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.

Unusual communication between the lingual nerve and mylohyoid nerves in a South Indian male cadaver: its clinical significance.

It is well known that variations in the branching pattern of the mandibular nerve frequently account for the failure to obtain adequate local anesthesia in routine oral and dental procedures, and also for the unexpected injury to branches of the nerves during surgery. During our routine dissection, we found the presence of a communicating branch between the mylohyoid and lingual nerves in a middle aged male cadaver. We also discussed its clinical and surgical implications in this report.

Accessory brachialis muscle: a case report.

Variations of arm flexors are not uncommon with the exception of brachialis muscle. The role of brachialis is critical as it is the primary flexor of the elbow joint. Variations of brachialis are rare in literature. We present a case of an accessory-brachialis muscle (AcBr), found during routine cadaveric dissection. The AcBr originated from the lateral aspect of the brachialis muscle and lateral intermuscular septum. During its course towards the elbow, it crossed over the radial nerve and the distal tendon splits into two. The medial slip ran over the ulnar artery and merged with the deep fascia covering the pronator teres muscle, whereas lateral slip was inserted to the fascia covering the supinator. In the ipsilateral arm, an additional lateral cutaneous nerve of forearm (LCNF) was found coursing over the brachialis muscle medial to the LCNF. Clinical consideration of the present variations has been discussed. The present variation should be considered in the etiology of radial-tunnel syndrome (RTS).

Anomalous origin of the lumbrical muscles: a study on South Indian cadavers.

Although variations in the attachments of the lumbrical muscles have been commonly reported, these have been seen mainly in the Caucasian population. The present study has been undertaken in South Indian population. The upper extremities of 24 South Indian (20 male and four female) cadavers were examined. Three instances of variant origins of the lumbrical muscles (two instances of the second and one of the first lumbrical) were seen. The muscles were unusually long extending to the level of the proximal border of the flexor retinaculum and in two of the cases it was taking origin from the flexor digitorum profundus tendon and its accessory belly. In one case it was taking origin from the flexor digitorum profundus and superficialis tendons. An anomalous origin of the lumbrical from muscles in the forearm has the potential to cause compression of the median nerve in the carpal tunnel.

Morphometry of posterior cerebral artery: embryological and clinical significance.

Posterior cerebral artery, terminal branch of basilar artery joins the posterior communicating artery to help complete the circulus arteriosus cerebri in human beings. A study of 89 formalin-fixed brain specimen of either sex and of Indian origin has showed that the mean length and diameter of the posterior cerebral artery was 6.75 +/- 1.482 mm and 1.7 +/- 0.7 mm respectively. Anomalous origin of the posterior cerebral artery was the only variation found during the present study. The incidence of occurrence of the particular variant was 2.2%. The variation did not have any sex or side predilection.

Accessory lateral pectoral nerves supplying the pectoralis major.

Certain surgical treatment failures of the brachial plexus lesions are due to the presence of anatomical variations. Anatomical knowledge of the pectoral nerves is of clinical importance during mastectomy, neurotization or other surgical procedures in the axilla. The present case describes three nerves arising from the lateral cord of brachial plexus supplying the pectoralis major muscle one below the other which was observed during routine dissection for undergraduate students. Knowledge of certain variations as in the present case may be advantageous for cosmetic augmentations during radical mastectomy where pectoralis major can be preserved because of its additional nerve supply in the lower part.

A case report on accessory brachialis muscle.

Supernumerary heads or slips of brachialis (anticus) muscle is one among the most striking variations, described and encountered in the dissection routine. Very few studies are quoted in the list of its anomalies. We present a unique occurrence of an accessory brachialis muscle (acBr) that formed a fibro-muscular tunnel after blending with the medial intermuscular septum in the lower part of the arm. This tunnel contained the median nerve, the brachial artery and few additional twigs that innervated the neighboring muscles. Because of its intimate topographical relation with the neurovascular bundle, there is no doubt about its role, in the etiogenesis of various compression syndromes. Also, the brachial flexors received innervation from the median nerve, due to the absence of the musculo-cutaneous nerve. We discuss in this report the possible embryogenesis and the clinical application of this variation that can aid the physicians in their approach and required treatment.

An accessory iliacus muscle: a case report.

