Ashwin Krishnamurthy

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.

A study of anatomical variability of the omohyoid muscle and its clinical relevance

OBJECTIVE The omohyoid muscle is a long, thin muscle consisting of superior and inferior bellies and an intermediate tendon, which runs obliquely in the lateral cervical region. The omohyoid is important in neck dissections because it is the surgical landmark for level III and IV lymph node metastases. METHODS In the present study, the anterior and posterior triangle of the neck was dissected in 35 male cadavers and observed for variations in the omohyoid bilaterally. Observations were focused on variations in number, attachments, and position of omohyoid. RESULTS Among the 35 cadavers studied, double omohyoid was present in one cadaver, inferior belly originated from the clavicle in three cadavers, superior belly merged with the sternohyoid in two cadavers, and the omohyoid received additional slips from the sternum in one cadaver. Standard attachment and position of the omohyoid was observed in the remaining cadavers. CONCLUSION Variations of this muscle are important because of its close relation to the large vessels and brachial plexus. Because of the direct adhesion of the intermediate tendon to the anterior wall of the internal jugular vein and its connection with it through a thin lamina of the pretracheal layer of the cervical fascia, the contraction of the omohyoid muscle has a direct effect on the lumen of this vessel.

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.

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.

Anatomical variation of radial wrist extensor muscles: a study in cadavers

OBJECTIVE The tendons of the extensor carpi radialis longus and brevis muscles are quite useful in tendon transfer, such as in correction of finger clawing and restoration of thumb opposition. Knowledge of additional radial wrist extensor muscle bellies with independent tendons is useful in the above-mentioned surgical procedures. METHODS The skin, subcutaneous tissue, and antebrachial fascia of 48 (24 on the right side and 24 on left side) male upper limb forearms were dissected. The following aspects were then analyzed: (a) the presence of additional muscle bellies of radial wrist extensors, (b) the origin and insertion of the additional muscle, and (c) measurements of the muscle bellies and their tendons. RESULTS Five out of 48 upper limbs (10.41%) had additional radial wrist extensors; this occurred in 3 out of 24 left upper limbs (12.5%) and 2 out of 24 right upper limbs (8.3%). In one of the right upper limbs, two additional muscles were found. The length and width of each additional muscle belly and its tendon ranged between 2 – 15cm by 0.35 – 6.4cm and 2.8 – 20.8cm by 0.2 –0.5cm, respectively. The additional radial wrist extensor tendons in our study basically originated either from the extensor carpi radialis longus or brevis muscles and were inserted at the base of the 2nd or 3rd metacarpal bone. CONCLUSION The present study will inform surgeons about the different varieties of additional radial wrist extensors and the frequency of their occurrence.

Origin of the sinoatrial and atrioventricular nodal arteries in South Indians: an angiographic study

FUNDAMENTO: Estudiar el suministro arterial del sistema conductor y su correlacion con la dominancia de las arterias coronarias en poblacion del Sur de la India. OBJETIVO: Determinar angiograficamente los origenes de la arteria del nodulo sinusal (AnSA) y la arteria del nodulo atrioventricular (AnAV) en indios. METODOS: El estudio incluyo 300 pacientes consecutivos (114 del sexo femenino y 186 del sexo masculino; edad promedio, 55 anos), habitantes de la region costera al Sur de la India, sometidos a cineangiocoronariografia debido a sintomas como dolor en el pecho, angina pectoris o test ergometrico positivo. Las angiografias incluyeron ambas arterias coronarias (derecha e izquierda) en posicion oblicua anterior derecha e izquierda. El origen de la AnSA y AnAV a partir de las arterias coronarias se observo y se correlaciono con la dominancia arterial. RESULTADOS: El nodulo SA (sinusal) recibio suministro por la arteria coronaria derecha (ACD) en el 53% de los casos, por la rama circunfleja (Cx) de la arteria coronaria izquierda (ACI) en el 42,66% de los casos, y en el 4,33% de los casos este nodulo fue irrigado por ambas arterias coronarias. El nodulo AV (atrioventricular) tambien recibio suministro sanguineo con mas frecuencia de la ACD (72,33% de los casos) que la rama Cx de la ACI (27,66%). Sorprendentemente, en ningun caso este nodulo recibio suministro de ambas arterias coronarias. CONCLUSION: Los resultados del presente estudio pueden auxiliar a los cirujanos cardiacos, sobre todo en cirugias relacionadas a valvulopatias, debido a la franca proximidad entre las ramas nodales y el complejo valvular.BACKGROUND To study the arterial supply of the conducting system and its correlation with the dominance of the coronary arteries in the South Indian population. OBJECTIVE To determine angiographically the origins of the sinoatrial nodal artery (SAna) and atrioventricular nodal artery (AVna) in Indians. METHODS The study included 300 consecutive patients (114 females, 186 males; mean age, 55 years) living in the southern coastal region of India, who underwent coronary angiography either for the symptoms of chest pain, angina pectoris or positive Treadmill Test. The angiograms contained both coronary arteries (right and left) in the right and left anterior oblique position. The origin of SAna and AVna from the coronary arteries was observed and correlated with the arterial dominance. RESULTS The SA (sinoatrial) node was supplied by the right coronary artery (RCA) in 53% of the cases, by the circumflex (Cx) branch of left coronary artery (LCA) in 42.66%, and by both coronary arteries in 4.33% of cases. The AV (atrioventricular) node was also more often supplied by the RCA (72.33% of cases) than by the Cx branch of the LCA (27.66%), and surprisingly in none of the cases was this node supplied by both coronary arteries. CONCLUSION The results of the present study may help cardiac surgeons, particularly in surgeries related to certain valvular disorders, due to the proximity of the nodal branches to the valve complex.

