Anatomical variations of the arrangement of structures at the pulmonary hilum: a cadaveric study.

PURPOSE: The aim was to study the anatomical variations of the arrangement of structures at the hilum of the lung. METHODS: The present study examined the hila of 110 cadaveric lung specimens of south Indian population. The anatomical variations of the arrangement of structures at the hilum were macroscopically observed. RESULTS: It was observed that the variations were higher in the left lung than in the right lung. The variations were observed in 16.1 % of right lungs and 48.2 % of the left lungs. There were some interesting anatomical variations like the two upper pulmonary veins, two pulmonary artery, two bronchi in the hilum of the left lung, three bronchi, four pulmonary veins and four bronchi. The present study was compared with a similar study from the same geographical location. It was observed that the frequency of variations and the hilar morphology of the arrangement of structures differ among the two separate studies from south India. CONCLUSIONS: The observations of the present study suggest that the pulmonary hilar morphology is extremely variable.

Arterial supply to the soleus muscle: an anatomical study with emphasis on its application in the pedicle flap surgery.

PURPOSE: To study the various patterns in the extra muscular part of arterial supply to the soleus muscle. METHODS: The study was carried out using 38 adult cadaveric lower limbs which were available from the Department of Anatomy of our institution. The vascular branches to the soleus were identified and traced till their point of entry into the soleus. These were considered as extramuscular branches (EMB) to the soleus. The distances of first and last branches from each artery were measured from the apex of head of fibula to their point of entry into the soleus and were expressed as proportion to the length of soleus. RESULTS: The present study observed that the soleus muscle is supplied by EMB of popliteal, posterior tibial and peroneal arteries. In 42.1% cases, there was no direct EMB from the popliteal artery to the soleus. The EMB of popliteal artery were located between 3.2 and 24.6% of the length of soleus. The EMB from the posterior tibial and peroneal arteries were located between 6.8-97.1% and 5.7-94.9% of the length of soleus, respectively. The proximal 25% of length of soleus received EMB from all the three arteries. CONCLUSIONS: The present study has provided additional information on the various patterns in the extra muscular part of arterial supply to the soleus muscle. This knowledge is important to the plastic and orthopedic surgeons while performing the pedicle flap surgeries. Our opinion is that the proximally based soleal muscle flaps are more beneficial in the surgical practice.

Morphometric study of the medial orbital wall emphasizing the ethmoidal foramina.

PURPOSE: Ethmoidal foramina on the medial orbital wall show a higher incidence of variation. Surgeons performing endonasal, anterior cranial fossa and medial orbital wall surgeries must be aware of these variations as they are a source of hemorrhage and also serve as landmark in proximity to the orbital apex. AIM: The present study aims to describe the morphometric distances of various ethmoidal foramina between anterior lacrimal crest to optic canal in south Indian dry human skulls. MATERIALS AND METHOD: The study was done on 44 adult dry human skulls. The occurrence of Ethmoidal foramina was noted by direct inspection. The distance of Ethmoidal foramina from anterior lacrimal crest to optic canal was measured with the help of ruler, probe and magnifying glass. RESULTS: The Posterior ethmoidal foramina were found in all 44 skulls bilaterally. Middle ethmoidal foramen was present in 12 and 13 skulls on right and left, respectively. Anterior ethmoidal foramen was found in 38 and 37 skulls on right and left, respectively. The distance between anterior lacrimal crest (ALC) and posterior lacrimal crest (PLC) was in the range of 3-8 mm and that of ALC to anterior ethmoidal foramen was in the range of 24-30 mm. The range of distance between anterior ethmoidal foramen to posterior ethmoidal foramen was 9-17 mm and that between posterior ethmoidal foramen to optic canal was 5-13 mm. CONCLUSION: These observations would help to predict the anatomical variations in the position of ethmoidal foramina with respect to anterior and posterior lacrimal crest and ensure the safe and precise performance of medial orbital wall surgeries to avoid injuries to the important neurovascular bundles passing through various foramina and fissures.

Morphometry of the thyroid cartilage, epiglottis and piriform sinus: An anatomical study.

