Anatomy & Organs

Lumbar vertebrae – structure, function & diseases

Lumbar vertebrae

The five lumbar vertebrae ( vertebrae lumbales ) of the human body form part of the spine. Since the lumbar spine has to bear a particular burden due to the weight and mobility of the trunk, damage or impairments to the lumbar vertebrae often lead to massive pain.

What are lumbar vertebrae?

The human lumbar spine consists of five lumbar vertebrae and is located in the lower part of the spine. It begins under the thoracic spine and runs to the sacrum ( Os sacrum ). Compared to the other vertebrae of the spine, the lumbar vertebrae are larger and all have a similar basic shape resembling a bean.They are numbered from one to five from cranial (that is, from above or toward the head) to caudal (that is, down, toward the feet). The fifth lumbar vertebra can be fused with the first vertebra of the sacrum, which is called sacralization. When viewed from the side, the spine is slightly curved. This curvature is called lordosis in a normal condition. An increased curvature leads to a hollow back or a so-called hyperlordosis . The opposite of this is the flat back .

Anatomy & Structure

Each lumbar vertebra consists of a lumbar vertebral body ( corpus vertebrae ), the lumbar arch ( arcus vertebrae ), four small vertebral joints, the spinous process ( processus spinosus ), the transverse process ( processus transversus ), and the vertebral foramen ( foramen vertebrale ). The vertebral arch is connected to the vertebral body by two strong feet, the pediculi arcus vertebrae . Together, the vertebral body and vertebral arch form the vertebral hole. The spinous process sits on the vertebral arch, the auxiliary process ( processus accessorius) arises from below the vertebral arch and occurs only in the lumbar vertebrae. 

In addition, there are four articular processes ( processus articularis superior and cranialis as well as processus articularis inferior and caudalis ) on both sides of the vertebral arch at the top and bottom , which allow a flexible connection to the vertebrae above and below. The teat process ( processus mamillaris ) is also located to the side of the upper articular process). On both sides of the lumbar vertebrae is the transverse process, which is comparatively long in the lumbar vertebrae. The vertebral foramina of adjacent vertebral bodies together with the vertebral arches form a bony canal, the spinal canal, which is also known as the spinal cord or spinal canal. There are also openings between adjacent vertebral bodies through which the spinal cord nerves can exit.

Function & Tasks

The lumbar spine is responsible for bearing the entire trunk load and passes this weight on to the sacrum. It stabilizes the torso and enables upright standing. The lumbar spine can be moved in different directions and thus enables different movement sequences. Mainly bending and recovery movements as well as movements to the side are possible.

Flexion and extension are possible with a healthy lumbar spine of 70 degrees. A tilt of 25 degrees to the side is possible. Due to the structure of the vertebral bodies and the position of the vertebral joints, rotational movements are only possible to a limited extent. The ability to rotate is therefore only about two degrees. Spinal mobility decreases with age.

The intervertebral discs ( Disci intervertebrales ) between the individual lumbar vertebrae have a buffering function. The lumbar vertebrae are surrounded by the lumbar muscles, which they offer attachment points. The muscles wrap around the spinous processes laterally. The lumbar spine cooperates with and is supported by the back muscles in their functions. The lumbar vertebrae, together with the intervertebral discs and the muscles, protect the spinal canal with the spinal cord with nerves and vessels running in it. The spinal cord ends in the adult human body at about the level of the second lumbar vertebra. Below it run spinal nerve roots arranged like a horse’s tailCauda equina . The intervertebral foramen or intervertebral foramen located between two vertebrae allows the respective spinal nerves to pass through.

Diseases & Ailments

Back pain often affects the lumbar region of the spine, as the lumbar spine is exposed to the greatest stress. The lumbar spine syndrome, LWS syndrome for short, summarizes back problems with a wide variety of causes. It comes to local, mostly dull and pulling back pain, which can radiate into the coccyx and the legs.Depending on the cause, the pain can be acute or chronic. In the case of a lumbago , which is also known colloquially as lumbago, acute low back pain occurs. Severe reflex muscle tension leads to restricted movement of the lumbar vertebrae and severe pain. A lumbago often occurs after lifting heavy loads, bending over or jerky movements, but it can also be caused by a previous bad posture.

Chronic low back pain can occur as a result of poor posture , inflammatory changes such as Bechterew’s disease or an increasing reduction in the size of the intervertebral spaces. Spondylarthrosis , which involves changes in the vertebral joints, can also lead to chronic back pain in the lumbar region.

Damage to the discs between the lumbar vertebrae can lead to a herniated disc , in which disc tissue compresses nerves or parts of the spinal cord, causing pain. A herniated disc is characterized by the pain radiating down the leg.

Severe contusion of the cauda equina, for example due to a herniated disc, leads to neurological deficits. In the case of spinal stenosis, the spinal canal is narrowed, and in the case of spondylolisthesis , interruptions in the vertebral arches cause instability of the lumbar vertebrae to the point of vertebral slippage. Scheuermann ‘s disease is a growth disorder of the spine that can lead to painful incorrect posture. Back pain rarely occurs due to tumor diseases .

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.