A case of early obliteration of the sagittal suture without effect on cranial deformation.

This paper describes a unique case of craniosynostosis in a female skull in which sagittal sutures were completely fused by adolescence. Despite sagittal synostosis, the skull was of normal shape and size. Regarding craniometric features, the synostotic normocephalic skull was markedly different than that of scaphocephalic skulls which typically result from premature obliteration of the sagittal suture.

The pudendum and the perversion of anatomical terminology.

The definition of pudendum is external genitalia. The term pudendum is used to describe external genitalia regardless of sex. The labia majora, labia minora, clitoris, penis, scrotum, testes, and so on are all parts of the human pudenda. The female pudendum is also called the vulva. Also, nonhuman species have pudenda. Pudendum is a term that has been part of the formal anatomical nomenclature for a millennium. Recently, the meaning of pudendum has been perverted and misinterpreted as synonymous with only the vulva and to come from an etymological root term with the narrowly defined meaning "to be ashamed." The misunderstanding of pudendum is twofold. First, pudendum describes the external genitalia indiscriminate of sex; however, terms such as pudendum muliebre/pudendum femininum and pudendum virile/pudendum masculinum have been used throughout history to identify pudenda with respect to sex. Second, the meaning of the root term pudere has been taken out of context. The meaning of the root term is inclusive of respect, modesty, honesty, honor, virtue, awe, veneration, and so on and has a positive connotation rather than a negative connotation, akin to sacrum, for example. Indeed, pudendum shares its etymological root with the names of goddesses and saints (e.g., Pudicitia, Saint Pudens, Saint Pudentiana). This manuscript provides details regarding anatomical etymology and both the historical and modern use of anatomical terminology related to pudendum. Furthermore, this manuscript remedies the perversion of pudendum and, in doing so, improves the anatomical lexicon.

Local exhaust ventilation systems for the gross anatomy laboratory.

The inability to exhaust airborne formaldehyde and other volatile organic compounds from a gross anatomy laboratory is an impediment to gross anatomical education. Despite the importance of removing harmful airborne chemicals, there is scant information regarding how to build effective local exhaust ventilation systems. In this study, various exhaust systems were built and assessed for exhaust flow, airborne formaldehyde removal, and noise production with the aim of identifying inexpensive and simple exhaust systems that can create a healthy and quiet exhaust flow from a downdraft dissection table. The results of the study include details regarding 11 local exhaust ventilation systems, including an exhaust system that produces an exhaust flow of 777cfm, allows no detectable airborne formaldehyde (0ppm) despite a 1000mL pool of formalin (composed of 37% formaldehyde) positioned directly beneath a formaldehyde-meter, and operates at a very low noise level (maximum of 69.2dBA with coexisting baseline room noise of 38.6dBA). Furthermore, the aforementioned local exhaust ventilation system costs less than $400 (USD) to build and can be assembled in a matter of minutes with minimal know-how. The local ventilation systems assessed in this study were capable of down-drafting air away from the breathing zone; therefore, the utilization of such local ventilation systems may have the additional benefit of decreasing the person-to-person transmission of aerosolized pathogens. This information marks an improvement in laboratory health and safety measures, facilitates the creation of gross anatomy laboratories, and improves access to gross anatomical education.

Anatomical variations of the acromial and coracoid process: clinical relevance.

PURPOSE: The acromial and coracoid process morphology is of clinical relevance due to associations with functional limitations and shoulder pathology. Our objective was to describe the anatomical characteristics of the acromial and coracoid process using computed tomography (CT). METHODS: Descriptive, observational, transversal and retrospective study. A total of 155 CT of patients without shoulder pathology, of both genders, and indistinct age were evaluated and grouped by age: Group 1 < 25 years; group 2 25-40 years; group 3 > 40 years. The following parameters were evaluated: Acromial type (AcT), vertical coracoid distance (VCD), acromial tilt (AT), acromial projection (AP), critical shoulder angle (CSA), type of the subcoracoid outlet (TSO), and the area of the subcoracoid outlet (ASO). RESULTS: Statistically significant differences were found between men and women for VCD (14.44 ± 4.79 vs. 11.76 ± 4.00 mm; p < 0.001) and AP (3.66 ± 4.71 vs. 1.62 ± 4.99 mm; p < 0.05) as well as between age groups 1 and 3 for AT (35.08 ± 11.53 vs. 28.41 ± 6.60; p < 0.05) and ASO (398.99 ± 153.91 vs. 255.56 ± 124.58 mm2; p < 0.001). An unexpected high ASO variation was identified with 11% of S-shaped acromion and 1.3% clock-shaped TSO. CONCLUSION: The age group between 25-40 years had the most uniform distribution of data. There is a high morphological variability present in an asymptomatic population, which should be considered in the clinical assessment such as shoulder impingement syndrome.

