Supernumerary Bones in the Walls of the Bony Orbit.

Occurrence of supernumerary bones in the walls of the orbit especially in the medial wall and the roof has been described in the literature. Studies of the prevalence of supernumerary bones in the bony wall of the orbit are scarce in the literature. Present study was undertaken to find the prevalence of supernumerary bones in the walls of the orbit in a collection of adult Indian skulls. In the present study three hundred and twenty six orbital walls from one hundred and sixty three skulls were examined for the presence of the sutural bones. Their location with reference to the sutures in the walls of the orbit and their size was noted. The supernumerary bones were found in 25 skulls (15.34 %) mainly in the lateral wall (11.04 %) and the roof of the orbit (4.29 %). Prevalence of such supernumerary bones in the walls of the bony orbit is of anthropological interest. Many of the bony ossicles were of sufficiently large size, enough to be visualized on lateral skull X-ray and could easily be mistaken for fracture of the bony wall of the orbit.

Subclavius posticus muscle: a case report

A rare case of subclavius posticus muscle observed in a male cadaver is reported here. Presence of such accessory muscles have been recognized as possible causes of neurovascular compression syndromes in this region. It has been suggested by several authors that presence of accessory muscles like subclavius posticus can be a potential cause of thoracic outlet syndrome.

Es reportado un caso raro de músculo subclavio posticus observado en un cadáver de sexo masculino. La presencia de tales músculos accesorios ha sido reconocida como posible causa de los síndromes de compresión neurovascular en esta región. Varios autores han sugerido que la presencia de músculos accesorios como subclavio posticus, puede ser una causa potencial del síndrome de salida torácica.

Accessory muscles of the lower calf.

Two rare cases of accessory muscle of the lower calf observed in dissecting room cadavers are described here. This muscle is supposed to occur in 1% bodies and is implicated in tarsal tunnel syndrome. Occurrence of such anomalous muscles should be considered while examining cases reporting with pain associated with swelling in the region of Achilles tendon since they may mimic a soft tissue tumour.

Variations of the location of the greater palatine foramina in dry human skulls.

Seventy-one adult skulls (58 dentulous skulls: 56 bilateral and 2 unilateral, 13 edentulous: 11 bilateral and 2 unilateral) of unknown sex were examined for the variations of the location of the greater palatine foramen. The location of greater palatine foramen (GPF) was noted with relation to mid sagittal suture (MSS), posterior palatal border (PPB), and maxillary molars by measuring the distances using a sliding caliper to the nearest millimeter. Difference in the distance of the foramen from MSS and PPG in both the skull types was found to be statistically insignificant. Commonest location of the foramen was found to be opposite to third molar tooth (85.95%), followed by the interval between second and third molar teeth (13.15%), and opposite to the second molar tooth (only one case - 0.88%). Well-formed bony canals were found along the groove for the palatine nerves and vessels unilaterally in the right side in two skulls. These observation may be of help to the dental surgeon during the peripheral block of maxillary nerve for the maxillo-facial surgery.

Retromolar foramen.

Of the many variants in the mandible, the retromolar foramen is the most important. The incidence of retromolar foramen was studied in a collection of 157 south Indian mandibles available at the department of Anatomy, St. John's Medical College, Bangalore. On each side of the mandible, the area behind the last molar tooth was inspected for the presence of retro molar foramen. Wherever present, their distance from the last molar tooth and their size if they were sufficiently large were measured with a sliding caliper to the nearest millimeter. Retromolar foramen were found to be bilateral in 8 mandibles (5.1%) and unilateral 20 [right: 9 (5.7%); left: 11 (7%)] mandibles. The diameter of the foramina was 2 mm on both sides.

The varying shape of the coronoid process of the mandible.

The coronoid process (meaning crow) is a flattened triangular bony process of the ramus of the mandible. It is usually directed upwards and slightly forwards in the living subject. The coronoid process is of clinical significance to the maxillofacial surgeon for reconstructive purposes. Several authors have described the varying shapes of the process. In the present study, the variable shape and surface area of the coronoid process were observed in a collection of 154 south Indian mandibles. Using the criterion proposed by Isaac and Holla (2001), the coronoid process of each side was inspected for the shape and direction, and surface area of the ramus and the coronoid process was also calculated. The shape of the coronoid process was bilaterally triangular in 16.2%, hook-shaped in 45.5%, rounded in 18.2% rounded and hook-shaped in 4.5%, and unilaterally triangular in 12.3%, hook-shaped in 11.7%, and rounded in 7.1% of the mandibles. The coronoid processes faced directly upward in 55.4%, forward in 40.7% and backward in 3.8% of the mandible.

