Cutaneous distributions of genitofemoral and ilioinguinal nerves to pubic, perineal and ventromedial thigh regions in Thais.

Objective: To determine the cutaneous distributions of genitofemoral (Gf) and ilioinguinal (Ig) nerves to pubic, perineal and ventromedial thigh regions in Thais. Methods: The present study was performed bilaterally in 98 halves of 49 embalmed cadavers. The cutaneous distributions of the Gf and/or Ig nerves to these regions were dissected, identified and recorded. Results: Based on the cutaneous distributions of Gf and/or Ig to pubic, perineal, and ventromedial thigh regions, five different types of cutaneous branching patterns of both nerves were identified. Type A (18.28% of cases) had only the branches of Gf to the mons pubis, anteroproximal part of the root of penis, the scrotal or labial and the ventromedial thigh regions but in type B (21.51% of cases) had only the branches of Ig to these regions. The most frequent type of these innervations was type C (39.78% of cases) with dominance of both nerves branching to these regions. In type D (8.60% of cases), having the branches of both nerves but with a dominance of Gf, consisted of 2 subtypes D-1 (2.15% of cases) and D-2 (6.45% of cases). In contrast to type D, type E (11.83% of cases) having the branches of both nerves but with a dominance of Ig, consisted of 2 subtypes E-1 (8.60% of cases) and E-2 (3.23% of cases). Conclusions: These findings would provide the marked anatomic variability of Gf and/or Ig nerves in pubic, perineal and ventromedial thigh regions in Thais, and may assist diagnosis, anesthetic nerve block and prevention nerve damage during surgery.

Anatomic variations of the superficial part of cervical plexus and its branches in Thais.

Objective: To evaluate the variations of superficial part of cervical plexus and its branches in Thais. Methods: We dissected bilaterally in 108 cervical plexuses in Thai cadavers. The anatomic variations of origins and its cutaneous branches of the superficial part of cervical plexus were identified and recorded. Results: The superficial part of cervical plexus derived from the ventral rami of C2, C3, and C4. Its branches consisted of the lesser occipital, great auricular, transverse cervical and supraclavicular nerves. These cutaneous (or superficial) nerves mainly derived from ventral rami of C2-C3 except the supraclavicular nerve from C3-C4. They supplied the skin and superficial structures of the head, neck and shoulder. The anatomic variations of these nerves occurred in both sides. There was no statistical difference with regard to either gender or side. Conclusions: The knowledge of the anatomic variations of cutaneous branches of the superficial cervical plexus from this study could be useful for clinicians in anesthesia blocks, surgical procedures, treatment of pain and abnormalities relating to these cervical nerves.

Accuracy of cranial and mandible morphological traits for sex determination in Thais.

Objective: To evaluate the accuracy of sexual dimorphism in the cranium and mandible of Thais using Krogman’s cranioscopy and the modified Krogman’s cranioscopy traits by grading and measurement. Methods: Data were from 101 dry adult skulls (66 males and 35 females) residing in central Thailand. Results: Sex determination using Krogman’s cranioscopy by an inexperienced person had a very high accuracy of 95.5% for males, 82.9% for females respectively and 91.1% overall. According to modified Krogman’s cranioscopy traits by grading, males had larger supraorbital tours, a rougher glabella region and more external occipital protuberance than females. Regarding modified Krogman’s cranioscopy trait by measurement, males had a wider base and a higher mastoid process, with longer and wider occipital condyles than females. Both later methods were also useful in the sexing of fragmented skulls. Conclusion: The cranioscopy study based on 14 traits according to Krogman’s cranioscopy is the best method for sex determination of individual unknown skulls. The modified Krogman’s cranioscopy trait by grading and by measurement is simplified and can very well predict the sexing of fragmented skulls.

Sex determination in Thai skulls by using craniometry: Multiple logistic regression analysis.

Objective: To evaluate sexual dimorphism in the cranium and mandible of Thais by using Jorgensenûs craniometry and to develop a statistical model to determine sex from craniometrical measurements and indices. Methods: One hundred and one Thai skulls (66 males and 35 females) which ranged in age from 18 to 86 years were studied. Results: According to craniometry, the skull of a male is larger and higher than that of a female. Considering each individual measurement, although 26 of 30 measurements and 5 of 14 indices showed a statistically significant difference between males and females, they had some overlaps. To predict gender more accurately, a multiple logistic regression model based on 4 skull measurements (mm) i.e., nasion-basion length (M5), maximum breadth of the cranium (M8), facial length (M40), and bizygomatic breadth of the face (M45) was developed as follows: In (odds) = Z = -52.5312 + 0.27 M5 - 0.1867 M8 + 0.1268 M40 + 0.319 M45 The probability of being males (P) is then ez/(1+ez). Using a cut off point for P of 0.5, this logistic model could correctly predict 82.9% (95% CI: 66.4%, 93.4%) of females and 92.1% (95% CI: 82.4%, 97.4%) of males respectively with the overall accuracy of 88.8% (95% CI: 80.8%, 94.3%). Conclusion: Jorgensenûs craniometry of the cranium and mandible can be used to determine gender among Thais via a multiple logistic regression model on M5, M8, M40 and M45.

