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.

Identifying iliotibial band graft length and incision site may minimise the potential risk of harming adjacent structures: A novel approach for surgeon guidance.

PURPOSE: The Iliotibial band (ITB) is a fibrous thickening of the fascia lata originating at the iliac crest and inserting at Gerdy's tubercle on the lateral tibia. The ITB significantly contributes to lateral knee stabilisation. Due to its size, tensile strength and easy access, it is widely used in orthopaedic surgery as an autograft during reconstruction procedures. Although ITB harvesting may result in complications, such as reduced knee extension or hip flexion, no safety margins or guidelines have been proposed for the procedure. Our aim was to determine the maximal safe length of an ITB graft, that is, that does not harm the lateral collateral ligament (LCL), tensor fasciae latae (TFL), gluteus maximus (GM) or adjacent structures, and reduce the complication rate. METHODS: The study included 50 lower limbs of 25 human cadavers, previously fixed in 10% formalin solution. The inclusion criterion was the lack of visible signs of surgical interventions in the study region. Forty lower limbs were included in the study: 16 female (mean age 83.1 ± 3.4 years) and 24 male (mean age 84.2 ± 6.8 years). Dissection was performed with a previously established protocol. Morphometric measurements were then obtained twice by two researchers. RESULTS: The mean femur length was 404.8 mm [female (F) = 397.3 mm, male (M) = 409.9 mm, standard deviation (SD): F = 23.8 mm, M = 24.1 mm]. The mean ITB length was 318.9 mm (F = 309.4 mm, M = 325.2 mm, SD: F = 25.7 mm, M = 33.7 mm). Longer femurs were associated with longer ITB (p < 0.05). The mean distance from the insertion of the GM to the myofascial junction of TFL and ITB was 34.6 mm (F = 34.5 mm, M = 34.6 mm, SD: F = 3.2 mm, M = 3.3 mm). The longer femurs or ITBs demonstrated a greater distance from GM insertion to the myofascial junction of the TFL and ITB (p < 0.05). CONCLUSION: ITB grafts longer than 21 cm may contribute to the greater risk of TFL rupture. Based on simple measurements of the femur length, the surgeon may assess approximate ITB length, and thus assess the length of the maximal graft length. Moreover, to avoid harming the LCL, the incision should be performed 5 cm proximal to the articular surface of the lateral femoral condyle or 13 mm proximal to the lateral femoral epicondyle. Such preparation and preoperative planning may greatly reduce the risk of complications during ITB harvesting, while performing, for instance, the over-the-top technique for anterior cruciate ligament reconstruction in skeletally immature patients. LEVEL OF THE STUDY: Basic I.

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.

Morphological variability of lateral femoral cutaneous nerve and its potential clinical significance.

BACKGROUND: The lateral femoral cutaneous nerve is derived from the dorsal branches of the L2 and L3 spinal nerves. It travels across the pelvis and heads towards the anterior superior iliac spine. It passes under the lateral part of the inguinal ligament and then divides into two branches, which are responsible for sensory innervation of the anterolateral and lateral skin of the thigh. However, the course of this nerve can vary morphologically. Numerous differences have been observed in its exit from the pelvis and in the number of its main trunks and branches. Additionally, its angle with the inguinal ligament and its placement in relation to other structures (such as the femoral artery, femoral nerve, and the sartorius and iliacus muscles) also vary. All of these variants have potential clinical implications. Therefore, the aim of this review is to present the morphological variability of the lateral cutaneous nerve and to explore how these anatomical differences can introduce clinical concerns. MATERIALS AND METHODS: Presented review of the literature was written based on over 30 studies. Comprehensive literature search was done using PubMed in order to study the morphological variability of lateral femoral cutaneous nerve (LFCN). To be included in this review studies needed to be meet certain criteria: been published before December 2023, present information valuable to this paper (variability of lateral femoral cutaneous nerve/clinical significance). The search included how LFCN vary either among fetuses and adults in the aim of providing more complex information about the variability of this nerve. During the search key words as following were used. No particular references were excluded from the analysis. All relevant studies were included, and citation tracking was used to identify publications. RESULTS: This review presents the description of variability of LFCN and its potential clinical impact. In the review differences in adult and fetuses were considered, morphological variability were divided into 4 groups: the origin of the nerve, the way it leaves the pelvis, the branching pattern, the angle between LFCN and surrounding structures and then, clinical significance were considered basing on available literature.

