Lecture 4 Flashcards
Lumbar Spine Overview
- 5 Vertebrae
- Flexion, extension, some lateral flexion and limited/restricted rotation
Functions:
- Wight bearing of upper body
Typical Lumbar Vertebrae: Vertebral Body
Large, wide, kidney shaped, thicker anteriorly then posteriorly
Typical Lumbar Vertebrae: Vertebral Foramen
Triangular, larher than that in thoracic spine, smaller then cervical
Typical Lumbar Vertebrae: Laminae
- Strong, broad and short in morphology
- Upper lumbar laminae are taller instead of wider
Typical Lumbar Vertebrae: Transverse Processes
- Long & slender
- TPs horizontal in L1-L3 & incline slightly upward L4-L5
- Consist of mammillary process and accessory process
Typical Lumbar Vertebrae: Mammillary Process
Small tubercles located on the posterior aspect of the superior articular processes
Typical Lumbar Vertebrae: Accessory Process
A small bony projection found on the posterior aspect of the transverse processes of the lumbar vertebrae
Typical Lumbar Vertebrae: Spinous Process
-Short & blunt
- Project almost horizontally
- Hatchet Shape
Typical Lumbar Vertebrae: Superior and Inferior Articular Processes
- Superior facets face medially
- Inferior facets face laterally
- Has mammillary process on their posterior aspect
L1
- Smallest
- Roughly inline with the anterior end of the 9th rib at a level called the transpyloric plane
L5
- Atypical
- Body is much deeper anteriorly then posteriorly contributing to the lumbosacral angle
- SP is smaller
- TP is thicker
Joints of Lumbar Vertebrae
- Intervertebral joints
- Facet joints
Facet joints in Lumbar
- J or C shaped
Functions:
- Protect from anterior shear, rotation and flexion
- Produces spinal motions including coupling movements
- Minimally restricts extensions and side bending
Muscles of Lumbar Region
- Quadratus Lumborum
- Erector Spinae
- Abdominal Muscles
- Accessory Muscles: Tranversospinalis group & Intertransversarii
Quadratus Lumborum
- Square shape muscle, deep layer of dorsolateral abdominal wall
- Run diagonally from rib and spine inferiorly and laterally towards illiac cres
- Attached to Lumbar TPs and 12th rib
Functions:
- Laterally flexes trunk
- Extends trunk when both contract
- Stabilizes 12th rib during breathing
Abdominal Muscles
- Transverse abdominus
- Internal abdominal Oblique
- External Oblique
- Psoas Minor
- Psoas Major
Psoas Major
- Attaches to TP of all lumbar vertebrae extending to lesser trochanter of femur
- Helps bend the trunk laterally & raises/flexes the trunk from supine position bilaterally
Erector Spinae (Lumbar)
- Illiocostalis, Longissimus & Spinalis
- Lumbar stabilization by providing compressive forces along the spine
- Assist with truk extension, spine stability & leg speed enhancement
- Most powerful extensors of vertebral column
Transversospinalis Group
- Medially located deep back muscles that extend between TP and vertebral arches or SP
Includes:
- Mutlifidus
- Semispinalis
- Rotatores
Multifidus Muscle
- Tranversopinalis Group
- Length of the back but is most developed in lumbar area
- Stabilizing and contralateral rotation of the spine
- Multifidus lumborum attached to mammillary process extending superiorly to the SP 2-5 level above
- Associated with lower back pain
Actions:
- Bilateral contraction = extends vertebral column
- Unilateral contraction = rotates vertebral column controlaterally
Semspinalis
- Transversospinalis group
- Longest fassicle of transversospinalis, with 6 segments
- Semispinalis cervicis, semispinalis thoracis
Rotatores
- Deepest muscles in tranvsersospinalis and shortest fassicles
- Rotatore capitis, rotatore cervicis, rotatores thoracis
Intertransversarii Muscles
- Lateral lumbar intertransversarii have attachments between TP & APs of L1-L4 & TP of succeeding vertebra
- Medial lumbar extend between the AP of each vertebra L1-L4 to the anterior tubercle of the TP below
Lumbar Spine: Biomechanics
- Well designed for flexion
- Occurs with unfolding or straightening of lumbar lordosis
- Segmental movement of flexion/extension = 12 degrees upper Lx
Increase to 20-25 L1/S1
Lumbar Spine: Flexion
ADD PERCENTSSS
- Superior vertebra will anterior tilt & forward gliding will occur
- Tensile forces placed on posterior annulus, lig. flavum, capsule & PLL
- Facet joints open up
Lumbar Spine: Extension
Superior vertebra will tilt & glide posteriorly:
- Narrowing of IV foramina = 20%
- Central canal is also narrowed
- Nucleus pulposus moves anteriorly
- Facet joints close
Lumbar Spine Flexion is resisted by:
- Joint Capsule = 39%
- Supraspinous/interspinous ligaments = 19%
- Ligamentum flvaum = 13%
- Intervertebral Discs = 29%
Lumbar Spine Extension is resisted by:
- Structures anterior to the fulcrum to be elongated (ALL, etc)
- Ability of IVD to compress
- Joint capsule tension
- Passive tension of Psoas major