An additional muscle belly of the first lumbrical muscle

IntroductionLumbrical muscles play a vital role in the precision movements of the hand, along with the thenar, hypothenar and interossei muscles. The variation in the lumbrical muscle is clinically significant.Case presentationDuring routine dissection of an adult male cadaver, we observed an additional muscle belly of the first lumbrical muscle took origin from the tendon of the flexor digitorum superficialis (FDS) to the index finger, close to the proximal margin of the flexor retinaculum.ConclusionThe presence of such an additional muscle in the carpal tunnel should be considered in the aetiology of carpal tunnel syndrome (CTS).

A morphometric study of foramen ovale.

AIM To note the morphological variations and morphometric details of foramina ovale in dry adult skulls of Indian origin. MATERIAL AND METHODS 82 dry adult human skulls of unknown sex and of Indian origin were obtained and variations in appearance and number of foramen ovale were noted. The length and width of the foramina ovale of both sides were determined using digital Vernier calipers and area (A) was also calculated and analyzed. RESULTS Out of 82 adult skulls, the values for the right side was 7.64 ± 1.194 mm, 5.128 ± 0.827 mm and 30.808 ± 7.545 mm2 and for the left side the values was 7.561 ± 1.123 mm, 5.244 ± 0.950 mm and 31.310 ± 8.262 mm2 respectively, for the mean length, width and area of the foramen ovale. The shape of foramen was typically ovale in most of the skulls (56.70%) with some bony variations such as spine, tubercles etc. CONCLUSION There was no statistically significant difference between the two sides in length, width and area of foramen ovale and there was a positive correlation between lengths and areas of both sides.

Morphometric Study of the Humerus Segments in Indian Population

El objetivo del estudio fue obtener las medidas de diferentes segmentos del humero y calcular la longitud del humero a partir de ellos. Fueron seleccionados 100 (51 izquierdos y 49 derechos) humeros adultos secos, separados por sexo, de poblacion india para analizar los detalles morfometricos de los segmentos dle hueso. La distancia entre cinco segmentos diferentes fueron establecidos: punto mas proximal de la cabeza humeral y la tuberosidad mayor (HA), cabeza del humero y cuello quirurgico del humero (HB), punto proximal y distal de la fosa olecraneana (HC), punto distal de la fosa olecraneana y la troclea del humero (HD), punto proximal de la fosa olecraneana y punto distal de la troclea del humero (HE) y, finalmente, la longitud maxima del humero (HL) medidas obtenidas por medio de una tabla osteometrica y un caliper analogo. Se realizaron regresiones lineales simples para correlacionar cada segmento con la longitud total del humero. Se obtuvieron resultados positivos en los segmentos de HB y HE de humero derecho. Formulas de regresion se obtuvieron para definir estimativos. En conclusion, nuestro estudio demostro que la longitud del humero puede estimarse a partir de las medidas de los diferentes segmentos del hueso, ayudando en casos forenses, anatomicos y arqueologicos con el fin de identificar cuerpos desconocidos o para determinar la estatura de la persona, asi como a cirujanos ortopedicos para el tratamiento de las fracturas proximales y distales del humero o para su reconstruccion.