reported presence of three Rectus Sternalis muscles in a single cadaver, one on right side and two on left side. The sternalis muscle takes its nerve supply from the internal or external thoracic or pectoral nerve in 55% of cases, intercostal nerves in 43% of cases, and both in 2% of cases [1, 5]. It is located on the human anterior pectoral wall, superficial to pectoralis major. The sternalis muscle: an uncommon anatomical variant among Taiwanese - Volume 193 Issue 2. Fig. Rectus sternalis is a rare muscle found in the anterior chest wall superficial to the pectoralis major muscle. Present in less than ten percent of the population . The sternal muscle, also known as sternalis, rectussternal, parasternal or japonicus is a curious case of anatomical variation of the anterior chest wall. Has varying shapes, contours and sizes and may mimic a mass lesion on mammogram. The pain is described as mild to moderate and is dull or aching. The pain of sternalis syndrome is intermittent. Case report.. major ip t. . Discussion The sternalis is a rare muscle of the anterior thoracic wall and has been defined in the anatomic literature (since 1604) the right rectus abdominis muscle. In one case accompanied by congenital partial absence of the pectoralis major muscle the sternalis muscle was examined to confirm its innervation by means of analysis of intramuscular nerve distribution. The sternalis muscle is a relative rarity that is believed to be prevalent in around 7-8% of the population. Relation of intercostal nerves displayed. the sternal membrane slightly below the angle of Louis; the Sternalis muscle has been encountered by many anatomists, inferior portion directly continued into the right pectoralis and its morphology, innervation and probable origin have major fibers. Innervation of pectoralis major is by both the lateral pectoral nerve, which innervates the clavicular head, and the medial pectoral nerve, which innervates the sternocostal head. It is regularly observed in lower animal but infrequently in humans. Plentiful examples of additional muscles can be found in the literature, for example, an accessory head of the pectoralis major, one or more sternalis muscles, various slips of muscle originating or inserting at unusual locations, and even a double pectoralis major [1-3, 6-8]. Figure 2. The sternalis is a thin band of muscle that rests in front of the pectoralis major muscle and runs parallel to the sternum. Barlow opines that morphologically, rectus sternalis represents the remains of panniculus carnosus. Supply by more than one nerve may result from fusion of separate muscle bellies into a single sternalis muscle [ 8 ]. On physical examination, a patient with sternalis syndrome exhibits myofascial trigger points at the midline over the sternum. 2. Frequently bilateral, the sternalis muscle is slender band of ï¬ bers running parallel to the sternum. 6. Although less is known about its origin and . We examined the operative records of 1,152 patients who underwent modified radical mastectomies between 1990 and 2000. The question of the double innervation of the sternalis muscle The innervation to the muscle could be traced to the 4th, 5th, and 6th anterior intercostal nerves. Often the variant anatomy was rare but benign, as in the case of this sternalis muscle dissected and prepared by Trinity's Professor of Anatomy Daniel John Cunningham (1850-1909). Palpation & Self-massage. Situation between the anterior thoracic superficial fascia and the pectoral fascia. It is located on the human anterior pectoral wall, superficial to pectoralis major. rectus sternalis muscle is derived either from pectoral nerves(55%) or intercostal nerves(43%) or both(2%) which has paved way for several hypotheses regarding its embryological origin. Jelev, in 2001, defined the characteristics of the sternalis muscle as follows. During a routine dissection, a muscle mass related to the sternum was found in the anterior wall of the right . Abstract The sternalis muscle is a well documented but rare muscular variation of the anterior thoracic wall. Kida and Kudoh found the sternalis muscle to be supplied by the pectoral nerves. In a routine dissection of the superficial chest muscles, graduate students in a human gross anatomy class exposed a large, well-developed sternalis muscle. The sternalis muscle was removed with the breast and was found to be a cylindrical muscle of approximately 8 cm in length and 2 cm in diameter. The sternalis muscle is an uncommon anatomical variant. According to them, it is a composite type of muscle [17]. This article will discuss the anatomy and function of the spinalis muscle. The homology debate from the literature reviewed Table 2 shows that the sternalis has been On