Lumbar Part 4 Flashcards
Anterior sacroiliac and Iliolumbar
Stabilize the anterior aspect of the SI joint
Iliolumbar attaches to ______ and ______
transverse process and helps to stabilize L4,5,S1
Interosseous (strongest SI ligament)
Rigidly binds sacrum with the ilium
Attach between sacrum and ilium
Short and long posterior sacroiliac
Stabilize the posterior aspect of the SI joint
Sacrotuberous
Distal attachment blends with the biceps femoris tendon
Attaches between sacrum and ischial tuberosity
Sacrospinous
Deep to the sacrotuberous ligament
When does SI movement increase in females? Why?
pregnancy due to ligaments relaxing
SI problems more likely during pregnancy or postpartum due to
relaxin
Nutation (“to nod forward”)
Anterior sacral-on-iliac rotation,
posterior iliac-on-sacral rotation, or
both motions performed simultaneously
Counternutation
Posterior sacral-on-iliac rotation,
anterior iliac-on-sacral rotation,
or both motions performed simultaneously
A stress relief mechanism within the pelvic ring, important during
walking, running, and childbirth
Nutation at the SI joints increases
compression and shear forces between joint surfaces which increases stability
Close-pack position of SI Joints:
full nutation
Nutation torque is produced by
gravity, passive tension of ligaments, and muscle activation
muscles that help stabilize the SI joint
Erector spinae and lumbar Multifidus
Diaphragm and pelvic floor muscles
Abdominal muscles
Hip extensors
Lat
Iliacus
Piriformis
Muscular Stabilization of SI Joint Generate active compressive forces against
articular surfaces
Muscular Stabilization of SI Joint
increase magnitude of
nutation torque
Pulling/tensing connective tissues that directly or indirectly reinforce the
joints
This force (weight of the body) tends to push sacrum inferiorly away from the
ilia (nutation)
Counter force upward from the legs through the pelvis pushes ilia into
sacrum
main stabilizers of the sacrum
SI, sacrotuberous and sacrospinous ligaments
- Symphysis Pubis is a Cartilaginous joint located between the two ends of the
pubic bones
Symphysis Pubis
Fibrocartilaginous disk joins the ends of the
hyaline cartilage-covered bones
Symphysis Pubis Stabilized by
superior and inferior pubic ligaments and the posterior ligament
Anterior aspect of symphysis pubis is reinforced by aponeurotic exapansions of several muscles
rectus abdominus
transverse abdominus
adductor longus
Pubic Symphysis Joint Provides stress relief throughout the ring of the pelvis during
walking, pregnancy, and childbirth
Pubic Symphysis Joint Can be unstable and painful after
pregnancy
Agonists
- Concentric contraction
- Isometric contraction – stabilization
Antagonists
- Relaxed
- Eccentric contraction
Trunk Muscle Stabilizers Establishes a firm base for muscles to
move the limbs
Intrinsic trunk muscle stabilizers:
Transversospinal group (semispinalis muscles, multifidi, and rotatores)
Interspinalis muscles
Intertransversarius muscles
Extrinsic trunk muscle stabilizers:
Abdominals
Erector spinae
Quadratus lumborum
Psoas major
Hip muscles that connect lumbopelvic region with the lower extremities
Trunk flexion phase: ends when
scapulae raised off mat
Performing sit-up in hip-flexed position assists the abdominals in keeping the pelvis
posteriorly tilted during the sit-up
Hip flexion phase: follows trunk flexion phase: an additional 70 to 90 degrees of
lumbar and hip flexion
Hip flexion phase of situp Stronger active contraction of the
hip flexors, particularly iliacus and rectus femoris
hip flexion phase More external and internal oblique activity than
rectus abdominis
hip flexion phase creates more pressure on
lumbar discs
