Structural Anatomy

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/29943

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Surface Projection of the Iliolumbar Ligament
(2020) Salem, Yasser; Demissie, Elias; Liu, Howe; Gorski, Richard
Surface Projection of the Iliolumbar Ligament Purpose: The iliolumbar ligament (ILL) is often a weak structure when one makes a sudden trunk side-bend or twisting motion, but its surface projection has not been reported before. The purpose of this study was to measure the ILL in relation to thumb inter-phalangeal joint (IPJ) width, since the IPJ is one of the most conveniently used measurement in rehab settings. Methods: Ten specimens from 5 previously dissected adult cadavers were utilized for parameters assessment. Forty physical therapy students were recruited for calculation of the average IPJ width. Data was collected with the Vernier caliper and then converted to the IPJ width. Results: The average IPJ width from students was 2.01cm. The ILL attaches on the posterior tip of the L5 transverse process and travels horizontally and a little posteriorly to attach on the iliac tubercle or posteromedial 1/3 of the iliac crest. The ligament is a band-like shape with about ½ IPJ in width and about 1 ¼ IPJ in length in a horizontal way, and its distal attachment is about 2 ¼ IPJ from the L5 spinous process. There were no bilateral difference of these assessed measurements. Conclusion: Results from this study would help rehab clinicians locate where the ligament is in terms of surface projection and further assist in the application of physical modalities like ultrasonic or electric stimulation treatment or even hands-on manipulation in a more concise and efficient way. Key words: iliolumbar ligament, cadaver, manipulation.
A Literature Review of Velopharyngeal Insufficiency and Stress Velopharyngeal Insufficiency in Wind Players
(2020) Behel, Kensley
A literature review was conducted to evaluate diagnostic tools, as well as surgical and non-surgical reparative options used to diagnose and rehabilitate musicians suffering from velopharyngeal insufficiency (VPI) in musicians. Purpose: The purpose of this paper is to inform music educators and physicians of the prevalence, underlying causes, and possible manifestation of VPI in their students. Methods: Databases (PubMed and Web of Science), a scholarly search engine (Google Scholar), and journal archives (Medical Problems of Performing Artists) were searched yielding a total of 395 possible studies. After the exclusion criteria were applied (must include a minimum of one wind instrumentalist), 32 studies were selected for analysis. Results: As a result, 23 case studies from 1970 and 2018 were found to include relevant information about symptoms, diagnostic tools, and treatment options pertaining to VPI and SVPI in musicians. Conclusions: Nasal grunting, hypernasality, facial grimacing, decreased vocal intensity, fatigue, and maladaptive articulation were some of the side-effects of VPI in musicians. VPI under stress, known as SVPI, has been characterized as a potentially career-preventing or career-ending phenomenon. Medical intervention is often recommended to diagnose and treat VPI in musicians. To improve the quality of medical care for these musicians, more instrument-specific research is needed in this area.
Third Gastrocnemius Muscle Head: A Case Report
(2020) Mong, Joy; Fisher, Cara; Wagner, Lianne
Introduction: The gastrocnemius is one of the muscles of the posterior leg. It usually has two heads, which originate from the medial and lateral condyles of the femur respectively. The two heads come together to form the bulk of the muscle and then fuse with the tendon of the soleus muscle to form the calcaneal tendon. This case report documents a unilateral third head of the gastrocnemius muscle. Background: The presence of a third head has recently gained attention for its possible involvement in popliteal vessel entrapment syndrome. The muscle's close proximity to the popliteal artery and vein can potentially cause pain and claudication. Surgical resection of the muscle has been found to provide symptomatic relief, however in one study, 20 out of 1,039 cases found a third head of the gastrocnemius in patients with pain, but without symptoms of claudication. Case Findings: During a detailed dissection of a 74 year-old male cadaver, a third head of the gastrocnemius muscle was found in the right leg. This atypical muscle head originated from the medial third of the lateral femoral condyle, ran inferolaterally across the joint space, merged with the medial aspect of the lateral muscle head. Conclusion: This case report documents a third head of the gastrocnemius. This variant could have possible clinical implications, such as popliteal vessel entrapment. Due to the incidence of a third muscle head in literature, in patients presenting with popliteal claudication symptoms, an atypical anatomical variant etiology should at least be considered by clinicians.