Bilateral absence of the musculocutaneous nerve: implications for humerus fracture and atypical median nerve palsy.

The absence of the musculocutaneous nerve represents a failure of the nerve to depart from the median nerve during early development. During a routine dissection of a 66-year-old white female cadaver, a bilateral absence of the musculocutaneous nerve was observed in the upper limbs. Muscles of the anterior flexor compartments of the arms including biceps brachii and brachialis were supplied by branches of the median nerve. The lateral cutaneous nerve of the forearm also branched from the median nerve. In a clinical case of a particularly high median nerve injury, a variation of an absent musculocutaneous nerve may not only result in typical median nerve palsy of the forearm and hand, but palsy in the arm that would manifest as deficiencies in both shoulder and elbow flexion as well as cutaneous sensory loss from the lateral forearm.

Duplication of the inferior vena cava: evidence of a novel type IV.

Anatomical variations of the inferior vena cava, including the double inferior vena cava or isolated left inferior vena cava, are uncommon and of great clinical importance. Inferior vena cava variations signify predisposition to deep vein thrombosis and may complicate retroperitoneal surgeries including abdominal aortic surgery. Failure to recognize such variations may predispose a patient to life- threatening complications. This prospective anatomical study assessed 129 cadavers for variations of the inferior vena cava. One of the 129 cadavers (0.78%) possessed a double inferior vena cava and none (0%) possessed an isolated left inferior vena cava. The left-sided inferior vena cava was of a larger diameter than that of the right-sided inferior vena cava - opposite of what would be seen in a Type III duplication. Therefore, this observation expands the three-type classification system to include a Type IV duplication.

Temporal dynamics of peripheral neutrophil and lymphocytes following acute ischemic stroke.

BACKGROUND: The immune response to acute ischemic stroke (AIS) is implicated in diagnosis, prognosis, and intervention; however, the temporal dynamics of leukocytes following AIS are poorly understood. The purpose of this study was to characterize peripheral leukocyte dynamics following AIS among individuals with poor and favorable outcomes. METHODS: A retrospective chart review was conducted among patients with a diagnosis of AIS who were treated at a comprehensive stroke center across a 3-year timeframe. Groups were defined according to stroke outcomes. Patients with poor outcomes were distinguished from those with favorable outcomes by discharge National Institute of Health Stroke Score, infarct size, and Modified Rankin Scale. Leukocyte counts were compared among controls and AIS outcome groups. RESULTS: The neutrophil-lymphocyte ratio (NLR) calculated at 48-72 h post-AIS was identified as the strongest predictor of outcome. NLR was significantly higher in the poor outcome group (8.68 ± 0.93) compared with both the favorable outcome (4.5 ± 0.51, p = 0.009) and control group (4.33 ± 0.66, p < 0.001). Patients with a 48-72 h NLR ≥ 4.58 were 5.58 times more likely to have a poor outcome than AIS patients with an NLR < 4.58. CONCLUSIONS: The results of this study improve the understanding of the immune response in AIS. Low neutrophil count relative to high lymphocyte count at 48-72 h post-AIS should be considered a predictor of a favorable stroke outcome. Conversely, high neutrophil count relative to low lymphocyte count at 48-72 h post-AIS should be considered a predictor of a poor stroke outcome.

A concise survey on 3D modeling in the science of anatomy.

This report provides a concise overview of the rendering and utilization of three-dimensional models in the field of anatomy. Anatomical three-dimensional virtual models are widely used for educational purposes, preoperative planning, and surgical simulations because they simply allow for interactive three-dimensional navigation across the human organs or entire body. Virtual three-dimensional models have been recently fabricated as accurate replicas of the anatomical structures thanks to advances in rapid prototyping technology.

3 D printed replica of the human temporal bone intended for teaching gross anatomy.

The anatomy of the human temporal bone is complex and, therefore, poses unique challenges for students. Furthermore, temporal bones are frequently damaged from handling in educational settings due to their inherent fragility. This report details the production of a durable physical replica of the adult human temporal bone, manufactured using 3D printing technology. The physical replica was printed from a highly accurate virtual 3D model generated from CT scans of an isolated temporal bone. Both the virtual and physical 3D models accurately reproduced the surface anatomy of the temporal bone. Therefore, virtual and physical 3D models of the temporal bone can be used for educational purposes in order to supplant the use of damaged or otherwise fragile human temporal bones.

