The previously undescribed variant of the thyrohyoid muscle and its potential impact on surgical procedures.

The thyrohyoid muscle belongs to the infrahyoid group located in the carotid triangle. It normally originates from thyroid cartilage and inserts into hyoid bone. Quite often, it is continuous with the sternohyoid muscle. Furthermore, there are variants that have their origin in the cricoid cartilage only, however, this occurs very rarely. During anatomical dissection, a two-headed variant of this muscle was found. One head had its origin in the cricoid cartilage and the other in the thyroid cartilage. This variant of thyrohyoid had not been previously described in the available literature. Therefore, we believe that it may be referred to as the cricothyrohyoid muscle. As the thyrohyoideus is often used as a landmark during surgical procedures in the prelaryngeal area and as a muscle graft, a thorough knowledge of its anatomy and variation is extremely important. We speculate that the two-headed version of this muscle may be problematic during surgical procedures in this region, however, it may also provide more options as a muscular graft.

Radial nerve compression: anatomical perspective and clinical consequences.

The radial nerve is the biggest branch of the posterior cord of the brachial plexus and one of its five terminal branches. Entrapment of the radial nerve at the elbow is the third most common compressive neuropathy of the upper limb after carpal tunnel and cubital tunnel syndromes. Because the incidence is relatively low and many agents can compress it along its whole course, entrapment of the radial nerve or its branches can pose a considerable clinical challenge. Several of these agents are related to normal or variant anatomy. The most common of the compressive neuropathies related to the radial nerve is the posterior interosseus nerve syndrome. Appropriate treatment requires familiarity with the anatomical traits influencing the presenting symptoms and the related prognoses. The aim of this study is to describe the compressive neuropathies of the radial nerve, emphasizing the anatomical perspective and highlighting the traps awaiting physicians evaluating these entrapments.

A very rare case of a thoracobrachialis muscle.

The anterior arm compartment includes the biceps brachii muscle, brachialis muscle, and coracobrachialis muscle, and they are characterized by different morphological variations. During standard anatomical dissection of right upper limb, an variant muscle was found. It originated from the fascia covering the long head of biceps brachii and from the tendon of pectoralis major muscle. It also connected to the brachial fascia. It also demonstrated a long thin tendon which was distally attached to the medial epicondyle of humerus. Knowledge about the morphological variations in this region is clinically important because of their direct correlation with neurovascular structures, which may lead to pathologies such as tingling, muscle weakness, paresthesia, and loss of sensation.

Morphological variations of the brachial artery and their clinical significance: a systematic review.

PURPOSE: Morphological variations of the brachial artery are quite commonly discovered in routine dissection and have been the subject of many studies. However, there is a need for a clear classification. This work presents morphological variations of the brachial artery, based on numerous case reports and studies created for the appropriate classification and interpretation among surgeons and radiologists. It also discusses the most important clinical aspects of the given varieties. METHODS: The research method is based on the combined interpretation of the researches based on numerous publications concerning both the principles of correctly classifying the described morphological variations of the brachial artery and the resulting clinical implications. This work considers atypical variations such as the presence of the superficial brachial artery, brachoradial artery, accessory brachial artery and absence of the brachial artery. Variations of the brachial artery in relation to the external and internal diameter of the vessel have also been discussed. RESULTS: After conducting a complex analysis of the collected data, the fundamental principles for classifying such variability as superficial brachial artery, brachioradial artery and accessory brachial artery were defined. Additionally, clinical implications resulting from the above like the impact of the superficial brachial artery on the median nerve neuropathy and the positive correlation between the brachioradial artery and increased danger of incorrect transradial catheterization were demonstrated. CONCLUSIONS: The clinical implications of the atypical arterial pattern within the upper limb are crucial during the angiography and surgical procedures so the variations affect the appropriate diagnosis and surgical intervention. Hence, the knowledge about the morphological variations of the brachial artery should be constantly broadened by radiologists and surgeons to improve the accuracy and effectiveness of the treatment process.

Case report of unusual insertion of the fibularis brevis muscle.

