for 24.11%（136 cases) and transverse ligaments accounting for 75.89% (428 cases). It was relatively common for the radiating ligaments in the segment of T1 and T9~12, but sparse in the segment of T2~8. Of these, 43.44% ligaments (245 cases) were located in the anterior part of the exit regions of the intervertebral foramina, 39.89% ligaments (225 cases) in the posterior, 11.35% ligaments (64 cases) in the upper part, 5.32% ligaments (30 cases) in the bottom part.   Conclusions    There are two types of ligaments in the exit regions of thoracic intervertebral foramina. The radiating ligament may be a kind of protective mechanism against traction, which can fix and protect the spinal nerve. Transverse ligaments may be one of the potential causes of rib or chest pain after thoracic compression fracture.

Key words: Extra-foramina ligaments,  ,  , T_1~12 intervertebral foramina,  ,  , Anatomy,  ,  , Non-midline pain