Morphometry and aberrant morphology of the adult human tricuspid valve leaflets.

The tricuspid valve complex has been studied since the beginning of the twentieth century, and variations in the structural orientation of the tricuspid leaflets has been reported before, as the occurrence of accessory leaflets poses a major problem during surgeries related to the tricuspid valve. In this study, 36 adult formalin-fixed human hearts were analyzed to compare the number, form and size of the tricuspid leaflets. The result shows that in right ventricles, the number of leaflets can vary from the routine three to as many as seven, and the localization of such accessory leaflets of the tricuspid valve differs between specimens. Five leaflet forms were the most common, and the 'typical' form of tricuspid valves with no accessory leaflets was only present in a small percentage of the cases studied. Measurements of the main and accessory leaflets showed that the anterior leaflets were the largest, followed by the inferior leaflets, while the septal and the accessory leaflets were the smallest in size. On the basis of these results, it is suggested that three leaflets of the tricuspid valve are relatively uncommon, with frequent occurrences of accessory leaflets. The multicuspidal form of the tricuspid valve therefore raises concern about understanding the functional and physiological significance of the accessory leaflets.

Aberrant Dual Origin of the Dorsal Scapular Nerve and Its Communication with Long Thoracic Nerve: An Unusual Variation of the Brachial Plexus.

Pre and post-fixed variations at roots of the brachial plexus have been well documented, however little is known about the variations that exist in the branches which arise from the brachial plexus. In this paper, we describe about one such rare variation related to the dorsal scapular and the long thoracic nerve, which are the branches arising from the roots of the brachial plexus. The variation was found during routine dissection. The dorsal scapular nerve, which routinely arises from the fifth cervical nerve root (C5), was seen to receive contributions from C5 as well as sixth cervical nerve (C6), while the long thoracic nerve arose from C6 and seventh cervical nerves (C7) only. Furthermore along with variations in origin of the dorsal scapular and long thoracic nerves, the brachial plexus was seen to exist as a prefixed plexus receiving a contribution from C4 nerve root. An aberrant communicating branch between the dorsal scapular and long thoracic nerve was also identified. Knowledge about the course and anatomy of such variations can be vital for understanding the aetiology of various conditions such as winging of scapula, interscapular pain, administration of cervical nerve blocks, surgeries and for effective management of regions and muscles supplied by dorsal scapular and long thoracic nerve.

Study of aortic- common iliac bifurcation and its clinical significance.

OBJECTIVE: To determine the position of the aortic bifurcation, angle of aortic-common iliac bifurcation in relation to the lumbar vertebra, diameter of distal aorta, length of common iliac, diameter of iliac at bifurcation in cadavers. MATERIALS AND METHODS: The present study was done on 25 cadavers (16 males, 9 females) used for the dissection by 1st year MBBS students. The dissections were performed by anterior approach to the lumbar vertebra. The position of the aortic bifurcation, aortic bifurcation angle were measured in relation to lumbar vertebra. The remaining parameters were measured with the help of digital vernier caliper. RESULTS: The aortic bifurcation was seen in between L3 and L5 vertebra in all the cases. In majority of cases, 16 (64%), the bifurcation was observed at the level of L4 vertebra. During statistical analysis, significant differences were observed in the mean values of aortic-iliac take off angles and in mean diameter of distal aorta. CONCLUSION: The exact location of aortic bifurcation is useful when invasive procedures are performed in the pelvis, laproscopic lumbar discectomy and lumbosacral total disc arthroplasty. The aortic bifurcation mostly found at the level of L4 vertebra in the present study similar to previous studies. The aortic bifurcation can be a reliable landmark for determining the lumbar vertebral segments on MRI or CT.

Anatomical variation: median nerve formation - a case vignette.

Variations in the arrangement and distribution of brachial plexus and its branches in the infraclavicular part are common and have been reported by several investigators since the 19th century. These variations are significant for the neurologists, surgeons, anesthetists and the anatomists. During routine anatomical dissection of the right axilla and infraclavicular region of a 45-year-old male cadaver, the medial root of the median nerve was found to receive a supplementary branch from the medial aspect of the terminal portion of the lateral cord of brachial plexus and the branch was passing infront of the axillary artery from lateral to medial side. The median nerve was formed by joining of the lateral and medial roots from the lateral and medial cords of brachial plexus, infront of brachial artery, lower down, at the junction of upper one-third and lower two-third of the arm, instead in the axilla. This variation could be one of the cause of pressure symptom which occurs on the axillary artery and also the injury which occurs on the lateral cord or upstream to the lateral cord, which may sometimes lead to an unexpected presentation of weakness of forearm flexors and thenar muscles.

Communication between Mylohyoid and Lingual Nerve: An Anatomical Variation.

Variation in the branching pattern of mandibular division of trigeminal nerve has remain one of the commonest cause among the surgeons for not obtaining adequate local anesthesia in routine oral or dental procedure. In this article, we discuss about a case of an unusual communication between mylohyoid and lingual nerve in a 50-year-old female cadaver seen in a routine dissection in medical college. The details of this anatomical variation and its clinical aspects are discussed.