Deep back Flashcards
What comprises the functional unit of the vertebral column?
Two vertebral bodies, the intervening intervertebral disc, and 2 pairs of facet joints.
What is meant by amplification by summation?
Taking a small amount of movement exhibited at a single functional unit of the vertebral column and multiplying it by the number of vertebra. Small amounts of motion are amplified into larger flexion/extension movements.
Where could you find a zygophyseal joint? Classify it.
Between inferior and superior articulating facets. They are synovial in nature.
Name the vertebral lever arms of the functional unit of the vertebral column.
Each vertebra has 3 pairs of lever arms: spinous process (fused in the midline into a single entity), transverse processes and costal elements (ribs).
What is the general function of these lever arms?
Serve as attachments for intrinsic mm. of the back.
List the superficial extrinsic mm. of the back.
Rhomboideus minor and major, levator scapulae, trapezius, latissimus dorsi.
What is the function of the superficial extrinsic mm. of the back?
They serve in attaching the upper limb to the torso (trunk).
List the intermediate extrinsic mm. of the back.
The serratus posterior superior and the serratus posterior inferior.
What is the general function of the intermediate extrinsic mm. of the back?
They act as accessory muscles of respiration.
What is the function of the intrinsic back mm.?
Postural in nature. Extension/flexion and lateral flexion of the vertebral column.
Anatomically how are the intrinsic back muscles grouped?
Into three layers: superficial, intermediate and deep.
Name the components of each muscle group.
Superficial: splenius capitis, splenius cervicis; intermediate: erector spinae mass (spinalis, longissimus and iliocostalis mm.); deep: semispinalis, multifidus, rotatores, intertransversarii and interspinales.
How are the intrinsic muscles innervated?
Segmentally, by individual dorsal rami along their length.
Which of these intrinsic muscle groups is most superficial?
Components of the erector spinae (spinalis, longissimus, iliocostalis).
Which of these intrinsic muscle groups is deepest?
Rotatores
