Clinical Anatomy of the Thoracolumbar Spine pdf - beginning slide 137

Back and Abdominal Muscles help us stay erect

Rotatores and Intertransversarii are deepest muscles in the spine, short moment arm, do not contribute much to movement, have 4.5-7.3 X more muscle spindles than Mulitifidus

Latissimus Dorsi:

• inserts: medial aspect of intertubercular groove of the humerus

• Actions: adducts, medically rotates and extends humerus

Need to know insertions of muscles for tests

Need to know the fiber directions of each muscle for the test as well as insertions!!

Thoracolumbar fascia: directly connects the spine and the deep abdominal muscles.

• three layers. Posterior, middle, anterior

  • Posterior makes diamond layer on back. Attaches to lumbar spinous processes, Interspinous ligaments and the median sacral crest.

    • Superficial lamina fibers are caudomedially oriented

    • Deep lamina are caudolaterally oriented

  • Middle layer attaches tips of TPs and intertransverse ligaments and extends superiorly from the iliac crest to the 12th rib

    • Lays behind the Quadratus Lumborum (QL)

  • Anterior layer covers the Anterior aspect of QL and attaches to the anterior aspect of Lumbar TPs

Lumbar spine extensors: longissimus, multifidus, iliocostalis

• All innervated by the Lateral branches of the dorsal rami

• All extend the spine with bilateral contraction and laterally flex the spine with unilateral contraction

• iliocostalis lumborum inserts to the posterior/inferior surfaces of the rib angles of the inferior 6-9 ribs

  • Extends the spine

  • Pars Lumborum

    • 4 overlying fascicles arising from L1-L4

    • Up to thoracic region

    • Attach to ilium and sacrum

• Iliocostalis thoracis

  • Inserts angles of the superior 6 ribs to C7

  • Action: extend and laterally flex thoracic spine

• Longissimus thoracis

  • Inserts to 3-12 ribs between tubercle and the angle and TP of Thoracic vertebra

  • Action: extend spine, lateral flexion

  • Pars Lumborum 5 fascicles from accessory presses and the adjacent medial end of the posterior surface of the lumbar TPs

    • All fascicle form tendons at their caudal ends, which join to form the lumbar intermuscular aponeurosis

      • Aponeurosis inserts on the ilium

    • Superior tendon attach to the ribs and TP from T1-T12

      • Each tendon extends 3-4cm

      • Muscle belly extends 7-8cm

      • Inferior tendons form the erector spinae Aponeurosis

• Erector Spinae consists of both lumbar and thoracic fibers

  • Lumbar are separate form thoracic fibers and have separate attachments

  • Lumbar fibers of longissimus and iliocostalis directly attach lumbar vertebrae to the illium

• Erector aponeurosis

  • Formed by the tendons of the longissimus thoracis par thoracis (medically) and the iliocostalis lumborum pars thoracis (laterally)

  • Lumbar fibers of the erector spinae DO NOT attach to the Apo.

• Spinalis Thoracis

  • Inserts upper thoracic SPs (T1-T4)

  • Action: extends thoracic spine

• Iliocostalis and longissimus par thoracis:

  • Thoracic portion is different fiber make-up than lumbar

    • 75% is Type I fibers in the pars thoracis

  • Long moment arms due to very superficial location

    • Greatest amount of extensor omens with a minimum of comprehensive load

• Iliocastalis and longissimus pars lumborum

  • Attach to the mammillary, accessory and transverse processes

• Multifidus

  • Spans 2-4 segments

• Multifidus lumborum

  • Arranged into 5 bands, each attaching to a single lumbar spinous process

  • Deep “laminar” fibers run from Mamillary processes ti the lamina 2 levels above

  • Superficial ribs from Mamillary processes to SP 3-5 levels about

• PSOAS Major: anterior

  • Not a lumbar stabilizer

  • Main action is hip flexion and hip stiffness

  • Inserts into lesser trochanter of femur

• Iliacus: inserts into lesser trochanter

• Iliopsoas it’s a combined name for Iliacus and Psoas major

• Quadratus Lumborum

  • Lumbar stabilizer

  • Has larger moment arm due to the attachment on the TPs

  • Activation increases with demand for spinal stability

  • Does not relax during flexion-relaxation phenomenon

  • Superior attach: 12th rib, L1-L4 TPs

  • Inferior attach: L5 TP, iliolumbar ligament, iliac crest

  • 3 layers with 3 (sometimes 4) fascicles arrangements:

