The unilateral muscular slip of the two-bellied Serratus Posterior Inferior muscle: a case report and a review of literature.

PURPOSE: The two-bellied serratus posterior inferior (SPI) muscle with a muscular slip is a rare variation of the back region, which can cause significant discomfort to patients. Patients typically present with symptoms of chronic pain syndrome, radiating back pain, myofascial pain, or lower back pain. This report describes a case of a female cadaver with a two-headed SPI muscle and a right muscular slip, along with a literature review. METHODS: A case of an unusual back muscle was observed in a female cadaver during advanced cadaver dissection of the back region. The SPI muscle was found deep to the latissimus dorsi muscle and superficial to the erector spinae and thoracolumbar fascia. Its oblique arrangement and insertion onto the 8th-11th costae were consistent with its known anatomy, but the presence of two separate fibrotendinous heads and an uncommon variance between the erector spinae and latissimus dorsi muscles was observed. RESULTS: The SPI muscle fibers were found to be attached to the 8th costa on the right side and displayed two heads on both sides. In our study, the presence of muscular and tendinous digitations towards the twelfth rib was not detected, which aligns with the characteristics described for types D and E. However, we observed a separation between the digitations. Therefore, it is appropriate to classify our findings as type E according to the established categorization. Simultaneously, an anomalous muscular slip, which did not conform to any of the aforementioned classifications, was identified as extending towards the 8th rib. CONCLUSION: The underlying cause of unilateral oblique muscular fiber extension is thought to result from aberrant muscle migration during embryonic development or alterations in tendon attachment sites. Differential diagnosis of unidentified lower back pain should consider the various types and alterations of the SPI muscle.

Anatomical study of the latissimus dorsi muscle flap / Estudio anatómico del colgajo del músculo latísimo del dorso

SUMMARY: The latissimus dorsi is a broad muscle that originates from the inferior thoracic spinous processes, thoracolumbar fascia, iliac crest, and inferior ribs. It inserts on the inferior aspect of the intertubercular groove of the humerus through a thin tendon. The study was conducted on 10 cadavers (7 male and 3 female). These specimens were dissected and examined to study the gross anatomical characteristics of the latissimus dorsi muscle. The dimensions of the latissimus dorsi muscle and its surface area were measured in all the cadavers. The branching pattern of the thoracodorsal vessels was recorded. The pedicle length and caliper were measured using Vernier calipers. On the 20 dissected sides, the thoracodorsal artery was found to be one of the terminal branches of the subscapular artery that originates in the axillary region. In 19 (95 %) cases, the thoracodorsal artery terminated in a bifurcation, giving off a medial and a lateral branch. The average size of the elevated flap of the latissimus dorsi muscle was 18 cm x 36 cm. The average pedicle length was 9.5 cm (range: 5 cm-14 cm), and the average diameter at its origin was 2.5 mm (range: 1.5 mm-3.5 mm). The average diameter of the vena comitans was 3.3 mm. The current study focuses on the anatomical features of the latissimus dorsi muscle and its blood supply to increase the success rate of operations in clinical practice.

RESUMEN: El músculo latísimo del dorso se origina en los procesos espinosos de las vértebras torácicas inferiores, la fascia toracolumbar, la cresta ilíaca y las costillas inferiores y se inserta en el surco intertubercular del húmero a través de un delgado tendón. El estudio se realizó en 10 cadáveres (7 mujeres y 3 hombres). Estos especímenes fueron disecados y examinados para estudiar las características anatómicas macroscópicas del músculo latísimo del dorso. En todos los cadáveres se midieron las dimensiones del músculo y su superficie. Se registró el patrón de ramificación de los vasos toracodorsales. La longitud del pedículo y el calibre se midieron con paquímetro Vernier. En los veinte lados disecados, se encontró que la arteria toracodorsal era una de las ramas terminales de la arteria subescapular que se originaba en la región axilar. En 19 (95 %) casos, la arteria toracodorsal terminaba bifurcándose en dos ramas, una rama medial y otra lateral. El tamaño promedio del colgajo elevado del músculo latísimo del dorso era de 18 cm x 36 cm. La longitud promedio del pedículo era de 9,5 cm (rango: 5 cm-14 cm), y el diámetro promedio en su origen era de 2,5 mm (rango: 1,5 mm-3,5 mm). El diámetro medio de la vena comitans era de 3,3 mm. El estudio actual se centra en las características anatómicas del músculo latísimo del dorso y su irrigación para aumentar la tasa de éxito de las operaciones en la práctica clínica.

