Exam 4 Flashcards
lumbar vertebrae are taller:
anterior
lumbar ligament that resists most motions?
iliolumbar ligament
disk is very wedge shaped at what level?
L5/S1
-to help with articulation with sacrum
weakest point at interbody joint:
where endplate meets bone
-endplate more strongly bound to the intervertebral disk than the bone
tension in disk during twisting motions:
about half of the fibers experiencing tension around disk
-reduced ability to resist torsion
iliac crest at what spinal levels:
L4-5
PSIS at what spinal level:
S2
tissue of annulus fibrosus:
fibrocartilage
zygaphophyseal joints resist what motion?
shear forces
lumbar spine flexion ROM:
40-50 degrees
lumbar spine extension ROM
15-20 degrees
lumbar spine lateral flexion ROM
20 degrees
lumbar spine rotation ROM
5-15 degrees
normal lumbopelvic rhythm:
40 flex L spine
70 flex hip
L spine open pack:
neutral
L spine closed pack
full extension
L-spine capsular pattern:
side flexion and rotation equally limited
-then extension
interbody joints innervated by:
ventral rami
z joint capsules innervated by:
dorsal rami
psoas major innervation:
L1 spinal nerve
-femoral nerve (L2-L4)
quadratus lumborum
1-3 lumbar spinal nerves
rectus abdominis innervation:
intercostal nerves T7-T12
abdominal innervations:
- lower intercostal (T7-T12)
- iliohypogastric
- ilioinguinal (L1)
which back muscles reduce anterior shear?
erector spinae
what force on the L-spine is more likely to cause an injury?
- shear
- compression can handle a greater extent
why is flexion more likely to cause injury in L-spine?
- does have more compression but not close to compression max
- causes shear force that is close to shear tolerance
approximate discal pressure standing in neutral:
400 N
max normal discal pressure:
10-15 kN compression
1000 N shear cyclic