The left and right supraspinous ligaments extend from the ischial spines to the sacrum and coccyx
The sacral part of the supraspinous ligament is the caudal end of the supraspinous ligament, that connects the spinous processes from the seventh spinous process to the coccyx
The sacral part of the supraspinous ligament covers the sacral hiatus – the caudal opening of the vertebral canal
The caudal block is performed by inserting the needle through the supraspinous ligament into the sacral hiatus
Sacral part of the suprapinous ligament (blue asterix); left sacrospinous ligament (magenta asterix); right sacrospinous ligament (red asterix)
