Axillary arch muscle and pectoralis quartus: an unusual combination of two variant supernumerary muscles in the axillary region - a case report.

Variant anatomy in the axillary region is of great clinical significance. It is one of the most frequently accessed regions for radical dissection surgery. During routine dissection of embalmed cadavers, we found a rare case of two accessory muscular slips emerging from the lateral border of latissimus dorsi (LD) and the inferolateral border of pectoralis major (PM), crossing the neurovascular structures in the axilla and merging distally together to the brachial fascia at the upper end of humerus below the bicipital groove. The accessory slip from LD is commonly referred to as the "axillary arch" in literature. We identified the accessory slip from the PM crossing over the axilla as pectoralis quartus. These aberrant slips can cause neurovascular compression in the axilla and can have clinical implications. Prior knowledge of the variant anatomy is the key to successful surgery in the axilla, thereby avoiding inadvertent injuries and post-operative complications.

Muscle Injury Around the Shoulder.

Acute shoulder tendon and intra-articular injuries are common and their imaging well described. However, a subset of patients present with more unusual acute shoulder muscle injury. Of these, pectoralis major muscle injuries are encountered the most often and are increasingly prevalent due to a focus on personal fitness, particularly bench-press exercises. Other muscle injuries around the shoulder are rare. This article reviews the anatomy, mechanism of injury, and the imaging findings in relation to injuries of these muscles around the shoulder. We focus on pectoralis major injury but also review proximal triceps, latissimus dorsi, teres major, and deltoid muscle injuries, providing imaging examples.

The Shoulder Trans-pectoralis Arthroscopic Portal Is a Safe Approach to the Arthroscopic Latarjet Procedure: A Cadaveric Analysis.

PURPOSE: To assess the proximity of neurovascular structures in a layered approach during medial portal placement and determine standardized measurements for establishing a portal medial to the coracoid used in arthroscopic Latarjet-type procedures. METHODS: Twelve shoulders (6 right and 6 left) in 6 fresh frozen cadaveric torsos were mounted in the modified beach-chair position. A standard posterior portal and 3 anterior portals-central, lateral, and medial-were used. A long spinal needle was placed along the path of the medial portal to the lateral tip of the coracoid, superficial to the conjoined tendon and pectoralis minor. A second long spinal needle was directed toward the medial base of the coracoid, penetrating the pectoralis minor. Superficial and deep plane dissections were performed, and distances to surrounding neurovascular structures were recorded. RESULTS: In the superficial plane, the cephalic vein and lateral pectoral nerve were located a mean distance (± standard deviation) of 4.6 ± 1.9 mm and 9.4 ± 2.6 mm from the spinal needle, respectively. In the deep plane, the axillary nerve was 24.9 ± 7.4 mm from the needle; the lateral cord of the brachial plexus, 25.5 ± 8.1 mm; the axillary artery, 34.1 ± 6.0 mm; and the musculocutaneous nerve, 42.2 ± 9.2 mm. The portal was consistently established 45.0 to 50.0 mm distal and 30.0 to 35.0 mm medial to the coracoid, which was a minimum distance of 10 mm to the lateral pectoral nerve. CONCLUSIONS: In a cadaveric model, the creation of a medial trans-pectoralis major portal used in the arthroscopic Bankart-Bristow-Latarjet procedure can avoid compromise of vital neurovascular structures, alleviating concerns of creating a portal medial to the coracoid. Portal placement 45.0 to 50.0 mm distal and 30.0 to 35.0 mm medial to the palpable tip of the coracoid process may be a safe approach to perform the arthroscopic Bankart-Bristow-Latarjet procedure. CLINICAL RELEVANCE: Creation of a portal medial to the level of the coracoid may pose a risk to neurovascular structures. This cadaveric study establishes a working zone for medial trans-pectoralis portal placement, which avoids vital neurovascular structures, and provides standardized measurements for establishing this portal for use in the arthroscopic Bankart-Bristow-Latarjet procedure.