Background: The goal was to measure the piriform sinus, epiglottis, and thyroid cartilage in our sample population. Methods: This study included 22 adult embalmed cadavers available in the Department of Anatomy. Dimensions were measured using a digital Vernier caliper. Results: The mean height of the thyroid laminae was 27 ± 1.4 mm at the right side and 25.5 ± 1.4 mm at the left side. Mean width of the thyroid lamina was 27.1 ± 1.3 mm at the right side and 27.4 ± 0.9 mm at the left side. The mean thickness of thyroid cartilage was found to be 4.4 ± 0.4 mm and 3.9 ± 0.5 mm over the right and left sides. The mean length, width and thickness of the epiglottis were 29.1 ± 0.5 mm, 22.2 ± 0.6 mm and 2.6 ± 0.3 mm correspondingly. The height, width and thickness of the right piriform sinus were 25 ± 0.5 mm, 14.2 ± 0.5 mm and 12.6 ± 0.5 mm, the same parameters were 25.3 ± 1.3 mm, 15.1 ± 0.7 mm and 13.3 ± 0.4 mm for the left side. Conclusions: The height and thickness of the thyroid cartilage were greater on the right side than on the left side (p<0.05). It was statistically observed that the width and thickness were greater on the left side than on the right side (p < 0.05). The data about the height, width and thickness of the thyroid cartilage, epiglottis and piriform sinus are essential during the laryngeal and other neck surgeries. They guide in the preoperative positioning, predicting the difficulty of intraoperative exposure and retractor pulling.

Variant facial artery in the submandibular region.

Facial artery has been considered to be the most important vascular pedicle in facial rejuvenation procedures and submandibular gland (SMG) resection. It usually arises from the external carotid artery and passes from the carotid to digastric triangle, deep to the posterior belly of digastric muscle, and lodges in a groove at the posterior end of the SMG. It then passes between SMG and the mandible to reach the face after winding around the base of the mandible. During a routine dissection, in a 62-year-old female cadaver, in Kasturba Medical College Mangalore, an unusual pattern in the cervical course of facial artery was revealed. The right facial artery was found to pierce the whole substance of the SMG before winding around the lower border of the mandible to enter the facial region. Awareness of existence of such a variant and its comparison to the normal anatomy will be useful to oral and maxillofacial surgeons.

Thickness and width of the menisci of adult knee joint: a descriptive cross-sectional observational study in cadavers.

Background: The goal was to determine the thickness and width of the knee joint meniscus at their different regions. The objective was to compare the dimensions at these regions and over the right- and left-sided specimens. Methods: The present study included 50 adult cadaveric knee joints, and 100 menisci (50 medial menisci and 50 lateral menisci) were studied. The meniscus was distributed into anterior, middle and posterior parts. Thickness and width at the mid-point of these three parts were determined by using the Vernier caliper. Results: The breadth of the medial meniscus was 8.38 ± 1.64 mm, 7.68 ± 1.92 mm and 13.93 ± 2.69 mm at the anterior, middle and posterior one-third regions. Same measurements for the lateral menisci at these regions were 9.84 ± 1.78 mm, 8.82 ± 2.01 mm and 10.18 ± 2.23 mm, respectively. The thickness of the medial meniscus was 4.49 ± 0.78 mm, 4.07 ± 0.81 mm and 4.79 ± 0.93 mm at these regions. The lateral meniscus thickness was 3.82 ± 0.69 mm, 4.43 ± 0.98 mm and 4.36 ± 0.8 mm, respectively. Conclusion: It is believed that this data is enlightening to the arthroscopic surgeon during the meniscus transplantation either by using synthetic material or allograft as the proper sizing of the meniscus is important to prevent complications due to inaccurate sizing.

Neurovascular foramina of the human clavicle and their clinical significance.

PURPOSE: To study the topographic anatomy and morphology of neurovascular foramina of the human adult clavicles. METHODS: The study comprised 52 clavicles, which were obtained from the anatomy laboratory. The clavicles were macroscopically observed for the number, location and direction of the nutrient foramina. The foramen index was calculated for each clavicle by applying the Hughes formula. RESULTS: The neurovascular foramen was observed in 50 (96.1%) clavicles. The foramen was single in 20 (38.5%) clavicles, double in 23 cases (44.2%), and there were more than 2 foramina in 7 clavicles (13.4%). The foramen was present at the middle 1/3 region in 92.3% clavicles, at the medial 1/3 region in 9.6% and at the lateral 1/3 part in 1.9% clavicles. It was on the inferior surface in 55.8% clavicles, on the posterior surface in 69.2% and at the superior surface in only 1.9% of clavicles. The average distance of the foramen from the sternal end was 64.4 mm and the mean foraminal index was 44.72. CONCLUSIONS: The present study observed that the foramina were more common on the posterior surface and were often multiple, directed toward the acromial end. Knowledge of the localization of nutrient foramina can be useful in certain surgical procedures to preserve circulation. We believe that the data obtained from the present study would be of interest to clinicians who are involved in procedures such as bone grafting, surgical approach for internal fixation and coracoclavicular ligament repair.

