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Journal of the Anatomical Society of India

A Study of Osteometric Measurements of Articular Facets From C3 to S1 (part 1)

Author(s): Patel M M, Singel T C, Gohil D V, Pandya A M.

Vol. 56, No. 1 (2007-01 - 2007-06)

Patel M M, Singel T C, Gohil D V, Pandya A M.

M.P.Shah Medical College, Jamnagar, Gujarat.

Abstract:

Osteometric measurements of articular(superior and inferior) facets from C3-S1 were carried out in spines of 40 bodies (920 adult, human, dried vertebrae) with the help of sliding vernier caliper, thread and scale. The study was carried out to obtain the parameters of articular facets which play a crucial role in construction of model of spine to understand spinal injuries and spinal mechanics.Because of change in direction of weight transmission through spine at cervicothoracic and lumbar region the present study found maximum area (A) for superior articular facets in cervicothoracic region at T1 and for inferior articular facets at C7; similarly the maximum facet area in lumbar region was at L5. An attempt was made to compare the present study readings with that of the readings by Panjabi et al because the parameters used by both the studies were same and the sole purpose of study to develop a model of spine for clinical diagnosis was also common for both the studies. Moreover as quoted by Panjabi et al that maximum sample size should be taken to construct a model of spine, the present study had taken a large sample size comprising of spines of 40 bodies (920 vertebrae) as against meagre number of sample size by Panjabi et al i.e. 276 vertebrae (12 spines). The parameters of articular facets as obtained from Present study showed the importance of construction of model of spine and to improve clinical diagnosis and treatment.

Key Words: Weight transmission, manual measurements, Area (A) and model of spine.

Introduction and Review of Literature:

The cervical vertebral articular processes are large and on each side they form the ends of a short pillar of bone, the articular mass, which carries the flat oval facets.In the thoracic region the articular facets are small and occupy the long axis of the vertebral column; whereas in the lumbar region the articular facets are large and sturdy and are reciprocally curved (superior and inferior articular facets).

The zygapophyseal or facet joints are extremely important structures in the biomechanical and clinical behavior of the spinal column (Pal and Routal, 2000).

The articular processes are considered to determine the range and direction of movements between any two vertebrae, (Pal and Routal, 1986).

The role of articular facets in the transmission of weight through spinal column is a well known fact, Pal and Routal (1986, 1987).

Earlier, Dennis (1983) and Louis (1985) were also of the opinion that throughout vertebral column, zygapophyseal joints play an important role in weight bearing.

Thus the articular facets do not merely serve to function limited movements. The role of articular facets in intervertebral joint kinematics has been studied earlier by Abumi et al,(1990); Adams et al,(1983); and Farfan et al, (1967). The facet joints have been definitely related to be a frequent source of low back pain, Badgley et al, (1941); Mooney,(1987); Shearly, (1974).

Dhall (1984), had stated that the size of articular facets can be correlated with the magnitude of stress imposed on them.

The mathematical models of the spine have been used to study the mechanical response of the spine to external forces by Shirazi-A dl et al (1984). Models of spine were also used to study the mechanics of spinal instrumentation by Goel et al (1988).

The mechanism of change in orientation of superior articular facets of the spinal column has been studied by many authors, Pal and Routal, (1999); Pal and Routal,(2000); Panjabi et al,(1993); Singer et al, (1988); Shinohara, (1997).

Radiological studies of the zygapophyseal joints in the thoracolumbar and lumbar region have been carried out by many authors, Singer et al, (1989); Schaik et al, (1997).

Pal and Routal (1986, 1987), in their studies of transmission of weight through spinal column had measured areas of superior and inferior articular facets and had selected various parameters like arch index, pedicle index, lamina index.

According to Panjabi et al (1993), because the accuracy of prediction by the models depends on the quality of the incorporated data, it is essential that high quality data sets be available.

Panjabi et al (1993), have worked on providing quantitative three dimensional anatomy of articular facets of the spinal column by taking into consideration the width, height, width/height ratio and area of superior and inferior articular facets of vertebrae.

As a result of the importance of articular facets in clinical setting and in understanding of basic spinal mechanics, and in continuation of our previous study: Orientation of superior articular facets from C3 to S1; the present study has been attempted to provide height, width, width/height ratio and area of superior and inferior articular facets of spinal column.