the left side both reach the sternalis; on the right side the upper of the two exhausts itself in branches to the great pectoral before it reaches the sternalis. National Journal of Clinical Anatomy Full-text search Case report: Bilateral sternalis muscles with a bilateral pectoralis . Occasionally a vertical strip of muscle is seen at the lateral border of sternum, which is named as 'Rectus sternalis (sternalis) muscle'. Patients who underwent conservative breast surgery or . We report a case of rectus sternalis on the right anterior thoracic wall of a 55-year . Double sternalis in male subject. It lies vertically alongside either side of the sternum, or breastbone, and covers the medial fibers of the pectoralis major muscle, those nearest the sternum. Sternalis muscle is a rare anatomic variant of the chest wall musculature, it is found in front of the sternal end of the pectoralis major parallel to the margin of the sternum. 2. Sternalis muscle innervation is quite enigmatic, imply-ing that the rule of the close relationship between mus-cle ontogeny and innervation may not apply for this muscle. The present investigation endeavors to discuss the anatomical, embryological and clinical relevance of a rare accessory muscle of the anterior chest wall of Asian origin found in a 40-year-old male cadaver. Sensory supply is from the 7-12 thoracic nerves. The sternalis typically sits in front of the pectoralis major, and parallel to the margin of the sternum. A study reported that 55% of the cases were innervated by branches of thoracic nerves, while 43% were by the intercostal nerves [4]. The Sternalis muscle has been nominated as a supernumerary anatomical variation; the highest prevalence is in China (23.5%) and the lowest in Chile (0.87%). 1. Unlike most muscles, its innervation varies considerably, but usually is served by intercostal nerves or the medial pectoral nerve. The innervation for the sternalis muscle can be easily damaged during dissection or surgery. Familiarity of the sternalis not only broadens the surgeon's knowledge of variations of chest wall anatomy but also provides reconstructive operations for wounds in the chest wall as well as adjacent regions. Fig. Innervation to muscles of the anterior thorax arises from different branches of the brachial plexus. Okajimas Folia Anat Jpn 1991; 67: 449-455. Rectus sternalis muscle: An anatomical variant of anterior chest wall. Sternalis Syndrome. The fusiform muscle belly tapered into a thin delicate tendon at the level of 4 th costal cartilage, continued, for a short distance along right sternal . Relation of intercostal nerves displayed. It is supplied by the anterior thoracic nerves and is probably a misplaced part of the pectoralis [1]. This muscle has been reported both in males and females, and in whites, blacks and Asians (Barlow, 1934; Kida & Kudoh, 1991; Shen et al. 5. Variation [] The sternalis muscle may be a variant form of the pectoralis major or the rectus The sternal muscle also called 'presternalis,' sternalis, rectus sterni or 'sternalis brutorum,' 'thoracicus' 1 is an interesting case of anatomical variation, being described in the literature as a small sternalis muscle such as "parasternalis" and "rectus sterni" muscle. Sternalis muscle also called rectus sternalis, rectus thoracis, or episternalis is an anomalous muscle of the anterior chest wall with unknown anatomical function. The anatomy of the sternalis is variable and it may be . Sternalis is a muscle that runs along the anterior aspect of the body of the sternum.. Intercostal nerves do not supply the sternalis muscle despite piercing through it(9). Various authors suggested the microdissection technique as nerves are often destroyed in this region. injury. The muscles are innervated by thoraco-abdominal nerves, these are continuations of the T7-T11 intercostal nerves and pierce the anterior layer of the rectus sheath. The sternalis has been grouped with the pectoral muscle group (pectoralis major) and with the abdominal muscle group (rectus abdominis and external oblique) because of common innervations. Occasionally, a coexistent trigger point is located in the pectoralis muscle or sternal head of the sternocleidomastoid muscle. Fig. Located on the right side, the muscle took origin by a small fleshy belly from the lower part of pectoral fascia, at the level of 7 th costal cartilage. Presence of this muscle can create confusion with tumours of the anterior chest wall during routine mammography. sternalis muscle is from internal or external thoracic or pectoral nerve in 55% of cases, intercostal nerves in 43% of cases, and both in 2% of cases [1,5]. during clinical approaches. The sternalis muscle may be a variation of the pectoralis major or of the rectus abdominis . Unilateral sternal muscle in an adult melanodermic cadaver is an article from MOJ Anatomy & Physiology for MedCrave Group. On each side two nerves pierce the great pectoral muscle and run inwards. What are the Symptoms of Sternalis Syndrome. Like the other two, it is made up of three parts. The sternalis muscle typically emerges via the upper part of the sternum and can show changing attachments such as the pectoral fascia, lower ribs, costal cartilages, rectus sheath, aponeurosis of the abdominal external oblique muscle.There is yet a lot of dispute about its innervation and its embryonic genesis. Sternalis is a rare muscle encountered in the subcutaneous plane. Sternalis muscle does not follow the relationship between muscle ontogeny and innervation. The sternalis muscle was first described in 1604, and since that time it has been repeatedly described with significant morphological variations [], innervation patterns [6, 8], and vascular supply [].Ge and colleagues enumerated three "types" of sternalis muscle variants in 2014 []: Type I or single bellied, Type II or multiheaded, and Type III or multibellied. the homology and innervation of sternalis, and there is an extensive literature. A cadaveric study was undertaken to report the incidence of sternalis muscle in cadavers of Asian origin. Figure 1. On each side two nerves pierce the great pectoral muscle and run inwards. Furthermore, the blood supply of the sternalis muscles were innervated by branches of the internal and external thoracic nerves, 43% by branch-es of the intercostal nerves and 2% both from the inter-costal and thoracic nerves.13 In their case, the sternalis muscle was innervated by the intercostal nerve. Shah AC. The pain is located around the sternum and may radiate into the arm. The first report which described it in alive subjects was made by Roubinowitch . The exposure of this muscle generated many student questions about M sternalis: its prevalence and appearance, its function, its development, and its evolutionary roots. It is regularly observed in lower animal but infrequently in humans. The 3rd-5th intercostal nerves entered the muscle from its deep aspect (feature not photographed). Spinalis and longissimus both have capitis, cervicis and thoracis parts, while iliocostalis has cervicis, thoracis and lumborum parts. There is no known muscle test that causes it to contract. Ex-tensive review of the literature comprising almost 200 ster-nalis muscles, reveals 55% innervated by branches of the internal or external thoracic nerves, 43% by branches of the intercostals nerves, and 2% from both the intercostals and Mastectomy is a commonly performed surgery for carcinoma of breast. Description. incidence of musculus sternalis in the population of Caldas (Colombia) and, therefore, 68 cadavers of adult individuals were us ed during a period of twenty years to determine the incidence of this muscle and describe its anatomical characteristics. Sternalis lie vertically alongside the sternum. Case 1. 1996). It lies superï¬ cial to the pectoral fascia, arises from the sheath of the rectus abdominis muscle or adjacent structures and terminates upon the pectoral fascia, upper sternum, costal cartilages, or the sternal or medial heads of the . The unique feature of present case study was the appearance of anterior thoracic wall having triangular pectoralis major muscle inspite of fan shaped. Arterial supply of sternalis muscle is from perforating branches of internal thoracic artery. The sternalis muscle is an anatomic variation well known to anatomists, but relatively unknown to clinicians and surgeons. Sternalis muscle does not follow the relationship between muscle ontogeny and innervation. The muscle is a wide band of muscular tissue located in the anterior thoracic wall, where fibers travel near-parallel to the sternum, inferior to the clavicles, aterior to the pectoralis major and the pectoral fascia. Sternalis Muscle in 83 year old Female A) Sternalis muscle within a . Intercostal nerves do not supply the sternalis muscle despite piercing through it [9]. As the muscle has no function, there are no activities that are known to overwork the sternalis. 7. O' Neill MN, Folan-Curran J. 2. [8] this muscle would have derived from the pectoralis major with its innervations from pectoral nerves or from the rectus abdominis with innervation from intercostal nerves. A total of 88 cadavers were studied over a period of six years and the sternalis was reported only in a single case and that too unilaterally. Its synergists and its antagonists remain . It is regularly observed in lower animal but infrequently in humans. The Sternalis muscle has been nominated as a supernumerary anatomical variation; the highest prevalence is in China (23.5%) and the lowest in Chile (0.87%).. Developed by renowned radiologists in each specialty, STATdx provides comprehensive decision support you can rely on - Sternalis Muscle On the left side both reach the sternalis; on the right side the upper of the two exhausts itself in branches to the great pectoral before it reaches the sternalis. Sternalis muscle innervation is quite enigmatic, implying that the rule of the close relationship between muscle ontogeny and innervation may not apply for this muscle. Presence of this muscle can superolaterally, Sternalis muscle reflected inferiorly pm - pectoralis major, pt - pectoralis tertius, sm - sternalis muscle, arrows - anterior branches of 2nd to 4th intercostal nerves (cut) winding around the medial border of sternalis (reflected caudally). Awareness of the location of the sternalis will help medical doctors avoid misdiagnosis during mammography or misjudgement during breast surgery. It is regularly observed in lower animal but infrequently in humans. We report a case of rectus sternalis on the right anterior thoracic wall of a 55-year . It is inserted at the level of the manubriosternal junction and arises from the sternal handlebar and with myofascial continuity with the sternocleidomastoid muscle. It is localized superficially to the pectoralis major and can cause a diagnostic dilemma during breast surgery, mammography, and computed tomography and magnetic resonance imaging scans, as its appearance mimics tumor pathology of the region. Double sternalis in male subject. The sternalis muscle .Ind J Med Sci 1968; 22: 46-47. Developed by renowned radiologists in each specialty, STATdx provides comprehensive decision support you can rely on - Sternalis Muscle It is mostly unilateral (in 70%.) 1992; Bradley et al. A cadaveric study was undertaken to report the incidence of sternalis muscle in cadavers of Asian origin. Sternalis muscle also called rectus sternalis, rectus thoracis, or episternalis is an anomalous muscle of the anterior chest wall with unknown anatomical function. It was proved that the sternalis muscle was supplied only by the pectoral nerves even in the cas … A total of 88 cadavers were studied over a period of six years and the sternalis . Kida MY, Kudoh H. Innervation of the sternalis muscle accompanied by congenital partial absence of the pectoralis major muscle. Fig. Sarikcioglu L et al. It presents in several morphological variants both unilaterally and bilaterally and has no apparent physiological function. Thieme E-Books & E-Journals. 38 The function of the sternalis muscle still remains unknown, but it may help to elevate the lower chest wall. The sternalis muscle is an uncommon anatomical variant. There are two different theories as to what the Sternalis was meant to be connected to. Various theories attribute towards the origin of the rectus sternalis muscle. Rectus sternalis is a rare muscle found in the anterior chest wall superficial to the pectoralis major muscle. Epidemiology Sternalis muscle also called rectus sternalis, rectus thoracis, or episternalis is an anomalous muscle of the anterior chest wall with unknown anatomical function. We present a review of the literature of the sternalis muscle with special emphasis on its clinical anatomy. Below you'll find a list of all posts that have been tagged as "sternalis" The Evidence of Anatomy Trains Myofascial Meridians Strain transmission along myofascial meridians might explain referred pain and offer a rationale for the development of more body-wide holistic approaches. Muscles that then might also be affected, are the pectoralis major and the pectoralis minor. (8) Recent surge in medical imaging and surgical procedures has brought this sternalis muscle into relevance in clinical practise. 5,6 Case Report Abstract . O' Neil and Folan-Curran reported that in 55% of the cases the muscle was innervated from the exter- The sternalis muscle is a normal anatomic variant of the chest wall. Sternalis muscle also called rectus sternalis, rectus thoracis, or episternalis is an anomalous muscle of the anterior chest wall with unknown anatomical function. muscular slips of pectoralis major muscle as well sternalis muscle were getting innervation from medial and lateral pectoral nerves as in (Figure 2). It lies between the superficial fascia and the pectoral fascia and is found in about 8% of the population. Kumar et al.7considers sternalis to be derived embryologically from theventral longitudinal column of External or internal thoracic nerve innervates the muscle in 55% of cases whereas 43% of cases are innervated by intercostal nerve and remaining by both [4]. The schematic representation of the findings can Sternalis