Incidence of vertebral artery of aortic arch origin, its level of entry into transverse foramen, length, diameter and clinical significance.

The aim of this study was to show the incidence of vertebral artery of aortic arch origin, its level of entry into transverse foramen, including extra- and intracranial morphometry, and clinical significance. A total of 266 embalmed cadavers were studied. We found 14 left vertebral arteries (5.3%) emerging from aortic arch. Most of the left vertebral arteries of aortic arch origin (78.6%) entered the fifth cervical transverse foramina, whereas most of the vertebral arteries of subclavian origin (94.7% left and 99.2% right) entered the sixth cervical transverse foramina. Their average prevertebral length was 8.24 ± 1.09 cm ,which was about twice as long as the right vertebral artery (3.88 ± 1.14 cm). The average outer diameters of the prevertebral part and ensuing intracranial part of the left vertebral artery of aortic arch origin were 4.36 ± 0.93 and 3.62 ± 0.62 mm, respectively. The mean corresponding diameters of the vertebral artery of subclavian origin were 5.06 ± 1.04 and 3.87 ± 0.83 mm, respectively. All of the vertebral arteries decreased significantly in size after entering the cranial cavity. The reduction in caliber of the intracranial part of the vertebral artery compared with the prevertebral part of its own vessel has never been reported elsewhere. Knowledge of such anatomical variations is important in interpreting CT angiography, anterior cervical decompression and aortic arch surgery to prevent iatrogenic injury of the vertebral artery.

Classification and incidence of pterion patterns of Thai skulls / Clasificación e incidencia de los patrones de pterion en cráneos de Tailandia

SUMMARY: The pterion, a landmark for neurosurgery, is the weakest part of the skull owing to relatively thin bone. Variant patterns of pterion can confuse the clinicians during diagnosis of the lateral skull fractures in emergency situations. Thedifferent pterion types of many races have been reported but not of Thais. In this study; therefore, we investigated the incidence of sutural pterion patterns on of Thai skulls. The infratemporal fossa of 110 sides from 55 dried skulls identified as Thais were observed and classified for individual pterion types. The results showed that the pterion patterns can be classified into 4 types; spheno-parietal (87.27 %), fronto-temporal (4.55 %), uni-epipteric (6.36 %), and multi-epipteric (1.82 %) types. It was found that the spheno-parietal type was dominant in males (61.81 %) than in females (25.45 %). The majority of the skulls showed bilateral symmetry (85.45 %) in all types and the unilateral ones were far less (14.55 %). In bilateral pterion incidence, the spheno-parietal type was approximately 93.61 % while the uni-epipteric type was not found. Moreover, the bilateral multi-epipteric type was found only in one female skull (2.13 %). These findings will be useful for the radiologists and the neurosurgeons concerning lateral skull fractures in emergency diagnosis.

RESUMEN: El pterion es un punto de referencia para la neurocirugía, y es la parte más débil del cráneo debido a estar conformado por hueso relativamente delgado. Los diversos patrones de pterion pueden confundir a los clínicos durante el diagnóstico de fracturas laterales de cráneo en situaciones de emergencia. Con excepción de los tailandeses, diferentes tipos de pterion se han reportado en muchas razas. hemos investigado la incidencia de diversos patrones de pterion en cráneos de Tailandia. Analizamos 110 fosas infratemporales, correspondientes a 55 cráneos secos del Noreste de Tailandia y se clasificaron de acuerdo al tipo de pterion. Los resultados mostraron que el pterion puede clasificarse en 4 tipos: esfeno-parietal (87,27 %), fronto-temporal (4,55 %), epiptérico (3,63 %) y multi-epiptérico (1,81 %). Se encontró que el tipo esfeno-parietal tuvo mayor incidencia en hombres (61,81 %) que en mujeres (25,45 %). Además, la incidencia de simetría bilateral (85,45 %) fue mayor que la unilateral (14,55 %). A nivel bilateral, el tipo esfeno-parietal fue de 93,61 %, mientras que el tipo epiptérico no se observó. Por otra parte, el tipo multiepiptérico fue encontrado bilateralmente en un solo cráneo femenino (2,13 %). Esta incidencia puede ser utilizada como un conocimiento básico para los radiólogos tailandeses sobre las fracturas laterales del cráneo en un diagnóstico de emergencia.

