Biomedical subjects

R Choudhry

Publications and source records attributed to R Choudhry.

At least 19 recordsLinked to original sources

PubMed2005

Unusual features associated with cranial openings of optic canal in dry adult human skulls.

One hundred and eighty six dry adult human skulls (372 sides) were studied in order to reveal the presence of unusual features--such as recess, fissure and notch--in the cranial opening of the optic canal. Recess, an extension of the lateral wall, was found in 229 (61.5%) sides. Fissure, an irregular discontinuity above the lateral recess, was observed in 158 (42.4%) sides. Notch, a gap in the posterior-most limit of the roof, was seen in 66 (17.7%) sides. These were commonly seen bilaterally. The etiology of these was attributed to the development of the optic canal. During intrauterine life the optic canal is in the form of a large keyhole shaped foramen, which slowly transforms into the adult canal. A developmental arrest at an early stage may lead to the formation of recesses and fissures.

Adult↗

PubMed2004

Morphological description of combined variation of distal attachments of fibulares in a foot.

An interesting case of peculiarity of the distal attachment of the three fibular muscles is reported in the left foot of a male adult cadaver of Indian origin. The fibularis brevis, just inferior to the fibular malleolus, gave off an additional slender tendon anteromedial to its main tendon. This was attached to the dorsal digital expansion of the little toe while its main tendon was inserted to the customary bone. The tendon of fibularis longus on the plantar aspect just medial to the cuboid tunnel received a prominent slip of attachment of the tendon of tibialis posterior. The fibularis tertius had two parallel-running tendons attached to the bases of the fourth metatarsal and the fourth and fifth metatarsals respectively. The combined variation of the three fibulares in a single foot has not been reported previously. The more distal attachment of the fibularis brevis in this case is a regression in evolution. Weakness of both the fibularis brevis and fibularis longus is found in pes cavovarus. The former can be used as a rotational graft in soft tissue loss of the leg.

Adult↗

PubMed2004

Imaging and morphology of the paracondylar process in a dry adult human skull: a case report.

An unusually long paracondylar process (PCP) was found articulating with the transverse atlantal process in a dry adult male skull. It was 13 mm long and 19 mm in circumference at its middle and projected to a lower plane than the styloid process of the same side. A radiograph revealed the structure of spongiosa of the PCP to be like mastoid cells. PCP can lead to clinical symptoms due to alterations in posture and functional limitations in neck movements. Thus awareness of this process, its topographical relations and its attendant problems is of importance to clinicians, radiologists, surgeons and chiropractors. In symptomatic cases surgical resection of this process can be attempted to relieve the symptoms. The craniovertebral junction constitutes a unique part of the somite-derived axial skeleton; the lowest part of the basioccipital component including this process develops from occipital sclerotomes. Developmental variations in this region can resemble deformities.

Adult↗

PubMed2004

Incidence and morphological study of zygomaticofacial and zygomatico-orbital foramina in dry adult human skulls: the non-metrical variants.

Morphological diversity in the form of multiple zygomaticofacial (ZF) foramina was studied in 165 dry, unsexed adult human skulls. Zygomatic bones revealed variation in the number of foramina on their orbital and facial aspects. These were absent in 72 (21.8%) sides. A single ZF foramen was seen in 148 (44.9%) sides. Two ZF foramina were found in 92 (27.9%) sides, out of which 29 (8.8%) sides had one zygomatico-orbital (ZO) foramen, while 63 (19.1%) sides had two ZO foramina. Three ZF foramina, a relatively uncommon occurrence, were found in 17 (5.1%) sides, which included eight (2.4%) sides with one less and nine (2.7%) sides with the same number of ZO foramina. Four ZF foramina were seen in one (0.3%) side with three on the orbital aspect, a feature not reported before. The zygomatic nerve may be disrupted on elevating periorbita from the lateral wall during orbital surgery, and care should be taken to prevent injury to the nerve during the lateral orbitotomy approach to access intraorbital soft tissue tumors.

Adult↗

PubMed2003

Morphology and imaging of bony projections on sigmoid sulcus with clinical implication.

Morphologically diverse osseous projections were observed on the anterior lip of the sigmoid sulcus in a study conducted on 318 dry unsexed adult human skulls belonging to the Indian race. For convenience of description, this lip was divided into a longer lateral part, a shorter medial part and a junctional angular part having bony attributes characterized into three types, crests (42.9%), plates (22.3%) and bridges (13.5%). The bridges were subtyped into incomplete (11.8%) and complete (1.7%). Crests and plates were present anywhere along this lip, while bridges were confined to the angle. Right and left differences were analyzed, which showed that the above findings were more frequent on the right than the left. Plates showed a higher incidence of variation between right and left sides as compared to crests and bridges. Five cadavers were studied, which showed retinacular bands attached to the projections blending with dura mater over the foramen magnum. It is postulated that these projections are caused by the traction of the fibrous dural bands. Axial CT scan revealed partial and complete osseous bridges spanning the sulcus. These projections are of relevance to surgeons working at the cerebellopontine angle. Their presence has not been reported previously.

