An unusual origin of a papillary muscle of the right ventricle.

Knowledge of anatomical variations of the heart are important to cardiac surgeons, cardiologists, and radiologist. During routine dissection of a 77-year-old male cadaver, we observed an unusual origin of a papillary muscle of the right ventricle arising from the atrioventricular aspect of the moderator band. This papillary muscle was 6.7mm long and 2.6mm wide. It gave rise to two chordae tendineae: one to the inferior (posterior) papillary muscle of the right ventricle and one directly to the inferior (posterior) leaflet of the tricuspid valve. Variants of the internal anatomy of the heart as exemplified in the present case report should be born in mind during image interpretation and invasive procedures of the right ventricle of the heart.

Duplication of the foramen rotundum: A rare case report.

Variations at the skull base can result in misinterpretation of radiological imaging and occasionally, iatrogenic injury. Here, we describe, to our knowledge, the second reported case of a duplicated foramen rotundum. The morphometrics of this finding are documented and the anatomy and potential clinical consequences of such an anatomical variation discussed. Such a finding is of archival value. Additionally, foramen rotundum duplication such as found in our case might also lead to complications while using, for example, transsphenoid approaches to the middle cranial fossa as well as various transfacial treatments for trigeminal neuralgia which rely on observing the foramina around the foramen ovale on fluoroscopy for correct positioning of needles and catheters.

An unusual location of the ansa cervicalis.

The ansa cervicalis (AC) is part of the cervical plexus and is formed by the ventral rami of spinal nerves C1-C3. It is usually formed by two roots that run parallel to each other and then form a loop anterior to the internal jugular vein. Herein, we report a rare case where the AC was found deep to the internal carotid artery and common carotid artery and had sympathetic contributions.

The jugular nerve: A review of this enigmatic structure.

The jugular nerve (JN) is described as joining the superior cervical ganglion to the vagus nerve. It has been studied extensively in many different animal species; however, there is very limited literature about humans. This review delves into various descriptions of this nerve's anatomy and animal studies aimed at deciphering its function. The goal is to shed more light on this understudied structure in humans.

Iliacus minor and psoas quartus muscles traversing the femoral nerve.

Anatomical variations of the nerves of the body can be relevant to surgical approaches anesthetic blockade, and other region procedures. Herein, we report a case of three muscle fascicles of the variant psoas quartus and iliacus minor muscles traversing the femoral nerve. Salient literature is reviewed regarding this phenomenon. Variations in the femoral nerve, such as illustrated in the current case, could also help explain hip and thigh pain, and failure of traditional anesthetic placement to block sensation from the femoral nerve completely. Given the procedural relevance of variations in the femoral nerve, further characterizations of nontraditional courses could help to avoid nerve injury during interventions.

A previously unreported variant of the auriculotemporal nerve.

Venous fenestrations are rare and when present often are not pierced by regional nerves. Herein, we report an unusual case of a fenestrated superficial temporal vein (STV). Anterior to the external ear, where the STV and superficial temporal artery normally travel with the auriculotemporal nerve (ATN), the nerve was found to pierce the STV. The fenestration within the STV was approximately 0.35mm in diameter, and there was no sign of compression of the ATN as it traversed this vessel. Following the site of penetration of the STV by the ATN, the nerve had a normal course into the skin and surrounding fascia. To our knowledge, this is the first report of a fenestrated STV being pierced by the ATN. Such an anatomical variation might be considered by clinicians who treat patients with pathology of this region.

Dual innervation of the mylohyoid muscle by the trigeminal and hypoglossal nerves: A case report.

During the routine dissection of a cadaveric specimen, the left mylohyoid muscle was found to be innervated by both the trigeminal and hypoglossal nerves. This variation was found unilaterally. To our knowledge this dual innervation of the mylohyoid muscle is an extremely rare variation. The possibility of these variants may lead to clinical consequences such as anesthesia failure and iatrogenic injury during surgical procedures in this region. We discuss this anatomical variation and possible developmental etiologies.

Postfixed lumbosacral plexus with split L5 ventral ramus and furcal nerve arising from L5.

Variations of the peripheral nerve plexuses are important to those clinicians who diagnose and treat patients with pathology of their parts. During routine dissection, a postfixed lumbosacral plexus with a furcal nerve arising from L5, not L4, was discovered. In addition, the case was found to have a split L5 ventral ramus. Such a variation might become clinically significant during clinical presentations of radiculopathy. With a better understanding of the fucal nerve variation presented here, along with previously documented variations, the diagnostic and treatment procedures for atypical radiculopathy can be refined, reducing the rates of nerve injury and failed back surgery.