Presence of incomplete superficial axillary arch and pectoralis quartus muscle in one male body / Presencia en un individuo de un arco axilar superficial incompleto y de un músculo pectoral cuarto

SUMMARY: The anatomical variations of the pectoralis major muscle (PMM) and latissimus dorsi muscle (LDM) range from agenesis to the presence of supernumerary fascicles with a variety of insertions and relationships with the muscles, fascia, vessels, nerves and skeletal components of the shoulder girdle and the axilla. Many of these variations are clinically irrelevant, but extremely interesting and revealing from the perspective of comparative anatomy, ontogeny, and phylogeny. In this report, we present two different supernumerary muscles in the chest of one adult male body, identified during dissection practice of undergraduate medical students at Universidad Surcolombiana. These supernumerary fascicles in the axillary region were caudal to the lower edge of the PMM on the right side of the chest, and in contact with the anterior edge of the LDM on the left side of the chest; each fascicle was inserted in the ipsilateral coracoid process. These observations are congruent with the pectoralis quartus muscle and an incomplete and superficial axillary arch, respectively.

RESUMEN: Las variaciones anatómicas del músculo pectoral mayor (MPM) y del músculo latísimo del dorso (MLD) van desde la agenesia hasta la presencia de fascículos supernumerarios con una variedad de inserciones y relaciones con los músculos, fascias, vasos, nervios y componentes esqueléticos de la cintura escapular y la axila. Clínicamente, muchas de las variaciones son irrelevantes, pero extremadamente interesantes y reveladoras desde la perspectiva de la anatomía comparada, la ontogenia y la filogenia. En este estudio, presentamos dos músculos supernumerarios diferentes en la pared torácica de un hombre adulto, identificados durante la práctica de disección de estudiantes de medicina de la Universidad Surcolombiana. Estos fascículos supernumerarios en la región axilar estaban caudales al margen inferior del MPM en el lado derecho del tórax y en contacto con el margen anterior del MLD en el lado izquierdo del tórax; cada fascículo se insertaba en el proceso coracoides ipsilateral. Estas observaciones son congruentes con el músculo pectoral cuarto y un arco axilar incompleto y superficial, respectivamente.

The concept of "whole perforator system" in the lateral thoracic region for latissimus dorsi muscle-preserving large flaps: An anatomical study and case series.

BACKGROUND: Previous studies have reported on the abundant cutaneous perforating blood vessels around the latissimus dorsi (LD) lateral border, such as a thoracodorsal artery perforator (TDAP) of septocutaneous type (TDAP-sc) and muscle-perforating type (TDAP-mp), or the lateral thoracic artery perforator (LTAP). These perforators have been clinically utilized for flap elevation; however, there have been few studies that accurately examined all the cutaneous perforators (TDAP-sc, TDAP-mp, LTAP) around the LD lateral border. Here, we propose a new "whole perforator system" (WPS) concept in the lateral thoracic region and a methodology that enables elevating large flaps with reliable perfusion in a muscle-preserving manner. METHODS: We first performed an anatomical study that verified the number and perforating points of all perforators around the LD lateral border using the results of dynamic contrast-enhanced magnetic resonance imaging of patients with breast cancer. Following the anatomical evaluation, we performed large muscle-preserving flap transfer that contained all of the perforators around the LD lateral border in an actual clinical setting. RESULTS: A total of 175 latissimus dorsi from 98 patients were included. The mean number of perforators (TDAP-sc + TDAP-mp + LTAP) per side was 4.51±1.44 (2-9); TDAP-sc was present in 57.1% (100/175) of cases, and TDAP-mp in 76.6% (134/175); the TDAP total prevalence rate (TDAP-sc + TDAP-mp) was 96.0% (168/175). The LTAP existence rate was 94.3% (165/175). Distance from the axillary artery to the TDAP-sc was 148.7±56.3 mm, which was significantly proximal to the TDAP-mp (183.8±54.2 mm) and LTAP (172.2±81.3 mm). CONCLUSION: The lateral thoracic region has an abundant cutaneous perforator system derived from the descending branch of the thoracodorsal and lateral thoracic arteries. Clinical application of the lateral thoracic WPS flap is promising, with a large survival area even with muscle-preserving procedures and requiring a relatively simple procedure.

