Latha V. Prabhu

Anatomical organization of aortic arch variations in the India: embryological basis and review

OBJETIVOS: Determinar a porcentagem e o tipo de variacoes do arco aortico em individuos indianos, bem como sua importância clinica e cirurgica e base embriologica. PACIENTES E METODOS: Em nossa investigacao, os padroes de ramificacao do arco aortico foram estudados em 62 cadaveres fixados em formalina de ambos os sexos, de origem indiana e com idade entre 45 e 79 anos. As dissecacoes foram realizadas em cadaveres preservados em formalina, e as variacoes do arco aortico foram observadas apos a exposicao das regioes toracica e cervical durante a dissecacao de rotina de alunos da graduacao do Kasturba Medical College, Mangalore, India. RESULTADOS: O arco aortico normal de tres ramificacoes foi encontrado em 56 cadaveres (91,4%); as variacoes foram encontradas em seis cadaveres (9,6%); 4,8% apresentavam origem comum das arterias carotidas; 1,6% tinham sequencia binominada, e o mesmo especime tinha a origem da arteria coronaria esquerda diretamente no arco aortico; 1,6% apresentavam a origem da arteria subclavia direita diretamente na aorta; 1,6% tinham como ramificacao do arco aortico uma arteria vertebral esquerda. Cinco de seis cadaveres com padrao de ramificacao anomalo do arco aortico eram do sexo feminino. Um cadaver do sexo masculino apresentou origem anomala da arteria vertebral esquerda diretamente no arco. CONCLUSAO: O amplo espectro de variacoes nos padroes anatomicos das ramificacoes do arco aortico na populacao indiana estava em concordância com outras populacoes mundiais. Embora as origens anomalas das ramificacoes do arco aortico sejam meramente variacoes anatomicas, informacoes precisas sobre elas e essencial para a cirurgia vascular na regiao do torax, cabeca e pescoco.

Supratrochlear foramen of the humerus: An anatomico-radiological study with clinical implications

Background. The supratrochlear foramen (STF) of the humerus has been a neglected entity in standard anatomy and orthopaedics text-books. The knowledge of the presence of STF in a humerus may be important for preoperative planning for treatment of supracondylar fractures. The presence of STF may also result in erroneous interpretation of radiographs. Methods. The STF was studied in detail in 384 (220 left side and 164 right side) human dried humeri of unknown sex and age. The topographical anatomy of the STF was studied in detail, morphometric measurements were taken, and the specimens were photographed. The humerus was also taken for radiological assessment of the STF and supratrochlear septum. Results. Out of the 384 bones studied, 132 cases (34.3%) showed the presence of STF. The STF was oval, round, and triangular in shape in 123, 7, and 2 cases, respectively. The mean length of the transverse diameter for supratrochlear foramen was 6.55 mm and 5.99 mm on the left and right sides, respectively. The mean length of the vertical diameter for STF was 4.85 mm and 3.81 mm on the left and right sides, respectively. Most of the bones that had no STF showed a translucency of septum, in 56.7% of the bones. Conclusions. The results of our study show that STF is more common on the right side, with the oval shape being more common. The respective sides did not exhibit any statistical significant differences. Presence of STF may be important for anthropological, clinical, and academic purpose.

Incidence of Extensor Digitorum Brevis Manus Muscle

The extensor digitorum brevis manus, a supernumerary muscle in the fourth extensor compartment of the dorsum of the wrist, is a relatively rare anomalous muscle. Extensor digitorum brevis should be included in the differential diagnosis of soft tissue masses on the dorsal aspect of the hand as it may mimic cystic, neoplastic, inflammatory, and infectious masses arising in the dorsum of the wrist. Seventy-two upper limbs of male and female cadavers were dissected and examined to study the pattern of extensor tendons of the index finger. In the present study, we observed three cases (4.2%) of the extensor digitorum brevis manus on the left side. In one cadaver (0.72%), there was an additional tendon arising from the extensor indices which was inserted to the radial side of the dorsal digital expansion of the index finger. The extensor digitorum brevis manus muscle (EDBM), an anatomic variant of the extensor muscle of the dorsum of the hand, is found in approximately 2% to 3% of the population. This variation is, therefore, clinically and surgically relevant because the EDBM may be the only muscle responsible for the independent extension of the second digit. The aim of the present study is to report the incidences of this muscle thereby creating awareness of its existence and of its characteristic appearance to surgeons.