The Effects of Resistance Exercise Selection on Muscle Size and Strength in Trained Women.

The study compared the effects of resistance training programs composed by multi-joint (MJ), single-joint (SJ) and the combination of multi- and single-joint (MJ+SJ) exercises on muscle strength and hypertrophy in trained women. Thirty participants were divided into groups that performed only MJ exercises, SJ exercises and MJ+SJ exercises for six months. Participants were tested for 1-repetition maximum (RM) and muscle thickness (MT) before and after the intervention. All groups showed significant gains on 1RM tests from pre- to post-training (P<0.01). However, MJ and MJ+SJ groups obtained greater gains in 1RM for the MJ exercises in comparison with the SJ group. Increases in 1RM for the SJ exercises were similar among groups, with the exception of leg curl, where the SJ group obtained greater gains than MJ and MJ+SJ. All groups obtained significant increases in MT from pre- to post-training for all muscle groups. However, MJ and MJ+SJ groups presented greater increases in gluteus maximus, quadriceps femoris and pectoralis major in comparison with the SJ group. Therefore, our results suggest that, in general, performing MJ exercises seems to be necessary to obtain optimal results from a resistance training program; however SJ might be necessary to provide optimal strength gains in knee flexion.

The clinical anatomy of variations of the pectoralis minor.

Shoulder pathology is a very common medical presentation and can be due to anatomical variations. Therefore, knowledge of variants is important for the clinician treating patients with such complaints so that misdiagnosis is minimized and iatrogenic injury prevented. A review of the literature was performed of the variant anatomy of the pectoralis minor muscle. The aim of this review is to better inform clinicians who might treat patients with shoulder pathology so that if identified, variants of the pectoralis minor muscle are better appreciated.

Dynamic accumulation of fatty acids in duck (Anas platyrhynchos) breast muscle and its correlations with gene expression.

BACKGROUND: Fatty acid composition contributes greatly to the quality and nutritional value of meat. However, the molecular regulatory mechanisms underlying fatty acid accumulation in poultry have not yet been cleared. The aims of this study were to characterize the dynamics of fatty acid accumulation in duck breast muscle and investigate its correlations with gene expression. RESULTS: Here, we analyzed the fatty acid profile and transcriptome of breast muscle derived from Pekin ducks and mallards at the ages of 2 weeks, 4 weeks, 6 weeks and 8 weeks. Twenty fatty acids were detected in duck breast muscle, with palmitic acid (C16:0, 16.6%~ 21.1%), stearic acid (C18:0, 9.8%~ 17.7%), oleic acid (C18:1n-9, 15.7%~ 33.8%), linoleic acid (C18:2n-6, 10.8%~ 18.9%) and arachidonic acid (C20:4n-6, 11.7%~ 28.9%) as the major fatty acids. Our results showed that fatty acid composition was similar between the two breeds before 6 weeks, but the compositions diverged greatly after this point, mainly due to the stronger capacity for C16:0 and C18:1n-9 deposition in Pekin ducks. By comparing the multistage transcriptomes of Pekin ducks and mallards, we identified 2025 differentially expressed genes (DEGs). Cluster analysis of these DEGs revealed that the genes involved in oxidative phosphorylation, fatty acid degradation and the PPAR signaling pathway were upregulated in mallard at 8 weeks. Moreover, correlation analysis of the DEGs and fatty acid composition traits suggested that the DEGs involved in lipogenesis, lipolysis and fatty acid ß-oxidation may interact to influence the deposition of fatty acids in duck breast muscle. CONCLUSIONS: We reported the temporal progression of fatty acid accumulation and the dynamics of the transcriptome in breast muscle of Pekin ducks and mallards. Our results provide insights into the transcriptome regulation of fatty acid accumulation in duck breast muscle, and will facilitate improvements of fatty acid composition in duck breeding.

Perforator Flaps Based on the Terminal Perforators of the Pectoral Branch of Thoracoacromial Vessels Axis: A Viable Option in the Head and Neck Reconstructions.

