Lumbosacral

Lumbosacral is an anatomical term that refers to the region where the lumbar spine meets the sacrum. It is used to describe structures, conditions, or procedures associated with the lower back and the base of the spine.

Anatomy: The lumbar spine contains five vertebrae (L1–L5). The sacrum is a triangular bone formed by fused S1–S5 vertebrae. The lumbosacral junction is at L5–S1, where the mobile lumbar spine articulates with the sacrum. The sacroiliac joints connect the sacrum to the pelvic bones. The lumbosacral plexus is formed by the ventral rami of L1–S4, providing motor and sensory innervation to the lower abdomen, pelvis, and lower limbs; the lumbosacral trunk (L4–L5) links the lumbar and sacral plexuses.

Clinical relevance: This region is a common source of axial low back pain and radicular symptoms. Conditions frequently affecting the lumbosacral area include lumbosacral strain, degenerative disc disease and spondylosis at L4–L5 or L5–S1, and disc herniation with possible compression of the L5 or S1 nerve roots. Anatomical variants such as lumbosacral transitional vertebrae can also be encountered.

Evaluation and imaging: Diagnosis is based on history and physical examination, supported by imaging. Plain radiographs assess alignment and instability; magnetic resonance imaging (MRI) is preferred for evaluating discs, nerves, and soft tissues; computed tomography (CT) offers detailed bone visualization and is useful in preoperative planning or complex fractures.

Treatment: Most lumbosacral complaints respond to conservative management, including physical therapy, activity modification, and nonsteroidal anti-inflammatory drugs. Injections (such as epidural or facet injections) may be considered for pain relief. Surgical options, when indicated, include decompression or fusion procedures at the lumbosacral junction (commonly L5–S1) to stabilize the spine or relieve nerve compression.