The supratrochlear foramen (STF) of the humerus is the aperture that forms when the septum separating the coronoid and olecranon fossa is perforated. There are no known studies in the literature on the STF among various South African ethnic groups. The presence and shapes of the STF were established by visual observation from a sample of 538 skeletonized individuals with paired humeri (1,076) and of equal numbers between the sexes. Measurements of the transverse (TD) and vertical (VD) distance of the STF were obtained using extended jaw calipers. An osteometric board was used to measure the epicondylar breadth (EB). Sliding calipers were used to measure the distance of the medial epicondyle to medial aspect of the STF (MB) and that of the lateral epicondyle to lateral border of the STF (LB). The prevalence of STF in the South African population was 32.5% and predominantly on the left with the highest incidence among the Sotho population (41%) and the lowest incidence in Whites (16%). Females (19.5%) had a higher frequency of the STF compared with males (13%). The STF occurred in oval (136), round (77), triangular (9), and irregular (34) shapes. The average EB in this study was 56.1 mm, whereas the average MB and LB were 25.4 mm and 26.3 mm, respectively. The average TD was 6.3 mm and average VD was 4.3 mm. These findings may be of clinical significance to surgeons and osteologists and may have anthropological or forensic importance.

The palmaris longus (PL) is a weak flexor of the wrist that may be harvested as a tendon graft and used in surgical procedures for reconstructive purposes. The PL is congenitally absent in 15% of the worldwide population. However, the frequency of absence varies considerably among different population groups, being as high as 63.9% in the Turkish population and as low as 3% in the black population in the Republic of Congo. In this study, South African persons of mixed race (n = 201) were assessed by two anatomists for the presence of the PL tendon using three clinical tests, namely the Traditional Test, Mishra's Test II, and the Gangata Test. The most reliable of the three tests used was determined using Kendall's coefficient of concordance. Of the total number of subjects used, 11.5% had absence (either bilaterally or unilaterally) of the PL tendon. There was a 5.5% bilateral absence of the PL. The study revealed that the PL tendon may present in six different patterns according to the clinical assessment tests applied, the presence or absence of the PL alongside the flexor capi radialis, and the degree of prominence of PL, if present. Using the Kendall's coefficient of concordance, the Mishra's Test II, and the Gangata Test, both involving abduction of the thumb, were found to be most effective in revealing the PL. The frequency of absence of the PL in South Africans of mixed race has been determined.

No abstract

Herbivorous mammals such as nutrias, guinea pigs, chinchillas, and mole-rats have a longitudinal mucosal colonic groove (furrow) in their ascending colon, which is thought to play a role in the colonic separation mechanism (CSM). It is not known whether this groove is structurally modified to adapt to this function in mole-rat species. The morphology of this groove was studied in 32 mol-rats, four species, one of which consisted of three subspecies, endemic to southern Africa and two species found in eastern Africa. The macroscopic morphology of the groove was documented, and samples for histological examination were taken. The groove was wide at its origin at the cecocolic junction and was lined on either side by a row of papillae with the opposing papillae slightly offset in arrangement. The papillated groove gradually decreased in size toward the distal part of the ascending colon where it disappeared. This pattern was similar in all species except in Heterocephalus glaber, where the papillae were absent and the groove was lined by two longitudinal ridges. A histological examination of cross sections revealed that the mucosa covering the inner and outer walls of the groove was rich in mucous-secreting goblet cells. The walls of the groove contained smooth muscle extending from the inner circular smooth muscle layer at the base to the tips of the papillae in all species examined as well as arteries, lymphatic vessels, and prominent sinusoid-like veins. The groove could be demonstrated both macroscopically and histologically in three Bathyergus suillus fetuses of varying sizes. The sinusoid-like veins present in all grooves, regardless of macroscopic shape, suggest that they have a role in the functioning of the groove.

The palmaris longus muscle (PLM) is described as a weak flexor of the wrist and a tensor of the palmar aponeurosis, but not a thumb abductor. The PLM is believed to aid thumb abduction through its insertion onto the thenar eminence. Two groups, both right hand dominant, were selected from 1,200 sampled participants. The first group comprised of 38 subjects with unilateral presence of the PLM and was used to determine the strength of thumb abduction. The second group comprised of 30 subjects, with bilateral presence of the PLM, and it was used to calculate the effects of hand dominance. A significant number of subjects with bilateral absence of the PLM were observed and undocumented. Using a dynamometer in subjects with unilateral presence of the PLM, the force of thumb abduction was significantly greater on the hand with a PLM than the one without it (P = 0.014), irrespective of hand dominance. In the second sample with bilateral PLM, thumb abduction on the dominant hand was 10% stronger than on the nondominant hand and was similar to the universally accepted average of 10% increase in grip strength of the dominant hand. Thus, 10% was deducted from all the dominant hands, and the force of thumb abduction remained greater on the hand with PLM than the hand without it (P = 0.049). The results of this study demonstrated the PLM to be involved in thumb abduction, and the authors therefore recommend that this action of the muscle be universally accepted by anatomists and hand surgeons.