BACKGROUND: The purpose of this article is to develop a new method for elevating the pedicled terminal pectoral perforator flaps (PTPPFs) and to resolve the difficulties and controversies that shroud the anatomy of terminal pectoral perforators from the pectoral branch of the thoracoacromial axis. AIM: Anatomical study was conducted to assess the feasibility of perforator flaps based on the terminal perforators of the pectoral branch of the thoracoacromial vessel axis. The knowledge that gleaned from this anatomical study was applied in the clinical scenario. A clinical retrospective study was conducted to evaluate the outcome of PTPPFs for the reconstruction of postexcisional head and neck defects. MATERIALS AND METHODS: Thirty cadaveric specimens were examined for the anatomy of the terminal musculocutaneous pectoral branch perforators. Thirty-two cases (22 males, 10 females) of various head and neck postexcision defects were reconstructed with the PTPPFs in a single-stage manner. Pectoralis major muscle with its innervation was spared in all cases. All the secondary defects were closed primarily. RESULTS: The maximum cutaneous paddle size was 156 cm harvested on a single best terminal pectoral branch perforator. The average size of the cutaneous paddle harvested was 73.47 cm. The flap complications noted (9.3%) were trivial, and all the flaps survived well. The average institutional computed score for esthetic and functional recovery at the donor and reconstructed site done by 2 independent observers were 4.56 and 3.78, respectively. CONCLUSIONS: The recruitment of the chest skin on the terminal pectoral branch perforators resulted in a long pedicle flap with adequate qualities like color match, texture match, and pliability. This flap shall serve as a primary option for pedicle and free flap head and neck reconstructions.

Pectoralis major tendon and enthesis: anatomic, magnetic resonance imaging, ultrasonographic, and histologic investigation.

BACKGROUND: This study evaluates the pectoralis major (PM) tendon humeral insertion, using imaging and histologic assessment in cadaveric specimens. Current descriptions of the pectoralis major tendon depict a bilaminar enthesis, and clarification of the anatomy is important for diagnostic and surgical considerations. MATERIALS AND METHODS: Fourteen fresh-frozen whole upper extremity specimens were used in this study. Magnetic resonance (MRI) and ultrasonographic (US) imaging of the PM muscles, tendons, and entheses were performed, followed by anatomic dissection and inspection. Morphology of the lateral tendon and entheses were evaluated, focused on the presence of layers. In 11 specimens, the lateral 3 cm of the PM tendon was carefully dissected from the footprint, whereas in 3 specimens, the tendon and humeral insertion were preserved and removed en bloc. Histology was performed in axial slabs along the medial-lateral length of the tendon and also evaluated for the presence of layers. RESULTS: The superior-inferior and medial-lateral lengths of the PM footprint were 75 ± 9 mm and 7 ± 1 mm respectively. In all specimens, the clavicular and sternal head muscles and tendons were identified, with the clavicular head tendon generally being shorter. The medial-lateral length of the clavicular head tendon measured 19 ± 8 mm superiorly and 9 ± 3 mm inferiorly. The medial-lateral length of the sternal head tendon measured 38 ± 8 superiorly and 41 ± 18 mm inferiorly. All specimens demonstrated a unilaminar, not bilaminar, enthesis with abundant fibrocartilage on histology. Three specimens demonstrated interspersed entheseal fat and loose connective tissue at the enthesis on MRI and histology. CONCLUSION: The PM tendon humeral insertion consists of a unilaminar fibrocartilaginous enthesis. US, MRI, and histology failed to identify true tendon layers at the enthesis. Delaminating injuries reported in the literature may originate from a location other than the enthesis.

Comparison of Myofascial Release Techniques on Pectoralis Minor Length, Glenohumeral Total Arc of Motion, and Skin Temperature: A Pilot Study.