Three Variations of the Dorsal Foot Musculature
(2020) Mong, Joy; Fisher, Cara; Wagner, Lianne
Introduction: This case report documents a unilateral muscular variation observed in a detailed dissection of the right dorsal surface of the foot in one cadaver. This region involves the extensor digitorum longus, extensor digitorum brevis, extensor hallucis longus, extensor hallucis brevis, and the dorsal interossei muscles. Background: There have been some rare documented cases of extensor hallucis longus variations, as well as rare extensor digitorum longus variations in literature, but there have not been any documented cases matching the morphology noted here. Case Findings: During a detailed cadaveric dissection of a 91 year old female cadaver, the right dorsal surface of the foot revealed multiple variations in the muscular anatomy. The first variation involved an accessory extensor digitorum longus tendon. This accessory tendon traveled inferiorly to the second tendon and inserted at the proximal region of the third middle phalanx. The second variation involved an accessory first dorsal interossei originating at the second metatarsal and inserting at the first proximal phalanx. The third variation involved an accessory muscle belly of the extensor digitorum brevis. This belly was found distal to the remainder of the muscle, originating at the fibular retinaculum and inserting at the second middle phalanx. Conclusion: Due to the multiple anatomical variations found in the right foot, it may be possible that this subject had an issue with abnormal gait or foot pain. Atypical knowledge of different anatomical variants could also help improve diagnosis of foot tendonitis and myofascial pain, as well as outcomes of tendon transfer surgeries.
Circumaortic Left Renal Vein
(2020) Craig, Matthew; Walter, Kathryn; Fisher, Cara; Ditter, Hannah
This case report documents a circumaortic left renal vein (CLRV) observed during a routine dissection of a 65-year-old male cadaver. Two distinct renal veins were observed arising separately from the hilum of the left kidney. The first left renal vein runs transversely to the inferior vena cava (IVC), passing anterior to the aorta. This preaortic renal vein follows the path of a typical left renal vein and drains both the left testicular and suprarenal veins. The second left renal vein runs inferiorly to the IVC within the coronal plane, passing the aorta posteriorly. An in-depth literature review revealed that various anatomical anomalies of the left renal vasculature have also been observed in addition to CLRV, such as multiple renal veins (MRV) and retroaortic left renal vein (RLRV). In the case of RLRV, the left renal vein passes posterior to the aorta. In the case of CLRV, a supranumerary retroaortic left renal vein exists in addition to a typical preaortic left renal vein. While these anatomical abnormalities may go undiagnosed in healthy individuals, they do have clinical implications such as correlation with nutcracker syndrome, which can lead to hematuria. Surgical implications of CLRV also include increased risk of hemorrhage during laparoscopic nephrectomies. Awareness of anatomical variations, such as the CLRV discovered in this cadaver, hold significant clinical implications and should be considered in pre-surgical work-up for various retroperitoneal surgeries.
Aberrant Extensor Digitorum Tendon Lies Superficial to Extensor Retinaculum
(2020) Son, Benjamin; Paez-Espinoza, Monserrat; Brevell, Bailey; Fisher, Cara; Evans, Zachary
BACKGROUND: The extensor digitorum muscle (EDM) is located on the posterior aspect of the forearm. The tendons of this muscle typically run deep to the extensor retinaculum (ER) and a fibrous sheath that, not only stabilizes and aligns the extensor tendons but prevents them from bowstringing with extension of the wrist. The ER has been used in the past as a graft source to treat Boxer's knuckle, an injury of the metacarpophalangeal (MP) joint capsule. This indicates the minor role the ER plays in physiologic function. EDM is innervated by the posterior interosseous nerve, a branch of the radial nerve, and is used in extending digits 2 through 5. CASE INFORMATION: This case report documents an anatomical variant that was found during routine dissection of a 66-year-old male cadaver's EDM. The most medial tendon of the EDM, attached distally to digit 5, was discovered to be passing superficial to the ER. CONCLUSION: To our knowledge, this anatomic variation has yet to be documented. The donor's medical history reports no motor dysfunction to the phalanges; thus it is suspected that this variation likely resulted in little to no complications for the donor. The lack of previous documentation on this variant, both in scientific literature and the donor's personal medical history, leads us to suspect that the variant is either uncommon or not of mechanical significance. We have theorized that this anatomical variance would present itself in a similar manner as the palmaris longus tendon.