Chiari I malformation with craniosynostosis and persistent falcine sinus draining into the straight sinus.

Owing to the interconnected nature of the brain, anatomical variations in one area often coincide with, or are caused by, abnormalities in another. During dissection of a specimen with both Chiari I malformation and craniosynostosis, a persistent falcine sinus was observed to drain into the straight sinus. Such a variant should be noted by physicians as it could alter treatment plans and require more detailed imaging procedures prior to surgical correction. Herein, we report the case and discuss the possible embryological origins and clinical significance of the variant.

Rare variation of the furcal nerve.

Variations in the course of the lumbar plexus and lumbosacral trunk have been explored with respect to variant nerve roots being indicated in atypical sciatic pain. Typically, the furcal nerve emerges from the L4 nerve root, with a single contribution. However, we report a case where the furcal nerve was found to arise not only from the L4 nerve but also from the obturator nerve. This anatomical variation is explored in terms of its clinical significance and implications in lumbar and sacral plexus associated procedures.

What is the suboccipital nerve? Tracking this confusing historical nomenclature.

Since its initial description in the 2nd century, the suboccipital nerve has maintained a number of varying terminologies. Many of these terms were created in the 18th and 19th centuries to describe the first set of cervical spinal nerves that exited the spinal cord between the cranium and the atlas. Though the many terminologies have been reduced to mainly the suboccipital nerve, there are still two prevalent definitions used for this nerve. Herein, we discuss the history of the first spinal nerve and its branches with special attention to varying terminologies over time. Recent literature has described the suboccipital nerve as the entire nerve or as simply the dorsal ramus of the C1 spinal nerve. This interchangeability may lead to confusion about the specific part of the nerve being discussed. Following a review of the literature, we recommend the term C1 spinal nerve be applied to the entire nerve, whereas, suboccipital nerve be reserved solely for the posterior branch of the C1 spinal nerve.

Dual innervation of the submandibular gland by nerve to mylohyoid and chorda tympani.

The chorda tympani typically utilises the lingual nerve and submandibular ganglion to transmit parasympathetic fibres to the submandibular gland. During a routine anatomy dissection, the submandibular gland was found to be innervated by both the lingual nerve and the nerve to mylohyoid. The clinical implications of this variant dual innervation to the submandibular gland is not clear due to its rarity: however, recognising such a variation should be borne in mind during surgical intervention near the nerve to mylohyoid.

Previously undescribed variant muscle connecting longissimus and semispinalis capitis muscles.

Thelongissimus capitis and the semispinalis capitis both function to bilaterally extend and unilaterally rotate the head. Typically, these muscles are distinct with origins and insertions at independent locations along the vertebral column. During a routine cadaveric dissection, an unusual muscle strip was identified between the longissimus capitis andsemispinalis capitismuscles on the left, posterior neck. This anatomical variation may have developed due to an incomplete or abnormal columnar segregation during gestation. The presence of this muscle strip contributes to previous case reports that have identified abnormal musculature between and along the longissimus and semispinalis muscles. Awareness of this muscular variant should be kept in mind by clinicians and surgeons who treat/operate this area of the body.

Simultaneous duplication of the tendon of plantaris with multiple tendinous connections into the crural fascia.

The plantaris muscle (PM) typically begins with a short, fusiform muscle belly and continues as a slim tendon traversing distally between the gastrocnemius and soleus to attach into the calcaneus directly or Achilles tendon. Conventionally, it has been of most interest as a donor for surgeons plantaris tendon (PT) grafting and recent studies have implicated the PT in the development of Achilles tendinopathy. During routine cadaveric dissection, one such anatomical variation was identified in a cadaver with two distal tendons of the PM and also multiple tendon connections into the crural fascia. While similar variants have been reported before in isolation, to our knowledge, this has been rarely reported illustrating the coexistence of a duplicated PT with simultaneous fascial connections into the crural fascia. The clinical implications of such a finding are discussed.

A rare case of dual origin of the left vertebral artery without convergence.