According to Pal and Routal (1986), the weight transmission in the cervical region occurs through three columns; an anterior column formed by the bodies and intervertebral discs and two posterior columns formed by articular pillars. They also suggested that the relative magnitude of compressive forces passing through the bodies and neural arches should alter with change of curvature at the cervicothoracic junction.

Materials and Methods:

The materials consisted of dried, adult human vertebral columns of 40 bodies (920 vertebrae) devoid of any pathology. Asliding vernier caliper was used for measurements. The maximum transverse width (W) of articular facets was taken to measure the width and maximum vertical height (H) was taken to measure the height of articular facets as shown in the figure. The maximum width and height of all articular facets were marked with the help of pencil. The height and width of articular facets of cervical and thoracic vertebrae were measured by keeping the sliding vernier caliper along the markings of pencil. The height and width of articular facets of lumbar and sacrum were measured with the help of thread and a scale; since they had a curved surface.

The width/height ratio was calculated by taking W/H of each and every vertebra (superior and inferior articular facets of left and right side) and thus taking their mean value. To calculate the area for each and every articular facet the present study followed the same formula as was used by Panjabi et al. The formula is area (A) = 3.14 (W X H) / 4.

Observations:

The present study showed that the width of superior articular facets was more than the height in cervical region and upper thoracic region as observed in tables-1 and 2. In the midthoracic region the height and width were almost equal.

The most important criteria that the present study had observed was that in the lumbar region, the superior articular facets showed that the width was more than the height from L1 to S1. But the same pattern was not observed in the study by Panjabi et al; as it showed that the width was less than height in lumbar region (L1 to S1) as shown in tables-1 and2.

The means of area for superior and inferior articular facets at all levels were shown in the above tables in comparison with Panjabi et al.

The present study showed that the area of superior articular facets followed a similar trend with its increase in cervical region till T1 or T2 and then its decrease in thoracic region till T10. The area (A) of superior articular facets in lumbar region increased uniformly till S1 with its maximum at S1. Panjabi et al also observed similar changes with respect to area as shown in tables – 1 and 2. The area of inferior articular facets as shown in tables – 3 and 4, also followed the similar pattern in cervical, thoracic and lumbar region as was noted in the area of their counterparts (superior articular facets), by the present study.

TABLE-1: Comparison of Left superior articular facets mean dimensions with Panjabi et al. PRESENT STUDY

PANJABI ET AL PRESENT STUDY
  W H A W/H W H A W/H
C3 10.8 10.6 81.9 1.02 10.15 10.46 0.98 80.94
C4 11.0 12.0 95.6 0.91 10.83 10.58 1.05 79.60
C5 11.8 11.2 87.2 1.05 11.04 9.58 1.17 74.31
C6 13.2 11.7 94.6 1.13 11.85 8.74 1.40 80.51
C7 12.8 10.7 83.9 1.20 12.92 8.35 1.56 81.09
T1 14.0 12.6 114.8 1.11 13.41 9.67 1.40 101.61
T2 12.1 13.0 93.2 0.94 10.52 10.22 1.06 85.91
T3 10.6 11.7 85.8 0.90 9.56 10.48 0.93 73.18
T4 10.3 11.5 79.6 0.90 9.17 9.25 0.96 59.57
T5 9.8 10.9 73.5 0.91 8.64 9.24 0.90 56.17
T6 10.1 11.8 77.8 0.86 8.58 9.15 0.95 61.86
T7 9.9 11.0 74.6 0.90 8.74 9.11 0.97 63.03
T8 10.3 11.7 78.0 0.89 8.78 9.07 0.97 63.67
T9 10.7 11.7 83.3 0.91 8.50 9.12 0.93 59.11
T10 12.9 12.4 94.8 1.04 9.52 9.16 1.05 65.33
T11 11.3 12.0 87.7 0.94 9.88 9.52 1.04 67.98
T12 10.5 12.5 88.4 0.84 9.16 9.84 0.93 65.77
L1 10.5 12.2 99.2 0.86 11.00 11.00 0.99 88.59
L2 11.4 14.6 148.2 0.78 13.31 12.46 1.09 126.94
L3 13.9 15.9 164.4 0.87 13.92 12.77 1.11 136.39
L4 15.3 17.3 194.3 0.89 14.96 12.85 1.18 146.04
L5 14.9 17.5 199.1 0.85 15.10 13.20 1.17 114.55
S1 -   -          


TABLE-2: Comparison of Right superior articular facets mean dimensions with Panjabi et al.

