Lumbar region Flashcards
What movements are available at the lumbar spine?
Flexion, extension, rotation, lateral flexion.
FLEXION is greater than extension and there’s more movement in the lower segments.
SIDE FLEXION is couples with rotation.
ROTATION is 1 degree at each segmental level with less rotation available at L5-S1 and a mean rotation of 8-12 degrees in each direction. Limited by facet joints.
What are the layers of the thoracolumbar fascia?
Posterior layer - superficial to the erector spinae and attached to the spinous processes.
Middle layer - between erector spinae and quadratus lumborum, attached to transverse tips.
Anterior layer - deep to quadratus lumborum, attached to anterior of transverse processes.
External Obliques
Origin: Outer surfaces of lower 8 ribs
Insertion: Linea alba, lateral lip of iliac crest
Action: Flexes trunk, ipsilateral side flexion, contralateral rotation, compresses abdominal contents
Nerve Supply: Anterior rami of T7-T12
Internal Obliques
Origin: Thoracolumbar fascia, lateral 2/3 of inguinal ligament, iliac crest
Insertion: Inf. border of lower 3 or 4 ribs, linea alba, pubic crest and pectineal line
Action: Flexes trunk, ipsilateral side flexion and rotation, compresses abdominal content.
Nerve Supply: Anterior rami of T7-T12 and L1.
Transverse Abdominus
Origin: Thoracolumbar fascia, medial lip of iliac crest, lateral 1/3 of inguinal ligament, CCs lower 6 ribs.
Insertion: Linea alba, pubic crest and pectineal line.
Actions: Compress abdominal contents but this is also a stability muscle.
Nerve Supply: Anterior rami of T7-T12 and L1
Rectus Abdominus
Origin: Pubic crest, pubic tubercle, pubic symphysis
Insertion: CCs of ribs 5 to 7, xiphoid process
Actions: Compress abdominal contents, flex trunk, tense abdominal wall
Nerve Supply: Anterior rami of T7-T12
What are the functions of the abdominals?
Trunk movement, sitting up from lying, getting out of bed, protection of the abdominal viscera, spinal stabilisation, abdominal pressure for (forced expiration, micturition, defecation, parturition, vomiting)
What are the layers of the rectus sheath?
Anterior layer: External obliques, internal obliques
Posterior layer: Internal obliques, transverse abdominus
MIDLINE IS LINEA ALBA
Quadratus Lumborum
Origin: Post border of iliac crest, iliolumbar ligament
Insertion: Inferior border of 12th rib and Tps L1-L5.
Actions: Muscle of inspiration, ipsilateral side flexion, lumbar extension
Nerve Supply: Anterior rami of T12-L4
Erector Spinae
ILIOCOSTALIS (most lateral) -
LONGISSIMUS
SPINALIS
Actions: Bilateral extension (controls flexion), lumbar lordosis, unilateral ipsilateral lateral flexion/rotation.
Nerve Supply: Posterior rami of adjacent thoracolumbar nerves.
Semispinalis (Thoracics) {Stability}
Origin: TP of thoracic 6-10
Insertion: SP of upper 4 thoracic & lower 2 cervical vertebrae
What other muscles contribute to the stability of the lumbar spine?
Multifidus, Interspinales, Rotatores, Intertransversus
(rotatores is best developed and deepest in the thoracic region)
Ant/Post longitudinal ligaments
Long ligaments that run along the length of the vertebral column, covers vertebral bodies & intervertebral discs. Anterior limits extension, posterior limits flexion
Ligamentum flavum
Short but thick ligament connects laminae of adjacent vertebrae from C2 to S1. In the neck they are thin and long, thicker in thoracic region and thickest in lumbar region. Mainly helps to limit flexion of lumbar spine.
Supraspinous ligament
Originates from C7 and inserts in sacrum. Limits flexion.