The fibularis brevis and fibularis longus muscles belong to the lateral compartment of the leg. The fibularis brevis is morphologically variable, especially in the number of tendons and place of insertion. Its type of insertion is correlated with the presence of a fibularis digiti quinti, which is also anatomically variable. We present a case study based on dissection of a seventy-three-year-old female cadaver with an unusual insertion of the fibularis brevis muscle. The tendon had three bands inserting into the fifth metatarsal bone. There was a coexisting fibularis digiti quinti, which was fused with the fibularis tertius muscle. Awareness of such anatomical variation could be useful during reconstructive surgery and planning rehabilitation protocols.

Anatomical variations of the tibialis anterior tendon.

INTRODUCTION: The tibialis anterior muscle originates from the medial part of the anterior compartment, from the upper two-thirds of the lateral surface of the tibia and the adjacent part of the interosseous membrane, and typically inserts to the medial cuneiform and first metatarsal bone. The goal of the study was to examine the insertion of the tibialis anterior tendon and create a classification in human fetuses. MATERIALS AND METHODS: Fifty spontaneously-aborted human fetuses (26 male, 24 female, 100 lower limbs), aged 18-38 weeks of gestation at death were examined. RESULTS: The classification comprised five types of tibialis anterior tendon insertion. The most common was Type V (60%), which was characterized by a single tendon inserting onto the medial cuneiform bone. The second most frequent was Type I (19%), which was characterized by a tendon which split into two equal-sized parts that insert to the medial cuneiform bone and the base of the first metatarsal. The third was Type II (12%), which was characterized by a tendon splitting into two different-sized parts that inserted onto the medial cuneiform bone (larger component) and the base of the first metatarsal (smaller component). The fourth type was Type III (5%), which was also characterized by a tendon splitting into two different-sized parts that inserted onto the medial cuneiform bone (smaller component) and the base of the first metatarsal (larger component). Finally, Type VI (4%), the least frequent type, was characterized by a tendon splitting into three different-sized parts, inserting onto the medial cuneiform bone (the smallest component) and the base of the first metatarsal (the middle and larger component). CONCLUSION: The tibialis anterior muscle is characterized by high variability in the approach of its tendon to the foot, at least in fetuses. This is classified in the present study for the first time.

Quadriceps or multiceps femoris?-Cadaveric study.

PURPOSE: The quadriceps femoris (QF) consists of four muscles: the rectus femoris; vastus medialis; vastus lateralis, and vastus intermediate. The tendons of all of these parts join together into a single tendon that attaches to the patella. The QF is a powerful extensor of the knee joint that is needed for walking. A growing number of publications have examined the fifth head of the QF muscle. There is no information about the possibility of other heads, and there is no correct classification of their proximal attachments. Further, the frequency of occurrence of additional heads/components of the QF remains unclear. METHODS: One hundred and six lower limbs (34 male and 18 female) fixed in 10% formalin solution were examined. RESULTS: Additional heads of the QF were present in 64.1% of the limbs. Three main types were identified and included subtypes. The most common was Type I (44.1%), which had an independent fifth head. This type was divided into two subtypes (A-B) depending on its location relative to the vastus intermediate. The second most common type was Type II (30.8%), which originated from other muscles: IIA from the vastus lateralis; IIB from the vastus intermediate, and IIC from the gluteus minimus. In addition, Type III (25%) was characterized by multiple heads: IIIA-two heads with a single common tendon; IIIB-two heads with two separate tendons; IIIC-three heads (lateral, intermediate, medial), and IIID-four heads (bifurcated lateral and bifurcated medial). CONCLUSION: The introduction of a new classification based on a proximal attachment is necessary. The presence of the fifth, sixth, seventh, or eighth head varies.

A very rare case of an accessory subscapularis muscle and its potential clinical significance.

The subscapularis muscle is the largest muscle of the rotator cuff and its main function is internal rotation. It is morphologically variable in both point of origin and insertion. The presence of an accessory subscapularis muscle can lead to brachial plexus neuropathy. This report presents a very rare accessory subscapularis muscle originating from two distinct bands on the subscapularis and teres major muscles. The insertion was divided among four tendons. The fourth tendon is bifurcated. One of these was connected to the tendon of the subscapularis muscle and the other three inserted into the base of the coracoid process of the scapula. This anomalous muscle has the potential to entrap the nerves of the posterior cord such as the axillary, lower subscapular, and thoracodorsal nerves.

The co-occurrence of a four-headed coracobrachialis muscle, split coracoid process and tunnel for the median and musculocutaneous nerves: the potential clinical relevance of a very rare variation.