CONTEXT: The pectoralis minor (PM) is an important postural muscle that may benefit from myofascial techniques, such as Graston Technique® (GT) and self-myofascial release (SMR). OBJECTIVE: To examine the effects of GT and SMR on PM length, glenohumeral total arc of motion (TAM), and skin temperature. DESIGN: Cohort. SETTING: Laboratory. PARTICIPANTS: Twenty-six healthy participants (19 females and 7 males; age = 20.9 [2.24] y, height = 170.52 [8.66] cm, and weight = 72.45 [12.32] kg) with PM length restriction participated. INTERVENTIONS: Participants were randomized to the intervention groups (GT = 12 and SMR = 14). GT and SMR interventions were both applied for a total of 5 minutes during each of the 3 treatment sessions. MAIN OUTCOME MEASURES: PM length, TAM, and skin temperature were collected before and after each intervention session (Pre1, Post1, Pre2, Post2, Pre3, and Post3) and at 1-week follow-up (follow-up). Separate intervention by time analyses of variance examined differences for each outcomes measure. Bonferroni post hoc analyses were completed when indicated. Significance was set a priori at P ≤ .05. RESULTS: No significant intervention by time interactions were identified for PM length, TAM, or temperature (P > .05). No significant intervention main effects were identified for PM length (P > .05), TAM (P > .05), or temperature (P > .05) between the GT or SMR technique groups. Overall, time main effects were found for PM length (P = .02) and temperature (P < .001). Post hoc analysis showed a significant increase in PM length for both intervention groups at follow-up (P = .03) compared with Post2. Furthermore, there were significant increases in temperature at Post1 (P < .001), Post2 (P = .01), and Post3 (P < .001) compared with Pre1; Post2 was increased compared with Pre2 (P = .003), Pre3 (P < .001), and follow-up (P = .01); Post3 increased compared with Pre3 (P = .01) and follow-up (P = .01). CONCLUSION: Serial application of GT and SMR to the PM did not result in increases in PM length or TAM. Regardless of intervention, skin temperature increased following each intervention.

Ultrasound Visualization of Torsional Anatomic Changes From External Rotation of the Anterior Shoulder.

The sonographic appearance of soft tissue can be altered with movement. This can be related to both position change as well as torsional stress. The objective of this article is to demonstrate sonographic anatomy of the anterior shoulder as it moves into full external rotation. METHODS: Ultrasound images were obtained in a healthy human subject. Conventional imaging locations were selected that are typically utilized to assess musculoskeletal and peripheral nerve anatomy as well as perform therapeutic injections. The transducer was centered over each region to obtain both short- and long-axis views. A pair of sonographic images was recorded for both imaging planes at each site: the first in anatomic neutral and second in full external rotation. In addition, a video recording was made at each site to track the movement of the muscles and nerves during external rotation. RESULTS: The rotator interval including the intertubercular groove and biceps brachii long head moves far laterally when viewed in short axis, and it becomes out of plane when viewed in long axis. The subscapularis is relatively poorly visualized with the shoulder in neutral position, but the tendon and more distal aspect of the muscle are well visualized in full external rotation. The pectoralis major tendon insertion is well visualized in long axis with the shoulder in both neutral position and full external rotation. Movement of the humerus and the pectoralis major insertion are seen with shoulder rotation. The muscle appears to tighten and lengthen. The pectoralis major muscle is also seen in greater detail in external rotation. The cord level of the brachial plexus is also visualized at the infraclavicular portion of the anterior shoulder. The medial, posterior, and lateral cords are visualized in relation to the axillary artery. The relative position of the cords is only minimally altered with external rotation; however, the overlying pectoralis minor is tightened, and its influence can be visualized. DISCUSSION: External rotation has a considerable effect on the sonographic appearance of the anterior shoulder. Targets used for therapeutic injections, such as the bicipital groove, rotate out of clear view. Some chemodenervation targets, such as the muscle of the subscapularis, can only be accessed with the shoulder in full external rotation. Full external rotation of the shoulder also places torsional stress on some of the anterior shoulder structures, such as the pectorals, which can provide diagnostic clues in certain pathologic conditions. CONCLUSION: Movement into external rotation changes the sonographic appearance of the anatomic relationships of the anterior shoulder. Knowledge of these torsional changes can have both diagnostic and therapeutic implications.