A DILATED, TORTUOUS UTERINE ARTERY: GROSS ANATOMICAL VARIANT AND CLINICAL SIGNIFICANCE
(2020) Fisher, Cara; Clark, Chelsea
Purpose: Dilated tortuous uterine arteries are associated with multipara, and the resultant decreased blood flow can lead to a multitude of pre- and post-partum complications. We report an anatomical variant, provide retrospective discussion on previous research, and advocate future efforts in identification specifically to aid in preeclampsia screening and prevention. Methods: A left hemisected pelvis of a 43-year-old embalmed female cadaver was dissected. It revealed a dilated tortuous ascending branch of the uterine artery. We used digital imaging measurement software (ImageJ NIH, Bethesda MD) to measure the artery. Results: The dilated tortuous segment contained a total of eighteen direction changes in a ~2cm span. Conclusions: This variant illustrates the substantial compression of uterine artery vasculature in the body to less than 1/3 of its true length, a common finding in multiparous women experiencing preeclampsia. We suggest research focusing on developing a reproducible, credible identification method for uterine artery variants in women presenting with associated symptoms in order to prevent dangerous clinical manifestations.
Variation in the Origination of the Right Obturator
(2020) Fisher, Cara; Vu, Katie; Narayanan, Neeraja
Background: Knowing the anatomical location and origins of pelvic vasculature in the human body is imperative while performing laparoscopic procedures to mitigate hemorrhages. The obturator artery is well known for having variations in its course and origin. The obturator artery is a branch of the internal iliac artery in 79% of humans and travels alongside the obturator nerve through the obturator canal to supply the adductor muscles in the medial compartment of the thigh. The likelihood of the obturator artery branching off from the external iliac artery is 19%. Case Information: During pelvic dissections, our cadaver (60 year old Caucasian male) presented with a tortuous obturator artery branching from the external iliac artery in the right lateral pelvic region. The right obturator artery branches at 10.2 cm from the junction of right the external iliac artery from the right common iliac artery. The variant artery then proceeded to travel through the obturator foramen alongside the obturator nerve. Conclusion: In majority of humans, the obturator artery branches from the internal iliac artery, but studies have shown that the obturator artery can also arise from the external iliac artery or the inferior epigastric artery. Surgeons and radiologists should be aware of such anomalies while performing pelvic surgery or interpreting angiographies. While it appears most individuals with obturator artery variation are asymptomatic, further studies would need to be conducted to determine other implications. This report aims to spread awareness of the possibility of such vasculature variations amongst future health-care professionals and anatomists.
SURGICAL MANAGEMENT OF A LEFT UPPER EXTREMITY ARTERIOVENOUS FISTULA PSEUDOANEURYSM: A CASE REPORT
(2020) Olivencia-Yurvati, Albert; Dhume, Mahima
Background: An arteriovenous fistula (AVF) is a constructed vascular anastomosis and the first line of vascular access for most patients undergoing dialysis. AVFs need months to mature and the high pressure may lead to local complications such as formation of pseudoaneurysms. Urgent evaluation and repair is needed if the pseudoaneurysm is at risk of rupture. Case Information: A 71-year-old female with an extensive past medical history including ESRD and hypertension presented to the vascular surgery clinic for evaluation of a bleeding left-sided distal AVF pseudoaneurysm measuring 2.4 x 2.1 x 4.5 cm on ultrasound. She elected to have an arteriovenous graft revision and repair of the fistula pseudoaneurysm. In the operating room, a semicircle tunneler was utilized and a polytetrafluoroethylene (PTFE) graft was implanted. The pseudoaneurysm was repaired by ligation technique. The anastomosis was created first in the venous limb and then the arterial limb and the pseudoaneurysm was excluded by repair to allow for thrombosis. At her two week post-operative evaluation in the clinic, the patient appeared to have recovered well. Conclusions: A pseudoaneurysm arising as a complication from chronic hemodialysis is most commonly from routine needle insertion at the site and can be prevented by rotating the access needle during dialysis. The first line non-invasive recommendation is an ultrasound guided manual compression at the neck of the pseudoaneurysm and surveillance. If there is a risk of rupture, guidelines recommend revision of the AVF and emergency ligation, such as in this case report.
