Computer-based examination of body posture - parameters

The following description contains explanation of the meaning and method of calculating the parameters determined during the examination. Prior to the examination itself we have to mark some characteristic points on patient’s body which will be visible in the computer photograph. At those points we place cursors. On the basis of their location all parameters are calculated.

The picture below shows the arrangement of individual points and their notations.

	Meaning of parameters: C7 – spinous process of the 7^th cervical vertebra (in the programme vertebrae numeration has been assumed, according to which the 7^th vertebra equals 0) KP – thoracic kyphosis (Attention: points KP, PL and C7 are corrected automatically by computer after editing the sagittal plane) PL – spinal point where kyphosis goes over into lordosis (defined in the middle of depth between KP and LL) LL – lumbar lordosis S1 – spinous process of the 1st sacral vertebra (vertebra no.18) Łl, Łp – lower shoulder-blade angle (left, right) Ml, Mp – posterior superior iliac spines (left, right) (Attention: here we can also mark the peaks of ilia) T1, T2 – left waistline (Attention: when T2, T4 waist incisures are not clearly visible, then we mark them at the same heights) T3, T4 – right waistline B2, B4 - shoulders (Attention: we mark them vertically over armpits T1, T3) B3, B4 (X1, X2) – point joining arm line with neck KS – occipital tuberosity, used to determine cervical segment angles (Attention: when we do not examine the cervical segment, we can place this point just above C7)
	[10]. Spinal curve length. This parameter is calculated according to ‘the shape of the spine’, i.e. through summing up distances between succeeding vertebrae. The length is defined in three dimensions (including the depth). The percent value is referred to the given patient’s height and results from the relation (length/height* 100%. [11]. DCK – Spinal height. The result constitutes the distance between the points C7 and S1, which is calculated only in vertical axis. The percent parameter is calculated as above. [12]. UK – Maximum deflection of spinous process line from the line C7-S1. The computer searches for maximum deflection of the spinous process from the straight line joining the points C7 and S1. The distance is defined in horizontal axis X. When the chosen process is located on the right side of the line C7-S1, the result is positive, when on the left – negative. Including the option of calculating the absolute value causes that the result does not consider the sign. Additionally, in the result printouts we can use the parameter 2 that informs about the number of the chosen vertebra. We have to remember the assumed notations according to which the spinous process of the vertebra C7 equals 0.
	[13]. KNT – Torso lateral inclination angle. The deflection of the line C7-S1 from the plumb-line in the frontal plane (to the right, to the left) is defined here. The value assigned is expressed in degrees. When the point C7 is located ‘on the right’ from S1, the result is positive, when ‘on the left’ – negative. The parameter ABS cancels the sign. [14]. KPT – Torso inclination forward angle. Similarly as for [13], however in the sagittal plane. It defines the body inclination ‘forward’ or ‘backward’. The value is positive, when C7 lies nearer than S1 (on greater convexity).
	[15]. KNM – Pelvic lateral inclination angle. The parameter defines the inclination of the line joining the points Ml and Mp in relation to the level. It takes on gradual values within the range: -180 up to +180. Consequently, when Mp ‘lies higher’ than Ml, then we have angles from 0 up to 180, otherwise -180 - 0. In such a case the calculated angle does not depend on which point lies ‘higher’ in relation to the other. The value given in millimetres stands for differences in the height of point location. From the coordinate Y of the point Ml we subtract the coordinate Y of he point Mp. The sign of this operation can be foreseen while bearing in mind that the reference point (0,0) is located in the left bottom corner of the working window. [16]. KSM –Pelvic torsion angle. Similarly as for [15], but calculated in the sagittal plane. When Mp lies on greater convexity than Ml, the result is a positive value.
	[17]. TT – Height difference of the waist triangles. The parameter is calculated in the frontal plane. The result equals distance l minus distance p. The ABS value gives a result without any sign. The value expressed in percentage is calculated on the basis of following relation: ( (distance l – distance p)/(distance l + distance p) )*100%. [18]. TS – Width difference of the waist triangles. Similarly as [17] for differences calculated in the X-axis.
	[19]. KRL, KRP – Arm line angle.