Adult↗

PubMed2003

Facial vein draining into external jugular vein in humans: its variations, phylogenetic retention and clinical relevance.

The superficial veins, especially the external jugular vein (EJV), are increasingly being utilized for cannulation to conduct diagnostic procedures or intravenous therapies. Ultrasound-guided venipuncture is a viable possibility in cases of variations in the patterns of superficial veins, and their knowledge is also important for surgeons doing reconstructive surgery. This study was done on 89 dissected adult cadavers (178 sides) and variations in patterns of termination of the facial vein (FV) into the EJV were studied. The FV in 16 sides (9%) was found to drain into the EJV, in two main patterns: type I and type II. Type I had the FV draining into the EJV with varying degrees of obliquity in a Y-shaped (6 cases, 37.5%), U-shaped (3 cases, 18.7%), tuning-fork-shaped (2 cases, 12.5%) or N-shaped (1 case, 6.2%) pattern. Type II showed an inverted A-shaped pattern (2 cases, 12.5%) or a stepladder-shaped pattern (2 cases, 12.5%) depending on the presence of one or more connecting conduits between the FV and EJV respectively. In Macaca mulatta(rhesus monkey) a pair of vertically disposed, subcutaneous veins placed nearly side by side and of equal caliber were seen on each side of the neck. The lateral vein was the EJV while the medial one took the course of the FV in the upper oblique segment and ran parallel to the EJV in the lower segment over the sternocleidomastoid, with one or two transverse communications. The anomalous patterns found in our study could be explained in terms of the regression and retention of various parts of the veins found in the rhesus monkey, or the drainage pattern found in horse, ox and dog, where the vein from the face drain into the external jugular vein, the internal jugular vein being either absent or a small vessel accompanying the carotid artery.

Adult↗

PubMed2001

Unusual facets on the acetabulum in dry adult human coxal bones: a morphological and radiological study.

A smooth facet was found antero-inferior to lunate surface of 48 acetabula, in a study conducted on 315 dry adult coxal bones, 26 of which (13 pairs) were of articulated pelves. Three different shapes of the facet were oval (56.3%), piriform (22.9%) and elongated (20.8%). The prevalence of the oval facet was higher in both sexes. In 37.5% bones it extended to superior ramus of pubis and in 62.5% it was limited within the acetabular margin. They were either discrete (58.3%) or continuous with the lunate surface (41.7%). The surface configuration was flat (29.2%), concave (43.7%) or grooved (27.1%). One male articulated pelvis showed a bilateral presentation. Measured along the long axis the size varied between 11 to 17 mm. The radiographs showed notching, antero-inferior to acetabular margin in grooved facets whereas concave and flat facets were seen as areas of rarefaction. It is postulated that this facet could be a consequence of a particular posture which results in traction of the ligaments attached to this area. This unusual feature has not been reported earlier.

Acetabulum↗

PubMed2000

Variation in shape of the lingula in the adult human mandible.

The lingulae of both sides of 165 dry adult human mandibles, 131 males and 34 females of Indian origin, were classified by their shape into 4 types: 1, triangular; 2, truncated; 3, nodular; and 4, assimilated. Triangular lingulae were found in 226 (68.5%) sides, truncated in 52 (15.8%), nodular in 36 (10.9%) and assimilated in 16 (4.8%) sides. Triangular lingulae were found bilaterally in 110, truncated in 23, nodular in 17 and assimilated in 7 mandibles. Of the remaining 8 mandibles with different appearances on the 2 sides, 6 had a combination of triangular and truncated and 2 had nodular and assimilated. The incidence of triangular and assimilated types in the male and female mandibles are almost equal. In the truncated type it was double in the male mandibles while the nodular type was a little less than double in the female mandibles.

Adult↗

PubMed1999

Morphologic and imaging studies of duplicate optic canals in dry adult human skulls.

Three dry adult human skulls, two with bilateral and one with unilateral duplication of the optic canal were found. Their gross morphologic features were studied. Optic canals were separated by a septum of variable thickness dividing the posterior part of the canal into a large canal in the usual position and a smaller one inferior to it. The skull with unilateral duplication of the right side had a bony bar forming the carotico-clinoid canal. One of the skulls was disarticulated and its sphenoid had bilaterally duplicated optic canals divided by thin septa, both having a slit. Conventional radiography and CT scans for the optic canal were performed on two of these skulls but not on the disarticulated bone, and the imaging representations of these features were correlated with the anatomic findings on the dry skull.