Muscle-sparing thoracotomy: Anatomy and technique.

The thoracotomy incision is essential for many thoracic surgery procedures. A number of different variations exist, and different techniques can be used, depending both on the patient and on the technical factors. The muscle-sparing technique was first described by Noirclerc et al. in 1973. [1] Initially, it was thought that preservation of the muscular structures compared with the results of a traditional posterolateral thoracotomy, in which the latissimus dorsi and sometimes the serratus anterior are often divided, would benefit long-term outcomes.  However, subsequent study results  have not demonstrated any difference in postoperative outcomes. The unequivocal benefit of a muscle-sparing approach is to preserve the latissimus dorsi for any future intervention, such as a procedure involving the chest wall and the intrathoracic flaps. In this video tutorial, we describe our approach to this commonly used incision, including the anatomy and the technical aspects used to provide optimal operative exposure and minimal postoperative complications while preserving the underlying musculature.

Variation of insertion of the pectoralis major in a cadaveric study: A case report.

RATIONALE: Typically, the tendon of the pectoralis major inserts into the crest of the greater tubercle of the humerus. However, anomalous insertion sites of the pectoralis major tendons have been noted. PATIENT CONCERNS: The cadaver of a 95-year-old Japanese man was selected from the bodies used for gross anatomy practice at the Tokai University School of Medicine in 2018. DIAGNOSIS: In this cadaver, the left side of the pectoralis major tendon appeared to insert at the crest of the greater tubercle and lesser tubercle of the humerus, forming a tunnel measuring 2.5 cm in total length. INTERVENTION: We removed the fat and skin around the shoulder joint and upper extremity for observational purposes and carefully examined the structures during gross anatomy. OUTCOMES: The medial side of the insertion of the pectoralis major tendon was not into the humerus but had combined with the tendon of the latissimus dorsi, which then loosely inserted into the humerus. As the roof and both walls comprised the tendon of the pectoralis major and the floor was formed by the tendon of the latissimus dorsi and humerus, the structure formed a tunnel. LESSONS: This study is important for orthopedic and rehabilitation physicians in treating diseases of the long head of the biceps brachii tendon. As part of management, the condition of the tendon of the pectoralis major should be confirmed using magnetic resonance imaging or echocardiography.

Nameless in anatomy, but famous among surgeons: The so called "deltotrapezoid fascia".

Acute dislocation of the acromioclavicular joint (AC-joint) often leads to disruption of the "deltotrapezoid fascia", a common aponeurosis of the deltoid and the trapezoid muscles. Various studies demonstrated that its reconstruction is crucial for functional recovery. Textbooks of anatomy, however, fail to mention this prominent structure that is also not listed in the Terminologia Anatomica provided by the Federative Committee on Anatomical Terminology (FCAT). Here, we demonstrate that the delta-trapezoid fascia is hardly visible in formalin-fixed, but prominent in fresh specimen. We provide an extensive anatomical description based on 11 specimens derived from eight body donators and show, as a major finding that different fixations massively impact on the structural integrity of the DTF. We hypothesize that modern (minimal-invasive) surgical strategies unraveled many structures of fundamental function that are not known by anatomists and therefore not covered by anatomical education.

Sex Differences in Ultrasound-Based Muscle Size and Mechanical Properties of the Cervical-Flexor and -Extensor Muscles.