A large modern Southeast Asian human skeletal collection from Thailand.

The Khon Kaen University Human Skeleton Research Centre has a large human collection consisting of 745 modern northeastern Thai (Isan) skeletons derived from bodies bequeathed to the Department of Anatomy during the period 1979-2014. The aim of this paper is to document the collection and address the question of whether the collection may be representative of local Isan people, or populations of the wider region of mainland Southeast Asia. This will determine its value as a reference collection for forensic anthropology in particular but also for all other fields of research about human skeletal biology. Sex is recorded for 99.6% of the skeletons, and age at death for 91.7%. The collection consists of two-thirds males, one-third females. It includes 10 individuals less than 19 years of age, and adults ranging in age from 20 to 109 years of age. Average age at death is 62 years. Other data available for smaller proportions of the collection include cause of death, occupation, and height and weight at the time of donation. Dates of birth are estimated to range from the late 19th Century to the most recent in 1988. Analysis of the demographic composition of the collection shows that is likely to be representative of the ancestral mix of the Isan people, and of the village farmers who still form a large portion of the Isan population. It may also represent 20th Century populations of much of Southeast Asia where agriculture dominates the economy. The collection forms a valuable resource for research on regional human skeletal characteristics for use in forensic anthropology.

Incidence of unusual formation of the median nerve in Thai-Northeast embalmed cadavers / Incidencia de la formación inusual del nervio mediano en cadáveres embalsamados del noreste de Tailandia

This study aimed to investigate the incidence of unusual formation of the median nerve in Thai cadavers. Two hundred and ninety-two upper limbs were dissected and observed. The results showed that 5 out of 292 (1.71 %) arms had unusual splitting of median nerve that supplied the flexor arm muscles. Concomitantly, the musculocutaneous nerve was absent. In 4 out of 5 variant arms (80 % or 1.37 % of total upper limbs), each median nerve was unusually formed by 3 roots; the first and second roots were from lateral cord and the third one from medial cord. The union of the second lateral and medial roots to become a median nerve distantly extended in the arm. The second lateral roots gave off small muscular branches to the upper part of flexor arm muscles. Knowledge of such anatomical variations is helpful for surgeons in performing of brachial plexus surgery.

Este estudio tuvo como objetivo investigar la incidencia en la formación inusual del nervio mediano en cadáveres tailandeses. Se disecaron y observaron 292 miembros superiores. En 5 casos (1,71 %) se presentó una división inusual del nervio mediano que suministraba los nervios para los músculos flexores del brazo. Concomitantemente, el nervio musculocutáneo estaba ausente. En 4 de los 5 casos (80 % o 1,37 % del total de los miembros superiores), cada nervio mediano se formó por 3 raíces; la primera y segunda raíces procedían del fascículo lateral y la tercera del fascículo medial. La unión de la segundas raíces lateral y medial formaban el nervio mediano distalmente en el brazo. Las segundas raíces laterales daban pequeños ramos musculares a la parte superior de los músculos flexores del brazo. El conocimiento de tales variaciones anatómicas es útil para los cirujanos en la realización de la cirugía del plexo braquial.

Classification of portal vein tributaries in Thai cadavers including a new type V.

PURPOSE: To compare portal vein tributaries in Thai with Thompson classification. METHODS: In 211 Thai cadavers, abdominal regions were dissected to identify the portal veins and their tributaries. The subjects were classified into types based on modes of drainage of the left gastric and inferior mesenteric veins. Percentages of all types of venous drainage were counted. RESULTS: There are four types of portal tributaries as defined by Thompson, type I_47.87 %, type II_13.27 %, type III_7.58 %, and type IV_29.86 %. There were 1.42 % of whose inferior mesenteric veins entered the joining angle of the superior mesenteric and splenic veins, and were classified as type V. The left gastric vein mostly drained into the portal vein in 79.15 %, while the inferior mesenteric vein emptied into the splenic vein mainly in 55.45 %. CONCLUSIONS: A new variance of portal tributaries in Thai cadavers is reported. The variations of portal vein formations are critical for liver surgery and interventional radiological procedures.