muscle innervation is quite enigmatic, imply- be seen in Figure 2. ing that the rule of the close relationship between mus- According to a classification described by Jelev et al, cle ontogeny and innervation may not apply for this the bilateral sternalis muscles we describe can be . The ipsilateral pectoralis major did not display morphological variation. Various authors suggested the microdissection technique as nerves are often destroyed in this region. Presence of this muscle can create confusion with tumours of the anterior chest wall during routine mammography. Its importance lies in that it should not be mistaken for a pathological lesion. the sternalis muscle is from internal or external thoracic or pectoral nerve in 55% of cases, intercostal nerves in 43% of cases, and both in 2% of cases(1, 5). In the literature it is also known as episternalis, presternalis . Presence of this muscle can create confusion with tumours of the anterior chest wall during routine mammography. The sternalis muscle is an anatomical variation that lies in front of the sternal end of the pectoralis major parallel to the margin of the sternum. One is the Pectoralis major, the other is the rectus abdominus, as in several cases the sternalis was actually found to have interlaced fibers with the rectus abdominus, but be enervated by the same nerve . Arterial supply of sternalis muscle is from perforating branches of internal thoracic artery. A matter of debate is the sternalis muscle. 39 On CT or MR studies, it is seen as a vertically oriented parasternal flat and bandlike structure surrounded by . 3. External or internal thoracic nerve innervates the muscle in 55% of cases whereas 43% of cases are innervated by intercostal nerve and remaining by both [4]. Key words: sternalis muscle Address for correspondence: Dr. Marios Loukas MD, PhD, Assistant professor, Department of Anatomy, American University of In a study be Saeed, et al. OA Anatomy 2014 Jun 10;2(2):16. The sternalis muscle ( TA: musculus sternalis 8 ), also known as rectus sternalis or parasternalis 7, is an uncommon chest wall accessory muscle and is of uncertain aetiology and function. But it is known that it may develop trigger points with acute angina pectoris or myocardial infarction. The innervation of the sternalis muscle is varied. The sternalis muscle is a strip of anterior and lateral muscle to the sternum and lateral to the pectoralis major muscle, with a population response of 5 to 8%. No one knows what it does! The muscle is a wide band of muscular tissue located in the anterior thoracic wall, where fibers travel near-parallel to the sternum, inferior to the clavicles, aterior to the pectoralis . 3. The prevalence of sternalis in the Kingdom of Saudi Arabia is about 4% based on a study of 75 adult cadavers and a retrospective study of 1580 adult females (none of the 1580 were found to have sternalis muscles). Spinalis is the most medial of the three erector spinae muscles. the bilateral sternalis muscles are very low around 1.7% and its concurrent existence with other rare anatomical abnormalities is even rarer [21]. It may be a variation of the pectoralis major or of the rectus abdominis. The sternalis is a muscle that is uncommonly but occasionally found in the human chest. During surgery, pectoral fascia is removed and pectoralis major muscle is laid bare. 2. Mostly it appears on medial posterior edge of the breast on CC views, but may also be detected on MLO projections. Contents 1 Structure 1.1 Prevalence 1.2 Variations 2 Function 3 Clinical significance 4 History The accessory muscle was discovered in the right pe … Saeed found the Sternalis muscle to be innervated by intercostal nerves. Fig. The muscle tissue was verified in histological examination. A unilateral rectus sternalis muscle was observed in a 80-year-old male cadaver. Sternalis muscle is a rare supernumerary muscle variant of . Skip to main content Accessibility help We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Innervation of the sternalis muscle is provided by branches of pectoral nerves (55%) and/or intercostal nerves (43%). 5. The sternalis muscle was first coined by Carbriolus in 1604 and subsequently by Du Puy in 1726. Photograph showing the sternalis muscle during the modified radical mastectomy opera-tion; sm — sternalis muscle. Sternalis Syndrome is an unusual cause of chest wall pain. O' Neil and Folan-Curran reported that in 55% of the cases the muscle was innervated from the external or internal thoracic nerves, 43% of the cases it was supplied by the . This muscle has been reported both in males and females . The function of sternalis is unknown. It is a myofascial pain syndrome, a painful condition of muscles of the chest wall.