CONTEXT: Neck pain (NP), neck injuries, and concussions are more prevalent in female athletes than in their male counterparts. Females exhibit less neck girth, strength, and stiffness against a perturbation. As part of the clinical examination for individuals with NP, ultrasound (US)-based imaging of the cervical muscles has become common. Muscle size or thickness and stiffness can be measured with US-based B-mode and shear-wave elastography (SWE), respectively. Information on reliability, normative values, and sex differences based on US-based muscle size or thickness and stiffness in young and athletic individuals is limited. OBJECTIVE: To evaluate sex differences in US-based muscle size or thickness and biomechanical properties of the cervical-flexor and -extensor muscles. DESIGN: Cross-sectional study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: A total of 13 women (age = 23.7 ± 1.9 years, height = 167.1 ± 6.1 cm, mass = 63.8 ± 5.6 kg) and 11 men (age = 25.6 ± 4.9 years, height = 178.7 ± 8.3 cm, mass = 78.9 ± 12.0 kg). MAIN OUTCOME MEASURE(S): The same examiner collected all measures, using US B-mode to scan the cross-sectional area and thickness of the longus colli (LC), sternocleidomastoid (SCM), cervical-extensor muscles, and upper trapezius (UT) muscle. The US SWE-mode was used to measure the stiffness of the SCM and UT. Independent t tests or Mann-Whitney U tests were calculated to determine sex differences. The intraclass correlation coefficient (ICC) measured intrarater test-retest reliability. RESULTS: Men had thicker SCMs than women (P = .01). No sex differences were present for longus colli cross-sectional area, cervical-extensor muscle thickness, or UT thickness (P > .05). In addition, no sex differences were evident for SCM (P = .302) or UT (P = .703) SWE stiffness. Reliability was good to excellent (ICC = 0.715-0.890) except for SCM SWE stiffness (ICC = 0.554). CONCLUSIONS: The only sex difference was in SCM thickness. However, smaller SCMs in women did not result in less SCM SWE stiffness. We provided normative values for US-based imaging of the cervical-flexor and -extensor muscles in young and athletic men and women.

Optimal Trapezius Electrophysiological Recording Site.

BACKGROUND: Various active recording electrode positions for the trapezius motor nerve conduction study have been suggested. OBJECTIVE: To determine the optimal recording site of the trapezius muscles in a spinal accessory nerve conduction study. DESIGN: Retrospective descriptive study. SETTING: Department of physical medicine and rehabilitation in a tertiary clinic center. PARTICIPANTS: Thirty-four patients between 33 and 82 years of age with preoperative head and neck cancer (68 upper and middle trapezius muscles). INTERVENTIONS: Analysis of compound muscle action potentials (CMAPs) of upper and middle trapezius. MAIN OUTCOME MEASUREMENTS: CMAP latency and amplitudes were obtained at five and four recording points with constant intervals on the horizontal line of the upper and middle trapezius, respectively. RESULTS: The maximum CMAP amplitude of the upper trapezius was (mean ± SD) 8.5 ± 1.4 mV with the recording at the midpoint between the C7 spinous process and the lateral margin of the acromion. The maximum CMAP amplitude of the middle trapezius was 4.2 ± 1.4 mV, recorded on the horizontal line at the junction of the middle and lateral thirds between the root of the scapular spine and the vertebral spinous process. CONCLUSION: The optimal recording site in motor nerve conduction study of the trapezius is the midpoint between the C7 spinous process and the acromion for the upper trapezius, and the junction of middle and lateral thirds of the line between the root of scapular spine and the vertebral spine for the middle trapezius.

The Accessory muscles of the Axilla.

The axilla is a region of clinical and surgical importance with plenty of anatomical variations. One of these is the presence of accessory muscles. The literature was reviewed in order to identify the different supernumerary muscles that are described in the axilla. Variant muscle slips arising from the pectoral muscle or latissimus dorsi muscle have been described. There still remains controversy regarding the phylogenetic origin of these different muscles. We described the most frequently reported muscles, their origin, and course. Further research is required regarding the innervation and influence on glenohumeral and scapulothoracic kinematics.

Options of bipolar muscle transfers to restore deltoid function: an anatomical study.

