3 Movements of the Trunk

Flexion

Rotation

Extension

TRUNK FLEXION

TRUNK FLEXION: Rectus Abdominalis

• O: Crest of Pubis & ligaments covering front of symphysis pubis.

I: By «3 portions into cartilages of 5th, 6th & 7th ribs.

• N: Lower intercostal nerves.

• Accessory Ms.:• Internal Obliques & external

obliques (reverse action).

TRUNK FLEXION: ROM

• In backlying: flex. of thorax on pelvis is possible until scapulae are raised from the table.

• Motion is mainly at the thoracic spine.

Fixation:

1) Reverse action of hip flexor muscles.

2) Weight of legs and pelvis.

TRUNK FLEXION: Rectus AbdominalisLimited ROM if:• Tension of the posterior longitudinal

ligament, ligamenta flava & interspinal & infraspinal ligaments.

• Tension of the spinal extensor muscles.

• Apposition of lower lips of vertebral bodies anteriorly with surfaces of subjacent vertebrae.

• Compression of intervertebral fibocartilages in front.

• Contact of lower ribs with abdomen.

Each vertebra is made up ofEach vertebra is made up of

TRUNK FLEXION: Testing Grade 1-0

•Note: observe deviation of umbilicus. •Upward movement indicates stronger contraction of upper section muscle,

& downward movement, stronger contraction of lower section.

Trunk Rotation: Internal & External Oblique

External Oblique:• O: 8 digitations from

external surfaces & inf. borders of lower 8 ribs.

• I: Ant. ½ of iliac crest & aponeurosis to pubic tubercle.

• N: Lower intercostals.

Trunk Rotation: Internal & External Oblique

Internal Oblique

• O: lateral half of upper surface of inguinal ligament, anterior 2/3 of iliac crest.

• I: Crest of pubis, linea alba, inf. bordres of cartilages of 3 last ribs.

• N: Lower intercostals.

Trunk Rotation: Int. & Ext. Oblique: ROM

ROM in backlying: until scapula on side of forward shoulder is raised from table.

Limited by:• Tension of annulus fibrosus

between vertebrae.

• Tension of oblique abdominal muscles on side opposite to those being tested.

• In thoracic area, tension of the costovertebral ligaments.In Lumbar area, interlocking of articular facets.

Fixation:• Reverse action of hip

flexors.

• Accessory muscles:– Lattissimus Dorsi.– Semispinalis.– Multifidus.– Rotatores– Rectus abdominis

(combined trunk rotation & flexion).

Facet jointsFacet joints::

Inter-vertebral disc Inter-vertebral disc (IVD)(IVD)::

Trunk Rotation: Int. & Ext. Oblique: Gr. 1 & 0

•Note: Observe deviation of umbilicus, which will move towards the strongest quadrant if there is a difference in strength of opposing oblique muscles.

Trunk Extension

5 muscles:• Iliocostalis Dorsalis• Longissimus dorsi• Spinalis dorsi• Iliocostalis lumborum

• Quadratus lumborum

• Sacrospinalis

Trunk ExtensionAccessory muscles:• Semispinales• Rotatores• Multifidus.

ROM:

• Thoracic spine extends only to approximately a straight line.

• Lumbar spine extends freely.

Fixation: • Contraction of gluteus max. &

hamstring muscles.• Weight of pelvis & legs.

• Limitation of ROM:

• Tension of anterior Longitudinal ligament of spine.

• Tension of ant. Abdominal Muscles

• Contact of spinous processes.

• Contact of inf. articular margins with laminae.

Thoracic Spine