Occipital emissary foramina in human skulls: an anatomical investigation with reference to surgical anatomy of emissary veins.

AIM: The objectives were to find the incidence and topography of the occipital emissary foramina in skulls of South Indian Region. MATERIAL AND METHODS: In the present study, 78 dried adult human skulls were examined. They were analyzed for the gross incidence and position of the occipital emissary foramen. The observations were made in the squamous part of the occipital bone from the posterior margin of the foramen magnum to the external occipital protuberance. RESULTS: From our observations, the occipital emissary foramen was present in 11 (14.1%) skulls. Left sided foramen was observed in 5 cases (6.4%), right-sided foramen in 4 (5.1%) and the median foramen was seen in 2 (2.6%) of the cases. CONCLUSION: The occipital emissary vein is present in a small percentage (14.1%) of cases. It was also demonstrated that its location is variable as to left, right or midline. Its location was closer to the foramen magnum than to the external occipital protuberance in all the specimens. The morphology of this subject is important to the neurosurgeons and plastic surgeons. The knowledge is of importance in suboccipital craniotomies as this foramen transmits the occipital emissary vein and will keep awareness among the surgeons to avoid the excessive bleeding.

Exploring the Morphology of Anterior Interosseous Nerve and Relating It to Its Clinical Conditions.

AIM: To study topography and variability in the origin of anterior interosseous nerve; to identify the branching pattern of the anterior interosseous nerve supplying the flexor digitorum profundus, flexor pollicis longus, and pronator quadratus muscles. MATERIAL AND METHODS: The present study included 70 formalin-fixed upper limbs of adult human cadavers. The origin of the anterior interosseous nerve was categorized into 3 types. The morphometric data obtained in this study were represented as mean± SD and the dimensions were given in millimeter. The measurements were compared statistically by using 'EZR software, version 1.38, 2019'. The 'paired t-test' was applied and the 'p' value less than 0.05 was considered as statistically significant. RESULTS: It was observed that the origin of the anterior interosseous nerve was extremely variable. It was ranging from the midepicondylar point of the elbow joint up to as below as 86mm from it. The distance of its origin from the midpoint of the pronator teres muscle ranged between 70 mm above the pronator teres muscle to 22 mm below it. In one of the forearms, the median nerve supplied the medial two tendons of the FDP, instead of the ulnar nerve. CONCLUSION: The present study provided additional information about the origin, topography, and distribution of the anterior interosseous nerve. The data will provide further insight into the causes of nerve compression syndromes. It will also help in planning the surgical approach into the distal humerus, elbow joint, and proximal ends of radius and ulna, without causing any nerve injury.

Dimensions of pes anserinus of the lower extremity, an anatomical study with its surgical implications.

The reconstructive surgeries utilize pes anserinus (PA) tendons, because of their lesser post-operative clinical deficits and donor site morbidity. These surgeries require anatomical knowledge about the extent of PA formation. The goal of this study was to determine the length and width of the PA formation. The objectives were to measure the distance of its upper limit, lower limit, and vertical distance from the tibial tuberosity (TT). The present descriptive cross sectional study included 53 embalmed cadaveric lower extremities. The upper and lower limits of PA were exposed with the careful dissection. Measurements of the dimensions were performed with the help of a digital vernier caliper (Mitutoyo Co., Kanagawa, Japan). The PA length, width, distance of its upper limit, lower limit, and vertical distance of it from the TT were 47.4±13.3 mm, 37.3±7.2 mm, 47.6±12.5 mm, 54.6±10.4 mm, and 39.1±14.2 mm, respectively over the right extremity. The same measurements were 46.3±14.7 mm, 39.1±9.4 mm, 39.1±5.9 mm, 49.5±8.2 mm, and 36.4±12.1 mm, respectively for the left extremity. The extent of PA was observed to be extremely variable. The preoperative knowledge about the dimensions of PA will help the plastic and orthopedic surgeon put the accurate skin incision, decreasing the donor site morbidity and biomechanical instability of the PA grafts. We suggest that, preoperative ultrasound measurement of the PA may help the operating surgeon to prevent the complications like injury to the infrapatellar branch of saphenous nerve.