PURPOSE: To outline the technical details and determine the ranges of two pedicled functioning flaps that are the upper pectoralis major (UPM) and latissimus dorsi (LD) to elucidate their respective indications with regards to deltoid impairment. METHODS: The UPM and LD bipolar transfers were performed in 14 paired cadaveric shoulders, one on each side. The UPM was flipped 180° laterally over its pedicle to be placed onto the anterior deltoid. The LD flap was elevated on its pedicle to be rotated and positioned onto the deltoid mid-axis. Their respective spans were defined according to the deltoid muscle origin and insertion. RESULTS: The UPM outreached the lateral edge of the anterior deltoid origin with a mean distance of 7.3 cm (range 4-9.1 cm) off the lateral edge of the clavicle. Distally, the flap consistently overcame the proximal end of the deltoid tuberosity for a mean distance of 2.1 cm (range 0.9-3.2 cm). The LD flap mdi-axis could be consistently placed onto the deltoid mid-axis; spans of the anterior and posterior borders of the LD flap averaged 1 cm (range - 1 to 2.3 cm) and 0.2 cm (range -1.8 to 1.9 cm), respectively. CONCLUSIONS: The UPM flap optimal indications would be cases with deltoid defects limited to its anterior portion, whereas the LD bipolar transfer could be used in more extensive lesions. Additionally, the distal span of both transfers appears to allow their use in the setting of a reverse shoulder arthroplasty with subsequent humeral lengthening. LEVEL OF EVIDENCE: Non-applicable-basic science study, cadaver dissection.

Latissimus Dorsi Tendon Rupture.

Isolated injury to the latissimus dorsi is rare. Partial tendon tears may be successfully treated nonsurgically. Complete tendon ruptures require surgical repair. Tendon repair can be approached either through an anterior deltopectoral incision with a secondary small posterior axillary incision or through a long posterior axillary incision. Suture anchors can be used to repair the latissimus dorsi to the humeral attachment. Although the literature is limited to single-patient case series, most patients have returned to full athletic activity after surgical repair.

Positional changes in distance to the pleura and in muscle thickness for dry needling.

OBJECTIVE: This study was conducted to measure and to determine differences in tissue depth in the upper back for two prone positions and to stratify the results by body composition and sex of the patient. In addition, muscle thickness changes with positioning were assessed. This information is important for clinicians who dry needle in the thorax area, cognizant of the dangers of inadvertently piercing the pleura or lung tissue. DESIGN: Descriptive cross-sectional. SETTING: Health and Human Performance laboratory at a university campus. PARTICIPANTS: Sample of convenience of 60 college-aged subjects, 20 subjects in three body composition groups. MAIN OUTCOME MEASURES: Distances from skin to lung tissue, skin to ribs and muscle thickness were measured and compared between two prone positions. RESULTS: There was a significant increase in depth to the lung tissue (0.7cm, 95% confidence interval 0.4-1.0cm) when using a bolster under the shoulder. There were also differences in depths between body composition classifications and between sexes, but not between sides. The average thickness of all muscles increased significantly by up to 0.4cm (95% confidence interval 0.3-0.5) when the shoulder was positioned in retraction. CONCLUSIONS: Positioning, body constitution and sex of the patient change tissue depth significantly and should be considered when dry needling. This change is largely attributed to a modification in muscle thickness.

Quantitative assessment of the growth dynamics of the teres major in human fetuses.

PURPOSE: The main objective of the study was to examine the use of teres major (TM) as a flap in the pediatric surgeries from an anatomical perspective by: (1) revealing the growth dynamics of the developing TM; (2) assessing the possible interconnecting structures between TM and latissimus dorsi (LD); (3) exposing the innervation patterns of TM in human fetuses. METHODS: Study was conducted on 50 fetuses (26 females and 24 males), on a mean gestational age of 22.86 ± 3.21 (range 18-30) weeks. All the measurements were collected with a digital caliper and a digital image analysis software. Additionally, structural relations between TM and LD were examined in detail and further classified. RESULTS: No significant difference of side and sex was detected on TM measurements (p > 0.05). Linear functions for the surface area, width, length of the superior and inferior margins of TM were detected as follows: y = - 257.142 + 18.334 × age (weeks), y = - 5.497 + 0.545 × age (weeks), y = - 1.621 + 1.068 × age (weeks), and y = - 2.147 + 1.284 × age (weeks), respectively. As classified in five types, a number of 33 muscular or tendinous connections between TM and LD were detected. Musculo-tendinous slips from TM to triceps brachii (TB) were evident in four sides. Innervation of TM was observed to be providing by the lower subscapular nerve in all the cases. CONCLUSION: First, linear functions, representing the developing fetal morphometry obtained by our study can be adapted for estimating the morphometric of this muscle in early childhood. Besides, acknowledging the diverse appointments of TM with the surrounding muscles such as LD and TB may facilitate the prevention of neurovascular structures and the application of surgical procedures during tendon transfers. In brief, our findings are highly potent to bring the attention of pediatric surgeons.

