During routine dissection studies, we encountered an aberrant muscle in the neck region of a 50 year-old female cadaver. The accessory muscle was on the left side. It arose from the superior angle of the scapula and lay over the brachial plexus and brachial artery then inserted to the first rib&#8217;s cartilage. According to its origin and insertion, the aberrant muscle was considered to be the subclavius posticus. The accessory muscle was innervated by a branch coming from the suprascapular nerve

Sarikcioglu, Levent

Sindel, Muzaffer

English

Via Medica Journals

Folia Morphol. Vol. 60, No. 3, pp. 229231Copyright ' 2001 Via MedicaISSN 00155659www.fm.viamedica.plC A S E  R E P O R T229Address for correspondence: Levent Sarikcioglu, Department of Anatomy, Akdeniz University, Faculty of Medicine, 07070 Antalya, Turkey,tel: +90 242 2274343 44316, fax: +90 242 227 44 82, 227 44 95, e-mail: levent@med.akdeniz.edu.trA case with subclavius posticus muscleLevent Sarikcioglu, Muzaffer SindelDepartment of Anatomy, Akdeniz University, Faculty of Medicine, Antalya, Turkey[Received 4 July; Revised 16 July 2001; Accepted 16 July 2001]During routine dissection studies, we encountered an aberrant muscle in theneck region of a 50 year-old female cadaver. The accessory muscle was on theleft side. It arose from the superior angle of the scapula and lay over the brachialplexus and brachial artery then inserted to the first ribs cartilage. According toits origin and insertion, the aberrant muscle was considered to be the subclaviusposticus. The accessory muscle was innervated by a branch coming from thesuprascapular nerve.key words: aberrant subclavius muscleINTRODUCTIONEisler (cited by Akita [1]) reported a muscle, termed byRosenmüller as subclavius posticus muscle, which arosefrom the first costal cartilage and inserted into the co-racoid process or the upper margin of the scapula.Tountas et al. [15] reported that this aberrantmuscle arises from the first rib cartilage, and passesbehind and beneath the clavicle and normal sub-clavius (above or beneath the subclavian vessels andbrachial plexus) to attach to the upper or cranialborder of the scapula or to the fascia over supraspina-tus. Forcada [6] reported a case with subclavius pos-ticus muscle which arose from the upper margin ofthe scapula and transverse scapular ligament, insert-ed in the superior side of the first ribs cartilage. Akitaet al. [1] reported the existence of this muscle in 12sides (4.8%) of 11 cadavers (8.9%) among 248 sidesof 124 cadavers.Several other muscles associated with the clavi-cle and first rib have been described. Tountas et al.[15] reported that M. scapulocostalis minor arosefrom the scapular notch and inserted onto the firstrib. Macalister (cited by Tountas [15]) found thismuscle in 7%, Mori [10] in 1% of 250 cadavers, Nishi(cited by Tountas [15]) in 12%, and Eisler (cited byAkita [1]) found only three examples. Scapulocosto-clavicular muscle, a variant of scapuloclavicularismuscle, arises from the upper border of the scapulaand inserts partly on the clavicle and partly on thefirst costal cartilage [15].Sometimes, subclavius muscle may have a fasciclewhich lay from superior angle of the scapula to themanubrium [7]. Tountas et al. [15] reported thata subclavius muscle had two slips. The upper slip in-serted onto the middle third of the clavicle. The lowerslip, after crossing the cords of the brachial plexusand axillary artery, passed deep to coracobrachialisand terminated by fusing with the tendons of latis-simus dorsi and teres major in the bicipital groove.In a second type, a lateral extension of subclavius mayjoin the scapula at the root of the coracoid process orextend to the superior margin of the scapula.CASE REPORTDuring routine dissection studies, we encountered anaberrant muscle in the neck region of a 50 year-oldfemale cadaver. The accessory muscle was on theleft side. It took its origin from the superior angle of230Folia Morphol., 2001, Vol. 60, No. 3the scapula and lay over the brachial plexus and bra-chial artery then inserted to the first ribs cartilage(Fig. 1). The accessory muscle was innervated bya branch coming from the suprascapular nerve.DISCUSSIONAkita et al. [2] reported that the origin and insertionof both subclavius posticus muscle and the excessof the inferior belly of the omohyoid muscle weresimilar; only the origins of the innervating branchesdiffered. They proposed that both muscles are de-rived from the intermediate region between the sub-clavius muscle and the inferior belly of the omohy-oid muscle, and could be innervated by the nerve tothe subclavius muscle or by the branch to the omo-hyoid muscle arising from the ansa cervicalis. It issuggested that these anomalies are derived froma common matrix, and are similar variations ratherthan different types of anomalies. Therefore, theseaberrant muscles could be termed the subclaviusposticus, regardless of their innervation [2].Tountas et al. [15] reported that these musclesinclude the scapuloclavicularis, a small muscle pass-ing from the root of the coracoid process and trans-verse scapular ligament to the back of