The coracobrachialis muscle (CBM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. Both the proximal and distal attachment of the CBM, as well as its relationship with the musculocutaneus nerve demonstrate morphological variability, some of which can lead to many diseases. The present case study presents a new description of a complex origin type (four-headed CBM), as well as the fusion of both the short biceps brachii head, brachialis muscle and medial head of the triceps brachii. In addition, the first and second heads formed a tunnel for the musculocutaneus and median nerves. This case report has clear clinical value due to the split mature of the coracoid process, and is a significant indicator of the development of interest in this overlooked muscle.

A proposal for a new classification of coracobrachialis muscle morphology.

INTRODUCTION: The coracobrachialis muscle (CRM) originates from the apex of the coracoid process, in common with the short head of the biceps brachii muscle, and from the intermuscular septum. It inserts to the medial part of the humerus between the attachment of the medial head of the triceps brachii and the brachial muscle. Both the proximal and distal attachments of the CRM, as well as its relationship with the musculocutaneus nerve, demonstrate morphological variability. MATERIAL AND METHODS: One hundred and one upper limbs (52 left, and 49 right) fixed in 10% formalin solution were examined. RESULTS: Three main types, with subtypes, were identified. The most common was Type I (49.5), characterized by a single muscle belly with a classical origin from the coracoid process, medially and posteriorly to the tendon of the biceps brachii. Type II (42.6%), characterized by two heads, was divided into two subtypes (A-B) depending on its origin: Type IIA, where one head originated from the coracoid process posteriorly to the tendon of the biceps brachii and the second head from the short head of the biceps brachii, and Type IIB, in which both heads originated from the coracoid process; however, the superficial head fused with the insertion of a short head of the biceps brachii, while the deep head was directly originating. Finally, Type III (7.9%) was characterized by three heads: two originated from the coracoid process (superficial and deep), and the third from a short head of the biceps brachii. Two types of insertion and two types of musculocutaneous nerve (MCN) relative to CRM could be distinguished. CONCLUSION: An adapted classification is needed for all clinicians working in this area, as well as for anatomists. The CRM demonstrates morphological variability in both its proximal and distal attachments, as well as the variable course of the MCN relative to the CRM. WHAT IS KNOWN ABOUT THIS SUBJECT "AND" WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE: Not much is known about the variability of coracobrachialis muscle. The present paper introduces a completely new classification, both clinical and anatomical.

Unusual case report of seven-headed quadriceps femoris muscle.

PURPOSE: We present a case of a seven-headed quadriceps femoris (QF) muscle and a systematic review of the literature concerning this anatomical variation. METHODS: During a routine dissection of the lower limbs of a 72-year old cadaver, a QF with supernumerary heads was identified. Each head of the muscle was photographed and subjected to further measurement. RESULTS: In addition to the four traditional heads of the QF muscle, we found a tensor of the vastus intermedius (TVI) muscle and two additional muscle bellies composed of tendons. Attachments of the TVI tendon and additional tendons were localized on the superior medial border of the patella. CONCLUSION: It is important to be aware of morphological variability of the quadriceps femoris muscle. The described case assists clinicist with avoiding misdiagnoses around the knee.

Very rare arrangement of the pes anserinus: potential clinical significance.

The pes anserinus superficialis is composed of the semitendinosus, gracilis and sartorius tendons. Normally, they all insert to the medial side of the tibial tuberosity, and the first two are attached superiorly and medially to the tendon of the sartorius muscle. During anatomical dissection, a new pattern of arrangement of tendons creating the pes anserinus was found. The pes anserinus comprised three tendons; the semitendinosus tendon was located superiorly to the gracilis tendon, and they both had distal attachments on the medial side of the tibial tuberosity. This seemed like the normal type, but the tendon of the sartorius muscle created an additional superficial layer, its proximal part lying just below the gracilis tendon and covering the semitendinosus tendon and a small part of the gracilis tendon. After crossing the semitendinosus tendon it is attached to the crural fascia significantly below the tibial tuberosity. Good knowledge of the morphological variations of the pes anserinus superficialis is necessary during surgical procedures in the knee region, especially anterior ligament reconstruction.

Lung segments from anatomy to surgery.