A More Precise Electromyographic Needle Approach for Examination of the Rhomboid Major.

BACKGROUND: Safe and accurate needle access to the rhomboid major (RM) during electromyography is challenging due to the overlying trapezius muscle and the risk of pneumothorax. OBJECTIVE: To investigate the RM anatomy associated with the trapezius using ultrasonography and to determine a safe and accurate needle insertion point for needle electromyography of the RM. DESIGN: Descriptive study. SETTING: Department of physical medicine and rehabilitation of a tertiary clinic center. PARTICIPANTS: Participants between 23 and 71 years of age without any diseases (N = 25; 13 men, 12 women; 50 scapulae) were included. INTERVENTIONS: Ultrasonography of the RM and trapezius muscles around the scapula. MAIN OUTCOME MEASURES: The point at which the lateral margin of the trapezius crosses the medial border of the scapula (point A) was determined. The probe was positioned at the level of the midpoint (point M) between point A and the inferior angle of the scapula. The horizontal distance from the point at which the RM was the thickest (point X) to point M was measured. At point X, the depth of the RM, RM thickness, and the depth of the pleura were measured. RESULTS: The mean age and body mass index were 37.4 ± 12.0 years and 22.3 ± 2.1 kg/m2, respectively. Point M was located at a mean distance of 3.9 ± 0.6 cm proximal to the inferior angle of the scapula. The mean distance between point X and point M was 1.0 ± 0.2 cm. At point X, the RM was at a mean depth of 9.7 ± 3.1 mm from the skin and had a mean thickness of 9.9 ± 1.8 mm. The pleura was observed at a mean depth of 28.4 ± 3.8 mm from the skin. CONCLUSION: Needle electromyographic examination of the RM can be performed easily and safely through the lower part of the RM that is not covered by the trapezius. LEVEL OF EVIDENCE: not applicable.

Pectoralis Major Tendon Insertion Anatomy and Description of a Novel Anatomic Reference.

Pectoralis major rupture is an uncommon injury often treated surgically, requiring anatomic knowledge of the tendon insertion. This study defines the pectoralis major tendon insertion footprint and a novel anatomic relationship. Twelve cadaver shoulders were evaluated andmeasured using a standard surgical ruler to demonstrate the normal anatomic footprint. Measurements were taken from the anterior medial margin of the articular surface of the humeral head to the superior margin of the pectoralis major insertion and its relation to the latissimus dorsi tendon insertion. The average length and width of the pectoralis major insertion were 73.3 ± 10.0 mm and 3.3 ± 0.54 mm, respectively, consistent with previous publications. On average, the superior margin of the pectoralis tendon was within 1 mm of the latissimus dorsi insertion and 41.2 ± 9.27 mm from the articular margin. These points form a new anatomic reference of the latissimus dorsi, providing an intraoperative reference point when performing pectoralis major muscle tendon repair. (Journal of Surgical Orthopaedic Advances 27(1):39-41, 2018).

The anatomy of the musculocutaneous latissimus dorsi flap for neophalloplasty.