We present a case of an anomalous accessory iliacus muscle in the iliac fossa which gets originated from the iliac crest and inserting along with iliopsoas, and appear to compress the L4 root of femoral nerve. During the routine dissection of a male cadaver aged 58 years, we found an accessory iliacus muscle. The L2 and L3 nerve roots joined the L4 root distal to the accessory iliacus muscle. The L4 root of the femoral nerve supplied accessory iliacus muscle. Accessory iliacus muscle might cause tension on the femoral nerve resulting in referred pain to the hip and knee joints and to the lumbar dermatome L4. The clinical significance of this variant muscle and its importance in the femoral nerve entrapment has been discussed.

Multiple muscular anomalies of upper extremity: a cadaveric study.

During routine cadaveric dissection, we encountered multiple muscular anomalies in a 58-year-old embalmed male cadaver. All the variations were encountered on the flexor compartment of right upper limb. The anomalies include an axillary arch (Aa) in the axilla, a third head of biceps brachii (Thb) in the arm, a reverse palmaris longus (Rpl) and a Gantzer's muscle (Gm) in the forearm and an unusually large palmaris brevis muscle (Pbm) in the palm. Anatomical description is achieved by measuring the length, width and attachments of the above-mentioned variants. The morphological and clinical significance of the anomalous muscles are discussed.

The palmaris longus muscle: its anatomic variations and functional morphology.

The functional morphology and evolution of the superficial forearm flexor, the palmaris longus, have long fascinated kinesiologists, physical anthropologists and anatomists alike. The anomalies, agenesis, variations and polymorphic presentation of the muscle, coupled with its biomechanical role in the performance of flexion and supination through distal articulations in the upper limb, have formed the base for many studies found in medical literature. We present data from published sources, along with our observations on the kinetics of palmaris longus, drawn from a series of dissections done on 30 cadavers. Complete agenesis was seen in four limbs. Reversal in the muscle-tendon orientation was seen in two limbs and duplication in one limb. The functional dynamics of the muscle and the clinical implication of its modifications in humans are discussed. We believe that every surgeon must be aware of the variations, since this, otherwise unimportant muscle, provides a very useful graft in tendon surgery.

Additional branches of celiac trunk and its clinical significance.

The anatomical variations of the abdominal arteries are important due to its clinical significance. Various types of vascular anomalies are frequently found in human abdominal viscera, during cadaveric dissection and diagnostic radiological imaging. The present report describes a variation in the celiac trunk as found during routine dissection in a 59-year-old male cadaver. The celiac trunk (CT) was unusually lengthy and took origin from the left antero-lateral surface of the abdominal aorta. Altogether, there were five branches, including three classic branches of CT. The left phrenic artery (LPA) was the first branch of the CT. The remaining four branches were left gastric artery (LGA), splenic artery (SA), common hepatic artery (CHA) and gastroduodenal artery (GDA). There was an arterial loop between the posterior branches of the superior pancreatico-duodenal artery (SPDA), arising from the GDA, and the posterior branch of the inferior pancreatico-duodenal artery (IPDA), arising from the superior mesenteric artery (SMA). The arterial loop formed by the above arteries, supplied the head of the pancreas and duodeno-jejunal flexure. The embryological and clinical significance of above variations has been described.

Multiple variations of the extensor tendons of the forearm.

Anatomic variations of the extensor tendons of the forearm are frequent and its knowledge is important to assess the diseased and traumatized hand. During routine cadaveric dissection in the Department of Anatomy, Kasturba Medical College, Mangalore, India, we came across unusual variations in the left upper limb of a 51-years-old male cadaver. The variants are, the complete absence of the extensor pollicis brevis (EPB), the abductor pollicis longus (APL) having six slips of insertion with additional muscle slip from the brachio-radialis (BR). The extensor digitorum communis (EDC) had five tendon slips, the extra tendon splits close to the metacarpo-phalangeal (MP) joint and contribute to the tendons of the ring and little fingers. The number of accessory tendons of APL has functional significance in the development of de Quervain's stenosing tendovaginitis. The present case is unique in the sense that, all the three variations are present in the ipsilateral upper limb. The occurrence of these anomalies and its clinical and embryological significance are discussed.

Ilio-femoral aneurysm masquerading as an inguinal abscess.

