Type III: MCG lying below ITA -„low‟ MCG
5.2. CERVICAL SYMPATHETIC CHAIN 1. COURSE AND RELATIONS
154 5.1 SAMPLE
The study was conducted on a sample size of fifty (100 sides) cadaveric specimens which consisted of forty fetuses (80 sides) and ten adults (20 sides). Since the fetal series comprised a greater number of the specimens compared to adults, it provided a unique overall view of the sympathetic nervous system in the fetus from its origin in the spinal nerves to its termination (Groen et al., 1987). It should also be noted that in fetuses, sympathetic nerve development beyond the 15mm stage, does not alter (Pather, 2001).
Since the parietal pleura in fetuses is thinner and more transparent, micro-dissection although challenging was possible and contributed to a significant sample size.
5.2. CERVICAL SYMPATHETIC CHAIN
155 fourth ganglion related to the vertebral artery as VG which Wrete (1959) concurred with.
This study reports a number of ganglia that varied from two (absent MCG and VG) to five (with double MCG and VG present). This did not concur with previous literature reviewed (Becker and Grunt, 1957; Ellison and Williams, 1969) and standard anatomical textbooks (McMinn, 1994; Standring et al., 2008).
The CSC was found to have a single interconnecting chain in 99% of these specimens and compared favourably with Kalsey et al‟s (2000) incidence of 83%. This study records a CSC that divides into multiple branches in a single specimen (1%). This finding has not been reported in any of the literature reviewed. The literature reviewed describes a double sympathetic chain in the cervical region as a possible occurrence (Mitchell, 1953) while Kalsey et al. (2000) provides evidence of this in 17% of their specimens distal to the SCG. This study concurs with Kalsey et al. (2000) in that no duplication of the CSC proximal to the SCG exists. The observation by Kadowaki and Lewett (1986) of a double strand CSC around the subclavian arteries termed AS was a constant finding in all the specimens in the present study; this also concurred with standard anatomical descriptions (Standring et al., 2008). This present study recorded no duplication of the CSC around the ITA, disagreeing with Ellison and Williams (1969).
156 CERVICAL GANGLIA
The literature reviewed describes a constant incidence of 100% for the SCG while varying incidences of the MCG (62.3% to 100%), VG (58% to 94.4%), ICG (13.9% to 62.5%) or CTG (37.7% to 100%) are reflected in Table 22 below. A review and description (with no statistical analyses) by Kadowaki and Lewett (1986) stated that the CSC consists of a series of ganglia that are variable in number and position, this study concurs as the CSC was also found to contain five ganglia in two specimens (2%).
TABLE 22: REPORTED PERCENTAGE INCIDENCES OF CERVICAL GANGLIA
AUTHOR n= SCG MCG VG ICG CTG
Pick &Sheehan (1946) 25 100 - - 20 80 Becker &Grunt (1957) 114 100 62.3 87.7 62.3 37.7 Ellison & Williams (1969) 24 100 75 58 - 88
Groen et al. (1987) 12 - - - - 100
Kalsey et al. (2000) 30 100 100 33.3 - 100 Pather (2001) 58 100 81.1 - 15.5 84.5 Kawashima (2005) 36 100 91.7 94.4 13.9 86.1
Kiray et al. 24 100 33.3 33.3 ? ?
Canan et al. 40 100 48 8 0 100
De Gama (2010) 100 100 71 48 45 48
157 5.2.2. SUPERIOR CERVICAL GANGLION
Standard anatomical literature describes the SCG as the largest (Standring et al., 2008) and most constant ganglion of the three cervical sympathetic ganglia (Ellison and Williams, 1957; Wrete, 1959; Standring et al., 2008). This study confirms the 100%
incidence of SCG, this concurred with the standard anatomical literature (Standring et al., 2008) and numerous authors (Mitchell, 1953; Becker and Grunt, 1957; Ellison and Williams, 1969). This study confirms that the SCG is constantly located behind the common carotid artery concurring with Kawashima (2005). This study also concurs with Standring et al. (2008) in that it is related to the internal carotid artery anteriorly; this was constantly found in all the adult specimens.
The SCG was found to have a fusiform (61%), oval-rounded (30%), elongated (6%) and irregular (3%) shape in the fetal specimens in this study. These findings compare favourably with those of Kalsey et al. (2000) with regards to the percentage of fusiform and elongated shapes [61% vs. 77% and 6% vs. 7%, respectively]. The findings of this study differ widely with those of Kalsey et al. (2000) with regard to the oval shaped SCG [30% vs.2%]. The fusiform shaped SCG was found in 61% in this study concurring with standard anatomical literature by Standring et al. (2008). This study also records oval- rounded, elongated and irregular shapes of SCG. This study concurs with Bhatnagar et al.
(2003) on the incidence of a large oblong fusiform SCG located anterior to prevertebral fascia at the level of the bifurcation of the common carotid artery bilaterally; this was found in three specimens in this study (3%). In this study, the SCG was not found to communicate with any of the cranial nerves or vertebral plexus or phrenic nerve; this differs from findings by Kalsey et al. (2000) and Kawashima (2005).
158 5.2.3. MIDDLE CERVICAL GANGLION
Standard anatomical literature (Standring et al., 2008) describes this ganglion as the smallest of the three cervical ganglia or sometimes absent or replaced by minute ganglia while Kalsey et al. (2000) describes the location of this ganglion as anterior or just superior to the ITA and states that it may connect to the ICG. The study concurs with standard anatomical literature (Standring et al., 2008) in that the MCG is the smallest cervical ganglion. This study also confirms that the MCG is occasionally absent as reported by Standring et al. (2008); this occurred in 29% of the specimens. A double MCG in a single CSC was found in 3% of these specimens, this compared favourably with Kalsey et al. (2000) (3% vs. 5%). This confirmed the findings of Pick and Sheehan (1946) in that the MCG may have a double occurrence or represented by a tiny knot. This differed widely from the findings of Becker and Grunt (1957) and Pather (2001) (3% vs.
39% and 25.9%, respectively). This study disagrees with Axford (1928) and Standring et al. (2008) in that the MCG is occasionally replaced by minute ganglia in the sympathetic trunk; this was not found in any of the specimens in this study.
In the present study the location of the MCG was differentiated into three types based on their relation with the ITA based on Becker and Grunt‟s (1957) description: