Examining the Forearm Intersection through Palpation and Ultrasonography.

BACKGROUND: Forearm intersection syndrome causes pain, swelling, and a rub at the dorsal distal forearm where the first extensor compartment muscles intersect with the second compartment tendons. Although primary care settings tend to treat mild cases, high-performance athletes may suffer from severe symptoms that require surgery. This proof-of-concept study aims to help detect the anatomical substrate of forearm intersection syndrome using palpation and ultrasonography when available. METHODS: Five individuals were studied using independent palpation and ultrasonography to identify the first dorsal compartment muscles and the second dorsal compartment tendons. The distances between the dorsal (Lister's) tubercle of the radius and the ulnar and radial edges of the first dorsal compartment muscles were measured to determine the location and extent of the muscle-tendon intersection. The palpatory and ultrasonographic measurements were compared using descriptive statistics and the paired t-test. RESULTS: The mean distances from the dorsal tubercle of the radius to the ulnar and radial borders of the first dorsal compartment muscles were 4.0 cm (SE 0.42) and 7.7 cm (SE 0.56), respectively, based on palpation. By ultrasonography, the corresponding distances were 3.5 cm (SD 1.05, SE 0.47) and 7.0 cm (SD 1.41, SE 0.63). Both methods showed a similar overlap length. However, ultrasonography revealed a shorter distance between the dorsal tubercle of the radius and the ulnar border of the first compartment than palpation (p = 0.0249). CONCLUSIONS: Our findings indicate that a basic knowledge of anatomy should help health professionals diagnose forearm intersection syndrome through palpation and, if available, ultrasonography.

Palpation and Ultrasonography Reveal an Ignored Function of the Inferior Belly of Omohyoid: A Case Series and a Proof-of-Concept Study.

BACKGROUND: Palpation, a traditional haptic ability, is used daily by practitioners of all medical and surgical specialties to assess patients. In the current study, one of the authors, in a routine clinical setting, was able to deduce the dynamic features of the putative inferior belly of omohyoid. This led to a proof-of-concept study that yielded results consistent with the clinical findings. METHODS: The first part of the study involved a survey of 300 rheumatic disease patients in whom the greater supraclavicular fossa was explored by palpation. While the patient kept the head straight, the clinician placed his middle three fingers 2.5-3 cm dorsal to the clavicle in the window between the sternocleidomastoid and trapezius clavicular insertions, explored the supraclavicular fossa, and palpated the paired contractile inferior belly of the assumed omohyoid during flexion in the three orthogonal planes. In the second part of the study, five normal subjects were examined in a similar manner by the same clinician and had independent ultrasonography performed on the dominant side. Descriptive statistics were used, and Yates' corrected chi-squared test was applied to certain nominal variables. Additionally, a comparative anterolateral bilateral neck dissection was performed in a cadaveric specimen. RESULTS: Both studies showed that the contractile structure was the inferior belly of omohyoid and that its contraction occurred during anterior neck flexion and was opposite to the side of neck rotation, resembling the sternocleidomastoid. CONCLUSIONS: Palpation uncovered a previously unknown function of the inferior belly of omohyoid, suggesting that physical examination of the musculoskeletal system based on palpation may lead to hypotheses worthy of exploration.

What happens under the flexor tendons of the fingers in dactylitis?

AIM: Tenosynovitis is one of the most frequently described inflammatory lesions in psoriatic dactylitis. The aim of the study was to assess by ultrasound the distribution of content within the synovial sheath of the finger flexor tendons in a cadaveric experimental model of tenosynovitis and to describe anatomically the elements of the space between the flexor tendons and the palmar aspect of the proximal phalanx of the fingers. MATERIAL AND METHOD: Silicone was injected under ultrasound guidance into the digital flexor sheath of the index finger of a hand specimen. Ultrasound images of the distribution of the filling of the flexor synovial space with the injected material were obtained. These images were compared with images from patients with psoriatic dactylitis. The palmar regions of the hand and fingers were dissected to check the distribution of the injected silicone in the synovial cavity. Additionally, we dissected the 2nd to 5th fingers of five cadaveric hands, including the one used for the experiment. RESULTS: During the injection of the substance, we observed an increasing homogeneous hypoechoic band around the flexor tendons that differed from the images of patients. Dissection of the specimen showed the injected silicone distributed throughout the digital flexor sheath to the distal interphalangeal joint. In addition, we provided an illustrated anatomical description of the elements located between the flexor tendons and the palmar aspect of the proximal phalanx, the inflammation of which could simulate flexor tenosynovitis. CONCLUSION: The observations of this study may contribute to a better understanding of the anatomical structures involved in PsA dactylitis.

Study of the functional relationships between the buccinator muscle and the connective tissue of the cheek in humans.

BACKGROUND: The buccinator muscle derives from the mesenchyme of the second pharyngeal arch. In adults, it has a quadrilateral shape, occupying the deepest part of the cheek region. Its function is complex, being active during swallowing, chewing, and sucking. To our knowledge, there are no studies that have specifically analyzed the relationship of the buccinator muscle fibers and neighboring connective tissue of the cheek in humans, neither during development nor in adults. Such relationships are fundamental to understand its function. Thus, in this study the relations of the buccinator muscle with associated connective tissue were investigated. METHODS: The buccinator muscle region was investigated bilaterally in 41 human specimens of 8-17 weeks of development. Moreover, four complete adult tissue blocks from human cadavers (including mucosa and skin) were obtained from the cheek region (between the anterior border of the masseter muscle and the nasolabial fold). All samples were processed with standard histological techniques. In addition, subsets of sections were stained with picrosirius red (PSR). Furthermore, immunoreactivity against type I and III collagen was also studied in adult tissues. RESULTS: The buccinator muscle showed direct relationships with its connective tissue from 8 to 17 weeks of development. Collagen fibers were arranged in septa from the submucosa to the skin through the muscle. These septa were positive for type I collagen and presented elastic fibers. Fibrous septa that were positive for type III collagen were arranged from the lateral side of the muscle to the skin. CONCLUSIONS: The intimate relationship between buccinator muscle fibers and cheek connective tissue may explain the complex functions of this muscle.

Palpation of the lateral bands of the extensor apparatus of the fingers. Anatomy of a neglected clinical finding.

This study aimed to determine by ultrasonography, and cadaveric dissection, whether the firm cords felt by palpation at the sides of the proximal phalanx (PP), actively flexing, and extending the proximal interphalangeal (PIP) joint while keeping the metacarpophalangeal (MCP) joint extended are the lateral bands (LBs) of the extensor apparatus. If so, palpation of the LBs could help evaluate hand conditions that impact the digits' intrinsic muscles. To this end, the PP of the middle and ring fingers of the dominant hand of seven subjects were studied by palpation on both sides. Ultrasonography (US) was performed with a hockey-stick transducer placed on the ulnar side. Five cadaveric hands were dissected, exposing the dorsal extensor apparatus. On palpation, a firm cord was consistently felt at the PP's sides in all subjects. These cords moved widely forward on PIP flexion and backward with PIP extension. By US scanning, the cords corresponded to the LBs. However, the forward movement had only a median of 1.8 mm (range 0.7-3 mm) in the middle finger and a median of 1.1 mm (range 0.3-2.7 mm) in the ring finger compared with an estimated 5-10 mm upon palpation. Cadaveric dissection confirmed the forward movement of the LBs in PIP flexion. We concluded that the firm cords felt at the PP sides are the LBs of the extensor apparatus. We confirmed their movement with the active flexion/extension of the PIP joint. Comparing the wide palpatory and the meager US motion, a haptic illusion of motion may be present.

A mini-incision carpal tunnel release technique to prevent pillar pain: A technical note.

Pillar pain represents one of the most common complications of classic open carpal tunnel release (CTR). This complication causes a sense of discomfort worse than the compression syndrome itself. We, herein, introduce a new treatment method for CTR through a mini-incision, which allows subcutaneously cutting the transverse carpal ligament (TCL) and releasing the median nerve without neurovascular complications. This mini-incision approach can allow the direct visualization and preservation of the thenar motor branch in those rare cases where it has an aberrant origin. For the past 10 years, we have consecutively performed this technique in the surgical treatment of 318 patients with the diagnosis of primary CTS, without developing any neurovascular and tendon injuries as well as pillar pain.

Basic morphological characteristics of coracoid grafts obtained by open and arthroscopic Latarjet techniques: A comparative study.

BACKGROUND: A knowledge of the anthropometric characteristics of the coracoid graft (CG) that can be obtained by the open and arthroscopic Latarjet techniques may be beneficial in the preoperative planning and intraoperative decision making for coracoid osteotomy and transfer. We have not found any study that compared the morphology of the CG that can be obtained from open and arthroscopic Latarjet techniques. The purpose of this study was to verify if the basic anthropometric characteristics of CGs are equivalent. HYPOTHESIS: We hypothesize that the basic anthropometric characteristics of the CGs are similar. METHODS: Twenty fresh-frozen human paired cadaveric shoulder specimens that had been randomly distributed in two groups of 10 specimens each were used. Two surgeons, each with experience in performing the open and arthroscopic Latarjet technique, performed these procedures in each of the respective groups (OG, open group; AG, arthroscopic group). A CT scan was performed. Using the volume rendering technique, a metric analysis of the volume, area and length of the CG were performed, evaluated and statistically analysed. RESULTS: There were no significant differences in length (p=0.162) (mean length, 22.6mm for OG and 23.6mm for AG). There were significant differences in the volume (p=0.031) and area (p=0.007) of the CG, being lower in the OG (mean volume, 2.8 cm3 for OG and 3.6 cm3 for AG; mean area, 9.9 cm2 for OG and 12.8 cm2 for AG). No significant differences were observed by sex or laterality. CONCLUSION: The mean lengths of the CGs that were obtained by each technique are equivalent. However, the areas and volumes of the grafts are different, being lower in the open surgery. These differences have not been an impediment to perform the technique. Our results corroborates that consolidation is more related to the preparation and placement than to the anthropometric characteristics of the CG. No significant differences were observed by sex or laterality. LEVEL OF EVIDENCE: Basic Science.

An unusual case of primate arterial pattern in a human upper limb / Un caso inusual de patrón arterial de primates en un miembro superior humano

During routine undergraduate dissections of the upper limb, variations on the usual arterial and muscular patterns were observed in a 68 year-old male cadaver. The arterial and muscular pattern found in our specimen is similar to that of some primates in the following terms. 1) Brachial artery duplicity, on the right side, with a superficial brachio-ulnoradial artery. 2) In the right upper limb, the biceps brachii muscle continued with the superficial muscles of the forearm. 3) The brachial artery on the left side, cross over in front of the median nerve, as the only artery of the arm with a network axillary pattern. 4) On both sides, the ulnar artery was superficial and originated at the elbow from superficial brachial arteries. 5) The right anterior interosseous artery intervened in the vascularization of the hand. These results suggest that this may be a case of early detention of human embryonic development and/or the persistence of phylogenetic older patterns. In the literature, we have found no reference to the presence of all these variations in the same individual. The objective of our study was to analyze these variations from an embryological and phylogenetic perspective.

Durante las disecciones de pregrado de rutina del miembro superior, se observaron variaciones en los patrones arteriales y musculares habituales en un cadáver macho de 68 años. El patrón arterial y muscular que se encuentra en nuestro espécimen es similar al de algunos primates en los siguientes términos. 1) Duplicidad de la arteria braquial, en el lado derecho, con una arteria braquioulnoradial superficial. 2) En el miembro superior derecho, el músculo bíceps braquial continuó con los músculos superficiales del antebrazo. 3) La arteria braquial en el lado izquierdo, se cruza frente al nervio mediano, como la única arteria del brazo con un patrón axilar en red. 4) En ambos lados, la arteria ulnar era superficial y se originó en el codo de las arterias braquiales superficiales. 5) La arteria interósea anterior derecha intervino en la vascularización de la mano. Estos resultados sugieren que este puede ser un caso de detención temprana del desarrollo embrionario humano y/o la persistencia de patrones filogenéticos más antiguos. En la literatura, no hemos encontrado ninguna referencia a la presencia de todas estas variaciones en el mismo individuo. El objetivo de nuestro estudio fue analizar estas variaciones desde una perspectiva embriológica y filogenética.

Comparison of Coracoid Graft Position and Fixation in the Open Versus Arthroscopic Latarjet Techniques: A Cadaveric Study.

BACKGROUND: Since the description of the arthroscopic Latarjet technique, discussion about the superiority of the open or arthroscopic procedure has arisen. The appropriate placement of the coracoid graft (CG) on the anterior glenoid neck is reported to be the most important step of the Latarjet procedure. PURPOSE: To verify if there are differences in the parameters that may affect the final position and fixation of CG obtained from the open and arthroscopic Latarjet techniques. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty fresh-frozen human paired cadaveric shoulder specimens were randomly distributed in 2 surgery groups (open group [OG] and arthroscopic group [AG]) with 10 specimens in each. Two surgeons, each with experience performing open and arthroscopic Latarjet techniques, executed these procedures: one surgeon performed all open techniques, and the other performed all arthroscopic techniques, respectively. After surgery, a computerized tomography scan was performed. The surgical time, the position of each CG, a series of variables that might affect the CG fixation, and the level of the subscapularis muscle split were evaluated. RESULTS: The mean surgical time was significantly longer in the AG (mean, 26 minutes for OG and 57 minutes for AG). Three intraoperative complications (30%) were identified in the AG, consisting of graft fractures. The CG was determined to be in an optimal cranial-caudal position in 90% of specimens of the OG and 44% of the AG (Fisher, P = .057). In both groups, the CG was placed in an optimal medial-lateral position in all specimens. In the OG, the degree of parallelism between the major axes of the glenoid surface and CG was significantly greater than in the AG (mean, 3.8º for OG and 15.1º for AG). No significant differences were observed in superior and inferior screw orientation between the groups. In the longitudinal and transverse directions, significant differences were found in the centering of the superior screw, being closer to the ideal point in the OG than in the AG. The location where the longitudinal subscapularis muscle split was performed was significantly higher in the AG. CONCLUSION: The open Latarjet technique required less surgical time; presented a lower number of intraoperative complications; and allowed more adequate placement of the CG, better centering of the screws, and a subscapularis muscle split closer to the ideal position. CLINICAL RELEVANCE: The reported benefits of the arthroscopic Latarjet technique seem less clear if we take into account the added surgery time and complications.

Early stages of development of the alar fascia (human specimens at 6-12 weeks of development).

In recent years, there has been much discussion concerning the cervical fasciae. The aim of this study is to confirm and to describe the development of the alar fascia as well as its relationship with nearby structures. Histological preparations of 25 human embryos (6-8 weeks of development) and 25 human fetuses (9-12 weeks of development) were studied bilaterally using a conventional optical microscope. Our study confirms the existence of the alar fascia and permits three stages to be established during its development. The initial stage (1st), corresponding to the 6th week of development (Carnegie stages 18-19), is characterized by the beginning of the alar fascia primordium in the retroesophageal space at the level of C7-T1. In the formation stage (2nd), corresponding to the 7th and 8th weeks of development (Carnegie stages 20-23), the alar fascia primordium grows upwards and reaches the level of C2-C3. In the maturation stage (3rd), beginning in the 9th week of development, the visceral, alar and prevertebral fasciae can be identified. The alar fascia divides the retrovisceral space (retropharyngeal and retroesophageal) into two spaces: one anterior (between the alar fascia and the visceral fascia and extending from C1 to T1, named retropharyngeal or retroesophageal space according to the level) and the other posterior (between the alar fascia and the prevertebral fascia, named danger space). We suggest that this latter space be named the retroalar space. This study suggests that alar fascia development is related to mechanical factors and that the alar fascia permits the sliding of the pharynx and the oesophagus during swallowing.

MRI inflammation of the hand interosseous tendons occurs in anti-CCP-positive at-risk individuals and may precede the development of clinical synovitis.

Interosseous tendon inflammation (ITI) has been described in rheumatoid arthritis (RA). Whether ITI occurs in at-risk individuals before the onset of clinical synovitis is unknown. OBJECTIVES: To investigate, by MRI, ITI in anti-cyclic citrullinated peptide (CCP)-positive at-risk individuals (CCP +at risk) and to describe the anatomy, prevalence and clinical associations across the RA continuum. METHODS: Hand MRI was performed in 93 CCP + at risk, 47 early RA (ERA), 28 established 'late' RA (LRA) and 20 healthy controls (HC) and scored for ITI, flexor tenosynovitis (TSV) and RA MRI scoring at the metacarpophalangeal joints (MCPJs). Cadaveric and histological studies were performed to explore the anatomical basis for MRI ITI. RESULTS: The proportion of subjects with ITI and the number of inflamed interosseous tendons (ITs) increased along the disease continuum (p<0.001): 19% of CCP +at risk, 49% of ERA and 57% of LRA had ≥1 IT inflamed . ITI was not found in any HC. ITI was more frequently identified in tender MCPJs compared with nontender MCPJs (28% vs 12%, respectively). No IT tenosynovial sheath was identified in cadavers on dissection or histological studies suggesting MRI findings represent peritendonitis. Dye studies indicated no communication between the IT and the joint. CONCLUSIONS: ITI occurs in CCP + at-risk individuals and can precede the onset of clinical synovitis. The ITs may be important nonsynovial extracapsular targets in the development and progression of RA.

Initial stages of development of the submandibular gland (human embryos at 5.5-8 weeks of development).

The aim of this study was to determine the main stages of submandibular salivary gland development during the embryonic period in humans. In addition, we studied submandibular salivary gland development in rats on embryonic days 14-16 and expression in the submandibular salivary gland region with the monoclonal antibody HNK-1. Serial sections from 25 human embryos with a greatest length ranging from 10 to 31 mm (Carnegie stages 16-23; weeks 5.5-8 of development) and Wistar rats of embryonic days (E) 14-16 were analysed with light microscopy. Five stages of submandibular salivary gland development were identified. The prospective stage (1), between weeks 5.5 and early week 6, is characterized by a thickening of the epithelium of the medial paralingual groove in the floor of the mouth corresponding to the primordium of the submandibular salivary gland parenchyma. At this stage, the primordium of the parasympathetic ganglion lies below the lingual nerve. The primordium of the submandibular salivary gland parenchyma is observed in rats on E14 in the medial paralingual groove with mesenchymal cells, underlying the lingual nerve. These cells are HNK-1-positive, corresponding to the primordium of the parasympathetic ganglion. The bud stage (2), at the end of week 6 in humans and on E15 in rats, is characterized by the proliferation and invagination of the epithelial condensation, surrounded by an important condensation of the mesenchyme. The pseudoglandular stage (3) at week 6.5 is characterized by the beginning of the formation of lobes in the condensed mesenchyme. The canalicular stage (4), between week 7 and 7.5, is characterized by the appearance of a lumen in the proximal part of the submandibular duct. The innervation stage (5) occurs during week 8, with the innervation of the submandibular and interlobular ducts. Nervous branches arriving from the parasympathetic ganglion innervate the glandular parenchyma. Numerous blood vessels are observed nearby. Our results suggest that submandibular salivary gland development requires interactions among epithelium, mesenchyme, parasympathetic ganglion and blood vessels.

Development of the long head of the biceps brachial tendon: A possible explanation of the anatomical variations.

The anatomical variations of the proximal portion of the long head of the biceps brachii tendon (LHBT) are rarely observed in clinical practice. However, an increase in the rate of shoulder arthroscopic surgery has led to an increase in the observation of anatomical variations of this region. The aim of this work was to analyze the development of the LHBT in 23 human embryos ranging from the 6th to 8th weeks of development. The LHBT develops from the glenohumeral interzonal mesenchyme in the 6th week. By week 7, the myotendinous junction of the LHBT develops. The anlage of the LHBT is separated from that of the glenohumeral capsule during week 8. Our results suggest that the most important period for the LHBT development occurs between the 6th and 8th weeks of embryonic development. Alterations during this critical period may cause anatomical variations of the LHBT. An additional case report from our own experience is provided as Supplementary material.

[Current knowledge of the temporomandibular joint morphology: clinical implications]. / Conocimiento actual de la morfología de la articulación temporomandibular: repercusiones clínicas.

The internal derangements of the temporomandibular joint (TMJ) are characterized by a displaced disk that acts as a obstacle to the joint movement causing a sound (click) associated with limited mandibular opening. These disorders can be accompanied by pain. The joint internal derangements are the most common inflammatory pathology of the TMJ, observing morphological changes, disk displacement, even in asymptomatic individuals. In this process seems to be involved the lateral pterygoid muscle. Our discussion will attempt to relate the possible sequence of morphological events that occur in these disorders and their influence on observed changes in the posterior region of the joint.

[Is the posterior segment of the temporomandibular joint capsule well defined?]. / Está definido el segmento posterior de la cápsula articular temporomandibular?

The temporomandibular joint (TMJ) is a complex joint due its development and filogeny. This complexity explains the lack of descriptions of the posterior joint capsule. Nowadays it is necessary to establish the limits of this joint part owing to a correct arthroscopic access. Dissecting human cadavers it will determine this joint segment and describe its anatomic relations.

[Epthelial derivates of the transversal groove of the stomodeum: parotid gland and juxtaoral organ]. / Derivados epiteliales del surco transversal del stomodeum: glandula parótida y órgano de chievitz.

A study was carried out in humans on the initial developmental stages of structures derived from the epithelial transversal groove of the primitive mouth. In O'Rahilly's stage 16, an epithelial condensation can be observed, the anlage of Chievitz's organ, while the anlage of the parotid gland was observed in O'Rahilly's stage 18. These structures are defined by their relationships with the mesenchyme and with their topographical location.

[Vascular canals. A model for the mandibular condyle growth]. / Canales vasculares. Un modelo para el crecimiento del cóndilo mandibular.

The vascular or cartilage canals of the mandibular condyle were studied in human fetuses, whose ages extended from the 9th to the 13th week of development. The vascular canals are firstly constituted by an invagination of mesenchimal cells which is in connection with the mesenchimal layer of the condyle envelope. During the 11th week of development a vessel penetrates in the invaginations. In the 12th and 13th weeks, the canals show a clearly defined pattern: some of them are located in the anterointernal region of the condyle, being those associated with the insertion of the lateral pterygoid muscle; two or three can be seen in the posterointernal region, whereas only one vascular canal, but th-e biggest one, is located in the posteroexternal region. This well defined disposition is related with the direction of the condylar growth during this period of the development.