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

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.

Palmar type of median artery as a source of superficial palmar arch: a cadaveric study with its clinical significance

The superficial palmar arch (SPA) and its contributing arteries are highly variable. The palmar type of median artery (PMA) can be involved in the formation of the SPA by replacing the superficial palmar branch of the radial artery (RA) or the ulnar artery (UA). The present study was undertaken to investigate the presence of the PMA and its contribution in the formation of SPA in 42 cadavers (84 upper limbs) of Indian origin. When there was a PMA, its outer diameter was measured in the carpal tunnel. The PMA was found in 13 upper limbs (15.4%), and of these ten incidences (11.9%), the PMA took part in the formation of SPA, and in three instances (3.5%), the PMA did not make up part of the SPA. Out of the ten cases in which the PMA contributed to the formation of SPA, in six cases (7.1%), the PMA anastomosed with the UA; in three cases (3.5%), the PMA anastomosed with both the UA and the RA, and in one incidence (1.1%), the PMA joined the arteria radialis indicis (deep branch of the RA) to complete the SPA. The outer diameters of the median arteries varied between 0.8 and 2.6 mm with the mean value of 1.7 mm. The present study concludes that the median-ulnar type of SPA was the most common type of SPA when the PMA was encountered as a source of superficial arterial arcade of the hand, followed by the radial-median-ulnar type. The vascular patterns found in this study are important to hand surgeons. The present study of PMA origin, course, and its contribution to the SPA will add to the existing knowledge of the vascular anatomy of forearm and hand.

Morphology of the medial meniscus of the knee in human fetuses

OBJECTIVES

The objectives were to study the morphology of the medial menisci in human fetal knee joints and to verify the developmental etiology of the discoid meniscus.

MATERIAL AND METHODS

The study was carried out on 106 fetal knee joints and the morphological variants of the shapes of the medial menisci were macroscopically noted and classified.

RESULTS

From our observations, 46.2% of the medial menisci were crescentic shaped, 23.6% were sided V-shaped, 13.2% had sided U-shape, 9.4% of them were sickle shaped, and 7.5% were C-shaped. In 54.71% of the cases, the medial meniscus shape was different on either side knees of the fetuses. No discoid medial menisci were seen.

CONCLUSIONS

The majority of the knees were having crescentic or semi lunar shaped medial menisci and the shape of the medial meniscus was different on right and left side knee joint of the fetuses in more than fifty percent of the cases. The observations favor Kaplan's theory, as there were no discoid medial menisci observed from the fetuses of various gestational ages. Even the youngest fetus (CRL 88 mm, 14 weeks of gestation) exhibited the medial tibial plateau incompletely covered by the menisci, which did not exhibit the discoid shape. The discoid meniscus must be an abnormal finding and is due to abnormal morphogenesis.

Morphometry of A1 segment of the anterior cerebral artery and its clinical importance

BACKGROUND AND AIM

Anterior cerebral artery, one of the terminal branches of the internal carotid artery is an important vessel taking part in the formation of circle of Willis. It supplies a large part of the medial surface of the cerebral hemisphere containing the areas of motor and somatosensory cortices of the lower limb. Aim of this study was the morphometry of A1 segment of the anterior cerebral artery.

MATERIALS AND METHODS

93 formalin fixed brain specimen of either sex and of Indian origin were studied. The mean length, mean external diameter and the anomalies present in A1 segment of the vessel were studied in detail and photographed.

RESULTS

The mean length of A1 segment of the vessel was 14.49+/-0.28 mm and 14.22+/-0.22 mm on right and left side respectively. The mean external diameter of the vessel on right and left side was 2.12+/-0.07 mm and 2.32+/-0.06 mm respectively. Narrowing, aneurysm formation, buttonhole formation and median anterior cerebral artery were the anomalies seen with an occurrence of 15.05%, 5.37%, 3.22% and 12.9%, respectively. The above anomalies did not have any sex or side predilection.

CONCLUSION

Knowledge of morphometry of the vessel will be of use to neurosurgeons while performing the shunt operation, in assessing the feasibility of such operations and in the choice of patients. From this study we infer that the morphometry of anterior cerebral artery varies in different population and that the neurosurgeons operating should have a thorough knowledge of the possible variations.

Anatomy of plantaris muscle: a study in adult Indians

AIM

The plantaris muscle (PM) and its tendon is subject to considerable variation in both the points of origin and of insertion. The present study was carried out to fi nd the different types of origin, insertion and possible variations of the PM in the population of southern costal region of India.

MATERIALS AND METHODS

52 embalmed (Formalin fixed) cadaver lower limbs of 26 males (age ranged 48-79 years, mean age 68 years) were dissected, to study the origin and insertion of PM. Various dimensions (length and width) of plantaris muscle belly and its tendon were also measured.