    • Posterior: iliolumbar fascicles

    • Middle: Lumbocostal fascicles

    • Anterior: iliocostalis fascicles

  • Action: extend spine when contracting bilaterally

    • Lateral flexion When contracting unilaterally

    • Depression and stabilization of the 12th rib

• Diaphragm

  • Dome-shaped muscle

  • Attaches to xiphoid process, inferior 6 ribs and costal cartilages

  • Fibers converge centrally to form a central tendon

  • Complete separates thoracic and abdominal cavities

• External abdominal oblique

  • Largest and most superficial of Abdominal muscles

  • Inserts on external oblique aponeurosis

    • Linea alba

    • Inguinal ligament

      • Pubic bone

    • Iliac crest

  • Action: flexion, contralateral rotation, ipsilateral lateral flexion

• Internal abdominal oblique

  • Insert: lower borders of 10th-12 rib

    • Internal oblique aponeurosis

    • Linea alba

    • Pubic crest and pectin pubis

    • Rectus sheath

  • Action: flex trunk

    • Ipsilateral lateral flexion, ipsilateral rotation

    • Tension the thoracolumbar fascia and the other fascia

• Oblique muscles can be regionally activate, depending on demand

• Transversus abdominis

  • Inserts: transversus abdominis aponeurosis

  • Produces little or no flexion force

  • Contracts wit the oblique muscles to increase intra-abdominal pressures

• Rectus Abdominus

  • Major flexor of the trunk

  • Inferior attachment: pubis, pubic tubercle, capsule of the pubic symphysis

  • Super attachment: 5-7th costal cartilages, Xiphoid process

  • Action: flexion of the trunk, maintain abdominal tone,

Intra-abdominal pressure

First Exam will cover everything up to this point!!

Exam 1 Review: Jeopardy

Joint class:

• Found between 2 long bones and consists of interosseous membrane: Syndesmosis

• considered slightly moveable: Amphiarthrosis

• Functional joint classification with No movement associated: Synarthrosis

• Function classification of a joint has 2 surfaces- 1 Concave and 1 convex: diarthrodial joint in particular a saddle joint

• Structural joint classification is Made of fibrocartilage: cartilaginous joint

Muscle attach:

• Attaches to the floor of intertubercular groove of the humerus: Latissmus Dorsi

• controls 70-80% of inspiration: Diaphragm

• Tips of TPs and extends laterally to the middle layer of the thoracolumbar fascia: iliocostalis lumborum par lumborum muscle

• Oriented from lateral to medial int he spine: erector spinae

• The lesser trochanter and one of the actions are hip flexion: PSOAS Major

Planes of move:

• type of motion will open up the Z-joints in the lumbar spine: flexion

• Structures arise from the pediculolaminar junction and project superiorly: superior articular processes (SAP)

• Joints found in coronal orientation. Resist shear forces because of sacral base angle: L5/S1 apophyseal joints

• Lateral bending occurs in this plane: Coronal

• Axial rotation occurs in this plane: Horizontal/transverse

Spondylo:

• Type of slippage is described as anterior translation of the vertebra: Anteriolisthesis

• 6 classifications of this condition: Spondylolisthesis

• Fracture does NOT indicate anterior slippage: Spondylolysis

• Vertebral condition indicative of Osteoarthritis or degenerative changes: Spondylosis

• Condition assoc. with traumatic experience: Type IV Spodylolisthesis

Spinal ligaments:

• restricts extension in the spine: ALL

• Connects anterior head of rib wit sides of 2 vertebrae and IVDs: Radiate ligament

• restricts all ranges of motion: IVDs

• Yellow ligament and thickened can cause stenosis: Ligamentum Flava

• Connects from SPs of one to SPs above and below: Interspinous ligament

Mech loads:

• two compressed objects slide past each other in opposite directions: shearing

• type of force when applied creates an effect that deforms a material at right Angles to its long axis: Bending/flexion

• Type of force when applied perpendicularly to the contact surface pushes or pulls one object directly giants another: compression

• Force pulls apart or separates a material: tension

• Movement increases the tension on the anterior fibers of the annulus fibrosis: extension