Lumbosacral joint

A critical junction that connects the lumbar spine to the sacrum, providing stability and mobility to the lower back.

The lumbosacral joint is the transitional area between the lumbar vertebrae (specifically the fifth lumbar vertebra, L5) and the sacrum, which is part of the pelvic bone. This joint plays an essential role in supporting body weight and facilitating movement by allowing a range of motion that includes flexion, extension, and some rotation.

Terminologia Anatomica

articulatio lumbosacralis

System

Musculoskeletal system

Function

The primary function of the lumbosacral joint is to ensure efficient transmission of forces between the upper and lower body while maintaining structural integrity. It allows for flexibility during movements such as bending and twisting, which are crucial for everyday activities. The joint also contributes to maintaining posture by balancing the weight of the body above it, reducing stress on the spinal column as well as the surrounding muscles and ligaments. The unique anatomical structure of the lumbosacral joint enables it to absorb impact and reduce shock during activities like walking, running, or jumping, providing a vital role in overall mobility and stability.

Location

The lumbosacral joint is located in the lower back region of the body, at the junction of the lumbar spine and the sacrum. Specifically, it is situated where the L5 vertebra, the last vertebra of the lumbar spine, meets the sacral base. This joint is positioned slightly above the area where the pelvis connects to the spine, making it a key point in the body’s alignment. It is surrounded by important ligaments and muscles that both stabilize and support movement, and it is in close proximity to the sciatic nerve, which extends down the back of each leg.

Did You Know?

The lumbosacral joint is a common site for lower back pain due to its critical role in load-bearing and its exposure to strain from various activities.
The angle of the lumbosacral joint can influence posture, with an increased angle often associated with excessive lordosis or swayback.
Injury or degeneration of the lumbosacral joint can lead to conditions such as sciatica, which is characterized by pain radiating down the leg.