# Lumbar vertebrae > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Lumbar_vertebrae > Markdown URL: https://mediated.wiki/source/Lumbar_vertebrae.md > Source: https://en.wikipedia.org/wiki/Lumbar_vertebrae > Source revision: 1329130605 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Five bones of the spine in the lower back Lumbar vertebrae Position of human lumbar vertebrae (shown in red). It consists of 5 bones, from the top down, L1, L2, L3, L4 and L5. Animation of L1 Details Insertions Psoas major muscle Nerve Lumbar nerves Identifiers Latin vertebrae lumbales MeSH D008159 TA98 A02.2.04.001 TA2 1068 FMA 9921 Anatomical terms of bone [edit on Wikidata] The **lumbar vertebrae** are located between the [thoracic vertebrae](/source/Thoracic_vertebrae) and [pelvis](/source/Pelvis). They form the lower part of the [back](/source/Human_back) in humans, and the tail end of the back in [quadrupeds](/source/Quadrupeds)[*[clarification needed](https://en.wikipedia.org/wiki/Wikipedia:Please_clarify)*]. In humans, there are five lumbar vertebrae. The term is used to describe the anatomy of humans and quadrupeds, such as horses, pigs, or cattle. [*[clarification needed](https://en.wikipedia.org/wiki/Wikipedia:Please_clarify)*] These bones are found in particular cuts of meat, including tenderloin or sirloin steak. ## Human anatomy In human anatomy, the five lumbar [vertebrae](/source/Vertebrae) are between the [rib cage](/source/Human_rib_cage) and the [pelvis](/source/Human_pelvis). They are the largest segments of the [vertebral column](/source/Human_vertebral_column) and are characterized by the absence of the [foramen transversarium](/source/Foramen_transversarium) within the transverse process (since it is only found in the [cervical region](/source/Cervical_vertebrae)) and by the absence of facets on the sides of the body (as found only in the [thoracic region](/source/Thoracic_vertebrae)). They are designated L1 to L5, starting at the top. The lumbar vertebrae help support the weight of the body, and permit movement. ### General characteristics Lumbar vertebrae The adjacent figure depicts the general characteristics of the first through fourth lumbar vertebrae. The fifth vertebra contains certain peculiarities, which are detailed below. As with other vertebrae, each lumbar vertebra consists of a *vertebral body* and a *vertebral arch*. The vertebral arch, consisting of a pair of *pedicles* and a pair of *laminae*, encloses the *vertebral foramen* (opening) and supports seven [processes](/source/Process_(anatomy)). #### Body The [vertebral body](/source/Vertebral_body) of each lumbar vertebra is kidney shaped, wider from side to side than from front to back, and a little thicker in front than in back. It is flattened or slightly concave above and below, concave behind, and deeply constricted in front and at the sides.[1] #### Arch The [pedicles](/source/Pedicle_of_vertebral_arch) are very strong, directed backward from the upper part of the vertebral body; consequently, the inferior vertebral notches are of considerable depth.[1] The pedicles change in morphology from the upper lumbar to the lower lumbar. They increase in [sagittal](/source/Sagittal_plane) width from 9 mm to up to 18 mm at L5. They increase in angulation in the axial plane from 10 degrees to 20 degrees by L5. The pedicle is sometimes used as a portal of entrance into the vertebral body for fixation with pedicle screws or for placement of [bone cement](/source/Bone_cement) as with [kyphoplasty](/source/Kyphoplasty) or vertebroplasty. The [laminae](/source/Lamina_of_the_vertebral_arch) are broad, short, and strong.[1] They form the posterior portion of the vertebral arch. In the upper lumbar region the lamina are taller than wide, but in the lower lumbar vertebra the lamina are wider than tall. The lamina connects the spinous process to the pedicles. The [vertebral foramen](/source/Vertebral_foramen) within the arch is triangular, larger than the [thoracic vertebrae](/source/Thoracic_vertebrae), but smaller than in the [cervical vertebrae](/source/Cervical_vertebrae).[1] #### Processes The [spinous process](/source/Spinous_process) is thick, broad, and somewhat quadrilateral; it projects backward and ends in a rough, uneven border, thickest below where it is occasionally notched.