True isolated atherosclerotic aneurysms of the superficial femoral artery are rare. In this paper, we report a case of ilio-femoral aneurysmatic dilatation masquerading as an inguinal abscess in 40-year-old male. This interesting case was accidentally found during dissection of pelvic vessels, in the Department of Anatomy, Kasturba Medical College, Mangalore. After going through the history of the patient . We found that he had the history of swelling in both groins being drained 20 years back, and also the multiple heterosexual exposures. The swelling was pulsatile, tender, and soft to firm in consistency and measured 7x3 cm. All physical signs were suggestive of an abscess and he was treated conservatively by ampicillin, gentamycin, metronidazole, and anti-inflammatory drugs. Fine needle aspiration yielded only frank blood. Subsequently, general condition of the patient deteriorated and died due to hypovolemic shock. Autopsy revealed a ruptured fusiform aneurysm measuring 10x5 cm at the junction of right external iliac with the femoral arteries measuring 3 cm in diameter. This case is an example of difficulties in diagnosing the rare arterial aneurysm, thus leading to misdiagnosis as an inguinal abscess. When only the blood is drawn during fine needle aspiration, one should suspect the swelling as an aneurysmatic dilatation.

Anomalous channels draining the internal iliac veins: embryological and clinical significance.

During a routine cadaver dissection, we have encountered an anomalous formation of inferior vena cava and abnormal channels communicating the two internal iliac veins with the inferior vena cava in a 67 year old male cadaver. The said channels which had a caliber of 5 mm on the left side and 15 mm on the right arose at a distance of 26 mm on the left and 35 mm on the right from the internal iliac vein termination. Both the said channels moved medially and joined one another and formed a common stem (Cs) which finally terminated at the junction of the termination of right iliac vein into the inferior vena cava. The lumen of the terminal part had a diameter of 18 mm and it was 20 mm in length. Anomalies of the inferior vena cava and renal veins occur infrequently but if unidentified can lead to significant morbidity during surgical exploration. An understanding of the embryologic development of the vena cava and its tributaries is necessary to understand the genesis of these sometimes complex anomalies and their accompanying anatomic variants.

Multiple anomalies involving testicular and suprarenal arteries: embryological basis and clinical significance.

Variations in the origin of arteries in the abdomen are very common but with the invention of new operative techniques within the abdominal cavity, the anatomy of abdominal vessels has assumed much more clinical importance. During routine dissection of the abdominal cavity, we came across multiple arterial anomalies involving testicular and suprarenal arteries. On the right side, there was double testicular artery (medial and lateral) and the right inferior suprarenal artery aroused from the medial testicular artery. The right inferior phrenic artery (IPA) and middle suprarenal artery took origin from a common trunk just above the origin of right renal artery (RRA). On the left side, the left testicular artery was arching over the lower tributary of the left renal vein proper (LRVP). Apart from the developmental and morphological interest in arching gonadal arteries, they are of practical importance from a clinical and surgical viewpoint. The embryological and clinical significance of above variations has been described.

Duplicated omohyoid muscle and its clinical significance.

The omohyoid muscle is one of the infrahyoid muscles with superior and inferior bellies. Variations of this muscle are clinically important because of its relation to the internal jugular vein as well as its significance in radical neck dissection. A duplicated omohyoid was observed during routine cadaver dissection, which is attached along with the usual inferior belly of the omohyoid into the transverse scapular ligament. Knowledge of anomalies of this muscle is important to minimize the complications during the surgical procedures of cervical region.

Clinical significance of a mysterious clival canal.

During routine osteology demonstration of the posterior cranial fossa we noticed a transverse bony canal in the middle third of the clivus of an adult male skull. The canal was situated 1.8 cm in front the anterior border of the foramen magnum. The length of the canal was 0.6 cm long. The possible embryological basis and clinical significance of the variation was discussed.

Arcuate foramen of atlas: incidence, phylogenetic and clinical significance.

Arcuate foramen is less known trait of the human atlas vertebra formed by a delicate bony spiculum, which arches backward from the posterior end of the superior articular process. Examination of 1044 human atlas vertebra revealed that the trait was present in 13.8% of the samples. The mean length of the arcuate foramen form was 7.16 mm on the left side and 9.99 mm on the right side in bilateral positive samples while it was 8.14 mm and 9.26 mm respectively in unilateral positive samples. The mean vertical height of this foramen was 6.57 mm on the left side and 6.52 mm on the right side in bilateral positive samples while it was 4.91 mm and 5.38 mm respectively in unilateral positive samples. The sides did not show any statistical significant differences. The importance of the arcuate foramen lies in the external pressure it may cause on the vertebral artery as it passes from the foramen transversarium of the first cervical vertebra to the foramen magnum of the skull.