In transgender surgery, the ideal neophallus is one that: (a) is constructed using a reproducible procedure, (b) possesses tactile and erogenous sensation, (c) is large and rigid enough (naturally, or using a prosthesis) to permit penetrative intercourse, (d) leaves acceptable donor site morbidity, (e) results in esthetically satisfactory appearance, and (f) allows for voiding while standing. The musculocutaneous latissimus dorsi (MLD) flap has favorable results in the area of neophalloplasty. Among its advantages are acceptable donor site appearance, stiffness sufficient for intercourse, and esthetically satisfactory genital appearance. The anatomy of the MLD flap supports the creation of a neophallus for transsexual anatomy revision. Herein, we give an overview of the advantages and disadvantages of the procedure, and the anatomical details and surgical steps involved. Novel illustrations were created from standard surgical text descriptions to clarify this topic for surgical training and patient understanding and decision making. A review of the relevant literature regarding the anatomy, procedure development, and outcomes is presented. The MLD flap uses part of the latissimus dorsi muscle with branches of the thoracodorsal vessels and nerve to construct a neophallus. A thin strip of muscle around the pedicle is harvested, resulting in a slightly curvilinear scar. The blood supply is connected to the femoral artery and saphenous vein or the deep inferior epigastric artery and vein, while the nerve is connected to the ilioinguinal nerve or the obturator nerve. The MLD flap for neophalloplasty is a reliable graft with a well concealed scar and low donor site morbidity. Clin. Anat. 31:152-159, 2018. © 2017 Wiley Periodicals, Inc.

Morphometric properties of the latissimus dorsi muscle in human fetuses for flap surgery.

PURPOSE: Although latissimus dorsi (LD) flaps are extensively used in a wide range of interventions, fetus studies on this subject are quite limited. This study aims to obtain detailed information about the morphometric features of LD, thoracodorsal artery (TDA) and nerve (TDN). METHODS: The study was carried out on both sides of 50 formalin-fixed human fetuses (22 male/28 female) with a mean gestational age of 24.5 ± 4.7 (range 18-36) weeks, which were in the inventory of Anatomy Department of Mersin University Faculty of Medicine. Dimensions of LD, lengths and width of TDA and TDN were measured. Surface area of LD was calculated using digital image analysis software. RESULTS: All samples had LD muscle. Neither gender nor side-significant differences were observed in relation with the numerical data of LD, TDN and TDA. Linear function of surface area was calculated as "y = - 1767.532 + 114.582 × Age (weeks)". LD was attached directly to the posterior part of iliac crest in 59 of 100 sides meanwhile in the rest 41, it was attached by the thoracolumbar fascia. TDA gave a branch to serratus anterior in 96 cases and 2 branches in 4 cases. TDN passed superficial to TDA in 84 and deep to TDA in 16 samples. TDN had bifurcation in 93, trifurcation in 6 and tetrafurcation in 1 side. CONCLUSION: Data obtained from this study can be useful for estimating the sizes of LD and related neurovascular structures, especially in neonate surgeries. Linear function of LD surface area can be helpful to design the flap dimensions in newborn surgeries. A throughout knowledge about the branching pattern of TDN and its location-wise relation with TDA should be kept in mind to prevent possible complications during harvesting LD flaps and TDN grafts.

Rare muscular variations identified in a single cadaveric upper limb: a four-headed biceps brachii and muscular elevator of the latissimus dorsi tendon.

Supernumerary or accessory heads of the biceps brachii are persistent muscular structures which can vary in number and location in the arm. Variations in other arm muscles, such as the coracobrachialis, can accompany supernumerary biceps brachii musculature in the upper limb. In this case report, we describe two rare muscular variants in a single adult male: a four-headed biceps brachii and the muscular elevator of the latissimus dorsi tendon. Additionally, accessory muscles of the brachialis and flexor digiti minimi brevis were identified in the upper limb. To our knowledge, the muscular variants identified here are considered rare, and their co-occurrence in a single upper limb has not been described previously. Also, a four-headed biceps brachii consisting of both the infero-medial and infero-lateral humeral heads has not been described previously to our knowledge. We postulate that the simultaneous appearance of several muscular variations may indicate a signaling disruption in embryogenesis during muscle patterning of the ventral limb bud. Knowledge of variant musculature in the arm is important for surgeons and clinicians as these muscles and their aberrant innervation patterns can complicate surgical procedures and may compress arteries and nerves producing upper limb pain and paresthesia. The clinical, functional and embryological implications of the upper limb variants are discussed.