Poland syndrome before Alfred Poland: the oldest medical description (Paris, France, 1803).

Here, we present a description of Poland syndrome from the second session of the Anatomical Society (Paris, France) on 11 December 1803 of congenital mammary absence and muscular atrophy on the right side. This case report predates the first official description of the disease published by Alfred Poland in Guy's Hospital Reports (London, 1841). Consequently, perhaps would it be necessary to do justice to its French discoverer, and to name from now on this nosological entity the "syndrome of Marandel"?

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.

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.

Qualitative and Quantitative Anatomy of the Proximal Humerus Muscle Attachments and the Axillary Nerve: A Cadaveric Study.

PURPOSE: To provide a quantitative and qualitative anatomic analysis of the pectoralis major, teres major, and latissimus dorsi on the humerus, as well as the deltoid tendinous attachments on the proximal humerus and acromion, and to quantitatively characterize the humeral course of the axillary nerve. METHODS: Ten nonpaired, fresh-frozen human cadaveric shoulders were analyzed. A portable coordinate-measuring device quantified the location of bony landmarks and tendon attachment areas. The tendon footprints were recorded by tracing their outlines and center points. The footprint areas of the tendons, the distances between the footprint areas and pertinent osseous and soft-tissue landmarks, and the distance between where the axillary nerve courses across the humerus relative to the acromion and greater tuberosity were measured. RESULTS: Of the 10 specimens, 9 (90%) had 5 distinct tendinous bands attaching the deltoid to the acromion; 1 specimen had 4 bands. The distances between the center of the deltoid footprint on the humerus and the centers of the pectoralis major, latissimus dorsi, and teres major tendon footprints on the humerus were 43.5 mm, 58.5 mm, and 49.4 mm, respectively. The shortest distances from the perimeter of the pectoralis major to the latissimus dorsi and teres major tendon footprints were 3.9 mm and 9.5 mm, respectively. The distance from the superior aspect of the greater tuberosity to the axillary nerve on the humeral shaft was 50.3 mm (95% confidence interval, 47.0-53.5 mm). The distance from the lateral acromion to the axillary nerve was 69.3 mm (95% confidence interval, 64.1-74.5 mm). CONCLUSIONS: The deltoid muscle had 4 to 5 tendinous insertions on the acromion, and the axillary nerve was 50.3 mm from the tip of the greater tuberosity. The distance between the lower border of the pectoralis major and the axillary nerve was 9.4 mm. CLINICAL RELEVANCE: Knowledge of the quantitative anatomy of the tendons of the proximal humerus and axillary nerve can aid in identifying structures of interest during open shoulder surgery and in avoiding iatrogenic axillary nerve injury. Furthermore, this study provides direction to avoid injury to the deltoid tendons during open surgery.

Quantitative Assessment of the Coracoacromial and the Coracoclavicular Ligaments With 3-Dimensional Mapping of the Coracoid Process Anatomy: A Cadaveric Study of Surgically Relevant Structures.

PURPOSE: To perform a quantitative anatomic evaluation of the (1) coracoid process, specifically the attachment sites of the conjoint tendon, the pectoralis minor, the coracoacromial ligament (CAL), and the coracoclavicular (CC) ligaments in relation to pertinent osseous and soft tissue landmarks; (2) CC ligaments' attachments on the clavicle; and (3) CAL attachment on the acromion in relation to surgically relevant anatomic landmarks to assist in planning of the Latarjet procedure, acromioclavicular (AC) joint reconstructions, and CAL resection distances avoiding iatrogenic injury to surrounding structures. METHODS: Ten nonpaired fresh-frozen human cadaveric shoulders (mean age 52 years, range 33-64 years) were included in this study. A 3-dimensional coordinate measuring device was used to quantify the location of pertinent bony landmarks and soft tissue attachment areas. The ligament and tendon attachment perimeters and center points on the coracoid, clavicle, and acromion were identified and subsequently dissected off the bone. Coordinates of points along the perimeters of attachment sites were used to calculate areas, whereas coordinates of center points were used to determine distances between surgically relevant attachment sites and pertinent bony landmarks. RESULTS: The CAL had a single consistent acromial attachment (mean area 77 mm [51.9, 102.2]) and then bifurcated into 2 bundles, anterior and posterior, that separately inserted on the lateral aspect of the coracoid. The footprint areas were 54.4 mm2 [31.7, 77.2] and 30.6 mm2 [23.4, 37.7] for the anterior and posterior CAL bundles, respectively. These anterior and posterior bundles attached 10.6 mm [8.4, 12.9] and 24.8 mm [12.3, 27.4] medial and proximal to the apex of the coracoid process, respectively. The minimum distance between the coracoid apex and the trapezoid ligament was 25.1 mm [22.1, 28.1] and was noted to be different in males (28.1 mm [25.1; 31.2]) and females (22.0 mm [18.2, 25.9]). The most lateral insertion of the CC ligaments on the clavicle the AC joint was 15.7 mm [13.1, 18.3]. The distance between the most medial to the most lateral point of the CC ligaments on the clavicle was 25.6 mm [22.3, 28.9], which accounted for 18.2% [15.8, 20.6] of the clavicle length. CONCLUSIONS: In contrast to previous findings, 2 different coracoid attachments (anterior and posterior bundles) of the CAL were consistently identified in all specimens. Moreover, a coracoid osteotomy for a bone graft for the Latarjet procedure should be performed at less than 28.1/22 mm from the apex of the coracoid in male/female patients, respectively. The CC ligaments' attachments on the clavicle were located 15.7 mm from the AC joint, which should be considered for reconstruction. CLINICAL RELEVANCE: During the Latarjet technique, to maintain the integrity of the CC ligaments, precise knowledge of differences between male and female anatomy is necessary during a coracoid osteotomy. Furthermore, when reconstructing the AC joint, the distance from the lateral aspect of the clavicle and the size of the attachments areas should be considered to better replicate the native anatomy.

Positional relationship between the pectoralis major and external abdominal oblique muscles for consideration during dual-plane breast augmentation.

During dual plane breast augmentation (DPBA), the costal origin of the pectoralis major (the PM) should be cut to ensure appropriate coverage and positioning of an implant. However, surgeons sometimes make inappropriate planar incisions and insufficient muscular incisions because the external abdominal oblique (the EAO) muscle partially overlaps the lateral portion of the PM. The goal of this study was to clarify the positional relationship between the PM and EAO with the aim of improving the accuracy of implant and muscular incisions during DPBA. Forty sides of 20 embalmed and fresh cadavers were dissected. The midline and midclavicular line (MCL) were used as reference lines for measurements. We clarified the overlapping patterns between the PM and EAO, and measured the distances from the MCL to the borders of those two muscles. The costal part of the PM originated from the 5th (25%), 6th (70%), or 7th rib (5%), respectively. The distances from the MCL to the lateral border of the PM at the 4th, 5th, and 6th ribs were 49.8 mm, 30.5 mm, and 6.3 mm, respectively. In 90% of the specimens, the PM and the EAO overlapped near the MCL. The width of the overlapping portion between the PM and EAO was about 25 mm. This study is one of the first to suggest an innovative approach for explaining the positional relationships between the PM and EAO. Our findings can be useful for surgeons attempting to produce optimal outcomes in DPBA, especially in procedures that involve patients of different races. Clin. Anat. 31:339-346, 2018. © 2018 Wiley Periodicals, Inc.

Classification of unusual insertion of the pectoralis minor muscle.