The glenoid fossa: Shape, inclination and version in Thais.

A study of the glenoid fossa in Thais was carried out in ninety five normal shoulders in cadavers from the Department of Anatomy, Faculty of Medicine Siriraj Hospital. The mean age of the cadavers at the time of death was 69.8 years. In order to provide basic structural information of the glenoid orientation in adult Thais, the work was done by using a custom-made scapula holder which kept the scapula the scapula in position in which the reference line superimposed with the axis of the scapula. The angular measurement performed by using a goniometer placed contact on both rims of the glenoid and center was superimposed with the reference line. Most of the scapulae, 85%, showed in upward inclination with the value of +6.7o+3.4o (mean + SD) and 13% scapulae tilted downward with -3.7o+1.9o. In a horizontal orientation, 81% of the scapulae faced backward (retroversion) with -5.5o+3.0o and 16% facing forward (anteroversion) with +3.8o+1.6o. The similar figures were also found in the scapula male and female cadavers; 8.5% of male scapulae had an upward inclination with +6.3o+3.3o and 13% a downward inclination with -3.7o+1.9o. Glenoid retroversion was found in 78% of male scapulae (-4.9o+2.7o) and 86% in the female scapulae (-6.1o+3.2o). The glenoid anterversion was found in 20% of male scapulae (+4o+1.5o) and 12% in female scapulae (+3.5o+1.9o). Statistacal analysis between genders and side showed no significant difference, nor a correlation to the dominatarm.

The scapula : Osseous dimensions and gender dimorphism in Thais.

Anatomic and morphometric study of the scapula in Thais was aimed to provide fundamental information for surgical procedures such as fixation device selection, arthrocopic portal placement, prosthetic design and positioning. Therty measurements were carried in 97 scapulas, 25 pairs from female and 23 pairs and one left side from male cadavers. The average age at the time of death was 69.82 years. The average length of scapula measured from the superior angle to the inferior angle was 13.93+1.11 cm. (mean+standard deviation). The thickness of the lateral border taken from the midpoint and 1 cm. from the edge was 0.82+0.20 cm. thicker than the medial border taken in the same manner (0.12+0.08 cm.). The inferior angle was more acute at 40.88+5.29 degrees and thicker than the superior angle (84.29+9.43 degrees). The superior border was thin and sharp; the suprascapular notch was presented on the border medial to the root of the coracoid process. The depth and shape of the suprascapular notch were variable. The length of the spin measured from the tip of the acromion process to its medial edge was 12.89+0.94 cm. The anteroposterior width of the spine measured were 0.60+0.15 and 1.78+0.29 cm. taken from 1 and 4 cm. away from its medial edge, respectively, and 4.15+0.43 cm. width meansured in the plane of the spinoglenoid notch. The dimensions of the acromion of the acromion process were 4.41+0.47 cm. X 2.50+0.37 cm. (L x W x T). The distance between the acromion and coracoid processes was 3.11+0.41 cm. The coracoids measurements were 4.04+0.41 cm. X 1.46+0.19 cm. X 0.74+0.12 cm. (L x W x T). The distance measured from the tip of the coracoid process to the bottom of suprascapular notch was 4.84+0.39 cm. The glenoid dimensions were 3.58+0.35 (superoinferior) and 2.73+0.31 cm. (anteroposterior). The thickness of the scapula neck was 1.91+0.37 and 1.02+0.27 cm. at 1 and 2 cm. away from the glenoid rims. Scapulas from male cadavers were significantly larger than those from female cadavers in 27 meansurements.

Anatomic variations of the sacral plexus in Thais.