Extensor carpi radialis brevis origin, nerve supply and its role in lateral epicondylitis.

Lateral epicondylitis (LE) or tennis elbow has been the subject of concern during the last 60 years, but the pathogenesis of the LE remains unclear. The LE can be due to the tendinogenic, articular or neurogenic reasons. Numerous theories have been put fourth in the recent past, out of which one of the most popular theories is that the condition results from repeated contraction of the wrist extensor muscles, especially the extensor carpi radialis brevis (ECRB) which may compress the posterior branch of the radial nerve (PBRN) at the elbow during pronation. We studied 72 upper limbs (36 formalin-fixed cadaver) for the origin, nerve supply and the course of PBRN in relation to the ECRB as one of the goal for the present study. The possible presence of an arch of the ECRB around the PBRN was also observed and recorded. The nerve to ECRB was a branch from the radial nerve in 11 cases (15.2%); from the PBRN in 36 cases (50%) and from the superficial branch of the radial nerve in 25 cases (34.7%), respectively. The ECRB had a tendinous arch in 21 cases (29.1%); a muscular arch in 8 (11.1%) cases and the arch was absent in 43 cases (59.7%). When the ECRB had a tendinous or muscular arch around the PBRN, it may compress the same and this condition may worsen during the repeated supination and pronation as observed in tennis and cricket players. The presence of such tendinous or muscular arch should be considered by orthopedicians and neurosurgeons, while releasing the PBRN during LE surgery.

An anomalous belly of sternothyroid muscle and its significance.

The sternothyroid muscle and other infrahyoid muscles play a vital role in the process of vocalization, swallowing and mastication by mobilizing the hyoid bone and thyroid cartilage. During routine dissection of a 70-year-old male cadaver, we observed an anomalous sternothyroid muscle. It was arising from the posterior surface of the manubrium sterni and partly from the cartilage of the first rib. After a distance of 3.3 cm, the belly of sternothyroid muscle was divided into lateral and medial fibers. The lateral belly was inserted above the oblique line on the lamina of the thyroid cartilage, but the medial additional belly turned into a tendon, which was crossing over the thyroid artery and inserted to the hyoid bone and intermediate tendon of digastric muscles. The superior thyroid artery was below the above tendon on its way to the thyroid gland. The muscle was innervated by a branch from the ansa cervicalis.

Dual innervations of mylohyoid muscle: a case report.

Mylohyoid and anterior belly of the digastric muscles are supplied by a branch from the inferior alveolar nerve called the mylohyoid branch. Here we present an unusual finding in a 60-year-old male cadaver in which the mylohyoid muscle is supplied by a branch from hypoglossal nerve in addition to its usual nerve supply. Hypoglossal nerve after giving superior root of the ansa cervicalis and muscular branches to thyrohyoid and geniohyoid muscles gave another branch to supply the mylohyoid muscle. Any variation in the formation and/or branching pattern of ansa cervicalis or hypoglossal nerve can cause confusion and may complicate the procedures involving this nerve such as skull base surgery, neck dissection, and anterior cervical spinal approach. Developmentally mylohyoid muscle is from the mesoderm of the first arch, therefore, must be innervated by the mandibular nerve. Hence, we report this uncommon variation based on embryology and the clinical implications.

Duplication of falx cerebelli, occipital sinus, and internal occipital crest.

The incidence of variations of falx cerebelli was studied in 52 adult cadavers of south Indian origin, at Kasturba Medical College Mangalore, after removal of calvaria. In eight (15.4%) cases, we observed duplicated falx cerebelli along with duplicated occipital sinus and internal occipital crest. The length and the distance between each of the falces were measured. The mean length of the right falces cerebelli was 38 mm and the left was 41 mm. The mean distance between these two falces was 20 mm. No marginal sinus was detected. Each of the falces cerebelli had distinct base and apex and possessed a distinct occipital venous sinus on each attached border. These sinuses were noted to drain into the left and right transverse sinus respectively. After detaching the dura mater from inner bony surface of the occipital bone, it was noted that there were two distinct internal occipital crests arising and diverging inferiorly near the posterolateral borders of foramen magnum. The brain from these cadavers appeared grossly normal with no defect of the vermis. Neurosurgeons and neuroradiologists should be aware of such variations, as these could be potential sources of hemorrhage during suboccipital approaches or may lead to erroneous interpretations of imaging of the posterior cranial fossa.

