Biomechanics Chapter 9

The spinous processes of the thoracic vertebrae limit movement in which plane? a. sagittal b. frontal c. transverse d. all of the above

sagittal

What type of joint occurs between the superior and inferior articulating facets of adjacent vertebrae? a. hinge (synovial) b. fibrous c. gliding (synovial) d. cartilaginous

gliding (synovial)

A typical geriatric disc has a fluid content that is reduced by approximately how much? a. 85% b. 35% c. 50% d. 5%

35%

Which statement is not true about the intervertebral discs? a. act as cushions between the vertebrae b. account for approximately 1/4 of the height of the spine c. are responsible for spinal movement due to compression d. all of the above are true e. all of the above are false

All of the above are true

Describe the range of motion in all three planes for each vertebral region relative to the other regions.

Frontal plane movement of the spine away from anatomical position is termed lateral flexion. The largest ROM for lateral flexion occurs in the cervical region with approximately 9-10 degrees of motion allowed at C4-C5. Somewhat less lateral flexion is allow in the thoracic region where the ROM between adjacent vertabrae is about 6 degree, except in the lower segments where lateral flexion capability may be between 8-9 degrees. Lateral flexion in the lumbar spine is also on the order of 6 degrees expect at L5-S1 where it is reduced to only about 3 degrees. Spinal rotation in the transverse plane is again freest in the cervical region of the spine with up to 12 degrees of motion allowed at C1-C2. It is next freest in the thoracic region where approximately 9 degrees of rotation is permitted among the upper motion segments. From T7-T8 downward the range of rotational capability progressively decreases with only about 2 degrees of motion allowed in the lumbar spine due to the interlocking of the articular processes there. At the lumbosacral joint, rotation on the order of 5 degrees is allowed.

Explain proper spinal position while lifting. Also, explain why twisting should be avoided when lifting.

Lifting with the legs is the proper way to lift and object. This minimizes trunk flexion and there by minimized torque generated on the spine by body weight. When the spine undergoes lateral flexion and axial twisting a more complex pattern of trunk muscle activation is required than for flexion and extension. Tension in antagonist trunk muscles produces a significant part of these increased loads. Asymmetrical frontal plane loading of the trunk also increases both compressive and shear loads on the spine because of the added lateral bending movement.

How do we help to prevent lower back pain?

Low back pain in the United States has been steadily increasing for more than the past decade. This could likely be a direct result with an increasing incidence of overweight and obesity, which is signficantly associated with low back pain in both men and women of all ages. Repeated loading such as which occurs in industrial work, exercise performance, and in jobs such as truck driving that involve vibration can all produce low back pain. Clinicians sometimes recommend abdominal exercises as both a prophylactic and a treatment for low back pain. In summary, we need to exercise to keep our backs healthy and strong while increasing core stability, maintain a healthy weight to prevent more loading and stress on our spines, and learning how to lift an object correctly can all help prevent or lower the risk of sustaining low back pain.

List and discuss the primary abdominal muscles, explaining how they perform motion in all three planes.

The main abdominal muscles are the rectus abdominis, the external obliques, and the internal obliques. Functioning bilaterally, these muscles are the major spinal flexors and also reduce anterior pelvic tilt. Unilateral tension developed by the muscles produces lateral flexion of the spine toward the tensed muscles. Tension development in the internal obliques causes rotation of the spine toward the same side. Tension development by the external obliques results in rotation toward the opposite side. If the spine is fixed, the interal obliques produce pelvic rotation toward the opposite side, with the external obliques producing rotation of the pelvis toward the same side.

List and describe the three abnormal deviations in the spinal curvature.

Three abnormal deviations of spinal curvatures include lordosis, kyphosis, and scoliosis. Lordosis is and exaggeration of the lumbar curve and is often associated with weakened abdominal muscles and anterior pelvic tilt. Causes of lordosis include congenital spinal deformity, weakness of the abdominal muscles, poor postural habits, and overtraining in sports requiring reapeated lumbar hyperextension. Kyphosis is an exaggeration of the thoracic curvature. Kyphosis can result from congenital abnormality, a pathology such as osteoporosis, in which one or more wedge-shaped vertebrae develop because of abnormal epiphyseal plate behavior. Scoliosis is a lateral deviation(s) in the spinal curvature. Lateral deformity is coupled with rotational deformity or the involved vertebrae, with the condition ranging from mild to severe. Scolosis may appear as either a C or an S curve.