[1] The superior and inferior [articular processes](/source/Articular_process) are well-defined, projecting respectively upward and downward from the junctions of pedicles and laminae. The facets on the superior processes are concave, and look backward and [medialward](/source/Anatomical_terms_of_location#Relative_directions); those on the inferior are convex, and are directed forward and lateralward. The former are wider apart than the latter since in the articulated column, the inferior articular processes are embraced by the superior processes of the subjacent vertebra.[1] The [transverse processes](/source/Transverse_process) are long and slender. They are horizontal in the upper three lumbar vertebrae and incline a little upward in the lower two. In the upper three vertebrae they arise from the junctions of the pedicles and laminae, but in the lower two they are set further forward and spring from the pedicles and posterior parts of the vertebral bodies. They are situated in front of the articular processes instead of behind them as in the thoracic vertebrae, and are [homologous](/source/Homology_(biology)) with the ribs.[1] Three portions or *tubercles* can be noticed in a transverse process of a lower lumbar vertebrae: the lateral or [costiform process](/source/Costiform_process), the [mammillary process](/source/Mammillary_process), and the [accessory process](/source/Accessory_process).[2] The costiform is lateral, the mammillary is superior (cranial), and the accessory is inferior (caudal). The mammillary is connected in the lumbar region with the back part of the superior articular process.[*[clarification needed](https://en.wikipedia.org/wiki/Wikipedia:Please_clarify)*] The accessory process is situated at the back part of the base of the transverse process. The tallest and thickest costiform process is usually that of L5.[2] ### First and fifth lumbar vertebrae The fifth lumbar vertebra from above The first lumbar vertebra is level with the anterior end of the [ninth rib](/source/Ninth_rib). This level is also called the important [transpyloric plane](/source/Transpyloric_plane), since the [pylorus](/source/Pylorus) of the stomach is at this level. Other important structures are also located at this level. They include fundus of the gall bladder, celiac trunk, superior mesenteric artery, termination of spinal cord, beginning of [filum terminale](/source/Filum_terminale), renal vessels, middle suprarenal arteries, and [hila of kidneys](/source/Renal_hilum). The fifth lumbar vertebra is characterized by its body being much deeper in front than behind, which accords with the prominence of the sacrovertebral articulation; by the smaller size of its spinous process; by the wide interval between the inferior articular processes, and by the thickness of its transverse processes, which spring from the body as well as from the pedicles.[1] The fifth lumbar vertebra is by far the most common site of [spondylolysis](/source/Spondylolysis) and [spondylolisthesis](/source/Spondylolisthesis).[3] Most individuals have five lumbar vertebrae, while some have four or six. Lumbar disorders that normally affect L5 will affect L4 or L6 in these latter individuals. ### Segmental movements The range of segmental movements in a single segment is difficult to measure clinically, not only because of variations between individuals, but also because it is age and sex dependent. Furthermore, flexion and extension in the lumbal spine is the product of a combination of rotation and translation in the sagittal plane between each vertebra.[4] Ranges of segmental movements in the lumbar spine are (in degrees):[5] L1-L2 L2-L3 L3-L4 L4-L5 L5-S1 Flexion/ Extension 12° 14° 15° 16° 17° Lateral flexion 6° 6° 8° 6° 3° Axial rotation 2° 2° 2° 2° 1° ### Congenital anomalies Main article: [Congenital vertebral anomaly](/source/Congenital_vertebral_anomaly) [Congenital vertebral anomalies](/source/Congenital_vertebral_anomaly) can cause compression of the [spinal cord](/source/Spinal_cord) by deforming the vertebral canal or causing instability. - Lumbarization of [sacral vertebra 1](/source/Sacrum), seen as 6 vertebrae that do not connect to [ribs](/source/Ribs). - Sacralization of the L5 vertebra is seen at the lower right of the image. - Congenital block vertebra of the lumbar spine. CT volume rendering. ## Other apes African apes have three and four