Bronchopulmonary segments are of increasing interest to clinicians because surgical procedures are emerging that maintain as much pulmonary function as possible. The conventional textbook borders between these segments, their many anatomical variations, and their numerous lymphatic or blood vessels, make them challenging for surgeons, especially thoracic surgeons. Fortunately, because imaging techniques such as three-dimensional-computed tomography are developing further, we can see the anatomical structure of the lungs in detail. Moreover, segmentectomy is now seen as an alternative to a more radical lobectomy, especially for lung cancer. This review explores the connection between the anatomical structure of the lungs, especially their segments, and surgical procedures. Further research on minimally invasive surgical procedures is timely as we can diagnose lung cancer and other diseases ever earlier. In this article, we will look at the latest trends in thoracic surgery. Importantly, we propose a classification of lung segments in reference to surgery difficulties due to their anatomy.

Anatomic Variations of the Calcaneofibular Ligament.

BACKGROUND: The lateral ankle joint comprises the anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL). The purpose of this study was to propose a classification of CFL morphology. METHODS: The material comprised 120 paired lower limbs from human cadavers (30 male, 30 female), mean age 62.3 years. The morphology was carefully assessed, and morphometric measurements were performed. RESULTS: A 4-part method for anatomic classification can be suggested based on our study. Type 1 (48.3%), the most common type, was characterized by a bandlike morphology. Type 2 (9.2%) was characterized by a Y-shaped band, and type 3 (21.7%) by a V-shaped band. Type 4 (20.8%) was characterized by the presence of 2 or 3 bands. Type 2 and 4 were divided into further subtypes based on origin footprint. CONCLUSION: The aim of our study was to describe variations of calcaneofibular ligament. Our proposed 4-part classification may be of value in clinical practice in future recognition of CFL injuries and in its repair or reconstruction. CLINICAL RELEVANCE: The anatomy of the CFL plays an important role in stability of the ankle. Greater recognition of anatomical variation may help improve reconstructive options for patients with chronic lateral ankle instability.

The quadratus femoris muscle anatomy: Do we know everything?

INTRODUCTION: The purpose of this study was to characterize the morphological variations in the quadratus femoris muscle (QF) and to create an anatomical classification that could be used in the planning of surgical procedures in this area, radiological imaging, and rehabilitation. MATERIALS AND METHODS: Ninety-two lower limbs from 46 cadavers, fixed in 10 % formalin solution, were examined. RESULTS: The QF muscle was present in all specimens. According to morphology, the QF muscle was classified into three types. The most common type was Type I, characterized by one muscular belly (78.3 %), while the second most common type was Type II, characterized by two bellies, was observed in 17.4 % of cases. The rarest type was Type III. It was characterized by three bellies and was found in 4.3 % of the cases. CONCLUSIONS: The current classification system on quadratus femoris morphological variability is novel. Morphological variants may contribute to clinical issues, such as the ischiofemoral impingement syndrome, that could arise from type I quadratus femoris. Hence, the current study may be applicated to planning surgical procedures, imaging, and rehabilitation.

The morphological variability of the piriformis muscle.

BACKGROUND: The aim of the study is to create several classifications of the piriformis muscle (PM): proximal and distal attachments, potential fusions, and the relationship with the sciatic nerve. It is the first comprehensive anatomical examination of this subject. MATERIALS AND METHODS: One hundred and twenty-four lower limbs from 62 cadavers, fixed in 10% formalin, were examined. RESULTS: The piriformis muscle was present in 120 limbs (96.8% of cases). Four types of proximal attachment were described (I-IV). The most common type was Type I, in which the proximal attachment was at the anterior surface of the sacrum, between S2 and S4 (52 lower limbs; 43.3%). The rarest type was Type IV, in which the proximal attachment was at the gluteal surface of the ilium near the margin of the greater sciatic notch and from the gluteus medius (12 cases; 10%). Three types of distal attachment were distinguished. The most common was Type 1, a single tendon. This type comprised two subtypes: A and B (105 lower limbs; 87.5%). The other two types accounted for 12.5% of the total. Fusions were noted between the piriformis muscle and adjacent muscles in 31.7%. Four patterns were observed in which the sciatic nerve ran against the piriformis muscle. The most common variation in the relationship was the common fibular nerve exiting superior to the piriformis muscle and the tibial nerve passing inferior to it (10 cases; 8.3%). CONCLUSIONS: The piriformis muscle is highly morphologically variable in both its proximal and distal attachments and its relationship with the sciatic nerve. There are four types of proximal attachment and three types of distal attachment. The piriformis muscle shows numerous fusions with its adjacent muscles: gluteus medius or minimus or superior gemellus. A new (fourth) type of relationship was demonstrated between the piriformis muscle and sciatic nerve. The piriformis muscle was absent in four cases.