Incidence of metopism in adult Thai skulls / Incidencia de metopismo en cráneos tailandeses adultos

The persistent metopic suture on adult skull (also known as metopism) can confuse the clinicians during diagnosis of the frontal bone fractures in emergency conditions. The incidences of metopism have been documented in many populations except in Thais. Therefore, this study was aimed to determine the incidence of metopism in adult Thai skulls. The identified 706 Thai dried skulls (481 males and 225 females) were carried out for metopic suture observations. The results showed that 53 skulls (7.51%) were present of the metopic sutures. The metopism observed could be classified into major two types (complete metopic suture (20 skulls [2.83%]) and incomplete metopic suture (33 skulls [4.67%]). For the incomplete metopic suture could be further classified into two subtypes, bregma-incomplete metopic suture and nasion- incomplete metopic suture. This incidence maybe a basic information for Thai radiologists to concern about metopic suture in emergency diagnosis of frontal bone fractures.

La persistencia de la sutura metópica en el cráneo adulto (también conocido como metopismo) puede provocar confusión en los médicos durante el diagnóstico de las fracturas de los huesos frontales en situaciones de emergencia. La incidencia de metopismo se ha documentado en muchas poblaciones, excepto en individuos tailandeses. Por lo tanto, este estudio tuvo como objetivo determinar la incidencia de metopismo en cráneos tailandeses adultos. Se identificaron 706 cráneos secos (481 hombres y 225 mujeres) y se llevó a cabo la observación de ls sutura metópica. Los resultados mostraron que en 53 cráneos (7,51%) estaba presente la sutura metópica. Según nuestras observaciones, el metopismo podría ser clasificado en dos tipos principales: sutura metópica completa (20 cráneos [2,83%]) y sutura metópica incompleta (33 cráneos 4,67%). A su vez, la sutura metópica incompleta podría ser clasificada en dos subtipos: sutura metópica incompleta "bregma" y sutura metópica incompleta "nasion". Consideramos que la indicedencia de metopismo registrado en este trabajo configura una información de relevancia para los radiólogos tailandeses en relación a la sutura metópica y el correcto diagnóstico en la emergencia de fracturas óseas frontales.

Awareness of the median sacral artery during lumbosacral spinal surgery: an anatomic cadaveric study of its relationship to the lumbosacral spine.

PURPOSE: The purpose was to investigate the median sacral artery (MSA) anatomical pathway in terms of its relationship to the lumbosacral spine. METHODS: The posterior wall and lumbosacral spine of 54 adult embalmed cadavers were dissected. The MSA emerging point was identified. The distance from its emerging point to the lateral border of the vertebral body was measured bilaterally. The pathway of the MSA from the emerging point to the sacral promontory was described together with the MSA length. All outcomes were independently measured by two observers. Statistics on obtained data were calculated. RESULTS: Most of the MSA emerging points were at the L5 vertebral body (94.4 %). The emerging point from the right and left lateral border of the L5 vertebral body was 3.31 ± 0.54 cm and 2.39 ± 0.51 cm, respectively. The MSA then lay along the middle one-third of the anterior surface of the lumbosacral junction. The mean length between the emerging point and the sacral promontory was 2.73 ± 0.97 cm. CONCLUSIONS: The MSA anatomy is important for prevention of intra-operative bleeding. For anterior lumbosacral surgery, the MSA should be identified and controlled before proceeding with the spinal surgery. For posterior bicortical sacral screw placement, the screw tip should be fluoroscopically checked to avoid inserting the screw tip into the mid sacral promontory. By first approaching the anterior sacral promontory, the surgeon will find the MSA within the middle one-third zone, and 2.47-2.99 cm cephalad to this, the iliac vessels. Knowledge of the MSA helps the surgeon to operate more safely.

Occipitalization of the atlas: its incidence and clinical implications.

OBJECTIVE: The aim of the present study was to investigate the incidence of occipitalization of the atlas among Thai dried skulls, in order to contribute to baseline awareness of this condition. MATERIALS AND METHODS: The skulls of 633 adult Thais from the collection maintained in the Department of Anatomy, Faculty of Medicine, Khon Kaen University, Thailand, were examined for evidence of occipitalization of the atlas. The skulls were well-preserved and did not show any traits of craniofacial deformation. The skulls for which the age and sex were unknown were excluded from the analysis. From the cadaveric records on each individual, we learned that the skulls belonged to 373 men (age of decease between 25 and 90 years), and 260 women (age of decease between 28 and 92 years). RESULTS: Occipitalization of the atlas was detected in 2 skulls (0.32%). The first case was a male skull (54 years of age at decease), where the atlas was partially fused to the occipital bone. The second case was also a male skull (59 years of age at decease) showing complete fusion of the anterior arch of the atlas. CONCLUSION: The incidence of occipitalization of the atlas is low; however, if present this abnormality may cause a wide range of neurological problems. Knowledge of occipitalization of the atlas may be of substantial importance to orthopedists, neurosurgeons, physiotherapists and radiologists dealing with abnormalities of the cervical spine. Mistaken diagnoses have led to delayed treatment and at times adverse results.

