Lumbopelvic Anatomy and Biomechanics

Lumbopelvic Anatomy and Kinematics

• Objectives include understanding normal lumbopelvic anatomy and arthrokinematics.
• Students will learn Fryette's laws of coupled motion.
• Students will practice palpating lumbopelvic structures.

Lumbar Spine

• The lumbar spine contains 5 lumbar vertebrae.
• Ligaments include the anterior longitudinal ligament, posterior longitudinal ligament, ligamentum flavum, and interspinal ligament.
• Facet joints vary in orientation, with half-moon, flat (normal), and asymmetric half-moon/flat shapes.
• Facet anomalies (tropisms) are present at the L5-S1 level.

Intervertebral Disc

• The intervertebral disc includes the endplate.

Lumbar Spine Muscles

• Includes superficial and deep muscles.
• Specific muscles include semispinalis capitis, iliocostalis cervicis, longissimus cervicis, spinalis thoracis, semispinalis thoracis, multifidus, rotator brevis, rotator longus, interspinales, and the short rotator.

Sacrum/Pelvis

• The sacrum is composed of 5 fused vertebrae.
• The coccyx is also part of the region and composed of 3-5 fused vertebrae.
• Ligaments such as the anterior longitudinal ligament, iliolumbar ligament, lumbosacral ligament, anterior sacroiliac ligament, sacrotuberous ligament, sacrospinous ligament, and short and long posterior sacroiliac ligaments are present.

Pelvis

• The pelvis is composed of the ilium, ischium, and pubis.
• Structures such as the iliac crests and ischial tuberosities are part of the pelvis.
• The pelvic inlet, sacrosciatic notch, ischial spine, and subpubic arch are key landmarks.
• Anatomical differences exist, with gynecoid and android types.

Sacral/Pelvic Muscles

• Superficial and deep muscles of the sacrum and pelvis include gluteus medius, gluteus maximus, piriformis, gemelli (superior and inferior), obturator internus, obturator externus, and quadratus femoris.

Lumbopelvic Nerves

• The lumbar and sacral plexuses are part of this region.
• Specific nerves are involved, but details are not provided in this presentation.

Osteokinematics

• Flexion in the lumbopelvic region is 40-60 degrees.
• Extension is 20-35 degrees.
• Lateral flexion is 15-20 degrees.
• Rotation is 3-18 degrees.
• Rotation is limited by facet joint orientation.
• Includes nutation and counternutation of the sacrum relative to the ilium.

Innominate Dysfunctions

• Common dysfunctions include inflares/outflares, anterior/posterior rotations, and upslips/downslips. These relate to the innominate bones.

Sacral Torsions

• Related to the oblique and transverse axes.
• Forward and backward sacral torsions are described in relation to these axes.

Arthrokinematics

• Facet joint sliding occurs without rolling.
• Intervertebral joints pivot and glide.
• Ball bearing occurs in intervertebral joints.

Fryette's Laws

• Law #1: In neutral spine, sidebending and rotation occur in opposite directions.
• Law #2: In flexion/extension, sidebending and rotation occur in the same direction.
• Law #3: Motion in one plane limits motion in other planes.

Palpation

• Includes bony landmarks such as spinous processes, top of iliac crests, PSIS, sacral base, S2 spinous process, inferior lateral angle of the sacrum, ischial tuberosities, ASIS, and AIIS, as well as pubic symphysis.
• Soft tissue palpation includes erector spinae, hip abductors, extensors/rotators, flexors, and adductors.

Explore lumbopelvic anatomy, lumbar spine structure, and intervertebral discs. Understand muscle functions and spinal biomechanics, including Fryette's laws. Focus on lumbar vertebrae, ligaments, facet joint variations, and sacral anatomy.