Biosafety measures to address challenges in expanding an anatomical laboratory
(2020) Nair, Maya; Reeves, Rustin; Yellott, Claudia; Tolulope Orimoloye, Helen
Introduction Laboratory work requires the use of potentially hazardous materials, sophisticated equipment, technical operations, and procedures to enhance discoveries. Health and biosafety considerations are made when designing laboratories, or when labs are renovated to accommodate more storage or research. The question then arises for the need of further biosafety requirements for a lab expansion. The anatomy laboratory at UNTHSC recently expanded their storage facilities to accommodate more donors to the Willed Body Program. Biosafety practices are crucial to prevent exposures to chemical and biological agents. There is a gap in knowledge about the biosafety challenges involved with the expansion of an anatomy lab. The purpose of this article is to evaluate the biosafety requirements and challenges for anatomical lab expansion. Methods Current regulations and recommendations for biosafety practices in anatomical laboratories from the State Anatomical Board of Texas will be reviewed to ensure compliance. A risk assessment of the laboratory will be performed to determine the potential hazards and the engineering requirements of safety protocols that will be needed during expansion. Materials and waste management, as well as air handling procedures will be reviewed, as well as the training procedures and Standard Operating Procedures (SOPs). The biosafety officer will ensure that the SOPs must cover hazard communication, accident and incident reporting system, personal protective equipment use, post-exposure and prophylaxis plan, transfer of equipment, and entry and exit procedures. Conclusion Our goal is to ensure the biosafety measures will help reduce the challenges in expanding the anatomical laboratory at UNTHSC.
Bilateral Omohyoid Variant
(2020) Reeves, Kirk; Fisher, Cara; Robert Wright, Tommy
Background: This case report describes and documents a bilateral anatomical omohyoid variant that was discovered during a routine cadaveric dissection. The omohyoid is one of the infrahyoid muscles consisting of a superior and inferior muscle belly, with an intermediate tendon connecting the two at an angle. While the omohyoid muscles play an important role in depressing the hyoid bone during phonation and swallowing, they also serve as an important surgical landmark for level III and IV lymph node metastasis. Therefore, it is important for clinicians to be aware of the variations that could occur with the omohyoid muscles and their subsequent potential side effects. Case Information: Careful dissection of the omohyoid muscles of a 92-year-old female cadaver revealed alterations from the normal anatomy. The left omohyoid muscle exhibited two inferior muscle bellies, with one having a midclavicular attachment and the other attaching to the superior border of the scapula. The right omohyoid displayed three different inferior muscle bellies, with one attaching to the midshaft of the clavicle, another attaching to the lateral aspect of the clavicle, and the last attaching to the superior border of the scapula. Conclusions: Aberrant omohyoid musculature has been described on numerous occasions and warrants significant consideration during a variety of procedures. Variations of the omohyoid muscle can have a range of clinical manifestations including torticollis, dysphagia, dyspnea, and they also serve as important surgical landmarks. Therefore, knowledge of omohyoid variants could lead to better management of patients with omohyoid disorders.