the clavicle,and pectoralis intermedius, a fleshy slip that arisesfrom the third and fourth ribs between pectoralismajor and minor and is inserted onto the coracoidprocess, derived from to the fifth cervical to first tho-racic myotomes.The aberrant muscle can be innervated by differ-ent sources. Sato et al. (cited by Akita [1]) proposedthat the aberrant muscles which run between thefirst costal cartilage and the upper margin of thescapula can be classified into two categories:1. The subclavius posticus muscle, which is inner-vated by a branch from the nerve to the subclaviusmuscle.2. A duplication of the inferior belly of the omohy-oid muscle, which is innervated by a branch frominferior belly of the omohyoid muscle.Apart from these sources, Forcada [6] reporteda subclavius posticus muscle innervated by a smallbranch from the suprascapular nerve. In the presentcase, innervation was from the same source. There-fore, this innervation pattern can be added to thisclassification.Few reports discuss the clinical significance ofthese aberrant muscles, although anatomic variationsat thoracic outlet region frequently cause vascularand/or nerve compression. The Paget-von Schröttersyndrome is one type of symptom complex of thethoracic outlet syndrome, and is recognised as spon-taneous or effort-related thrombosis of the axillo-subclavian vein [4, 5, 12]. It is noted that subclavianvein is compressed between the subclavian muscleand the first rib during the movements of abductionFigure 1. Aberrant muscle in the neck region. A. Macrophotogra-phy; B. Schematic drawing; *subclavius posticus muscle, Acr acromion, BP  brachial plexus, FR  first rib, SA  sub-clavian artery, SAM  scalenus anterior muscle, SAS  superi-or angle of scapula, SCMM  sternocleidomastoid muscle.ABSASSAMBPSAFRAcr231Levent Sarikcioglu et al., Subclavius posticus muscleor retraction of the shoulder [3, 14]. Makhoul [9]reported that developmental variations were identi-fied in 86 scalene and 39 subclavius muscles or theirinsertions in out of 175 patients. Kunkel and Machle-der documented osseous and musculotendinousabnormalities in 18 patients [8].When the clinician refers to a mass as locatedwithin the posterior triangle, the lesion may be withinthe superficial space, the posterior cervical space, orthe paraspinal portion of the prevertebral space. Inmost cases, the lesion can be seen on axial imagingwithin the posterior cervical space [11, 13]. By care-ful examinations, using MR imaging of the supras-capular region, such aberrant muscle may be diag-nosed. It is recommended to take into account thepossible existence of such an aberrant muscle dur-ing the examinations of patients with thoracic out-let syndrome, especially in those with symptoms ofvenous compression.ACKNOWLEDGEMENTSWe thank Mr H. Gezer, Mr N. Sagiroglu, and H. Sav-cili for their technical assistance.REFERENCES1. Akita K, Ibukuro K, Yamaguchi K, Heima S, Sato T (2000)The subclavius posticus muscle: a factor in arterial,venous or brachial plexus compression? Surg RadiolAnat, 22: 111115.2. Akita K, Tsuboi Y, Sakamoto H, Sato T (1996) A case ofmuscle subclavius posticus with special reference toits innervation. Surg Radiol Anat, 18: 335337.3. Aziz MA (1979) Muscular and other abnormalities ina case of Edwards syndrome (18-trisomy). Teratology,20: 303312.4. Burger P, Schwarzbach C, Wagemann W (1987) Paget-von Schroetter syndrome. Therapeutic possibilities,early and late results. Zentralbl Chir, 112: 179187.5. Dinkelaker F, Eisele R, Haring R (1982) Paget-von Schro-etter syndrome. Current status of diagnosis and ther-apy. Med Welt, 33: 671675.6. Forcada P, Rodriguez-Niedenfuhr M, Llusa M, CarreraA (2001) Subclavius posticus muscle: supernumerarymuscle as a potential cause for thoracic outlet syn-drome. Clin Anat, 14: 5557.7. Goss CM (1973) Grays Anatomy. Lea & Febirger, Phi-ladelphia, pp. 454.8. Kunkel JM, Machleder HI (1989) Treatment of Paget-Schroetter sydnrome. A staged, multidisciplinary ap-proach. Arch Surg, 124: 11531157.9. Makhoul RG, Machleder HI (1992) Developmental anom-alies at the thoracic outlet: an analysis of 200 consecu-tive cases. J Vasc Surg, 16: 534542.10. Mori M (1964) Statistics on the musculature of theJapanese. Okajimas Fol. Anat. Jap, 40: 195300.11. Parker GD, Harnsberger HR, Smoker WR (1991) Theanterior and posterior cervical spaces. Semin Ultra-sound CT MR, 12: 257273.12. Sievert T, Maike HW, Wildmeister W (1991) Paget-vonSchroetter syndrome: case description in the light ofthe literature. Z Gesamte Inn Med, 46: 375380.13. Smooker WR (1991) Normal anatomy of the infrahyoid neck:an overview. Semin Ultrasound CT MR, 12: 192203.14. Terfold ED, Mottershead S (1948) Pressure the cervi-co-brachial junction (an operative and anatomicalstudy). J Bone Joint Surg, 30B: 261263.15. Tountas C, Bergman R (1993) Anatomic variations ofthe upper extremity. Churchill Livingstone, New York,pp. 223224.

A case with subclavius posticus muscle

https://journals.viamedica.pl/folia_morphologica/article/download/16483/13118

A case with subclavius posticus muscle

Abstract

Similar works

Full text

Available Versions

Via Medica Journals