Never undescribed four - headed plantaris muscle.

The plantaris is a small muscle of the superficial posterior compartment of the leg. It originates at the lateral supracondylar line of the femur and the knee joint capsule, from where it continues distally, forming a long and slender tendon distally attached to the calcaneal tuberosity. During standard anatomical dissection four-headed plantaris muscle was found and all of its heads connected to each other as a single muscle belly passing into tendinous structure which was distally attached as a standard plantaris muscle. The first head originated from the popliteal surface of the femur. The second one was originated from distal Kaplan fiber. In turn, the third and fourth heads were proximally attached to the lateral femoral epicondyle. Knowledge about morphological variations is necessary because of its potential clinical significance, which means not only neurovascular compressions, but also surgical procedures.

Accessory part of the deltoid muscle.

The shoulder and arm region has numerous morphological variations. The deltoid muscle usually consists of three parts: anterior, middle and posterior. This case report describes a very rare deltoid muscle variant, an addition to the spinal part that is attached proximally at the infraspinatus fascia and the spine of the scapula. The distal attachment transforms directly into the brachialis muscle. Additional parts can affect the biomechanics and function of the joints significantly.

A three-headed plantaris muscle fused with Kaplan fibers: potential clinical significance.

The plantaris is a short, small muscle that usually originates at the popliteal surface of the femur and has a long, thin tendon that typically inserts into the calcaneal tuberosity. Its role and degree of development have been objects of debate for years. Some authors consider it a vestigial muscle while others believe it is a process of its development. The clinical significance of plantaris muscle is usually related to its morphological variation, which is common and well described in the literature. These variations are often a risk factor for many ailments and disorders. We would like to present another, very rare case of three-headed plantaris muscle (fused with distal Kaplan fibers), and consider what clinical implications it may have.

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.

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.

An unreported innervation of the coracobrachialis longus by the radial nerve: a potential pitfall for clinicians.

PURPOSE: The aim of the presented case is to describe an unprecedented innervation of the coracobrachialis longus muscle by the radial nerve. METHODS: An 82-year-old body donor at death was subjected to a routine anatomical dissection for teaching and research purposes at the Department of Anatomical Dissection and Donation in Lodz, Poland. RESULTS: We have found an additional branch of the radial nerve, which departed from it just below its beginning. Its initial section ran alongside the radial nerve in the axilla, then headed medially accompanying superior ulnar collateral artery. Then, it reaches the coracobrachialis longus muscle and is the only one to innervate it. CONCLUSIONS: The brachial plexus (BP) is very variable and well understood. Nevertheless, we must remember that there may still be variations in its structure, which may involve problems at every stage of diagnosis and treatment of diseases associated with its structures. Their knowledge is extremely important.

The effect of morphological variability of Dorello's canal on surgical procedures - a review.

Dorello's canal is an arched structure of bone-fibrous character located in the petroclival venous confluence atop the petrosal bone in the petroclival region. It is bordered by the petrosphenoidal ligament, the petrous part of the temporal bone and the lateral border of the upper part of clivus. Its content in the vast majority of variants comprises the abducens nerve, the inferior petrosal sinus, the venous drainage and the dorsal meningeal artery or its medial branch. With the development of microsurgical techniques, this area has gained huge clinical importance, mainly concerning the order in which the above-mentioned elements (especially the position of the abducens nerve) are arranged in relation to each other. These structures appear in different variant forms and necessitate an individual clinical approach. The main purpose of this review is to present condensed information about possible intercorrelations among them and to indicate, on the basis of the available literature and research, possible surgical approaches and the need to consider the variability when treatments in this region are planned.