Infraorbital foramen location in the pediatric population: A guide for infraorbital nerve block.

BACKGROUND: Infraorbital nerve blocks are often performed for the management of postoperative pain associated with cleft lip correction. Infraorbital nerve block procedures depend on the identification of the infraorbital foramen; however, there is little information regarding the infraorbital foramen location in the pediatric population. AIMS: The aim of this study was to identify the location of the infraorbital foramen in the pediatric population relative to a midpoint between the nasospinale and jugale. METHODS: The study assessed the location of 152 infraorbital foramina relative to a midpoint between the nasospinale and J on dry crania. Crania were from individuals ranging in age-at-death from 6-month fetal to 18 years. The population was subdivided into fetal/infant (≥6 months fetal age-<2 years), child (≥2-<12 years), and adolescent (≥12-≤18 years) groups for comparison. RESULTS: The average distance of the infraorbital foramen from the nasospinale-to-jugale midpoint was 1.55 ± 0.78 mm (Mean ± SD) in the fetal/infant group, 0.80 ± 0.91 mm in the child group, and 1.31 ± 1.68 mm in the adolescent group. Furthermore, infraorbital foramina tended to be located medial to the nasospinale-to-jugale midpoint in the fetal/infant population, directly upon or superomedial to the nasospinale-to-jugale midpoint in the child population, and directly upon or superior/superolateral to the nasospinale-to-jugale midpoint in the adolescent population. CONCLUSIONS: The infraorbital foramen was located within 2 mm, on average, from the nasospinale-to-jugale midpoint regardless of age group. Therefore, the nasospinale-to-jugale midpoint may serve as useful means of identifying the location of the infraorbital foramen in the pediatric population and aid in optimizing infraorbital nerve block procedures. The information in this report is valuable in general, but may be particularly useful in developing countries where there is a lack of ultrasound training and availability for health care providers; or places where infraorbital nerve block may be the sole anesthetic modality for cleft lip surgery, even among adolescent patients.

The Infraorbital Foramen Is Located Midway Between the Nasospinale and Jugale: Considerations for Infraorbital Nerve Block and Maxillofacial Surgery.

Identification of the infraorbital foramen is important in infraorbital nerve block and the prevention of iatrogenic injury of the infraorbital nerve in maxillofacial surgeries. This study assessed the location of 887 infraorbital foramina from 518 adult crania of varied sex and population. The study assessed the midpoint of a line segment spanning from nasospinale to jugale (NS-J) relative to the infraorbital foramen. The mean distance of the NS-J midpoint from the infraorbital foramen was 2.1 ±â€Š1.9 mm (mean ±â€ŠSD) with a mode of 0 mm (266:887; 30%). The NS-J midpoint was located in the same plane or inferior to the infraorbital foramen in 98.4% of sides (873:887). There were no significant differences between sexes, populations, or sides with regard to the NS-J midpoint to infraorbital foramen distance. The NS-J midpoint can be used to locate the infraorbital foramen in both females and males of varied populations regardless of craniofacial diversity. The results of this study will aid in infraorbital nerve block procedures and maxillofacial surgery.

Metopism: a Study of the Persistent Metopic Suture.

Metopism, the persistence of the metopic suture in adulthood, is a clinically significant radiographic finding. In addition to masquerading as a fracture of the frontal bone, a persistent metopic suture may be associated with other clinically significant anatomical variations including frontal sinus abnormalities. Several geographically and craniofacially distinct populations have yet to be assessed for the prevalence of metopism. This study aimed to determine the prevalence of metopic sutures in adult crania of diverse populations among which scant research exists. A total of 505 adult crania were examined for the presence of a metopic suture. A total of 13 (2.57%) demonstrated metopism. Among subpopulations, metopism was present in 8.06% (5:62) of European crania, 15.38% (2:13) of East Asian crania, 2.20% (2:91) of Egyptian crania, and 2.86% (1:35) of Bengali crania. Metopism was also found in 1 Chilean, Roman, and Tchuktchi cranium, respectively. Metopism was not seen in crania from individuals of African (non-Egyptian) descent (0:62), Peruvians (0:144), Malayans (0:23), or Mexicans (0:23). Among sexes, metopism was present in 3.77% (8:212) of females and 1.79% (5:279) of males. The prevalence of metopism differs between populations and sexes. The results of this study provide anthropological, developmental, and clinical insight with regard to metopism.