The aim of this study was to examine the variation of the sacral plexus in Thais in terms of its origin, branches, and variation in each branch. Anatomical dissections were conducted in 150 halves of formalin-embalmed cadavers. All preserved cadavers were Thais, ranging in age from 35 to 85 years old, 86 males and 64 females. The sacral plexus was markedly comprised of the fourth lumbar to fourth sacral ventral rami (L4-S4) in 98.67% of the plexuses (or 148 cases) except for two plexuses (1.33% of the plexuses) those were derived from the ventral rami of the fourth lumbar to fifth sacral ventral rami (L4-S5). The sacral plexus, lying on the posterior wall of the lesser pelvis to the piriformis muscle, has nine named branches. Six of these are distributed to the buttock and lower lomp, including 1) Nerve to the Quadratus Femoris and Gemellus Inferior, 2) Nerve to the Obturator Internus and Gemellus Inferior, 3) Superior Gluteal, 4) Inferior Gluteal, 5) Posterior Femoral Cutaneous and 6) Sciatic. The other branches supply structures belonging to the pelvis, including 7) Nerve to the Piriformis, 8) Pudendal and 9) Pelvic Splanchnic. The variant of origination and formations of all branches occur on both side. However, the anatomic variability of the plexuses was not statistically different with regard to either side or gender. The results from this study provided additional information and new insights into the sacral plexus in terms of its origins, branches, and variations of each branch that might be useful in medicine, anesthesia, surgery and physical therapy.

Anatomic variations of the lumbar plexus in Thais.

The aim of this study was to examine the variation of the lumbar plexus in Thais in terms of its origin, branches, and variation of each branch. Anatomical dissections were conducted in 150 halves of formalin-embalmed cadavers. All preserved cadavers were Thais, ranging the age from 35 to 85 years old, 86 males and 64 females. The lumbar plexus was markedly composed of the first to fourth lumbar ventral rami (L1-L4) in 81.33% of the plexuses (or 122 cases), but its origin varied, as it was derived from the ventral rami of the twelfth thoracic to fifth lumbar ventral rami (T12-L5) in 18.67% of the cases. Eight branches of the plexus were found, including seven typical branches and an additional branch. The seven typical branches occured in 100% of cases, and they were the iliohypogastric, ilioinguinal, genitofemoral, lateral cutaneous nerve of the thigh, femoral, obturator nerve and lumbosacral trunk. The additional branch, the accessory obturator nerve occurred in only 3.33% of the cases. In conclusion, the variation pattern of the plexuses occurred on both sides. However, the anatomic variability of the plexuses was not statistically different with regard to either side or gender. The result from this study provided additional information different with regard to either side or gender. The results from this study provided additional information and new insights into the lumbar plexus in terms of its origins, branches, and variations of each branch that might be useful in medicine, anesthesia, surgery and physical therapy.

Anatomical variation course of the lateral femoral cutaneous nerve as it exits the pelvis in Thais from the central region.

The aim of this study was to examine in detail the course and location of lateral femoral cetaneous nerve (LFCN) as it emerges from the pelvis in Thais. The anatomy of the LFCN was studied through the dissection of 107 halves of formalin-embalmed Thai cadavers ranging in age from 37 to 94 years. The LFCN is formed by the union of posterior divisions of ventral rami of the second and third lumbar spinal nerves (L2 – L3). The site at which the nerve exits the pelvis is quite variable. Depending on the anatomical location which varies from superficial and posterior, to medial and deep, to anterior superior iliac spine (ASIS) and origin of the sartorius muscle, five different types as identified by Aszman et all1 were confirmed : type A, posterior to the anterior superior iliac spine across the iliac crest (1.86%); type B, medial to the anterior superior iliac spine and ensheathed in the inguinal ligament (9.34%); type C, medial to the anterior superior iliac spine and ensheathed in the tendinous origin of the sartorius muscle (46.72%); type D, medial to the anterior superior iliac spine located in the interval between sartorius muscle and iliopsoas muscle deep to the inguinal ligament (40.18%); type E, medial to the anterior superior iliac spine, deep to the inguinal ligament, overlying the iliopsoas fascia, and contributing the femoral branch of genitofemoral nerve (1.46%). The majority of the LFCN course and location as it exits the pelvis are type C (46.72%), and type D (40.18%). There is no statistical difference with regard to either gender or side of thigh.

Anatomical variations of the ansa cervicalis in Thais.

The aim of this study was to examine the variation of ansa cervicalis in Thais in terms of its origin, formation and relation to the great vessels of the neck. Anatomical dissections were examined bilaterally in 108 cervical plexuses of Thai cadavers ranging in age from 34 to 87 years. There were 57 male and 51 female cervical plexuses. The ansa cervicalis which consists the first to third cervical ventral rami (C1-C3), is formed by the junction of the superior and inferior roots. Its anatomical course and morphology are complicated by the variable lengths, origins, and relations with the great vessels of the neck. Twenty types of ansa cervicalis were classified into 5 different groups according to the length of ansa loop as compared with the level of cricoid cartilage and the relation of the inferior root of the ansa to the internal jugular vein. Depending on the origins of the inferior and superior roots, each group consisted of various types. Group I and II had long ansa loops with the inferior root lying lateral to the internal jugular vein in group I, and nedial to the vein in group II. Similarly, group III and IV had short loops of the ansa with the inferior root lying lateral to the internal jugular vein in group III, and medial to the vein in group IV. However, group V was not related to the criteria. It was suggested that the majority of ansa cervicalis were found to be group IV and group I. The variation of ansa cervicalis patterns occurred in both sides. This was not statistically different with regard to either gender of side. The results of this study provide additional information and new insights into the variation of the ansa cervicalis which may have useful applications in laryngeal reinnervation surgery and anrsthesia.