PANJABI ET AL PRESENT STUDY
  W H A W/H W H A W/H
C3 11.4 12.5 101.3 0.91 10.65 9.73 1.12 78.88
C4 12.0 12.3 104.2 0.96 10.84 10.28 1.09 80.62
C5 12.3 12.0 107.0 1.04 11.08 9.52 1.18 77.37
C6 11.6 10.2 79.5 1.14 11.44 8.41 1.40 75.88
C7 12.3 12.1 79.9 1.02 13.46 8.08 1.68 82.98
T1 12.3 12.6 102.9 1.06 13.30 9.30 1.46 97.25
T2 11.7 12.2 80.0 0.96 10.48 9.85 1.09 81.47
T3 10.8 10.8 79.7 1.0 9.80 9.52 1.04 68.27
T4 10.5 10.8 74.9 0.95 9.50 14.71 1.00 99.78
T5 10.6 12.1 85.6 0.88 9.44 8.96 1.06 61.84
T6 9.6 11.7 74.7 0.83 8.96 9.00 1.00 63.82
T7 9.6 11.9 75.8 0.80 8.56 8.78 0.98 59.57
T8 10.0 11.5 77.5 0.87 8.74 8.63 1.02 59.83
T9 11.0 12.1 82.1 0.91 9.04 8.62 1.06 59.31
T10 11.5 12.0 87.0 0.96 9.68 8.76 1.09 63.47
T11 11.4 12.5 98.9 0.91 10.08 9.32 1.09 64.98
T12 11.2 13.4 100.8 0.84 9.29 9.42 0.98 60.88
L1 10.2 12.7 96.7 0.80 10.25 10.33 0.96 75.77
L2 11.1 14.6 138.0 0.76 13.04 11.85 1.13 120.45
L3 13.8 16.0 170.3 0.86 13.85 12.69 1.10 133.68
L4 14.1 16.1 175.0 0.88 15.04 12.77 1.20 145.92
L5 16.3 17.4 211.9 0.93 15.20 12.85 1.20 113.04
S1 - - - - 15.81 13.48 1.19 167.96


TABLE-3: Comparison of Left inferior articular facets mean dimensions with Panjabi et al.

PANJABI ET AL PRESENT STUDY
  W H A W/H W H W/H A
C3 11.0 11.9 91.7 0.92 10.10 8.90 1.15 70.81
C4 11.1 11.5 85.7 0.97 10.54 9.14 1.17 75.67
C5 12.3 11.5 86.4 1.07 11.07 8.87 1.26 77.92
C6 13.1 12.2 94.4 1.07 11.38 8.17 1.40 73.44
C7 13.9 13.9 114.6 1.0 10.90 9.23 1.21 79.34
T1 13.2 13.3 94.4 0.99 9.88 9.31 1.07 72.71
T2 11.0 11.8 86.8 0.93 9.28 9.09 1.02 66.82
T3 10.4 10.7 78.9 0.97 8.85 8.63 1.03 60.76
T4 9.8 11.0 73.2 0.89 8.57 8.67 0.99 59.56
T5 9.7 11.2 74.6 0.87 8.13 8.28 0.98 53.92
T6 9.7 11.1 73.7 0.87 8.18 8.33 0.98 54.26
T7 10.3 11.0 76.7 0.94 8.18 8.24 1.00 53.75
T8 10.7 11.6 80.8 0.92 8.36 8.39 1.00 55.97
T9 12.6 12.5 99 1.01 9.48 9.00 1.06 68.08
T10 11.4 11.7 89.8 0.97 9.67 9.60 1.01 74.18
T11 10.9 12.5 92.4 0.87 9.43 9.63 0.98 72.85
T12 9.8 12.7 90 0.77 9.47 9.93 0.96 74.92
L1 10.7 15.2 125.9 0.88 10.77 11.37 0.95 97.52
L2 12.2 16.3 153.6 0.73 11.81 12.53 0.95 117.70
L3 13.4 16.4 167.9 0.82 12.43 12.90 0.97 126.86
L4 14.1 15.6 167.9 0.90 12.83 12.90 1.00 131.28
L5 16.1 17.3 182.7 0.93 13.58 13.23 1.03 142.41
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