Variability in the origin of the obturator artery

INTRODUCTION General surgeons dealing with laparoscopic herniorrhaphy should be aware of the aberrant obturator artery that crosses the superior pubic ramus and is susceptible to injuries during dissection of the Bogros space and mesh stapling onto Cooper’s ligament. The obturator artery is usually described as a branch of the anterior division of the internal iliac artery, although variations have been reported. MATERIALS AND METHODS The present study was conducted on 98 pelvic halves of embalmed cadavers, and the origin and course of the obturator artery were traced and noted. RESULTS In 79% of the specimens, the obturator artery was a branch of the internal iliac artery. It branched off at different levels either from the anterior division or posterior division, individually or with other named branches. In 19% of the cases, the obturator artery branched off from the external iliac artery as a separate branch or with the inferior epigastric artery. However, in the remaining 2% of the specimens, both the internal and the external iliac arteries branched to form an anastomotic structure within the pelvic cavity. CONCLUSION The data obtained in this study show that it is more common to find an abnormal obturator artery than was reported previously, and this observation has implications for pelvic surgeons and is of academic interest to anatomists. Surgeons dealing with direct, indirect, femoral, or obturator hernias need to be aware of these variations and their close proximity to the femoral ring.

The accessory heads of flexor pollicis longus and flexor digitorum profundus: Incidence and morphology

Kiloh–Nevin syndrome caused by compressive neuropathy of the anterior interosseous nerve in the forearm is believed to occur because of its compression by the accessory head of flexor pollicis longus (FPLah). Gantzer described two accessory muscles, the more frequent is the FPLah and the less frequently observed is the flexor digitorum profundus accessory head (FDPah). Many studies have reported the prevalence, origin, insertion, nerve supply, and relations of these accessory muscles, most of them focusing on the FPLah. This study was designed to investigate the prevalence, morphology, relation to median and anterior interosseous nerve, and also the coexistence of both the accessory heads. A total of 126 upper limbs of the embalmed cadavers were examined in this study. Fifty‐eight limbs (46.03%) showed the presence of the FPLah and 18 limbs (14.28%) had the FDPah. The most common origin of both the accessory muscle bellies was from the under surface of the flexor digitorum superficialis. The FPLah inserted into the FPL muscle at varying levels with 80% inserting into the proximal third of FPL, whereas the FDPah in all cases ended near the level of the wrist joining with one or more tendons of the FDP. Clinical implication of the variation is discussed. Clin. Anat. 21:252–258, 2008.

Pterygospinous bar and foramina in Indian skulls: incidence and phylogenetic significance

Incomplete or complete ossification of the pterygospinous ligament is uncommon. Entrapment of mandibular nerve and its branches was reported due to this anatomical variation, when found. The aim of the present study is to investigate the incidence of the pterygospinous bony bridges in Indian dry skulls. A total of 416 adult dry skulls of Indian origin were studied. In 9.61% of the samples the pterygospinous bony bars were found, out of which 5.76% was complete and 3.84% was incomplete. Such variations are of clinical significance while dealing with mandibular nerve and its branches and various clinical symptoms related to it.

Morphological analysis and morphometry of the foramen magnum: an anatomical investigation.

