Worawut Woraputtaporn

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 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.

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.

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 roo t 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. Knowled ge of such anatomical variations is helpful for surgeons in performing of brachial plexus surgery.

Classification and Incidence of Pterion Patterns of Thai Skulls

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. Thediff erent pterion types of many races have been reported but not of Thais. In this study; therefore, we investigated the incidence of sutural pte rion patterns on of Thai skulls. The infratemporal fossa of 110 sides from 55 dried skulls identified as Thais were observed and classified for indivi ual pterion types. The results showed that the pterion patterns can be classified into 4 types; spheno-parietal (87.27 %), fronto-t emporal (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