lumbar vertebrae, ([bonobos](/source/Bonobo) have longer spines with an additional vertebra) and humans normally five. This difference, and because the lumbar spines of the extinct *[Nacholapithecus](/source/Nacholapithecus)* (a [Miocene](/source/Miocene) hominoid with six lumbar vertebrae and no tail) are similar to those of early *[Australopithecus](/source/Australopithecus)* and early *Homo*, it is assumed that the [chimpanzee–human last common ancestor](/source/Chimpanzee%E2%80%93human_last_common_ancestor) also had a long vertebral column with a long lumbar region and the reduction in the number of lumbar vertebrae evolved independently in each ape [clade](/source/Clade).[6] The limited number of lumbar vertebrae in [chimpanzees](/source/Chimpanzee) and [gorillas](/source/Gorilla) result in an inability to [lordose](/source/Lordosis) (curve) their lumbar spines, in contrast to the spines of [Old World monkeys](/source/Old_World_monkey) and *Nacholapithecus* and *[Proconsul](/source/Proconsul_(mammal))*, which suggests that the last common ancestor was not "short-backed" as previously believed. [7] ## Additional images ### MRI - MRI lumbar spine with degeneration (sagittal T2 FRFSE) - MRI lumbar spine with degeneration (sagittal T1 FSE) - MRI lumbar spine with degeneration (sagittal FAST STIR) - MRI lumbar spine pre-hemilaminectomy (sagittal T2 FRFSE) - MRI lumbar spine pre-hemilaminectomy (sagittal T1 FSE) - MRI lumbar spine pre-hemilaminectomy (sagittal FAST STIR) - MRI lumbar spine post-hemilaminectomy (sagittal T2 FRFSE) - MRI lumbar spine post-hemilaminectomy (sagittal T1 FSE) - Contrast MRI lumbar spine post-hemilaminectomy (sagittal T1 FSE FS) ### Illustrations - 3D image of a lumbar vertebra - Position of lumbar vertebrae (shown in red). Animation. - Same as the left. Bones around the lumbar vertebrae are shown as semi-transparent. - Shape of lumbar vertebrae (shown in blue and yellow). Animation. - Vertebral column. - Muscles of the iliac and anterior femoral regions. First lumbar vertebra second highest vertebra seen. - Orientation of vertebral column on surface. T3 is at level of medial part of [spine of scapula](/source/Spine_of_scapula). T7 is at [inferior angle of the scapula](/source/Inferior_angle_of_the_scapula). L4 is at highest point of [iliac crest](/source/Iliac_crest). S2 is at the level of [posterior superior iliac spine](/source/Posterior_superior_iliac_spine). Furthermore, C7 is easily localized as a prominence at the lower part of the neck.[8] - Vertebral column - Illustration highlighting lumbar spine. - A lumbar vertebra seen from the side - Ossification of lumbar vertebrae ## See also - [Bertolotti's syndrome](/source/Bertolotti's_syndrome) - [Spinal disc herniation](/source/Spinal_disc_herniation) - [Lumbar spinal stenosis](/source/Lumbar_spinal_stenosis) - [Degenerative disc disease](/source/Degenerative_disc_disease) ## References *This article incorporates text in the [public domain](/source/Public_domain) from [page 104](https://archive.org/stream/anatomyofhumanbo1918gray#page/104/mode/2up) of the 20th edition of* [Gray's Anatomy](/source/Gray's_Anatomy) *(1918)* 1. ^ [***a***](#cite_ref-Gray's_1-0) [***b***](#cite_ref-Gray's_1-1) [***c***](#cite_ref-Gray's_1-2) [***d***](#cite_ref-Gray's_1-3) [***e***](#cite_ref-Gray's_1-4) [***f***](#cite_ref-Gray's_1-5) [***g***](#cite_ref-Gray's_1-6) [***h***](#cite_ref-Gray's_1-7) *[Gray's Anatomy](/source/Gray's_Anatomy)* (1918), see infobox 1. ^ [***a***](#cite_ref-Postacchini99p19_2-0) [***b***](#cite_ref-Postacchini99p19_2-1) Postacchini, Franco (1999) *Lumbar Disc Herniation* [p.19](https://books.google.com/books?id=i-An_XbHpJcC&pg=PA19) 1. **[^](#cite_ref-3)** Eizenberg, N. et al. (2008). *General Anatomy: Principles and Applications*, p. 17. 1. **[^](#cite_ref-4)** Hansen; et al. (2006). ["Anatomy and Biomechanics of the Back Muscles in the Lumbar Spine With Reference to Biomechanical Modeling"](https://web.archive.org/web/20101114135151/http://www.medscape.com/viewarticle/542466_2). *Spine*. **31** (17). Medscape: 1888–99. [doi](/source/Doi_(identifier)):[10.1097/01.brs.0000229232.66090.58](https://doi.org/10.1097%2F01.brs.0000229232.66090.58). [PMID](/source/PMID_(identifier)) [16924205](https://pubmed.ncbi.nlm.nih.gov/16924205). [S2CID](/source/S2CID_(identifier)) [43352264](https://api.semanticscholar.org/CorpusID:43352264). Archived from [the original](http://www.medscape.com/viewarticle/542466_2) on November 14, 2010. 