Four-headed biceps and triceps brachii muscles, with neurovascular variation.

Anatomical variations of the biceps brachii and triceps brachii have been described by various authors, but the occurrence of four-headed biceps brachii and triceps brachii in an ipsilateral arm is rare and has not been reported before in the literature. During routine cadaveric dissection in the department of anatomy, Kasturba Medical College, Mangalore, India, various unusual variants were noted in the left arm of a cadaver of a 67-year-old man. The variants include a four-headed biceps, a four-headed triceps, communication between the musculocutaneous and median nerves, and a high origin of deep brachial artery from the axillary artery. The occurrence of these anomalies and the clinical and morphological significance are discussed.

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.

Incidence of accessory phrenic nerve and its clinical significance: a cadaveric study.

UNLABELLED: The description of accessory phrenic nerve (APN) in the standard textbooks and available literature is vague and sometimes limited to few lines. The incidence of APN varies a great deal from 17.6 % to 80.9 % in the available literature. The aim of the present study was to calculate the incidence and variation of APN in Indian population. MATERIAL AND METHODS: Forty five adult formalin-fixed cadavers (35 male, 10 female; 90 sides) used for gross anatomy dissection for undergraduates; during the 2 year period 2006-2007 were considered. Findings were recorded at different stages of the dissection. RESULTS: Out of 90 body sides studied, the APN was present in 48 sides (53.3 %). In 17 of the above sides the APN was confined to the cervical region (Cervical type) and in 31 sides the APN entered the thorax (Thoracic type), all anterior to the subclavian vein (SV). In eleven specimens the APN was found bilaterally. CONCLUSION: The incidence of APN, with its course and relation to the various structures in cervical and thoracic region will help the surgeons while performing internal thoracic artery (ITA) grafting and other radical neck surgery.

The morphology of meningo-orbital foramen in south Indian population.

When present, the meningo-orbital foramen forms an additional link between the orbit and the middle cranial fossa. It contains an arterial anastomose between the middle menigeal artery--the meningo-lacrimal branch and the lacrimal artery--the meningeal branch. The incidence of this foramen is known to vary between 28-82.9%. In the present study of 138 dry adult skulls of South Indian origin, the meningo-orbital foramen was present in 80.4% of population. The mean distance of the meningo-orbital foramen from the supra-orbital notch was 34.14 mm (29-38 mm) and from the fronto-zygomatic suture it was 26.10 mm (28-35 mm). The incidence and location of the meningo-orbital foramen may be of surgical significance to ophthalmologists (Tab. 1, Fig. 3, Ref. 7).

An unusual course and entrapment of the lingual nerve in the infratemporal fossa.

The infratemporal fossa is one of the most difficult regions of skull base to access surgically. The presence of the ossified pterygospinous and pterygoalar ligaments makes it more critical and difficult to access, with an occasional entrapment of structures like the mandibular nerve (MN) and its branches. During a routine dissection of an adult male cadaver, an unusual course of the lingual nerve (LN) was found with an entrapment of the nerve between the ossified pterygospinous ligament and the medial pterygoid muscle. Furthermore, all the three branches of the posterior division of the mandibular nerve communicated with each other by two anastomosing branches. The clinical significance of the present variations has been discussed (Fig. 1, Ref. 23).

An anomalous left external jugular vein draining into right subclavian vein.

Knowledge of the varying drainage patterns of superficial veins of head & neck, in particular, jugular veins are not only important for anatomists but also for the surgeons operating at this level and to clinicians in general. The variations are important also for interventional radiologists, who perform trans-jugular procedures, such as port implantations and trans-jugular intra-hepatic porto-systemic shunts or selective venous samplings. Results of recent studies report that the superficial veins, especially the external jugular vein, have been increasingly utilized for cannulation to conduct diagnostic and therapeutic procedures. We report a very unusual left-sided presentation of external jugular vein in an embalmed male cadaver. Embryological evaluations of the anomaly was done & compared with available literature, which showed that the observed variation is rare (Fig. 1, Ref. 12).