Spine II Flashcards
What is the action limit for low back compression?
3300 Newton’s
4 General conclusions about annulus injury:
- disc must be bent to full ROM to herniate
- herniation associated with repeated loading in range off thousands of time (fatigue)
- herniation linked with sedentary occupations and sitting posture
- herniation occur in younger spines, those w/higher water content and more hydraulic behavior
Disc Buldge
Expansion of disc material beyond its normal border (e.g., a normal disc during compression, or a degenerated disc with decreased disc height) – the AF is bulging
Protrusion
Discrete localized bulge in the AF, the disc material is displaced (i.e., the NP has protruded through the inner layers of AF) – a true herniation
Extrusion
NP has protruded through all layers of AF, but remains attached to disc of origin
Sequestration
A free disc fragment is located in epidural space can migrate superiorly, inferiorly, medially, or laterally
Damage to annulus of disc appears to be associated with _____ _____ spine for repeated period of time
fully flexing
Muscles create force:
- Forces play roles in moment production for movement
2. Forces stabilize joints for safety and performance
Rotatores and Intertransversarii
- small rotator muscles of spine
- attach to adjacent vertebrae=create axial twisting torque
Function of Intertransversarii
lateral flexion
Intertransversarii and rotatores ar rich in:
muscle spindles
Extensors: Longissimus, Iliocostalis, and Multifidus Groups
major extensors of thoracolumbar spine
Thoracic region of muscles contain 75%
slow twitch fibers
Lumbar region fibers:
more evenly mixed
Pars thoracis components attach:
to ribs and vertebral fibers with long tendons
Long tendons:
run parallel to spine to their origins on posterior surface of sacrum and medial border of the iliac crest
Lumbar components generate:
shear forces together with extensor moment on superior vertebrae
Posterior shear forces support:
anterior reaction shear forces of upper vertebrae that are produced as upper body is flexed forward in a typical lifting posture
Multifidus muscle forces:
affect only local areas of the spine
Multifidus muscles are involved in:
producing extensor torque but only provide ability for corrections at specific joints that may be foci of stress
The functional significance of Abdominal Fascia is made more important by:
connections of aponeurosis with pectoralis major, together with fascial elements that cross midline to transmit force to fascia (and abdominal muscles) on opposite side of abdomen
Rectus Abdominis:
major trunk flexor and most active during sit-ups and curl-us
Why is rectus abdominis partitioned into sections?
to limit bulking upon shortening and sections also have a bead effect
What does beaded rectus allow?
lateral transmission of forces from oblique muscles forming a continuous hoop around abdomen
What do Intermuscular tendons and fascia prevent?
fibers of rectus from being ripped apart laterally from these hoop stresses
What are the three layers of the abdominal wall?
external, oblique, internal oblique and transverse abdominis
Layers of abdominal wall involved in:
flexion and appear to have flexor potential enhanced
Why do layers of abdominal wall appear to have flexor potential enhanced?
b/c of their attachment to linea semilunaris
What does the linea semilunaris do?
redirects oblique forces down rectus sheath to effectively ↑ flexor moment arm
Obliques involved in:
torso twisting and lateral bend
Obliques appear to:
play a role in stabilization since they increase activity when under axial compression
What enhances stability in obliques?
combination and transverse activation with elevated intra-abdominal pressure
What form a containing hoop around entire abdomen?
Obliques together with transverse abdominis
What is hoop around abdomen composed of?
abdominal fascia and posterior lumbodorsal fascia
The psoas muscles is:
major stabilizer of lumbar spine
Quadratus Lumborum appears to be highly involved with
stabilization of lumbar spine, together with other muscles, suggesting clinical focus may be warranted
When lumbar spine in neutral lordosis:
only muscle contributions need be considered in
What is stressed as spine flexes, bends and twists?
passive tissues
What assists in restricting excessive flexion and extension
ALL and PLL
Ligamentum flavum is:
80% elastin and 20% collagen
Ligamentum flavum acts as:
a barrier to material that could buckle and encroach on cord in some regions of ROM
Supraspinous ligament provides:
resistance against excessive forward flexion
Interspinous ligament provides:
collateral action as it guides sliding motion of facet joints and checks posterior shear of superior vertebrae
What are torn spinal ligaments a result of?
ballistic loading-particularly slips and falls or traumatic sporting activity with spine at its end range of motion
Lumbodorsal Fascia is:
strong tissue with a well-developed lattice of collagen fibers,
Function of LDF:
may be that of an extensor retinaculum or nature’s back belt and fulfills a proprioceptive function
LDF is not
a significant active extensor of spine
LDF is part of:
Part of “hoop” around abdomen posteriorly, abdominal fascia anteriorly, and active abdominal muscles laterally