Nasal morphology and health disparities in asthma: A study assessing semi-automated tools for processing computed tomography scans in 3D morphometric research
(2020) Maddux, Scott D.; Kim, Suhhyun; Das, Siddharth
Purpose: As the nasal complex is predominantly responsible for respiratory heat and moisture exchange, it has been suggested that abnormal nasal anatomy may increase asthmatic symptoms. Recent research has increasingly turned to medical imaging modalities, requiring processing of large samples (n>10,000). The lack of automated procedures for scan processing has represented a significant obstacle for such studies. Accordingly, the purpose of this project was to evaluate the applicability of a newly developed subroutine for the NIH-funded 3D Slicer program to semi-automate the alignment of cranial CT-scans into the Frankfort Horizontal plane for subsequent morphometric assessment as a part of a larger asthma-related study. Methods: Selected CT scans were drawn from 5,221 asthma and control cohorts from JPS hospital in Fort Worth, TX. Each scan was first processed using traditional methods for aligning the cranium into the Frankfort Horizontal plane, followed by a trial employing a new python-based alignment subroutine for "SlicerMorph" extension on 3D Slicer for comparison. Results: Overall, the subroutine showed a significant improvement in image processing times, reducing alignment time for a single scan by approximately 60%. The accuracy of alignment was found to be substantially improved due to the relative ease of locating three fiducial landmarks (left orbitale, left porion, right porion) for alignment compared to the traditional method. Conclusion: This novel subroutine allows for efficient processing of CT scans. Furthermore, we expect use of this subroutine will significantly decrease intra- and inter-observer error, increasing the accuracy of obtained morphometric data.
Multiple Anatomical Variations in a Pair of Cadaveric Feet
(2020) Aten, Kristopher; Fisher, Cara; Daniel, Catherine
Background: The intrinsic muscles of the foot consist of all muscles that originate and attach to the foot itself (as opposed to those that originate in the leg and insert onto the foot). These muscles include the lumbricals, extensor digitorum brevis, and flexor digitorum brevis, among others, which primarily assist with movement of the toes and in stabilizing the arches of the feet. Case report: During a routine dissection of a pair of cadaveric feet and legs, several variants in the intrinsic musculature of the foot were noted. Bilaterally, there was an absence of the 4th lumbrical and the 4th muscle belly of the flexor digitorum brevis. Also found, were bilateral accessory tendons of the extensor digitorum brevis. While variations of all of these muscles are reported in the literature, there are few descriptions describing bilaterality of the variants described in this specimen. For example, multiple publications describe the absence of at least one lumbrical of the foot in 1-9% of specimens, but only three descriptions of bilateral absence were found on literature review. Discussion: The intrinsic muscles of the foot play an important role in the biomechanics of gait. In addition, the extensor digitorum brevis muscles are frequently used as flaps to repair defects of the foot and ankle. Knowledge regarding the type and incidence of variations in the anatomy of these muscles, therefore, caries true clinical significance and would likely benefit from further research in both cadaveric specimens and living human subjects.
Multiple Lateral Cervical Musculature Variation: A Case Report
(2020) Mong, Joy; Fisher, Cara; Wagner, Lianne
Introduction: The paired anterior, middle, and posterior scalene muscles are found in the lateral neck. The anterior scalene originates from the transverse processes (TPs) of C3-C6 and inserts on the first rib. The middle scalene originates from the TPs of C2-C7 and also inserts on the first rib. The posterior scalene originates from the TPs of C5-C7 and inserts on the second rib. The levator scapulae originates from C1-C4 and inserts on the angle of the scapula. This case report documents multiple anatomical variations of the scalenes and levator scapulae in the lateral neck. Background: While there have been case studies on other scalene variations, including the scalenus minimus, there are no documented cases matching the morphologies noted here. Case Findings: Detailed dissection revealed multiple muscle variations. The first, an accessory middle scalene muscle with two bellies. The superior belly originates at C1-C5 TPs, running in an inferomedial fashion, anterior to the middle scalene. The inferior belly runs in an inferior fashion, anterior to the middle scalene, with some fibers inserting on the middle scalene and the remainder merging with the first intercostal fibers. The second, an accessory levator scapulae muscle, with two bellies coming off the 3rd belly of levator scapulae and attaching to C5. The final variation, the posterior scalene muscle attaching to the first rib instead of the second. Conclusion: Some possible clinical implications of this variant include cervicogenic headaches, thoracic outlet syndrome, and compression of the brachial plexus.
