Rajalakshmi Rai

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.

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.

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.

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.

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.

A Comparison of Vitamin A and Leucovorin for the Prevention of Methotrexate-Induced Micronuclei Production in Rat Bone Marrow

INTRODUCTION Methotrexate, a folate antagonist, is a mainstay treatment for childhood acute lymphoblastic leukemia. It is also widely used in a low dose formulation to treat patients with rheumatoid arthritis. In rats, methotrexate is known to induce micronuclei formation, leading to genetic damage, while vitamin A is known to protect against such methotrexate-induced genetic damage. Leucovorin (folinic acid) is generally administered with methotrexate to decrease methotrexate-induced toxicity. OBJECTIVES We aimed to determine whether vitamin A and leucovorin differed in their capacity to prevent formation of methotrexate-induced micronuclei in rat bone marrow erythrocytes. The present study also aimed to evaluate the effect of combined treatment with vitamin A and leucovorin on the formation of methotrexate-induced micronuclei. METHODS Male and female Wistar rats (n=8) were injected with 20 mg/kg methotrexate (single i.p. dose). The control group received an equal volume of distilled water. The third and fourth groups of rats received vitamin A (5000 IU daily dose for 4 successive days) and leucovorin (0.5 mg/kg i.p. dose for 4 successive days), respectively. The fifth and sixth groups of rats received a combination of vitamin A and a single dose of methotrexate and a combination of leucovorin and methotrexate, respectively. The last group of rats received a combination of leucovorin, vitamin A and single dose of methotrexate. Samples were collected at 24 hours after the last dose of the treatment into 5% bovine albumin. Smears were obtained and stained with May-Grunwald and Giemsa. One thousand polychromatic erythrocytes were counted per animal for the presence of micronuclei and the percentage of polychromatic erythrocyte was determined. RESULTS Comparison of methotrexate-treated rats with the control group showed a significant increase in the percentage of cells with micronuclei and a significant decrease polychromatic erythrocyte percentage. Combined methotrexate and vitamin A therapy and combined methotrexate and leucovorin therapy led to significant decreases in the micronuclei percentage and an increase in polychromatic erythrocyte percentage when compared to rats treated with methotrexate alone. Leucovorin was found to be more effective than vitamin A against the formation of methotrexate-induced micronuclei. CONCLUSIONS Both vitamin A and leucovorin provided significant protection against genetic damage induced by methotrexate.

Accessory neurovascular foramina on the lingual surface of mandible: Incidence, topography, and clinical implications

CONTEXT It was suggested that the accessory neurovascular foramina of the mandible might be of significance in relation to the effectiveness of local anesthesia following the routine inferior alveolar nerve block. AIMS To investigate the incidence of neurovascular foramina over the lingual surface of the mandible in South Indian population. SETTINGS AND DESIGN The study was conducted at the department of anatomy. MATERIALS AND METHODS The study included 67 human adult dry mandibles, the exact ages and sexes of which were not known. The location and number of neurovascular foramina were topographically analyzed. STATISTICAL ANALYSIS USED Descriptive statistics. RESULTS The foramina were observed in 64 mandibles (95.5%) and were often multiple in most of the cases. They were located between the two medial incisors in 8 mandibles (1.9%), between the medial and lateral incisor in 34 mandibles (50.7%; 25-bilateral; 7-right; 2-left), between the lateral incisor and canine in 7 mandibles (10.4%; 2-bilateral; 3-right; 2-left), between the canine and first premolar in 6 cases (8.9%; 3 on each side). Foramina were also present around the genial tubercle in 56 mandibles (83.6%). Among them, 52 mandibles showed a single foramen just above the genial tubercle, 34 mandibles had foramina below the tubercles, 13 mandibles had foramina on the right side of genial tubercle and 17 were having on the left side. CONCLUSION Since the anatomical details of these foramina are important to various fields of dentistry and oncology, the present investigation was undertaken. The clinical significance and implications are emphasized.

Hypoplastic posterior tibial artery and the enlarged peroneal artery supplying the posterior crural region: a rare variation

Variacoes arteriais de partes distais dos membros inferiores estao bem documentadas e podem ser demonstradas com o auxilio de ultra-sonografia Doppler ou por arteriografia. Entretanto, a ausencia ou variacao da arteria tibial posterior e um raro achado. Apresentamos um caso de arteria tibial posterior hipoplasica que terminava suprindo o musculo solear. Esse suprimento arterial variante foi fornecido pela arteria peroneal aumentada que continuava como arteria plantar lateral. Estar consciente dessas variacoes e importante para cirurgioes vasculares ao realizarem reconstrucoes arteriais em procedimentos de derivacao femorodistal, bem como para ortopedistas durante correcao cirurgica do pe torto.

Unilateral Pectoralis Minimus Muscle: A Case Report

Presencia de musculos supernumerarios en la region pectoral han sido reportados. En un cadaver de un hombre se describe la presencia de un musculo Pectoralis Minimus. El musculo se localizaba profundo al musculo pectoral mayor y superomedial al musculo pectoral menor. La variacion se relacionaba con las ramas de los vasos toracoacromiales donde una de las ramas pasaba entre el musculo pectoral menor y la variacion muscular. La hiperabduccion del brazo puede comprimir estos vasos provocando sintomas vasculares. Estas variaciones se deben tener en cuenta durante los procedimientos quirurgicos en la region pectoral.

Relationship between the deep peroneal nerve and dorsalis pedis artery in the foot: A cadaveric study

The aim of our work was to study the relationship between deep peroneal nerve (DPN) and dorsalis pedis artery (DPA) so that the frequency of these variations can be kept in mind by the angiographers and surgeons to ensure safe surgical approach during flap surgery. Ninety‐two legs in 46 cadavers were dissected to study the relationship between DPN and DPA on the dorsum of the foot. The relationship of neurovascular bundle of the dorsum of the foot was classified into four types. Type I: division of the DPN distal to the midpoint between the two malleoli (observed in 26 limbs). In Type II, the division of the DPN was midway between the two malleoli (seen in 20 limbs). Both Type I and II are further divided into two subtypes (a and b) depending upon the crossing pattern of terminal branches of the DPN over DPA. In Type III, multiple branches of DPN were noted in two limbs. In Type IV, the looping pattern of DPN around the DPA was considered and was seen in eight limbs. Awareness of possible variations in the relationship of the DPA to DPN on the dorsum of the foot is important for vascular and reconstructive surgeons. Because it might help in decreasing confusion when considering treatment options like microvascular anastomosis in reconstruction of the leg. Clin. Anat. 21:705–712, 2008.