1. **[^](#cite_ref-5)** White, Augustus A.; Panjabi, Manohar M. (1990). *Clinical Biomechanics of the Spine* (2nd ed.). Philadelphia, PA: J.B. Lippincott. p. 107. [ISBN](/source/ISBN_(identifier)) [0-397-50720-8](https://en.wikipedia.org/wiki/Special:BookSources/0-397-50720-8). 1. **[^](#cite_ref-6)** McCollum, MA; Rosenman, BA; Suwa, G; Meindl, RS; Lovejoy, CO (March 15, 2010). "The vertebral formula of the last common ancestor of African apes and humans". *Journal of Experimental Zoology Part B: Molecular and Developmental Evolution*. **314** (2): 123–34. [doi](/source/Doi_(identifier)):[10.1002/jez.b.21316](https://doi.org/10.1002%2Fjez.b.21316). [PMID](/source/PMID_(identifier)) [19688850](https://pubmed.ncbi.nlm.nih.gov/19688850). (Abstract) 1. **[^](#cite_ref-7)** Lovejoy, C. Owen; McCollum, Melanie A. (October 27, 2010). ["Spinopelvic pathways to bipedality: why no hominids ever relied on a bent-hip-bent-knee gait"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2981964). *Philos Trans R Soc Lond B Biol Sci*. **365** (1556): 3289–99. [doi](/source/Doi_(identifier)):[10.1098/rstb.2010.0112](https://doi.org/10.1098%2Frstb.2010.0112). [PMC](/source/PMC_(identifier)) [2981964](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2981964). [PMID](/source/PMID_(identifier)) [20855303](https://pubmed.ncbi.nlm.nih.gov/20855303). (Introduction) 1. **[^](#cite_ref-8)** Anatomy Compendium (Godfried Roomans and Anca Dragomir) ## External links Wikimedia Commons has media related to [Lumbar vertebrae](https://commons.wikimedia.org/wiki/Category:Lumbar_vertebrae). - ["Lower Back Pain Condition, Treatment and Exercise"](https://www.spineuniverse.com/conditions/back-pain/low-back-pain/lower-back-pain-condition-treatment-exercise). SpineUniverse. Retrieved February 15, 2017. - ["Virtual Spine — Online Learning Resource"](http://pie.med.utoronto.ca/VSpine/index.htm). Toronto Western Hospital Department of Anesthesia and Pain Management. Retrieved February 15, 2017. v t e Bones of the torso Vertebrae General structure Body Arch pedicle lamina notch Vertebral foramen Intervertebral foramen Processes transverse articular spinous Spinal canal Cervical vertebrae Uncinate process of vertebra Transverse foramen Anterior tubercle Carotid tubercle Posterior tubercle Atlas lateral mass anterior arch posterior arch Axis dens Vertebra prominens Thoracic vertebrae Costal facets superior inferior transverse Uncinate process of vertebra Lumbar vertebrae Processes accessory mammillary Sacrum Base sacral promontory Ala of sacrum Lateral surface sacral tuberosity Pelvic surface anterior sacral foramina Dorsal surface posterior sacral foramina Median sacral crest Medial sacral crest Lateral sacral crest Sacral canal sacral hiatus Coccyx none Thorax Rib cage Ribs true ribs false ribs floating ribs Parts angle tubercle costal groove neck head Sternum Suprasternal notch Manubrium Sternal angle Body of sternum Xiphisternal joint Xiphoid process Thoracic cage Superior thoracic aperture Intercostal space Costal margin Infrasternal angle v t e Spinal nerves Cervical C1 C2 C3 C4 C5 C6 C7 C8 anterior Cervical plexus Brachial plexus posterior Posterior branches of cervical nerves Suboccipital – C1 Greater occipital – C2 Third occipital – C3 Thoracic T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 anterior Intercostal Intercostobrachial – T2 Thoraco-abdominal nerves – T7–T11 Subcostal – T12 posterior Posterior branches of thoracic nerves Lumbar L1 L2 L3 L4 L5 anterior Lumbar plexus Lumbosacral trunk posterior Posterior branches of the lumbar nerves Superior cluneal L1–L3 Sacral S1 S2 S3 S4 S5 anterior Sacral plexus posterior Posterior branches of sacral nerves Medial cluneal nerves Coccygeal anterior Coccygeal plexus posterior Posterior branch of coccygeal nerve [Portal](https://en.wikipedia.org/wiki/Wikipedia:Contents/Portals): - [Anatomy](https://en.wikipedia.org/wiki/Portal:Anatomy) Authority control databases National Czech Republic Latvia Other Terminologia Anatomica --- Adapted from the Wikipedia article [Lumbar vertebrae](https://en.wikipedia.org/wiki/Lumbar_vertebrae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Lumbar_vertebrae?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.