PURPOSE: The pectoralis minor muscle (PMi) generally originates from the third, fourth, and fifth ribs and inserts on the medial and superior margins of the anterior portion of the coracoid process. Variations in the shape and attachment point of the PMi could cause discomfort in the shoulders. The aim of this study was to observe the types of morphological insertion patterns and attachment sites of the PMi. METHODS: Seventy-four sides of fresh, embalmed Korean (42 sides; mean age 78 years) and Thai (32 sides; mean age 78 years) cadavers were dissected to analyze the morphological insertion types and attachment sites of the PMi. RESULTS: Unusual insertion patterns were evident in about 23% of the samples. When the portion of the PMi tendon ran over the coracoid process, the most common attachment site was the glenohumeral joint capsule. We also confirmed the attachment of the PMi to the clavicle. Costal attachments of the PMi that extend from the second rib to the fourth rib were observed frequently as well. CONCLUSIONS: Unusual insertion patterns of the PMi are common. Some authors consider that tendon attachment to the joint capsule can cause shoulder pain. In addition, the PMi tendon could be utilized in acromioclavicular joint reconstruction. Surgeons need to be aware of the possibility of a PMi variant being found during surgery even when this is not visible in magnetic resonance or ultrasound imaging.

Evidence of the sternalis muscle in two South African cadavers.

The sternalis muscle is an infrequent, non-pathological anatomical variant typically misrepresented in a clinical context. It presents with 3-8% prevalence, according to cadaveric studies. The muscles were identified during routine cadaver prosection at the School of Anatomical Sciences, University of the Witwatersrand. Here, we report two cases of the sternalis muscle in two South African White cadavers. Analysis of the sternalis muscles revealed unilaterally present, distinctly defined muscle masses on the right (case number 1, female) and left (case number 2, male) hemithorax, lateral to the sternum. The muscles occurred with a prevalence of 2.25% within the cadaveric population examined. The prevalence of the sternalis muscle is generally low, especially in the European population. Their presence represents the remnants of the cutaneous muscles in the ventral thorax of lower animals. Clinically, the sternalis muscle may be misinterpreted as a pathological mass or lesion, thus accurate knowledge regarding its variations and prevalence is of importance.

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).

In Vivo Analysis of Biceps Tendon Characteristics in Subpectoral Tenodesis.

PURPOSE: To report the in vivo characteristics of the long head of the biceps tendon (LHBT); to evaluate the relation of age, gender, height, weight, and body mass index to the length and sutured and tubularized diameter of the LHBT; and to determine the smallest possible tunnel diameter for a subpectoral biceps tenodesis (SPBT) that can accommodate most patients. METHODS: The study included 66 patients (33 men and 33 women) with an average age of 54 years (range, 29-73 years) undergoing SPBT. After tenotomy, the length from the biceps musculotendinous junction to the released end was measured. The tendon was transected 3 cm proximal to the musculotendinous junction and sutured, and the diameter was measured. The depth of the reamed tunnel was recorded. RESULTS: The average tendon length was 84.0 mm, measuring 91.9 mm in men and 76.2 mm in women (P < .001), and the average tendon diameter was 4.4 mm, varying slightly between men (4.5 mm) and women (4.3 mm) (P < .001). Mean bone tunnel depth was 17.5 mm, with 19 mm in men and 16.1 mm in women (P < .001). Patient height showed a significant relation to both tendon length and tendon diameter. Weight was not correlated with tendon diameter but did show a significant relation to tendon length. CONCLUSIONS: We have characterized the in vivo length and diameter of the LHBT at the time of an SPBT. Our findings have shown that there was a statistically significant gender difference in tendon length and diameter, but the diameter of the sutured tendon, which was placed into the tunnel, averaged 4.4 mm and ranged from 3.5 to 5 mm for all ages, both genders, all heights, and all weights. This finding is clinically relevant in that a small tunnel measuring 5.5 mm or less is sufficient to perform an SPBT. LEVEL OF EVIDENCE: Level IV, case series, anatomic study.