AIM The objectives were to study the morphology of the foramen magnum in dry skulls and to evaluate its antero-posterior diameter, transverse diameter and the foramen magnum index. MATERIAL AND METHODS The foramen magna of 53 dry human cadaver skulls that were obtained from the neuroanatomy laboratory were examined. Different shapes of the foramen magnum were macroscopically noted and classified. The antero-posterior and transverse diameters were measured and the average foraminal index was calculated. RESULTS The foramen magnum shapes were determined as a round shape in 22.6% of cases, egg shape in 18.9%, tetragonal in 18.9%, oval in 15.1%, irregular in 15.1%, hexagonal in 5.6% and pentagonal in 3.8% of the cases. In 20.7% of skulls, the occipital condyle was observed to protrude into the foramen. The mean antero-posterior and transverse diameter of the foramen magnum was determined as 31 ± 2.4 mm and 25.2 ± 2.4 mm respectively. The average foramen magnum index was 1.2 ± 0.1. CONCLUSION The present study has determined the various shapes of foramen magnum and its morphometry. The data obtained may be of useful to the neurosurgeon in analyzing the morphological anatomy of craniovertebral junction. The findings are also enlightening for the anthropologists, morphologists and clinical anatomists.

Accessory transverse foramina in the cervical spine: incidence, embryological basis, morphology and surgical importance.

AIM To study the incidence of accessory foramina transversaria in cervical spine and to analyze them morphologically with emphasize on their embryological and surgical importance. MATERIAL AND METHODS The study included 363 human cervical vertebrae which were procured from the bone collections of the Department of Anatomy. The foramen transversarium was observed macroscopically on both sides of all the vertebras, the accessory foramina were noted. RESULTS Out of 363 specimens, only 6 (1.6%) vertebrae showed the accessory foramina. Among them 5 (1.4%) vertebra had double foramina and only 1 (0.3%) vertebra showed three foramina. Only 1 (0.3%) vertebrae showed the foramen on both sides and the remaining 5 (1.4%) had unilateral foramina. Among the unilateral, 4 were present on the right side and only 1 was on the left side. No vertebrae showed the absence of foramen transversarium. CONCLUSION The present study observed the accessory foramina transversarium in 1.6% of cases. The unilateral presence was more common than the bilateral. The surgical anatomy of these variations is important for the neurosurgeons and radiologists for interpreting the computed tomogram and magnetic resonance image scans. Their morphological knowledge is clinically important since the course of the vertebral artery may be distorted in such situations.

A rare case of bilateral sternocleidomastoid muscle variation

An abnormal sternocleidomastoid (SCM) muscle was encountered bilaterally during routine dissection of the head and neck region of a 60 year old male cadaver. The SCM muscle of both the sides had an additional sternal head arising from the capsule of the sternoclavicular joint and the supero-lateral border of the manubrium sterni. The clinical significance of the present variation is immense, as it might cause difficulty in assessing the vital neurovascular structures of the neck during surgical procedure.

Morphological and topographical anatomy of nutrient foramina in the lower limb long bones and its clinical importance

BACKGROUND Knowledge regarding nutrient foramina of bones is useful in surgical procedures such as microvascular bone transfer in order to preserve the circulation. The objective of the present study was to study the morphology and topography of nutrient foramina and to determine the foraminal index of the lower limb long bones to provide detailed data on such features. METHOD The study comprised examination of 206 lower limb long bones which included femora, tibiae and fibulae. The nutrient foramina were identified analysed macroscopically and the foramen index calculated. Each bone was divided into five parts and topographical analysis was performed on each section. RESULTS Femora had single nutrient foramen in 47.7% of the cases, double foramen in 44.2% of the cases, triple in 3.5% of the cases and an absence of foramen in 4.6%. In the case of tibiae, 98.6% showed single foramen and in 1.4% of the cases, the foramen was absent. With respect to fibulae, 90.2% had single foramen and foramen was absent in 9.8%. The mean foraminal index was 38.9 for the femora, 32.5 for tibiae and 49.2 for fibulae. The majority (51.3%) of the foramina in the femora were located at the 2/5(th) part, 98.3% of the tibiae foramina at the 2/5(th) part and 60% of the fibulae at the 3/5(th) part. CONCLUSION The study provides information on the morphology and topography of nutrient foramina in lower limb long bones. The double foramina were more common in femur and rare in the tibia and fibula. The foramina of the femur and tibia were commonly observed at their upper part, whereas in the fibula they were present on the lower part. This knowledge of the nutrient foramina has to be kept in mind during surgical procedures.