Functional Anatomy of the Lumbar Spine and Abdominal Wall: Difference between revisions

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=== Lumbar Lordosis ===
=== Lumbar Lordosis ===
Lumbar lordosis is a key adaptation to bipedal locomotion in the human lineage. Dorsoventral spinal curvatures enable the body's center of mass to be positioned above the hip, knee, and ankle joints, and minimize the muscular effort required for postural control and locomotion.  
The natural curve for the lumbar spine is lordosis. It defines lumbar spine alignment in saggital plane, however it is the pelvis that is "the cornerstone of spinal sagittal alignment". <ref name=":0">Diebo BG, Varghese JJ, Lafage R, Schwab FJ, Lafage V. Sagittal alignment of the spine: What do you need to know? Clin Neurol Neurosurg. 2015 Dec;139:295-301.</ref> The curve of the sacrum  determines the lumbar curve.  
 
The lumbar spine sagittal alignment offers two main benefits during locomotion: <ref name=":0" />
 
* Allows the body's centre of mass to be positioned above the hip, knee, and ankle joints
* Minimises the muscular force used for postural control  
 
Assessment of the lumbar spine alignment must include the analysis of the lower limbs alignment.  The results from the knee flexion angle measurement and pelvic shift can help identify the compensatory mechanisms as a consequences of the sagittal plane malalignment. <ref>Schwab F, Lafage V, Boyce R, Skalli W, Farcy JP. Gravity line analysis in adult volunteers: age-related correlation with spinal parameters, pelvic parameters, and foot position. Spine (Phila Pa 1976). 2006 Dec 1;31(25):E959-67.</ref>


== Abdominal Wall Structure  ==
== Abdominal Wall Structure  ==

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Introduction[edit | edit source]

add text here relating to clinically relevant anatomy of the condition

Key Terms[edit | edit source]

Axes: lines around which an object rotates. The rotation axis is a line that passes through the centre of mass. There are three axes of rotation: sagittal passing from posterior to anterior, frontal passing from left to right, and vertical passing from inferior to superior. The rotation axes of the foot joints are perpendicular to the cardinal planes. Therefore, motion at these joints results in rotations within three planes. Example: supination involves inversion, internal rotation, and plantarflexion.

Bursae: reduce friction between the moving parts of the body joints. A bursa is a fluid-filled sac. There are four types of bursae: adventitious, subcutaneous, synovial, and sub-muscular.

Capsule: one of the characteristics of the synovial joints. It is a fibrous connective tissue which forms a band that seals the joint space, provides passive and active stability and may even form articular surfaces for the joint. The capsular pattern is "the proportional motion restriction in range of motion during passive exercises due to tightness of the joint capsule."

Closed pack position: the position with the most congruency of the joint surfaces. In this position, joint stability increases. For example, the closed pack position for the interphalangeal joints is full extension.

Degrees of freedom: the direction of joint movement or rotation; there is a maximum of six degrees of freedom, including three translations and three rotations.

Ligament: fibrous connective tissue that holds the bones together.

Open (loose) pack position: position with the least joint congruency where joint stability is reduced.

Planes of movement: describe how the body moves. Up and down movements (flexion/extension) occur in the sagittal plane.Sideway movements (abduction/adduction) occur in the frontal plane. The transverse plane movements are rotational (internal and external rotation).

Lumbar Spine Structure[edit | edit source]

Lumbar vertebrae[edit | edit source]

L1-L5 are known as lumbar vertebrae. However 10–17.4% of adults presents with spinal abnormality of having the 6th lumbar vertebra.[1] This abnormality may influence the saggital parameters including a diminished sacral tilt and more vertical sacrum. [2] The presence of additional lumbar vertebra can be associated with a decrease in the number of thoracic vertebrae (individuals with eleven thoracic vertebrae).

