Spinal Column

General Structures

Looking Posteriorly:

Curves:

Thoracic Kyphosis –

Lumbar Lordosis –  

Cervical Lordosis –

Three Basic Movements of Spinal Column:

1. Flexion & Extension –
2. Lateral Flexion –
3. Rotation –

Movements can occur at different vertebral articulations of spinal column.

Two Parts of Vertebrae:

1. Vertebral Body – support function; transmit loads, receives weight, etc.
2. Vertebral Arch – Primarily helps to protect spinal cord that goes through spinal foramen.

-         Spinous Process – posteriorly                    Provide attachment sites

-         Transverse Process – laterally                    for muscles & ligaments

Vertebral Notch – Inferior & Superior :

                        Provide an entry for nerves to leave spinal cord to body.

Joints between vertebral bodies:

Intervertebral Discs

-         Between each vertebrae.

• Importance of Discs during loading:

Pressure:

-         Standing (hunched over) ­ pressure to ~200%.

-         Lifting an object with bad mechanics - ­ ~5x.   

-         Lifting an object that’s heavy and cannot be lifted - ­ ~3x.

-         Standing with object in front - ­ ~2x.   

                * Best sitting position is reclined with lumbar support.

Ligaments

• 2 Longitudinal Ligaments: entire length of spinal column

1. Anterior Longitudinal – anterior aspect of all vertebral bodies.

2. Posterior Longitudinal – posterior aspect of vertebral bodies.

Interspinous & Supraspinous Ligaments:

Muscles

• Erector Spinae (group of muscles) – main extensors of spinal column.

-         can help with lateral flexion.

• Interspinalis – extension of spinal column.
• Intertransversirii – lateral flexion.
• Multifidus – extension and rotation to opposite side of muscle.
• Rotatores – extension and rotation to opposite side of muscle.
• Semispinalis Cervicis – extension and contralateral rotation.
• Semispinalis Thoracis – extension and contralateral rotation.

Rib Cage

§         12 pairs of ribs:

-         Ribs # 1-7 – Are true ribs because they articulate directly with the sternum.

-         Ribs # 8-10 – Articulate with vertebrae in back; and their costocartilage articulates with costocartilage of rib # 7.

-         Ribs # 11 & 12 – Are floating ribs. They connect in the back but do not articulate with anything in the front.

Function:

            Mainly protect heart and lungs; also major arteries and veins.

            Their structures allow for respiration.

Muscles that assist with breathing

Inspiration: when they contract, they pull rib cage up and apart.

§         Diaphragm – main muscle of inspiration.

§         Steinocleidomastoid, Scalenes, Intercostals (Internal & External)

-Inspiration primarily occurs with function of the diaphragm.

Expiration: usually active during forced expiration.

§         Internal Intercostals.

§         Abdominals: External, Internal, Transversus Obliques.

Abdominal Muscles

• Flexors of lumbar spine  (Control extensors)

  Rectus Abdominis – main abdominal muscle.               Originate on rib cage
• External Oblique                                                                 and insert on pelvis
• Internal Oblique – originates on pelvis, inserts on rib cage.
• Transverse Abdominis (perpendicular) – deepest of all.

Involved during lifting – contract to put pressure on internal organs (pressure ball) within abdomen, which presses against lumbar vertebrae. This supports the lumbar vertebrae to avoid excessive extension.

Weak abdominals are a risk for lumbar lordosis.

Tight Iliopsoas pulls the lumbar vertebrae into extension – may cause lordosis.