assessment and objective findings (dia- gram 3). The doctor will often note that, in one direction, both eyes of the patient can be seen but in the opposite direction, only one can be seen, indicating a differ- ence in rotational ability. A unique aspect of the Trigenics treatment system is that it encourages the patient to take an active role in their treatment. The test is done bilaterally, and may need to be performed more than once in order to correctly de- termine the side of reduced axial rota- tional range of motion. A decreased axial rotation range of motion will be evident when the surrounding stabilization mus- cles of the spine are in a hypertonic state. Any difference in axial rotational range of motion from one side to the other would constitute a positive Oolo-Austin test. In order to fully understand the pur- pose of the Oolo-Austin test, we must first have a good understanding of the muscles that are being tested. According to Han- sen et al., “In order to fully determine the segmental actions of a muscle, it is neces- sary to know the exact sites of attachment as well as the lines of action with respect to the joints it crosses”(2) . The back has multiple layers of mus- cles. The more superfi cial muscles of the back are considered the prime movers and include the trapezius, latissimus dor- si, rhomboid major, rhomboid minor, and levator scapulae. The intermediate layer consists of the serratus posterior superior and the serratus posterior inferior(5) . For the purpose of this article, I am going to focus on the deep muscles of the back that act directly on the vertebral column. Both the erector spinae and the multifidus are crucial muscles for movement and stabili- zation of the spine respectively(5) . The lumbar and thoracic erector spi- nae muscles include the iliocostalis, lon- gissimus, and spinalis. Upon unilateral contraction, the erector spinae laterally fl ex and ipsilaterally rotate the spine, and upon bilateral contraction, they extend the spine and depress the ribs(2) . Accord- ing to Gray et al, the erector spinae origi- nate from the anterior surface of a broad and thick tendon, the erector spinae apo- neurosis(2) . The muscle fi bres form a large fl eshy mass, which in the upper lumbar region, splits into three columns: spina- lis (medial), longissimus (intermediate), and iliocostalis (lateral). The muscles lie in the groove on the side of the vertebral column, lateral to the multifi di, and are covered by the thoracolumbar fascia. In general, the erector spinae cross the lum- bar region without attachment to the lum- bar vertebrae(2) . The musculotendinous fi bres of the lumbar erector spinae consist of two parts – a medial and a lateral division – which are labelled as longissimus thoracis pars lumborum and iliocostalis lumborum pars lumborum, or simply a superficial and deep part(2) . Each fascicle attaches directly to the iliac crest. The fascicle of both parts lumborum (longissimus and il- iocostalis) can be resolved into horizontal and vertical vectors(2) . Unilateral contrac- tions fl ex the vertebral column in a lateral direction, and bilateral contraction pro- duces posterior sagittal rotation (2) . Thus, they are well suited to co-operate with multifi di to oppose the fl exion effect of the abdominal muscles when they act to rotate the trunk(2) . The deep paraspinal muscles include the semispinalis, multifi di, and the deep rotators(2) . Upon unilateral contraction, they laterally flex and contralaterally rotate the spine, and upon bilateral con- traction, they extend the spine(2) . The multifi di consist of a number of fleshy and tendinous fasciculi, which lie deep to the foregoing muscles and fill the groove at the sides of the spinous processes of the vertebrae, from the sacrum to the axis (C2)(2) are capable of producing extension, lat- eral fl exion, and rotation(2) . According to Gray et al., they . However, the study by Hansen et al. shows that when the multifi di are studied only as individ- ual muscles, they seem to act more as sta- bilizers rather than prime movers of the vertebral column(2) . They used EMG to confi rm this result, in which it was found that the multifi di play a role in control- ling intersegmental motion(2) . The rotational components of these two muscle groups, work antagonistically to each other whereas the opposite sides of each group work synergistically. When considering the spine as a whole, it con- sists of multiple vertebrae with a wealth of possible movements(2) . However, it is the tissues connecting the vertebrae as well as the shape and orientation of the facets that constrain the movement con- siderably. Thus, the spine relies on its abil- ity to constrain movement between the 48 • CANADIAN CHIROPRACTOR | SEPTEMBER 2008 www.canadianchiropractor.ca
Chiropractic + Naturopathic Doctor September 2008: Page 48
