The Spine and Pelvis: Structured as a Functional Unit
The lumbar spine, sacroiliac joint, and pelvis work closely together. Problems in any one of these areas affect overall posture and movement coordination. That is why, when treating back pain, it is important not only to examine individual structures but also to take a holistic view of how the spine, pelvis, joints, and muscles interact.
Structure of the Spine
The human spine consists of 24 vertebrae and is divided into three sections: the cervical spine with seven vertebrae, the thoracic spine with twelve, and the lumbar spine with five. Wear and tear, improper strain, or sudden overexertion can frequently lead to lumbago (nonspecific back pain), facet joint osteoarthritis, or herniated discs. In the case of a herniated disc, the disc can press on nerve structures and cause pain that radiates into the buttocks or legs.
Spine and spinal cord
With the exception of the two upper cervical vertebrae, each of these vertebrae consists of a vertebral body at the front and a vertebral arch at the back. They enclose a large opening: the vertebral foramen. Together, the vertebral foramina form the vertebral canal (or spinal canal), through which the spinal cord and its nerves pass. On both sides of the vertebral arch of each vertebra are an upper and a lower articular process.
The intervertebral discs are located between the vertebral bodies. Thanks to their firm, elastic core and the surrounding firm fibrous ring, they enable the absorption and transmission of applied forces. The vertebral bodies bear these forces due to their box-like shape.
Intervertebral disc view from above
Facet joints between the vertebrae
The inferior articular processes of a vertebra form a zygapophyseal joint with the superior articular processes of the vertebra below, thereby connecting the two vertebrae. Instead of the term “zygapophyseal joint,” the shorter term “vertebral joint” or the term “facet joint” is commonly used. The constant strain from body weight and the wide range of possible movements make the facet joints of the cervical spine (C-spine) and lumbar spine (L-spine) prone to discomfort and wear and tear. This often leads to lower back pain.
The main function of the facet joints is to enable or limit movement in the individual segments of the spine. The articular surfaces of the vertebral joints are slightly oval in shape and about one and a half centimeters wide or high. They are covered by a thin layer of cartilage and surrounded on the outside by a joint capsule made of connective tissue. Inside the joint, as with any other joint, there is a mucous membrane: the synovial membrane. It serves to nourish and lubricate the articular cartilage.
Anatomy of the Pelvis
The Sacroiliac Joint (SIJ): The Connection Between the Spine and the Pelvis
Pelvic, front view
The sacroiliac joint (Articulatio sacroiliaca), or SIJ for short, connects the spine to the pelvis. It is located between the sacrum and the two iliac crests. Other terms for it include the “sacroiliac joint” or “sacroiliac joint” (SIG). Although the SIJ has very limited mobility, it plays a central role in force transmission between the upper body and the legs. Experts refer to these slight movements as nutation and contranutation. For example, during childbirth, the width of the pelvic ring increases due to a nutation movement of the sacroiliac joints, which facilitates the birth of the child.
Although the SIJ is often referred to in the singular in everyday language, there is a left and a right sacroiliac joint. The sacroiliac joints are stabilized by a tight ligamentous apparatus. If a dysfunction occurs, this is referred to as SIJ syndrome. Typical symptoms include deep-seated back pain in the buttock area, which often occurs on one side. The discomfort may worsen when walking, standing, or turning over in bed and is often mistaken for disc problems.
The pelvis and the symphysis
The pelvis forms the bony connection between the spine and the lower extremities. It consists of the sacrum, coccyx, and the hip bones—the ilium, pubis, and ischium. This structure provides stability and distributes stress evenly.
At the front of the pelvis, the symphysis connects the two pubic bones. This cartilaginous joint has minimal mobility but must withstand high tensile forces. Overuse or improper strain can cause symphysis pain that radiates to the groin, lower abdomen, or lower back. For example, pregnant women often suffer from pain in the pubic bone (symphysis pain).
Highlights
The comfort line bandages and orthoses from medi
Comfort line
