Frequency of palmaris longus absence and its association with other anatomical variations in the Egyptian population.

The palmaris longus (PL) is one of the most variable muscles in the human body. Racial differences in its variation have been documented. Several studies have attempted to correlate PL absence with other anatomical variations. This study was conducted to determine the prevalence of absence of PL, correlate it with gender and body side and to determine its association with other anatomical variations in the Egyptian population. The presence of PL was clinically determined in 386 Egyptians using the standard technique. All subjects were examined for the presence of the flexor digitorum superficialis (FDS) to the fifth finger. Allen's test was done to assess the completeness of the superficial palmar arch (SPA). The overall prevalence of absence of the PL in Egyptian subjects was 50.8%. There was no significant difference in PL absence with regard to the body side but a significant difference was seen as regards gender and when bilateral absence of PL was compared to its unilateral absence. Absence of FDS tendon to the fifth finger was seen in 1.3% subjects. There was no association between the absence of the FDS tendon to the fifth finger and either presence or absence of PL and also between the absence of PL and the incompleteness of SPA in both genders. In conclusion, the prevalence of absence of PL in the Egyptian population represents one of the highest rates of absence to be reported for this muscle, which is significantly different from that in other ethnic groups.

The prevalence of absence of the palmaris longus muscle in the Bahraini population.

Absence of the palmaris longus muscle has been well documented in several populations at a prevalence rate ranging between 2.2 and 63.9% which varies according to race, sex, and side of the body. There is little documentation of the prevalence of absence of this muscle from populations in the Arabian Gulf region. We examined 1,043 subjects, 3-85 years old, from the Kingdom of Bahrain for the presence or absence of the palmaris longus muscle using the conventional test for the presence of this muscle. Statistical analyses investigated the association of muscle absence with sex, hand dominance, and laterality. The palmaris longus muscle was absent in 36.8% of subjects. Bilateral absence (19%) was more common than unilateral absence (17.9%) with preponderance in female subjects. The muscle was absent more often on the left side than the right (P = 0.003). In the right upper limbs the muscle was absent in female subjects more than male subjects (P = 0.031). This study reaffirms that there is population variation in the frequency of absence of the palmaris longus muscle. The tendon of the palmaris longus bifurcated at the wrist in 7.1% of subjects, with male subjects showing this feature more frequently than female subjects in the right hand (P = 0.037) and the left hand (P = 0.030). This has not been reported before. The clinical significance of our findings is discussed.

Population variation in the incidence of the medial (hamate) facet of the carpal bone lunate.

Studies on the wrist joint have shown two types of the carpal bone lunate. In type II lunate there is a facet on the medial side of the lunate for articulation with the proximal pole of the hamate; such a facet is absent in type I lunate. Type II lunates have different kinematics, are more prone to clinically relevant degenerative changes in the hamato-lunate joint and are an uncommon cause of ulnar-sided wrist pain. Ninety plain radiographs showing postero-anterior views of the wrist (52 right and 38 left wrists) were studied in a population of Malays from Malaysia (mean age 48 years; age range 23 to 67 years) to determine the incidence of type I and type II lunates. Our findings were compared with those in other reports in the literature. In Malays, only 24 wrists (26.7%) showed a type II lunate compared to a reported incidence of 50% or more in populations from the Western world. Such a low incidence of type II lunate has not been reported before and may represent a genetic variation in Malays. Consequently, osteoarthritis of the hamate or lunate may play a less significant role in causing ulnar-sided wrist pain in Malays. In conclusion, the prevalence of type II lunate might vary in different population groups and further studies could be necessary to confirm this observation.

Assessment of anatomy in a problem-based medical curriculum.

In the problem-based learning (PBL) approach to medical education, students are expected to be trained more by applying processes of reasoning than by memorization of facts. In a PBL curriculum, as with others, it is necessary to match the assessment to the learning process. A detailed description of the testing of anatomical teaching-learning outcomes at the Arabian Gulf University (AGU) is presented. In addition to describing the general principles and guidelines as well as the process of continuous assessment, we have given examples of the multiple-choice questions, patient management problems, and objective-structured practical examinations, which compose our end-of-unit examination and test both vertical and horizontal integration of themes. Students have the opportunity to review the examination after publication of the results. We believe that our approach to the assessment of anatomy tests effective integration of factual knowledge with the principles of problem-solving through the different formats of the components of our examinations.