Adult↗

PubMed1999

Upregulation of connexin 26 is a feature of keratinocyte differentiation in hyperproliferative epidermis, vaginal epithelium, and buccal epithelium.

In epidermis, it has been suggested, intercellular communication through gap junctions is important in coordinating cell behavior. The connexins, may facilitate selective assembly or permeability of gap junctions, influencing the distribution of metabolites between cells. Using immunohistochemistry, we have compared the distribution of connexins 26 and 43 with that of proliferating cells (Ki67 labeling) in normal epidermis, hyperplastic epidermis (tape-stripped epidermis, psoriatic lesions, and viral warts), and vaginal and buccal epithelia. Connexin 43 was abundant in spinous layers of all epidermal specimens and in vaginal and buccal epithelia. Connexin 26 was absent from the interfollicular and interductal epidermis of normal hair-bearing skin, and nonlesional psoriatic epidermis but present at very low levels in plantar epidermis. Connexin 26 was prominent in lesional psoriatic epidermis and viral warts and in vaginal and buccal epithelia. In three independent experiments connexin 26 appeared in a patchy intercellular distribution in the basal epidermis within 24 h of tape stripping, proceeding to more extensive distribution in basal and suprabasal layers by 48 h. The increase in connexin 26 preceded that in cell proliferation. In vaginal epithelium, buccal epithelium, and viral warts connexin 26 was restricted mainly to suprabasal, nonproliferating cells. In psoriatic lesional epidermis connexin 26 was also located mainly in suprabasal, nonproliferating cells. Connexin 26 was present in a patchy distribution in the basal layer of psoriatic lesional epidermis, but double labeling for connexin 26 and Ki67 showed that many connexin 26 positive basal cells were nonproliferative, suggesting that connexin 26 may be related to differentiation rather than to proliferation. These observations would be consistent with a role for connexin 26 containing gap junctions during both early and later stages of keratinocyte differentiation in hyperplastic epidermis and in vaginal and buccal epithelia.

Cell Differentiation↗

PubMed1998

Morphology of human suprarenal glands: a parameter for comparison.

Forty suprarenal glands were studied, 20 being dissected from aborted fetuses of 9 to 36 weeks' gestation and 20 obtained from human cadavers of ages 1 day to 60 years. All the specimens were from a Northern India population. The side and shape of each suprarenal gland was noted and documented. The length, breadth, thickness and volume of each gland were measured and tabulated in terms of age. The mean length, breadth and thickness in fetuses of 9-36 weeks were found to be 1.4 cm, 1 cm and 0.45 cm respectively. In the postnatal age group the measurements were 4.5 cm, 2.08 cm and 0.66 cm respectively. The commonest shape of the suprarenal glands on left side was semilunar but on the right side it was highly variable: triangular, tetrahedral, inverted Y or V shaped. On comparison of the gross measurements with available ultrasound and CT scan data it was found that both the length and thickness in the population studied were greater than reported in the literature. A knowledge of these variations is very important in diagnosis of abnormalities of the suprarenal gland, of which tumoral enlargement is rather common.

Adolescent↗

PubMed1998

Os capitatotrapezoid: a case report.

A case of fused capitate and trapezoid, the os capitatotrapezoid (OCT), was found in an articulated right hand of a male skeleton. Fusion was almost complete except for shallow grooves demarcating the line of fusion on the proximal and distal aspects. Radiology revealed a normal trabecular pattern and no joint cavity within these fused bones. The styloid process of the third metacarpal was absent.

Adult↗

PubMed1998

Anatomical description and frequencies of bony projections on the cerebral aspect of the petromastoid part of the temporal bone in dry adult human skulls.

A morphological peculiarity was observed in the form of bony projections on the upper part of the medial border of the groove for the sigmoid sulcus on the internal surface of the mastoid part of the temporal bones. In a study on 636 temporal regions of 318 dry unsexed adult human skulls of Indian origin, 101 (15.9%) temporal bones exhibited these elevations. These ranged from being inconspicuous tubercles to well-defined sharp spines. In 73 (72.3%) cases, a projection was present unilaterally, more commonly on the right side and in 28 (27.7%) it was bilateral. A subjective assessment of the size showed the projections to be small (70; 69.3%), medium (16; 15.8%) and large (15; 14.8%).

Adult↗

PubMed1997

Changing patterns of gap junctional intercellular communication and connexin distribution in mouse epidermis and hair follicles during embryonic development.