A case of dual origin of the left vertebral artery was encountered in a dissection course for medical students in 2014. Two vertebral arteries were observed on the left side. One arose from the aortic arch between the origin of the left common carotid artery and the left subclavian artery, entered the transverse foramen of the 4th cervical vertebra, and coursed upward into the transverse foramen. The other arose from the left subclavian artery as expected, divided into two branches anterior to the cervical vertebrae, and entered the transverse foramina of the 6th and 7th cervical vertebrae. Both branches flowed into the anterior spinal artery. Moreover, as seen in other anomalies, 3 arterial fenestrations were observed in the cranial arteries. This case is extremely unique with respect to the following points: the 2 ipsilateral vertebral arteries did not combine to form 1 vertebral artery, the vertebral artery of subclavian artery origin entered the transverse foramen of the 7th cervical vertebra, and 3 fenestrations were observed in the intracranial arteries. This is a very suggestive case for neurosurgeons and radiologists who perform treatments involving the vertebral artery.

Perforation of the temporomandibular joint disc: cadaveric anatomical study.

The aim of this human cadaveric study was to investigate the relationship between temporomandibular joint disc perforation and bony changes of the mandibular condyle. Overall, 135 cadaveric mandibles were used (69 male, 66 female; all White). Mean age at death was 78.7 years. Perforation of the disc was investigated. Differences in the area of the perforation according to the different types of bony change (erosion, flattening, osteophyte) were evaluated. Perforation of the disc was observed in 34.8% of all mandibles, occurring unilaterally in 53.2% of cases and bilaterally in 46.8%. The prevalence of perforation was 16.4% in cadavers <80 years old (67 heads) and 52.9% in those ≥80 years old (68 heads) (P < 0.001). Osteophyte formation was always identified along with other bony changes (21.7%) and never in isolation. The area of the perforation was significantly larger in the groups with bony changes (one, two, or three changes) than in the 'no bony change' group. The group with osteophyte formation showed a significantly larger perforated area than the group without osteophyte formation; likewise, the group with flattening showed a significantly larger perforated area than the group without flattening. Osteophytes and flattening are probably secondary bony changes that occur following disc perforation. Based on this study, disc perforation should be suspected when these findings are identified on imaging.

Ascending palatine branch from the lingual artery with multiple other variations of the external carotid artery.

The external carotid artery (ECA) is the major blood supply for structures in the head and neck. Typically, it has 8 separate branches; but there are many anatomical variations, making it difficult to predict surgical outcomes and complications without 3-dimensional imaging. This case study focuses on a cadaver with multiple anatomical variations in the ECA, i.e., lingual, facial, occipital, ascending pharyngeal, and posterior auricular arteries, found during routine dissection of the right cadaveric neck. We also discuss the incidences of several other anatomical variations of the ECA branches and their surgical implications and potential complications.

Accessory anterior ethmoidal nerve and artery: a cadaveric case report.

The anterior ethmoidal artery (AEA) is an important surgical landmark for procedures involving the anterior cranial fossa. Many variations in the location and branching pattern of the AEA have been reported throughout the literature. These anatomical variations are important for surgeons to be familiar with as injury to the AEA can lead to massive haemorrhage, orbital haematomas, and cerebrospinal fluid rhinorrhoea. Anatomical landmarks such as the ethmoidal foramen can be used to identify the location of the AEA; however, it is also important to consider that the foramen may have variable presentations. If there is ever difficulty with identification of the AEA, surgeons should pursue a high-resolution computed tomography to minimise the risk of surgical complications. In this report, we present a rare case of a variant accessory anterior ethmoidal artery and nerve, and variations in the ethmoidal foramen found during cadaveric dissection.

The first histological observation of a C1 posterior arch defect.

Deficiencies in the posterior arch of C1 have been well-studied with incidences ranging from 5.65% to 3% and five different classifications. Unfortunately, there is a paucity of information describing the detailed anatomy, muscle attachments, and histology of cases with a C1 posterior arch deficiency. We found a case of an isolated unilateral posterior arch defect in the 83-year-old male cadaver. Histology revealed that the posterior arch defect was filled with collagen fibres and fibrocartilaginous tissue without muscle or bony tissues. This is the first report detailing the histological findings of a posterior arch defect of C1.

Connection between V2 and V3 parts of the trigeminal nerve at the internal cranial base.

Anatomical variations can occasionally result in unexpected findings on physical examination. Here, we report two cases of seemingly unique connections between V2 and V3 parts of the trigeminal nerve. In these two cadaveric specimens, at the foramen ovale, small neural connections, confirmed with histology, were identified joining V2 to specifically, the motor root of V3. The findings of these two cadaveric specimens and the potential clinical ramifications are discussed.