Variation of the mylohyoid: implications for Ludwig angina, cervical contouring, and digastric muscle transfer.

The mylohyoid (MH) musculature separates the sublingual and submandibular spaces and is, therefore, important with regard to the spread of infection and space occupying lesions. Moreover, the MH may be elevated and included in the myocutaneous submental island flap or sutured in conjunction with the platysmas and the anterior bellies of the digastric muscles (ABDMs) to add stability to submental muscular medialization procedures. Therefore, variation in the anatomy of the MH musculature must be considered in the management of the spread of infection and space occupying lesions as well as in surgical planning. This report reviews mylohyoid variations and documents a unique case in which several suprahyoid muscular variations occurred concurrently. The variations included isolated anterior bellies of the mylohyoid inserting into the geniohyoid thereby forming mylo-geniohyoid muscles as well as isolated posterior bellies of the mylohyoid inserting into the ABDM and the intermediate tendon of the digastric muscle thereby forming mylo-digastric muscles. Surgeons operating in the suprahyoid region should be aware of potential anatomical variation of the mylohyoid to develop contingency plans.

The submental arrowhead variation of the mylohyoid and anterior belly of the digastric muscles.

PURPOSE: Submental anatomical variation is of clinical importance with regard to head and neck surgeries. One such anatomical variation is that of additional musculature joining the intermediate tendon of the digastric muscle to the midline of the mylohyoid musculature-a variation which this report refers to, accordingly, as an arrowhead variation. Though the arrowhead variation has been described in several case reports, it has not been subject to cross-sectional study. The purpose of this study is to determine the prevalence of the arrowhead variation. METHODS: Prevalence of the arrowhead variation was assessed in 19 cadavers via gross dissection. RESULTS: Two of the 19 cadavers (10.5%) were found to have arrowhead variations. The arrowhead variation was found in one male (1:11; 9.1%) and one female (1:8; 12.5%), respectively. CONCLUSIONS: This report demonstrates that the submental arrowhead variation of the anterior digastric and mylohyoid musculature has been reported in isolated case reports since the nineteenth century. This report is the first cross-sectional study of the arrowhead variant, identifying it in approximately one in ten individuals and in both sexes. Therefore, the presence of an arrowhead variation should be regularly considered with regard to diagnosis of submental masses. Likewise, the arrowhead variation should be considered in the preoperative planning of the myriad operations performed in the submental region.

The Use of Ultrasonography to Identify the Intersection of the Dorsomedial Cutaneous Nerve of the Hallux and the Extensor Hallucis Longus Tendon: A Cadaveric Study.

Terminal branches of the superficial fibular nerve are at risk of iatrogenic damage during foot surgery, including hallux valgus rigidus correction, bunionectomy, cheilectomy, and extensor hallucis longus tendon transfer. One terminal branch, the dorsomedial cutaneous nerve of the hallux, is particularly at risk of injury at its intersection with the extensor hallucis longus tendon. Iatrogenic injuries of the dorsomedial cutaneous nerve of the hallux can result in sensory loss, neuroma formation, and/or debilitating causalgia. Therefore, preoperative identification of the nerve is of great clinical importance. The present study used ultrasonography to identify the intersection between the dorsomedial cutaneous nerve of the hallux and the extensor hallucis longus tendon in cadavers. On ultrasound identification of the intersection, dissection was performed to assess the accuracy of the ultrasound screening. The method successfully pinpointed the nerve in 21 of 28 feet (75%). The sensitivity, positive likelihood ratio, and positive and negative predictive values of ultrasound identification of the junction of the dorsomedial cutaneous nerve and the extensor hallucis longus tendon were 75%, 75%, 100%, and 0%, respectively. We have described an ultrasound protocol that allows for the preoperative identification of the dorsomedial cutaneous nerve of the hallux as it crosses the extensor hallucis longus tendon. The technique could potentially be used to prevent the debilitating iatrogenic injuries known to occur in association with many common foot surgeries.

A Review of Extensor Hallucis Longus Variants Featuring a Novel Extensor Primi Internodii Hallucis Muscle Merging With Extensor Hallucis Brevis.