RESULTS

Three types of origin and equal number of insertion were noticed in the present study. The PM took origin from type I: Lateral Supracondylar ridge, Capsule of Knee joint and Lateral head of gastrocnemius in 73.07% cases; type II: Capsule of Knee joint and Lateral head of gastronemius in 5.76% cases; type III: Lateral Supracondylar ridge , Capsule of Knee joint , Lateral head of gastrocnemius and fibular collateral ligament in 13.46% cases. The plantaris tendon was inserted into type I: to the flexor retinaculum of foot in 28.84% cases; type II: independently to the os calcaneum in 36.53% cases; type III: to the tendocalcaneus at various levels in 26.92% cases. In four lower limbs (7.69%) the plantaris muscle was completely absent. Additionally the length and width of the plantaris muscle and its tendon were measured to know any side difference. There were no statistically significant differences between the measurements of left and right side (p>0.05).

CONCLUSION

Present study will help the surgeons while attempting various surgical procedures in and around the posterior aspect of knee involving plantaris.

Case report of high origin of radial, ulnar, and profunda brachii arteries, its clinical implications and review of the literature

Arterial variations in the arm are of potential clinical implications as it is a frequent site of injury and also involved in many surgical and invasive procedures. During a dissection of the right upper extremity, an abnormal high origin of the radial and ulnar arteries was found. The brachial artery had a very short segment without any branches, divided into the radial and ulnar arteries at the upper third of the arm. The course and branching pattern of these radial and ulnar arteries in the arm are discussed. It was also observed that the profunda brachii artery was represented by two separate branches arising from the posterior circumflex humeral artery. Accurate knowledge of these variation patterns is of considerable clinical importance in the conduct of reparative surgeries around the shoulder and fracture management of the humerus. These additional data of arterial anomalies to contemporary anatomical literature are of interest to clinicians, in particular vascular and plastic surgeons and radiologists.

Co-existence of superficial brachio-ulno-radial arterial pattern and persistent median artery

The arteries of the upper limbs are situated in a deep plane and are the favourable sites for intra-arterial cannulation. During routine dissection of the left upper limb of a 52-year-old female cadaver, we observed a superficial arterial pattern which was of superficial brachio-ulno-radial type. The right upper limb of the same individual did not show any abnormal arterial pattern. This superficial arterial system was also associated with a palmar type of median artery. The clinical significance of the anomalous arterial system of the upper limb is discussed.

Variation and clinical significance of extensor pollicis brevis: a study in South Indian cadavers

BACKGROUND

de Quervain's disease is a condition in which there is pain in the radial styloid process caused by stenosing tenosynovitis of the abductor pollicis longus (APL) or/and extensor pollicis brevis (EPB) tendons in the first extensor compartment of the wrist. In this study we studied variations in the tendons of the EPB in the first extensor compartment and its site of insertion.

METHODS

One hundred fifty six upper limbs from adult cadavers of south Indian origin were dissected to observe the number of EPB tendons and the presence of an osseo-fibrous septum in the first extensor compartment of the wrist.

RESULTS

The EPB had a single tendon in 133 limbs, double tendons in 17 limbs and triple tendons in only 6 limbs. The EPB was present in all of the upper limbs in our study. In 34.6% of cases, the tendons of the EPB were separated from the tendons of APL by an osseo-fibrous septum in the first extensor compartment.

CONCLUSION

Variation in the number of EPB tendons and site of insertion should be taken into consideration by clinicians and surgeons when performing surgical decompression of the first extensor compartment of the wrist in de Quervain's syndrome. Surgical failure may occur due to overlooking variations in EPB tendons or septation of the first extensor compartment.

Co-existence of superficial brachio-ulno-radial arterial pattern and persistent median artery

The arteries of the upper limbs are situated in a deep plane and are the favourable sites for intra-arterial cannulation. During routine dissection of the left upper limb of a 52-year-old female cadaver, we observed a superficial arterial pattern which was of superficial brachio-ulno-radial type. The right upper limb of the same individual did not show any abnormal arterial pattern. This superficial arterial system was also associated with a palmar type of median artery. The clinical significance of the anomalous arterial system of the upper limb is discussed.

Duplication of falx cerebelli, occipital sinus, and internal occipital crest

The incidence of variations of falx cerebelli was studied in 52 adult cadavers of south Indian origin, at Kasturba Medical College Mangalore, after removal of calvaria. In eight (15.4%) cases, we observed duplicated falx cerebelli along with duplicated occipital sinus and internal occipital crest. The length and the distance between each of the falces were measured. The mean length of the right falces cerebelli was 38 mm and the left was 41 mm. The mean distance between these two falces was 20 mm. No marginal sinus was detected. Each of the falces cerebelli had distinct base and apex and possessed a distinct occipital venous sinus on each attached border. These sinuses were noted to drain into the left and right transverse sinus respectively. After detaching the dura mater from inner bony surface of the occipital bone, it was noted that there were two distinct internal occipital crests arising and diverging inferiorly near the posterolateral borders of foramen magnum. The brain from these cadavers appeared grossly normal with no defect of the vermis. Neurosurgeons and neuroradiologists should be aware of such variations, as these could be potential sources of hemorrhage during suboccipital approaches or may lead to erroneous interpretations of imaging of the posterior cranial fossa.