Morphological variations of the lung fissures and lobes.

BACKGROUND: Knowledge of the position of fissures of the lungs is necessary for the appreciation of lobar anatomy and thus locating the bronchopulmonary segments. METHODS: Morphological variations of fissures and lobes of the lungs were studied in 30 pairs of lungs from cadavers. RESULTS: Five right-sided lungs showed absence of horizontal fissure, 19 showed incomplete horizontal fissure. Eleven right-sided and 14 left-sided lungs showed incomplete oblique fissure and two right-sided lungs showed both absence of horizontal fissure and an incomplete oblique fissure. Accessory fissure was seen in three left-sided and one right-sided lungs. CONCLUSIONS: Awareness regarding anatomical variations is essential for performing lobectomies and segmental resection and interpreting radiological images.

Mylohyoid bridging in South Indian mandibles.

The incidence of the bony bridging of the mylohyoid groove of the mandible was studied in a collection of two hundred and twenty five south Indian mandibles. The bony bridging was noticed in 6.39% of the mandibles studied. The incidence of this trait shows a wide range of variation among the different population groups of India. The bony bridging of the mylohyoid may be useful as a non-metric trait in population studies when used in combination of other non-metric traits.

Incidence of morphological variants of mandibular lingula.

The ligual of mandible is a tongue shaped bony projection on the medical surface of the ramus close to the posterior margin of the mandibular foramen. Since the inferior alveolar nerve enters the mandibular foramen to supply the strctures of the lower jaw, the relationship of lingula to the inferior alveolar nerve is of clinical significance to dental surgeons. It becomes a necessety to know the morphology of linguls so as to preserve the important structures during surgical interference of mandible around the lingula region. The present study was undertaken mainly to establish the frequency of various morphological types of lingula in adult human mandibles of South Indian background. The material for this study comprised of a collection of 147 (294 sides) dry adult human mandibles. In each mandible, the lingula was scored using the classification proposed by Tuli et al (2000). More frequently observed bilaterally were the Truncated and Nodular types. These two types occurred more frequently unilaterally as well. The assimilated type, whether unilateral or bilateral was more or lesws similar in frequency along with other non metric variants of the skull, morphological types of lingula can also be useful as anthropological marker to assess population and recial distances.

The direction and location of mental foramen and incidence of accessory mental foramen in south Indian mandibles.

One hundred and forty two south Indian mandibles of unknown sex were examined for the variations of the location and direction of the mental foramen. Accessory mental foramen were also looked for. The findings have been compared with those of other studies in the literature. Topography of the mental foramen is of practical importance to the dental and maxillo-facial surgeon for purpose of anesthesia and surgical procedures.

Posterior bridging of the atlas vertebra in south Indians.

The vertebral artery is vulnerable to compression in its course between foramen transversarium and the foramen magnum during extreme rotation of the head and neck. This situation may be aggravated by the presence of posterior or lateral bridge of the atlas and result in compromised blood flow. The incidence of the bony ring formed by posterior bridging has been demonstrated in atlases of various races across the world: it varies between 1.875% to 29.2%. In an examination of sixty south Indian atlases it was found in 11.7% of the cases. The presence of this bony bridging should be taken in to account during a surgical manipulation of the cervical spine.

Paracondylar foramen--a new anomalous aperture of the occipital bone.

A new anomalous apperture has been identified by the author in association with the occipital bone. It was situated in the interval between the jugular fossa and the occipital condyles. Out of 118 skull bases examined four instances of this anomalous apperture were found (2 complete and 2 incomplete). The author speculates that they may transmitting the posterior condylar emissary vein in the absence of the condylar canal or in its abrrent course to the jugular foramen. In view of its topographical location the author proposes the name--'Paracondylar foramen' to this anomalous apperture.