Intercornual ligament
Ligamentum intercornuale
A small ligament on each side at the back of the sacrococcygeal joint, joining the cornu of the sacrum to the cornu of the coccyx.
At a glance
- English
- Intercornual ligament
- Latin (TA2)
- Ligamentum intercornuale
- System
- Ligament
- Region
- Abdomen
- Side
- Paired, left and right
About the intercornual ligament
At the lower end of the back of the sacrum, the sacral canal opens as the sacral hiatus, and on either side of this opening the bone projects downwards as a small rounded process, the sacral cornu. Facing it from below, the first coccygeal vertebra sends up a matching process, the coccygeal cornu. These cornua are the remnants of the articular processes that join one vertebra to the next higher up the column. The intercornual ligament is the short fibrous band that joins the two cornua on each side.
Because the cornua stand in for articular processes, the ligament can be thought of as the remains of a small joint capsule. It forms part of the ligamentous ring around the sacrococcygeal joint, together with the anterior, posterior and lateral sacrococcygeal ligaments and a small intervertebral disc. Between the cornua and the lateral sacrococcygeal ligament a gap remains on each side through which the fifth sacral nerve passes out.
The ligament is small and has received little detailed study, so its exact extent is not well described. It helps steady the coccyx on the sacrum and limit its bending forwards and backwards, movements that occur when sitting down and during straining.
The cornua and the ligaments around them are practical landmarks. Feeling the two sacral cornua guides a needle into the sacral hiatus for a caudal epidural injection, the hiatus lying between them. Injury to the joint and its ligaments from a fall onto the buttocks is a common cause of coccydynia, pain at the tip of the spine that is worse on sitting.
Attachments and function
- Attaches from
- The sacral cornu, beside the sacral hiatus.
- Attaches to
- The coccygeal cornu of the first coccygeal vertebra on the same side.
- Function
- Joins the sacral and coccygeal cornua and helps steady the coccyx on the sacrum at the sacrococcygeal joint.
Anthromica
See the intercornual ligament where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