Unusually high incidences of pars interarticularis fractures have been documented in which of the following groups of athletes? a. female gymnasts b. interior football linemen c. weight lifters d. all of the above

all of the above

Lack of flexibility in which of the following muscle groups can cause anterior pelvic tilt? a. hip flexors b. erector spinae c. quadratus lumborum d. all of the above e. none of the above

all the above

Movement of the spine occurs in which plane(s)? a. sagittal b. frontal c. transverse d. all of the above

all the above

In anatomical position, where is the center of gravity located relative to the spine? a. posterior b. inferior c. anterior d. lateral

anterior

The most superior cervical vertebrae is called what? a. atlanto-axial b. cephalo-axial c. atlas d. axis

atlas

Contraction of the rectus abdominis causes __________ flexion of the spine. a. unilateral b. bilateral c. eccentric d. isometric

bilateral

Which part of the vertebrae bears the most weight? a. lamina b. superior articulating facet c. body d. inferior articulating facet

body

What causes the pumping action (influx and outflux of water containing nutrients and waste) of the intervertebral discs in adults? a. blood supply b. body motion c. neural activity d. both A and B e. all of the above

body motion

Transverse or spinous process fractures may result from which of the following? a. extremely forceful contraction of the attached muscles b. the sustenance of a hard blow to the back of the spine c. both A and B d. none of the above

both A and B

Which muscle(s) cause spinal rotation to the left (i.e. left lateral rotation)? a. left internal oblique b. right external oblique c. left rectus abdominis d. both A and B e. all of the above

both A and B

Which of the following are potential consequences of spinal fractures? a. paralysis b. death c. both A and B d. none of the above

both A and B

Which of the following helps the spine absorb shock? a. spinal curves b. intervertebral discs c. ligaments d. both A and B e. all of the above

both A and B

Which of the following is not true about lordosis? a. often accompanied by anterior pelvic tilt b. can be caused by poor abdominal flexibility c. often a result of weight gain and/or pregnancy d. all of the above are true

can be caused by poor abdominal flexibility

Which of the following vertebral regions has the best range of motion? a. cervical b. lumbar c. thoracic d. sacral

cervical

What is the most common type of spinal loading during daily activities? a. compression b. tension c. shear d. torsion

compression

(T/F) To minimize postural adaptations, a back pack load should be as high as possible near the shoulders.

false

What is the result when part of the nucleus pulposus of the disc protrudes and presses on a nerve? a. stress fracture b. herniated disc c. stress fracture d. contusion

herniated disc

The condition of exaggerated thoracic curvature is known as which of the following? a. lordosis b. kyphosis c. scoliosis d. none of the above

kyphosis

What action(s) do posterior trunk muscles cause when they contract unilaterally? a. extension b. hyperextension c. lateral flexion d. medial rotation

lateral flexion

Lateral deviations in spinal curvature are called what? a. lordosis b. kyphosis c. scoliosis d. all of the above

scoliosis

What is the most common type of vertebral fracture? a. fracture to the coccyx b. stress fracture of the pars interarticularis c. cervical fracture d. none of the above

stress fracture of the pars interarticularis

The articulations between adjacent vertebral bodies are which of the following types of joints? a. pivot joints (synovial) b. hinge joints (synovial) c. symphysis joints (cartilaginous) d. none of the above

symphysis joints (cartilaginous)

Which of the following spinal curves are present at birth? a. the thoracic and sacral curves b. the cervical and lumbar curves c. the thoracic and cervical curves d. the cervical and sacral curves

the thoracic and sacral curves

Attachment to the ribs limits range of motion in which vertebrae? a. cervical b. lumbar c. sacral d. thoracic

thoracic

What musculoskeletal problem causes the most absences from work? a. carpal tunnel syndrome b. low back pain c. ankle sprain d. medial tibial stress syndrome

low back pain

Which vertebrae are the largest? a. thoracic b. lumbar c. cervical d. sacral

lumbar

How many pairs of ribs do humans have? Does this differ from the number of thoracic vertebrae? a. 7 pairs of ribs; Yes it differs - we have 10 thoracic vertebrae b. 6 pairs of ribs; No it does not differ - we have 6 thoracic vertebrae c. 12 pairs of ribs; No it does not differ - we have 12 thoracic vertebrae d. 24 pairs of ribs; Yes it differs - we have 12 thoracic vertebrae

12 pairs of ribs; No it does not differ - we have 12 thoracic vertebrae

(T/F) Lumbar spondylolysis is more prevalent in men than women.

True

(T/F) Obese individuals typically display increased anterior pelvic tilt and lumbar lordosis.

True