A rare variation of posterior cord brachial plexus branching coexisting with the intercalated ectopic muscle.

During a dissection of the brachial plexus we found a rare variation of left posterior cord branching coexisting with an unusual intercalated ectopic muscle. This muscle originated from the shoulder joint capsule at the lesser tubercle on insertion of the subscapularis then pierced between the brachial plexus, enclosed by two roots of the radial nerve, and inserted into the upper part of the latissimus dorsi muscle. The variant posterior cord divided into two roots; a thin lateral and thick medial root. The lateral root gave off the thoracodorsal nerve that penetrated and also innervated the ectopic muscle. The medial root gave off five nerve branches; two upper subscapular, one lower subscapular, one axillary and one terminal branch. A terminal branch fused with the lateral root to form a loop enclosing the ectopic muscle then continued as the radial nerve. This type of variation may be useful to interpret unexplained clinical signs and symptoms and provided additional knowledge to surgeons who perform brachial plexus surgery.

The right ovarian artery arising from the right inferior phrenic artery: a case report.

OBJECTIVE: To report a case of the right ovarian artery arising from the right inferior phrenic artery. MATERIAL AND METHOD: The authors carried out the standard dissection survey of 810 embalmed female cadavers between 1983 and 2010. RESULTS: The authors encountered a case of the right ovarian artery arising from the right inferior phrenic artery in a donated cadaver aged 53 years at decease. CONCLUSION: With the advent of intra-abdominal laparoscopic techniques, the anatomy of the ovarian artery has assumed much more importance.

Incidence of the accessory internal thoracic artery and its safety area in the thoracic wall.

OBJECTIVE: To provide the incidence, origin, size and the safety area of the accessory internal thoracic artery (AITA) in the fourth intercostal space. MATERIAL AND METHOD: One hundred and thirty two thoracic cages were dissected and examined for the presence of AITA. The origin, course, diameter and location in the fourth intercostal space of detected AITA were investigated. RESULTS: AITA with diameter ranging from 0.6 to 3.05 (mean = 1.76 +/- 0.69) millimeters existed in 10 of 132 (7.58%) cadavers. They originated from the upper part of the internal thoracic artery, close and inferior to the subclavian artery (0-3 cm, mean = 2.4 +/- 0.78) and ran inferolaterally on the deep surface of the thoracic wall and ended in the second to the sixth intercostal spaces. Most of them ended in the fifth intercostal spaces (28.57%). The artery was present bilaterally in 4 cases (3.03%) and unilaterally in 6 cases (4.55%). Most of these arteries were located close to the midaxillary line (0-3 cm, mean = 1.73 +/- 1.18) in the fourth intercostal space which is endangered in several surgical procedures such as thoracoscopy. CONCLUSION: Even the incidence of AITA is low (7.57%) but when present, it is endangered in thoracic surgical procedures. The safety area of AITA for surgical procedures in the fourth intercostal space is at least 3 centimeters anterior to the midaxillary line.

Left sided inferior vena cava: a case report.

OBJECTIVE: To report a case of left sided inferior vena cava (IVC). MATERIAL AND METHOD: The authors carried out the standard dissection survey of939 embalmed cadavers between 1974 and 2008. RESULTS: The authors encountered a case of left sided IVC in a male donated cadaver aged 65 years at decease. The IVC formed behind the left common iliac artery at the L5 vertebra and coursed proximally on the left of the aorta until it reached the left renal vein and then crossed anterior to the abdominal aorta to assume the normal right side. At the point of crossing, it received the left renal vein. The right renal vein emptied into the IVC on the right side. CONCLUSION: In the era of laparoscopic urological surgery, preoperative diagnosis of this uncommon but important entity is essential to prevent unwarranted surgical mishaps.