The extensor hallucis longus (EHL) muscle/tendon complex has been used in a variety of tendon transfer and tenodesis surgeries to correct iatrogenic hallux varus deformity, equinovarus foot deformity, clawed hallux associated with a cavus foot, and dynamic hyperextension of the hallux and, even, to prevent pedal imbalance after transmetatarsal amputation. Although it is usually considered a unipennate muscle inserting into the dorsum of the base of the distal phalanx of the hallux, a vast majority of EHL muscles possess ≥1 accessory tendinous slips that insert into other neighboring bones, muscles, or tendons, which can complicate these surgeries. The present report reviewed the reported data on EHL variants and describe a new variant, in which the tendons of the extensor primi internodii hallucis muscle of Wood and extensor hallucis brevis muscle merged together proximal to the tarsometatarsal (Lisfranc) joint, a site of rupture for extensor tendons of the foot. The reported variant might have contributed to the development of the clawed hallux seen in our patient and could complicate its operative management by mimicking the normal extensor digitorum longus tendon. Knowledge of the EHL variants and the particular muscular pattern described in the present review could improve the diagnosis and tendon transfer and tenodesis operative planning and outcomes.

Clival canal and clival foramen development in the fetal and infant basioccipital.

PURPOSE: There is a paucity of research regarding both the development and the prevalence of the clival canal or clival foramen in fetuses. Reports that have examined child and adult populations have posited ideas for the development of the canal and foramen; however, they have done so in the absence of anatomical data from the fetal population. Therefore, the present study was performed to elucidate the development of the clival canal and foramen through the assessment of perinatal basioccipitals. METHODS: This study analyzed 104 basioccipital bones, 60 from fetuses and 44 from newborns and infants. Dorsal surfaces of basioccipitals were assessed for the presence of anatomical variation with particular attention to the presence of clival canals and foramina. Among cases in which the presence of a clival canal or clival foramen was suspected, cannulation was performed for verification. RESULTS: Of the 104 basioccipitals analyzed, 1 (0.96%) had a clival foramen. Clival canals were identified in seven basioccipitals (7:104; 6.73%), four of which were from fetuses. Trends in anatomical variations among basioccipitals were also identified and categorized. These categories were then evaluated relative to age in order to elucidate ontogeny. A model is presented to explain the development of the clival foramen, the clival canal, and the basioccipital, in general. CONCLUSIONS: The presence of a clival canal or foramen should be considered even among individuals of fetal age. The findings of this osteological study suggest that the clival canal and foramen develop around vascular structures and, therefore, signify vascular connections among nearby venous plexuses.

The Shape of the Foramen Ovale: A Visualization Aid for Cannulation Procedures.

Several neurosurgical procedures, including rhizotomy for the management of trigeminal neuralgia, cannulate the foramen ovale (FO) to access intracranial structures. Cannulation procedures, including those utilizing neuronavigational technology, are occasionally complicated by anatomical variation of the FO, sometimes resulting in miscannulation and subsequent adverse events. The FO, while commonly thought of as oval-shaped, has also been described as "almond," "banana," "D shape," "pear," and "triangular." Because of the importance of the FO in neurosurgical procedures and the misunderstanding of FO shape, the aim of this study is to objectively describe the shape of the FO and its most likely shape variation. A total of 211 FO were evaluated by geometric morphometric analysis. A consensus shape is presented for the FO. No significant difference was found between the shapes of left- and right-sided FO. The most likely shape variation of the FO occurs as an inverse relationship between the anteromedial-posterolateral and anterolateral-posteromedial aspects of the foramen. The capacity to visualize the average FO shape and understand the most likely shape variance, as illustrated by this report, will aid neurosurgeons in their approach to procedures requiring cannulation of the FO.

The Retaining Ligament of the Anterior Digastric Muscle.

The anterior belly of the digastric muscle (ABDM) is important in numerous esthetic surgeries including rhytidectomy, alteration of the cervicomental angle via partial resection of the ABDM muscle belly, and suprahyoid muscular medialization and suspension. Recently, the connection between the ABDM and the mylohyoid muscle (MH) has been proposed as important for the mechanism of the digastric corset procedure. This report refers to the connection between the ABDM and the MH as a type of retaining ligament of the anterior digastric muscle (RLAD). This report is the first to directly demonstrate the existence of the RLAD, via photograph and video, and document variation in its attachment sites, its composition, and its behavior when traction forces are applied. In addition to the importance of the RLAD in plastic surgery, the RLAD may affect neurovascular structures between the ABDM and MH and serve as a physical barrier separating the submental fascial space from the submandibular fascial space and, therefore, influence the spread of infection.