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.

Morphology of the lacrimal sac and nasolacrimal duct in adult human cadaver

The lacrimal sac (LS) is a dilated structure that lies in the lacrimal fossa, and the nasolacrimal duct (NLD) is the continuation of LS from its neck up to the inferior meatus of the nose. A study of 50 specimens of formalin-fixed adult cadavers of both sexes of Indian origin was conducted. The morphological features like length and breadth of LS and NLD, along with the histology of LS has been observed. The mean length of LS and NLD on the right side was 10.5 mm (1.04) and 16 mm (2.6) respectively, whereas the mean breadth of the above structures, on the right side was 6 mm (0.63) and 5.66 mm (0.81) respectively. The mean length of LS and NLD on the left side was 10.57 mm (1.13) and 16.42 mm (2.29), whereas, the mean breadth of the same structure on the left side was 6.71 mm (0.95) and 5 mm (0.81) respectively. The sides did not show any significant statistical difference but when the correlation between the length and breadth of LS is considered, significance was observed in the lacrimal sac of the left side. No variations were observed in the gross structure of LS and NLD. Microscopic study showed the presence of elastic fibers in LS. The importance of LS and NLD is that the blockage of this lacrimal passage is the most common cause of epiphora (watering of the eye). The presence of elastic fibers in this study confirms the hypothesis that the sac elasticity may perform a dynamic role, in forceful evacuation of lacrimal fluid in reverse direction (Tab. 2, Fig. 3, Ref. 10). Full Text (Free, PDF) www.bmj.sk.

An anomalous belly of sternothyroid muscle and its significance

The sternothyroid muscle and other infrahyoid muscles play a vital role in the process of vocalization, swallowing and mastication by mobilizing the hyoid bone and thyroid cartilage. During routine dissection of a 70-year-old male cadaver, we observed an anomalous sternothyroid muscle. It was arising from the posterior surface of the manubrium sterni and partly from the cartilage of the first rib. After a distance of 3.3 cm, the belly of sternothyroid muscle was divided into lateral and medial fibers. The lateral belly was inserted above the oblique line on the lamina of the thyroid cartilage, but the medial additional belly turned into a tendon, which was crossing over the thyroid artery and inserted to the hyoid bone and intermediate tendon of digastric muscles. The superior thyroid artery was below the above tendon on its way to the thyroid gland. The muscle was innervated by a branch from the ansa cervicalis.

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.

An additional muscle belly of the first lumbrical muscle

Introduction

Lumbrical 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 presentation

During 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.

Conclusion

The presence of such an additional muscle in the carpal tunnel should be considered in the aetiology of carpal tunnel syndrome (CTS).

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.

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 - 15 cm by 0.35 - 6.4 cm and 2.8 - 20.8 cm by 0.2 0.5 cm, 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.

An unusual course and entrapment of the lingual nerve in the infratemporal fossa

The infratemporal fossa is one of the most difficult regions of skull base to access surgically. The presence of the ossified pterygospinous and pterygoalar ligaments makes it more critical and difficult to access, with an occasional entrapment of structures like the mandibular nerve (MN) and its branches. During a routine dissection of an adult male cadaver, an unusual course of the lingual nerve (LN) was found with an entrapment of the nerve between the ossified pterygospinous ligament and the medial pterygoid muscle. Furthermore, all the three branches of the posterior division of the mandibular nerve communicated with each other by two anastomosing branches. The clinical significance of the present variations has been discussed (Fig. 1, Ref. 23).

Multiple supernumerary muscles of the arm and its clinical significance

During routine cadaveric dissection of the flexor compartment of the right arm, multiple supernumerary muscles were observed in a 56-year-old male cadaver. There were three supernumerary muscles took taking origin independently from the humerus distally to the insertion of coracobrachialis muscle. The upper two supernumerary muscles were attached to the common tendon of the biceps brachii muscle and considered as its additional heads. The third supernumerary muscle passed between the biceps brachii and brachialis muscles, then crossed obliquely the brachial artery and median nerve nearing cubital fossa to get inserted in to the radial side of the humeral head of the pronator teres. The clinical significance of the above variations is discussed (Fig. 1, Ref. 16).

Morphometry of posterior cerebral artery: embryological and clinical significance

Posterior cerebral artery, terminal branch of basilar artery joins the posterior communicating artery to help complete the circulus arteriosus cerebri in human beings. A study of 89 formalin-fixed brain specimen of either sex and of Indian origin has showed that the mean length and diameter of the posterior cerebral artery was 6.75 +/- 1.482 mm and 1.7 +/- 0.7 mm respectively. Anomalous origin of the posterior cerebral artery was the only variation found during the present study. The incidence of occurrence of the particular variant was 2.2%. The variation did not have any sex or side predilection.