An improved method for whole mount embryo preparations from chick embryos.

Background : Embryology studies require good quality embryonic images. In addition, many teratology studies require the critical gross examination of embryos to determine the exact stage of embryonic development, or the extent of malformations. Objectives : The present study was designed to develop an improved method for preparing embryos. Materials and Methods : Sixty fertilized chicken eggs were divided into 6 groups of 10 and incubated at 38 oC foe various time periods (18, 20, 25, 30, 55, 72 hrs) depending on the developmental stage of the embryos. After incubation, the embryos were removed from the shells and yolk sacs. In each group, 5 embryos were stained using the Mayer’s carmine technique and the remaining 5 embryos were stained using the improved method. By the new method, the embryos were macerated in 3% potassium hydroxide for different length of time before the Mayer’s carmine staining. Results : It was found that the whole mount chick embryos which were stained with Mayer’s carmine after maceration were of better quality than those stained using the routine Mayer’s carmine technique. The new method gave superior preservation, clarity and contrast of the normal embryonic details. Interestingly, the advantage of the new method was clearly noted in the later stage of embryonic development, at the 30-somite and 30-somite stages. Using the routine Mayer’s carmine technique, the development of heart, circulation, and nervous system were not clearly differentiated, since those structures were concealed by soft tissues and/or many structures. In contrast, the new technique facilitated identification and allowed us to understand the whole development process of those structures. Conclusions : The new method improves the visibility of embryonic details normally seen or not seen with the Mayer’s carmine technique. It permits good quality photographs to be produced rapidly and consistently for the standard gross embryo analyses in embryology and teratology.

Non-rotation of the midgut in adults.

Two cases of non-rotation of the midgut were detected in cadaveric bodies from the Department of Anatomy, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand. They were both female, aged 83 and 32, respectively. In both cases, the duodenum, jejunum, ileum, and colon lay in the unrotated position with the small intestine occupying the right half and the large intestine occupying the left half of the abdominal cavity. Additionally, the duodenojejunal junction remained on the right side of the abdomen, whereas the caecum and ascending colon lay in the midline, with the terminal ileum entering the right side of the caecum. The appendix entered the left side of the caecum. Interestingly, they had had no clinical symptoms during life. These abnormalities implied that midgut rotation during embryonic period occurred only as far as 90-degrees counterclockwise instead of the usual 270-degree rotation. To our knowledge, this is the first report of asymptomatic non-rotation of the midgut in Thailand. The variation found in the present study provides additional information concerning the variation seen in human anatomy and should be considered in patients with atypical symptoms related to the gastro-intestinal tract.

The inferior transverse scapular ligament in Thais.

Eighty-four shoulders of cadavers were dissected to determine the prevalence of the inferior transverse scapular (Spinoglenoid) ligament. Three types of the structures, forming an arch above the suprascapular nerve ad vessels at spinoglenoid notch, were classified in this study. Type I, the inferior transverse scapular fascia, was found in 45 cases (53.6 percent). Type II, the inferior transverse scapular membrane, was present in 30 cases (35.7 percent). This membrane was formed by bands of fascia distinct from the surrounding tissues. Type III, the inferior transverse scapular ligament, was present in 9 cases (10.7 percent). The ligament extended from the lateral border of the spine of the scapula to the margin of the glenoid cavity. Type I was the most common and type III was the least. Type I and type Ii were not true ligament. The study can serve as a reference to the inferior transverse scapular ligament in Thai and remind the neurologist or neurosurgeon that suprascapular nerve compression may result from lesions of the inferior transverse scapular ligament.

Evaluation of anatomical study in Siriraj medical students after changes in medical curriculum.

After the medical curriculum of the Faculty of Medicine, Siriraj Hospital, was changed, the premedical period was reduced from two years to one year. Academic credit was also decreased from 73 to 50 credits. Basic knowledge in Biology of medical students who studied under the new curriculum was less than the students who studied the old one. Evaluation of the Students’ Anatomical knowledge revealed that there was no significant difference among three groups of medical students. This indicated that the reduction of curriculum did not effect academic performance of medical students.