No abstract

Single bony landmark may not help in locating SH because of anatomical variations. Depth of hiatus less than 3 mm may be one of the causes for failure of needle insertion. Surrounding bony irregularities, different shapes of hiatus and defects in dorsal wall of sacral canal should be taken into consideration before undertaking caudal epidural block so as to avoid its failure.

The knowledge of sacral hiatus anatomy is imperative in clinical situations requiring caudal epidural block for various diagnostic and therapeutic procedures of the lumbosacral spine to avoid failure and dural injury. In this study, a detailed anatomic study of the sacral region was carried out on 49 male adult Indian cadavers. Dorsal surface of sacral region was dissected to study sacral cornua, sacral hiatus, and the dimensions of triangle formed by the right and left posterosuperior iliac spines with apex of the hiatus. Midsagittal sections were subjected for various anatomical measurements. The angle of needle insertion and the depth of caudal space were noted. Cornu was not palpable bilaterally in 7 (14.3%) and palpable unilaterally in 12 (24.5%) specimens. Mean (standard deviation) distance between apex of hiatus and coccyx tip was 57.5 (8.7) mm and length of sacrococcygeal ligament was 34.2 (7.4) mm. The dimensions of the triangle were found to be interchangeable in 25 cadavers. Once the needle is introduced into the canal after penetrating the sacrococcygeal ligament, it should not be advanced >5 mm to prevent dural puncture. The level of maximum curvature of sacrum was S3 in 34 (69.4%) of cases. The dural sac was found to terminate at S2 in 41 (83.6%). The mean (SD) angle of depression of the needle was 65.7 (5.5) (range 58-78). The measurements described for the identification of the sacral hiatus, optimal angle of depression, and depth of the needle may improve the safety and reliability of a caudal epidural block.

The shape of the thyroid gland, its extension as the pyramidal lobe (PL) and attachments of the levator glandulae thyroideae (LGT) were studied in 410 male and 160 female adults from the Chandigarh zone in northwest India during medicolegal autopsies performed in the department. Whereas the measurements of the gland were recorded in 210 subjects, the weights were taken only in 160 instances. The shapes of the glands were: lateral lobes (LL) with isthmus (50.2%), horseshoe-shaped gland (36.8%), gland with separate lobes (7.9%) and irregularly shaped gland (5.1%). No sexual dimorphism was seen in the incidence of various shapes of the gland. The incidence of the PL and LGT was 28.9% and 19.5%, respectively. Neither a PL nor LGT was present in irregularly shaped glands. The mean weight of the gland was 15.01+/-7.69 g in males and 13.16+/-5.64 g in females. Sexual and age-wise differences in weights were found to be statistically insignificant. A survey involving 152 subjects in 2 villages in Chandigarh showed that it is an iodine sufficient zone. The size and weight of thyroid glands in adults of the two genders were found to be smaller than in western Caucasian and Japanese subjects.

The objective of this work was to study the morphometry and morphology of the round window (RW) and its relationships with the internal carotid artery, jugular bulb (JB), facial nerve and oval window (OW). Fifty cadaveric temporal bones were microdissected to expose the medial wall of the middle ear. The areas around the RW were cleared and its shape, height and width were noted. Its distances from the carotid canal (CC), jugular fossa (JF), facial canal (FC), and OW were measured. Oval, round, triangular, comma, quadrangular, and pear shapes of RW were observed. The average height and width of the RW were 1.62 ± 0.77 mm and 1.15 ± 0.39 mm, respectively. There was a statistically significant correlation (r = 0.4, P < 0.01) between the height and width. The distances between the RW and the CC, JF, FC, and OW were in the ranges 4.39-11.05 mm, 0.38-8.65 mm, 2.99-6.3 mm, and 1.39-3.57 mm, respectively. In 8% of cases, the distance between the RW and the JF was <1 mm. There were no statistically significant differences with regard to age group, gender, or side. Electrode insertion can be challenging in cases where the height and width of the RW are <1 mm. The thin bone separating the roof of the JF from the RW (<1 mm in 8%) highlights a potential risk of injury to the JB during cochleostomy placement. This information could be useful for selecting cochlear implant electrodes in order to avoid potential risks to vital neurovascular structures during implant surgery.