The lumbar vertebrae are located between the 12th thoracic vertebra and the sacrum bone. They are the largest vertebrae of the human body. Each lumbar vertebra contains the following structural elements:

  • Vertebral body
    • kidney-shaped
    • wider from side to side than from front to back
    • the posterior aspect of the vertebral body changes from concave to convex
  • Vertebral foramen
    • triangular in shape
    • larger than in the thoracic vertebrae but smaller than in the cervical vertebrae
  • Two pedicles
    • posterior element of the lumbar vertebra
    • attach to the cranial half of the vertebral body
    • becoming shorter, broader and more lateral from L1 - L5
  • Two laminae
    • flat and broad
    • two pedicles and two laminae are forming the vertebral arch
    • centrally connects to spinous process
  • Spinous process
    • projects perpendicularly from the body
    • short and sturdy
    • describe as "hatchet-shaped"lumbar spine spinous process
    • point of muscle and ligaments attachement
  • Two transverse processes
    • located on the posterior surface
    • project laterally on each side of the vertebra
    • long and slender
    • points of muscle and ligaments attachement
    • L1-L3 projecting horizontally
    • L4-L5 projecting upward
  • Four articular processes[3]
    • two superior articular facets and two inferior articular facets
    • the point where two facets are joining is called the zygapophyseal joints

Lumbar Lordosis[edit | edit source]

The natural curve for the lumbar spine is lordosis. It defines lumbar spine alignment in saggital plane, however it is the pelvis that is "the cornerstone of spinal sagittal alignment". [4] The curve of the sacrum determines the lumbar curve.

The lumbar spine sagittal alignment offers two main benefits during locomotion: [4]

  • Allows the body's centre of mass to be positioned above the hip, knee, and ankle joints
  • Minimises the muscular force used for postural control

Assessment of the lumbar spine alignment must include the analysis of the lower limbs alignment. The results from the knee flexion angle measurement and pelvic shift can help identify the compensatory mechanisms as a consequences of the sagittal plane malalignment. [5]

Abdominal Wall Structure[edit | edit source]

add text here relating to diagnostic tests for the condition

Bones and Articulations of the Lumbar Spine[edit | edit source]

intervertebral disc joint

zygapophyseal joint or the facet joint.

Lumbar Spine Kinematics[edit | edit source]

Lumbar Spine Ligaments[edit | edit source]

anterior longitudinal ligament

posterior longitudinal ligament
ligamentum flavum

intertransverse ligaments.

supraspinous ligament

Differential Diagnosis
[edit | edit source]

add text here relating to the differential diagnosis of this condition

Resources
[edit | edit source]

add appropriate resources here

References[edit | edit source]

  1. Yan YZ, Li QP, Wu CC, Pan XX, Shao ZX, Chen SQ, Wang K, Chen XB, Wang XY. Rate of presence of 11 thoracic vertebrae and 6 lumbar vertebrae in asymptomatic Chinese adult volunteers. J Orthop Surg Res. 2018 May 23;13(1):124.
  2. Yan YZ, Wang B, Huang XQ, Ru X, Wang XY, Qu HB. Variation in Global Spinal Sagittal Parameters in Asymptomatic Adults with 11 Thoracic Vertebrae, four Lumbar Vertebrae, and six Lumbar Vertebrae. Orthop Surg. 2022 Feb;14(2):341-348.
  3. Waxenbaum JA, Reddy V, Williams C, Futterman B. Anatomy, Back, Lumbar Vertebrae. 2022 Aug 1. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–.
  4. 4.0 4.1 Diebo BG, Varghese JJ, Lafage R, Schwab FJ, Lafage V. Sagittal alignment of the spine: What do you need to know? Clin Neurol Neurosurg. 2015 Dec;139:295-301.
  5. Schwab F, Lafage V, Boyce R, Skalli W, Farcy JP. Gravity line analysis in adult volunteers: age-related correlation with spinal parameters, pelvic parameters, and foot position. Spine (Phila Pa 1976). 2006 Dec 1;31(25):E959-67.