Unilateral Soleus Hypertrophy in Case of Severe Varicose Veins
(2020) Blackwood, Taylor; Fisher, Cara; Ames, Kyle
Background: Efficient transport of blood and lymph relies on competent intraluminal valves that ensure unidirectional fluid flow through the vessels. Dysfunction of venous valves is associated with venous hypertension, varicose veins, venous stasis, and thrombosis that can lead to edema and ulcerations. If valves in the perforator veins are incompetent, the high pressures generated in deep veins by calf-muscle contraction can be transmitted to the superficial system, and to the microcirculation in skin, creating ambulatory venous hypertension. In situations where varicose veins coexist with deep vein incompetence, our team postulates that the increased pressure in the superficial veins and perforator veins can lead to a compensation by the lower extremity musculature to overcome the pressure load, leading to hypertrophy of that musculature. Case Information: During routine dissection of a 67-year-old Caucasian female cadaver, a unilateral hypertrophied right soleus muscle was discovered. In the present case, this manifested with severe varicose veins on the same side of the cadaver as the hypertrophied right soleus muscle. Conclusions: Unilateral hypertrophy associated with varicose veins is sparsely recognized or reported and the association should be further explored. The practicing clinician should be aware of the possibility of unilateral calf muscle hypertrophy resulting from varicose veins when working up deep venous thrombosis or unilateral peripheral edema. Recognizing this association could help to prevent delay in diagnosis and reduce unnecessary testing. Various treatments for varicose veins are wide ranging and include compression stockings, sclerotherapy, venoactive drugs, thermal ablation, and surgical interventions.
Anatomical Variation of the Splenius Capitis Muscle
(2020) Fisher, Cara; Wright, Tommy; Reeves, Kirk
Background: This study involves the post-mortem dissection of a unique orientation of muscle fibers branching from the splenius capitis. The splenius capitis muscle is part of the superficial back, which functions bilaterally to extend the head and unilaterally to flex and rotate to the ipsilateral side. The splenius capitis originates on the spinous processes in the cervical region and inserts into the mastoid process of the temporal bone and lateral one-third of the superior nuchal line of the occiput. Case Information: The muscle variant arose from the medial border of the along the superior nuchal line, traveled lateral to the primary muscle body for 6.1 cm, and inserted into the fascial layer below the mastoid process. Careful attention was paid to accompanying variations in neurovasculature and musculoskeletal function during the dissection. However, no additional structures were found to be travelling along the novel fibers. Due to the small size of the fiber and the insertion into the superficial fascia, no change in function was proposed to be caused by the variant. Conclusions: Due to the variability in musculoskeletal formation in the muscles of the back, care must be taken during surgical procedures in which anatomical variants could alter or impede surgical technique. In addition, variations in musculature of the back must be considered in patients undergoing long-term tension headaches. Careful dissections should be performed in the future to identify anatomical variations.
Anatomical Variation in a Deep Back Muscle and Possible Implications
(2020) Meehan, Grace; Park, Clair; Riggs, Alison; Hayes, Olivia; Fisher, Cara; Floyd, Jillian
Background: The longissimus thoracis muscle is a part of the erector spinae muscle group, originating from the thoracolumbar fascia, and inserting onto the transverse processes of the first through twelfth thoracic vertebrae. The multifidus muscle originates from the posterior superior iliac spine (PSIS) and inserts on the spinous processes; it is involved in extension and stabilization of the vertebrae in localized movements. Dysfunctions of these muscles are often associated with low back pain, a common complaint among U.S. patients. Case Presentation: This case study describes a novel anatomical variation in the musculature of the deep back discovered during a routine dissection of a 72-year-old female cadaver. The variation identified in this subject is located unilaterally on the right side, from the PSIS, and ends at the transverse process of the third lumbar vertebrae. Conclusions: Based on our literature review, we have concluded that the variation is an atypical deep back muscle. Future studies could examine the effects of these variants, and their implication, in somatic and physiological dysfunctions, such as scoliosis.