A Rare Variation of the Levator Scapulae Muscle: A Case Report and Review of Literature.

Muscle variations in the posterior neck region are mainly categorized as variations in the origin and insertion of the muscles and the presence of accessory slips or rudimentary muscles. The levator scapulae muscle is a variable muscle with several different types of variations described throughout the literature. Herein, we report a rare unilateral case of an accessory slip from the levator scapulae. Aberrant muscle slip originates from the distal one-third of the levator scapulae. Then, it passes upwards and outwards above a vascular bundle containing a superficial branch of the transverse cervical artery and vein. The deviant muscle slip inserts onto the superior nuchal line. Muscle variations in the neck's posterior region and the levator scapulae's variations, as per se, have the utmost clinical significance since they might be mistaken for tumor mass. Moreover, such variations might be deceptive during surgical procedures in the region. Therefore, detailed knowledge of such complex muscular variations in the posterior region of the neck is paramount for surgeons and radiologists alike.

A very rare case of the accessory palmaris longus muscle and clinical significance.

The palmaris longus muscle is located in the forearm region. It morphological variability was noted during standard anatomical dissection of the upper limb. The muscle was characterized by a normal course, i.e. originating from the medial humeral epicondyle and inserting to the palmaris aponeurosis, but a small additional tendon attached to the flexor retinaculum was observed in its distal part. An accessory palmaris longus muscle was also observed nearby. Interestingly, this accessory muscle was reversed, and the first part was not muscular, but tendinous, represented by two tendons originating from the common muscular mass attached to the medial epicondyle of the humerus; these later connected together, creating one muscle belly distally attached to the flexor retinaculum. This additional structure was innervated by a neural branch from the median nerve and the ulnar artery was responsible for blood supply. The course of the median nerve is also clinically important, because before entering the carpal tunnel, it was located directly under the accessory palmaris longus muscle. In turn, the ulnar artery passed through a special hole created by the flexor digiti minimi brevis and flexor retinaculum, before passing under the palmaris brevis muscle.

Localization of the gracilis muscle motor points - key considerations for botulinum neurotoxin injection and electrical stimulation.

INTRODUCTION: Muscle motor points are considered the best sites for electrode positioning in electrical stimulation and, by some researchers, for botulinum neurotoxin injections. The aim of this study is to locate the motor points in the gracilis muscle to improve muscle function maintenance and treatment of spasticity. MATERIAL AND METHODS: Ninety-three gracilis muscles (49 right, 44 left), fixed in 10% formalin solution, were subjected to the research. All nerve branches running towards the muscle were precisely traced to each motor point. Specific measurements were collected. RESULTS: The gracilis muscle presents multiple motor points (median of 12), all of which were localized on the deep (lateral) side of the muscle belly. Generally, motor points of this muscle were spread between 15% and 40% of the reference line length. CONCLUSION: Our findings may help clinicians identify appropriate locations for electrode placement during electrical stimulation of the gracilis muscle; they also deepen our understanding of the correlation between motor points and motor end plates and improve the application of botulinum neurotoxin injections.

Congenital, Acquired, and Trauma-Related Risk Factors for Thoracic Outlet Syndrome-Review of the Literature.

Thoracic outlet syndrome is a group of disorders that affect the upper extremity and neck, resulting in compression of the neurovascular bundle that exits the thoracic outlet. Depending on the type of compressed structure, the arterial, venous, and neurogenic forms of TOS are distinguished. In some populations, e.g., in certain groups of athletes, some sources report incidence rates as high as about 80 cases per 1000 people, while in the general population, it is equal to 2-4 per 1000. Although the pathogenesis of this condition appears relatively simple, there are a very large number of overlapping risk factors that drive such a high incidence in certain risk groups. Undoubtedly, a thorough knowledge of them and their etiology is essential to estimate the risk of TOS or make a quick and accurate diagnosis.