	[20]. UL – Height difference of the lower shoulder-blade angles (inclination). Defined similarly as for iliac spines (parameter [15]) [21]. UB – Depth difference of the lower shoulder-blade angles (torsion). Similarly as parameter[16]. [22]. OL – Distance difference of the lower shoulder-blade angles from the spine. The segments between succeeding points of the spinous processes are approximated by straight lines. The result equals distance l minus distance p. The percent result equals ((distance l minus distance p)/(distance l + distance p) )*100%.
	[23]. DKS – Cervical segment height. Estimated between points C7 and KS GKS – Cervical segment depth. Maximal indentation estimated from the plumb-line crossing point C7. [24]. Total spinal height. Between points S1_KS = DCK+DKS
	[25]. KLB – Inclination angle of shoulder line. All parameters are estimated similarly to inclination of pelvis line (parameter[15])
	[26]. WBS – Coefficient of asymmetry of shoulders in relation to KK (of point S1) The difference in distance in the horizontal axis is estimated off the straight line crossing point S1. All parameters are determined similarly to parameter [22]. [27]. WBC – Coefficient of asymmetry of shoulders in relation to point C7. Similarly to parameter [26], whereas the reference point is the spinous process of the 7th cervical vertebra (parameter C7).
	[28]. Lateral inclination and inclination forward angle of the cervical segment C7-KS in relation to C7 The values are estimated similarly to parameter [13,14]. [29]. Lateral inclination and inclination forward angle of the cervical segment KP-KS in relation to KP
	[30]. ALFA – Lateral inclination of lumbosacral segment. [31]. BETA –Lateral inclination of thoracolumbar segment.  [32]. GAMMA – Lateral inclination of upper thoracic segment. [33]. DELTA – Total amount of curvatures. DELTA=ALFA+BETA+GAMMA. [34]. MI – Compensation coefficient. MI=KKP-KLL, (parameter[40], parameter[35]). [35]. KLL – Lumbar lordosis. KLL=180-(ALFA+BETA).
	[36]. DLL - Length of S1-LL. [37]. RLL –Length of S1-PL. [38]. GLL – Depth of LL-PL. [39]. WLL – Depth to length indicator. WLL=GLL/RLL. [40]. KKP – Thoracic kyphosis. KKP =180-(BETA+GAMMA). [41]. DKP – Length of C7-KP. [42]. RKP – Length of C7-PL. RKP[%]=100%*RKP/DCK. [43]. GKP – Depth of KP-PL. [44]. WKP – Depth to length indicator. WKP=GKP/RKP.
	The parameters below help defining the shape of vertebral column in the frontal plane. [45] Number of arches. Number of spinal crossings with the line C7-S1. [46] Right-sided arch: length, rise, angle [47] Left-sided arch: length, rise, angle
	Parameter definition of chosen sections [48][50] rotation is assigned similarly to parameter [16]. [49][51] costal hump is calculated in relation to spine line
	In the latest software version a new (automatic) method of analysis and calculation of spine parameters in the sagittal plane has been introduced. These parameters have been marked with the ending (a). The PL point is assigned as cross-cut of the segment C7-S1 with the spine curve. The KP point indicates the arch arrow of thoracic kyphosis ( place of maximum distance of the arch from its chord - C7-PL segment). The LL point indicates the arch arrow of lumbar lordosis [52] Length of thoracic kyphosis DKP(a) - C7-PL distance Length of lumbar lordosis DLL(a) - PL-S1 distance The values standardized as unities are calculated according to following formulas DKP/(DKP+DLL) ; DLL(DKP+DLL); and the proportion DKP/DLL. [53] Depth of thoracic kyphosis GKP(a) - length of arch arrow of kyphosis. GLL(a) - kyphosis depth. Standardized values: GKP/(GKP+GLL); GLL(GKP+GLL); GKP/GLL; [54] Depth indicator to the length of kyphosis WKP = GKP/DKP; of lordosis WLL = GLL/DLL; standardized as above [55] Surface of kyphosis PKP; surface of lordosis PLL [56] Angle of thoracic kyphosis KKP = 180-GAMMA-BETA_K Angle of lumbar lordosis KLL = 180 - ALFA - BETA _L [57] Individual angles are designated in relation to the segment C7-S1, thanks to this the analysis depends on the inclination of the whole body. To increase the accuracy of the parameter designation two independent measures of the angle BETA_K for kyphosis and BETA_L for lordosis have been introduced.

Evaluating the results of the examination we assume that a correct body posture is an axially symmetrical posture, whereas all deflections from this symmetry constitute deformities of different grade. As it is not possible to show on patient’s skin physiological points with accuracy greater than 5mm, we assume that the limit of accidental error of the method amounts to 1cm. Therefore, we can talk about the asymmetry of shoulder-blades, when it exceeds 1.5cm, and about more serious cases with asymmetry going over 2.5cm.

We hope that some physiological standards will soon be created that would unify the descriptions of performed examinations.