In the mouse embryo between embryonic days 12 (E12) and 16, regular arrays of epidermal placodes on the mystacial pad develop into whisker follicles. This system was chosen for analysis of gap junctional intercellular communication during differentiation. The patterns of communication were studied by microinjection of the tracers Lucifer yellow-CH (LY-CH) and neurobiotin (NB), while immunofluorescent staining was used to study distribution of connexins 26 and 43. Extensive communication was seen between keratinocytes in developing hair pegs or, in later-stage hair follicles, in the germinative matrix. Coupling between adjacent hair pegs via interfollicular epidermis was not observed. Coupling also became restricted as follicular cells differentiated to form outer root sheath, inner root sheath, and hair shaft. Extensive gap junctional coupling is characteristic of keratinocytes that are rapidly proliferating (as in hair pegs and germinative matrix). Follicular keratinocytes commence differentiation shortly before restriction of gap junctional coupling becomes evident. Dermal mesenchymal cells undergoing different modes of differentiation also exhibit differences in gap junctional coupling, as evidenced by poor transfer of LY-CH between cells in dermal condensations of hair follicles compared with extensive transfer elsewhere in the dermis. LY-CH and NB were not transferred between epidermal or follicular epithelium and mesenchyme, arguing against a direct role for gap junctions permeable to known second messenger molecules or nucleotides in epithelial-mesenchymal interactions in this system. The distribution of connexins 26 and 43 in epidermis and hair follicles changed during differentiation but there was no correlation with changing patterns of dye transfer, indicating an unexpected degree of complexity in the relationship between gap junctional intercellular communication and connexin protein distribution during development.

Animals↗

PubMed1997

Facial vein terminating in the external jugular vein. An embryologic interpretation.

The external jugular v. (EJV) is increasingly being used for therapeutic procedures and monitoring by clinicians. In view of this clinical relevance, dissection was done on the head and neck regions in 40 adult cadavers of Indian origin to detect variations of the EJV. Though several patterns of tributaries were found, a facial v. (FV) of considerable size was observed coursing obliquely to join the EJV in the neck in four cases (5%). The distance of the junction of the FV and the EJV from the angle of the mandible ranged between 55 and 104 mm. This may represent a persistent communication of the primitive linguofacial v. with the secondarily developing EJV. This anastomotic channel is present for some time in the fetus but later undergoes retrogression. Its persistence in some individuals results in this variation.

Adult↗

PubMed1997

Academic performance of various categories of students admitted to Lady Hardinge Medical College, New Delhi.

A retrospective study of 4 consecutive academic batches of students was conducted to analyse the performance level of students in 3 university examinations of MBBS. The students were divided into 3 categories based on the criteria of entrance into the medical college. The category I included students who entered through a tough pre-medical test, category II comprised those nominated by government and defence personnel and category III included the Schedule Caste and Schedule Tribe students. The results of the category I was remarkably better than that of II while that of category III was dismal. The last two categories had a large number of students leaving the college without completing their course resulting in 5.4% wastage of precious medical seats and psychological distress. Necessary remedial measures must be planned at the earliest.

Adult↗

PubMed1996

Double-lumen esophagus: formation of a new lumen or septation of the existing one?

Presented here are two cases in which two esophageal lumens were identified at endoscopy. One patient had a history of antireflux surgery and both patients had received esophageal dilations. Both patients have done poorly with standard esophageal dilation and are not considered likely to gain from surgery. The mechanism of formation of the second lumen is not certain in Case 1, but in Case 2 a self-contained perforation appears to be the likely mechanism. There is no clear definition of "double-lumen esophagus" in the literature. The term is used at times interchangeably with esophagogastric fistula. We propose that the phrase "double-lumen esophagus" is a morphologic description and should be used only when the two lumens are of nearly equal diameter. The term "fistula" should be used whenever that is the likely mechanism. Hence, Case 1 of our report is the true double-lumen esophagus, while Case 2 is an esophagogastric fistula. Since patients do poorly with standard dilation, newer endoscopic modalities may have a role in the management of these rare but difficult cases.

Aged↗

PubMed1996

Precondylar tubercles on the basiocciput of adult human skulls.

The basiocciput of 265 Indian adult human skulls was examined for precondylar tubercles, which are single or paired osseous formations anterior to the occipital condyles and foramen magnum. Of the 14% of skulls displaying these tubercles unilaterally or bilaterally, 5.3% demonstrated ridges, 4.9% showed spines and 3.8% exhibited processes. Sexual dimorphism was evident with female skulls showing a higher incidence (8.7%) compared with male skulls (5.3%). The corresponding atlas vertebrae were normal. These craniovertebral anomalies may have clinical relevance for lesions at the foramen magnum.

Adult↗