Intermuscular Lipoma: A Case Report
(2020) Fisher, Cara; Bilbao, Jorge
ABSTRACT: Background: Lipomas are the most common type of soft-tissue tumors. Superficial lipomas account for about 50% of all soft-tissue tumors and are usually found in the upper back, neck, proximal extremities, and abdomen. Deep-seated lipomas are far less common and usually found in the lower extremity, trunk, shoulder, and upper extremity. Case Presentation: In our study we report a case of a deep-seated, intermuscular lipoma with a rare location in the erector spinae musculature of the lower back. This mass was found during a routine dissection of a 68-year-old male cadaver and it serves to expand knowledge on the anatomical aspects of rare intermuscular lipoma locations. On gross examination, the lipomatous mass was seemingly circumscribed with a uniform, yellowish adipose color, lobulated surface, and soft consistency. Histological examination exhibited a discrete mass of uniform, mature adipocytes, which are clearly delineated from the surrounding musculature. Conclusions: These findings are diagnostic of a well-circumscribed intermuscular lipoma. It is important to note that these lesions are benign and have no metastatic potential. Knowledge of rare intermuscular lipoma locations is necessary for clinicians and surgeons during diagnostic and therapeutic procedures. It is necessary that current clinical guidelines take rare variants into consideration.
Levator Glandulae Thyroideae
(2020) Fisher, Cara; Laborde, Alfred; Blackwood, Taylor
Background: Levator Glandulae Thyroideae (LGT) is an accessory fibromuscular band that originates from the hyoid bone and inserts on the thyroid gland. It is an embryological remnant of contested origin and functions in elevation of the thyroid gland. The incidence of LGT is suggested to be approximately 1 in 6. Case Information: During routine dissection of a 70-year-old African American male cadaver a midline Levator Glandulae Thyroideae muscle was discovered which contained glandular tissue of the pyramidal lobe of the thyroid. The muscle fibers originated from the left side of the hyoid bone and passed superficially over the thyroid cartilage with insertion into the right side of the thyroid gland. Upon deeper dissection, it was noted that the LGT created a permanent indentation within the left aspect of the thyroid cartilage notch. This cadaver was noted to also have an anatomical variation in his neck region with his left external jugular vein coursing superficially to the clavicle. The cause of death is suspected to be unrelated and was noted to be metastatic esophageal carcinoma. Conclusions: Variations in cervical anatomy are common and knowledge of these variants is critical for surgeons to achieve quality patient outcomes. Clinicians using ultrasonography and CT imaging should be aware of the LGT to prevent a misdiagnosis of tumor or thyroglossal duct infection. While further study is needed to determine the embryological origin of the LGT, we postulate that the impression in the thyroid cartilage will help anatomists discover those details.
The Sternalis Muscle: A Case Report
(2020) Fisher, Cara; Kadado, Kevin
Background: The sternalis muscle is considered to be a rare anatomical variation found in about 5-6% of cases. First discovered in the early 1600s, the sternalis muscle has been a controversial topic due to variations that exist in its morphology, innervation and vascular supply. Method: During a routine dissection of a 73-year-old (Male) cadaver, a single, large sternalis muscle was discovered on the left thoracic wall. Nine other donors were dissected (n=10) to look for the presence of other sternalis muscle variants. Results: Out of ten cadavers, one sternalis muscle was identified. The sternalis muscle was located on the left thoracic wall. The proximal tendon was a continuation of the sternocleidomastoid, with the medial and lateral borders of the muscle attaching to the pectoral fascia. At the superior border of the 4th rib, the medial aspect of the muscle has a firm attachment to the gladiolus. Laterally the muscle attaches firmly to the 5th rib. Both aspects of the muscle attach inferiorly to the 6th rib via a diffuse tendon and blend in with surrounding deep fascia. Muscle fibers are vertical in orientation. Conclusion: The sternalis muscle is clinically relevant and should be considered by radiologists and surgeons when dealing with the thoracic wall. The sternalis muscle can be mistaken for a breast nodule on mammography, which can lead to unnecessary testing if clinicians are unaware of its existence.

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