Central Annals of Vascular Medicine & Research Case Report *Corresponding author Kunwar P Bhatnagar, Department of Anatomical Sciences and Neurobiology, University of Louisville, 7000 Creekton, USA, Tel: 150-2456-4779; Email: bhatnagar@ The Anomalous Human Levator louisville.edu Submitted: 08 February 2021 Claviculae Muscle: A Case Accepted: 20 February 2021 Published: 24 February 2021 ISSN: 2378-9344 Report Copyright © 2021 Bhatnagar KP, et al. Kunwar P Bhatnagar1* and Timothy D Smith2 OPEN ACCESS 1Department of Anatomical Sciences and Neurobiology, University of Louisville, USA 2School of Physical Therapy, Slippery Rock University, USA Keywords • Anomalous muscle • Levator claviculae Abstract • omo-trachelien • Omocervicalis This case report describes the observation of a unilaterally present anomalous levator claviculae muscle in a 66 -year-old human male. The observations were made during routine laboratory dissections. In our 80- • Sternomastoideus some years of cumulative human dissection education prior to this detection, this was the first observation (with about 45 cadavers dissected yearly) of this muscle. The levator claviculae muscle was observed with intact nerve supply from the ventral ramus of C3, indicating its functional status. The muscle was lambda (λ)-shaped with its stem oriented cranially, attaching to the fascia of the longus capitis muscle at the level of the transverse process of the fourth cervical vertebra. More inferiorly, the stem splits into a pars medialis and pars lateralis each with fascial attachments to the clavicle within the middle third of the bone. Both parts had fascial attachments to the clavicle within the middle third of the bone, and the lateral part passed medial to the external jugular vein. Elsewhere in the neck, the inferior belly of the omohyoideus muscle also split into medial and lateral heads, attaching separately to the scapula. Knowledge of infrequent anatomical anomalies is helpful in isolating pathologies (e.g., cervical cancers) from other infrequent, but non-pathological structures that may be detected in routine screenings. Lastly, in a review of comparative anatomical findings, we assert the levator claviculae muscle is a partial homologue of the omocervicalis of other mammals. INTRODUCTION to-clavicular attachments. In other mammals, the omo-cervicalis (omotransversarius) has similar attachments [5]. The levator claviculae is an anomalous muscle that passes from the mid-cervical vertebral level to the clavicle. It is rare in For the reasons outlined above, the levator claviculae can humans [1,2] and similar variants are known in other mammals be regarded as one element among a small number of muscles (see below). Embryologically, the levator claviculae belongs that belong to the region of the trapezius and levator scapulae. to the sternomastoid-trapezius group which takes its origin However, possibilities that distinct variants exist as opposed from the accessorio-cervical primordium. This variant muscle to variable attachments of a single muscle remain two viable conclusions at present. Because there could be attributed either to the levator scapulae or scalenes topographically, yet such a conclusion is not supported on ontogenetic or phylogenetic grounds [3]. the variants seen in humans. Are so few reports, it is difficult to conclude which explains The muscle has a history of varied nomenclature (Table In addition, its frequency remains highly tentative. Indeed, in our own experience of a cumulative 80 years of continual cleido-cervicalis and cleidotrachelian in human studies, and omo-trachelian1, see references in therein).studies of It otherhas been mammals specifically (the latter called term the observation of the anomaly. This report adds to the state of dissecting instruction, the present case represents our first sometimes used for humans as well). Other named muscles that knowledge on this rare variant. occupy the same vicinity have been described, such as cleido- CASE PRESENTATION occipitalis. Based on origins and insertions alone (Table 1), there is reason to doubt that the described muscles represent During routine laboratory dissection of an embalmed, homologous elements. In many but not all of the works that used 66-year-old male cadaver, a rare abnormal neck muscle was observed unilaterally on the right side. Then, the posterior but sometimes at the highest cervical levels and sometimes at and anterior triangles of the neck were carefully dissected to expose the relationship of this muscle to adjacent structures lowerthe above levels. muscle Moreover, names, the cervical cleido-occipitalis attachments [4] arehas specified,occipital- Cite this article: Bhatnagar KP, Smith TD (2021) The Anomalous Human Levator Claviculae Muscle: A Case Report. Ann Vasc Med Res 8(1): 1125. Bhatnagar KP, et al. (2021) Central within the neck, as well as its innervation. The dissected regions were photodocumented and subsequently an illustration was prepared. Table 1: Selected data on anomalous neck muscles. Nomencla- Attachments Comments Source ture used fascia of the longus capitis muscle (C4 level); two heads levator cla- (medial and lat- this study viculae eral) with fascial attachments to the clavicle may attach to “distal cervical vertebrae” (p levator cla- atlas, axis; acromi- Photograph of the anterolateral neck, color-enhanced to demonstrate 435); innervated [16] Figure 1 viculae al end of clavicle structures. by cervical ventral rami that also go to the levator claviculae muscle (LC) including the medial and lateral heads (M,L) trapezius inferiorly.The sternocleidomastoid * denotes to nerves muscle to theis reflected. levator claviculae. a) anterolateral b) Superolateral view showing view, levator cla- upper neck; lateral showing the omohyoid muscle, including the medial and lateral heads (M,L) of [3] viculae third of clavicle the inferior belly of the omohyoid (Oi). Abbreviations: ACs/i: ansa cervicalis, superior/inferior root; C2, C3, C4: ventral “up to the level rami of cervical spinal nerves C2-C4; CC: Common Carotid Artery; CL: Clavicle; of the transverse attachments in- levator cla- GAn: Greater Auricular Nerve; H: Hyoid bone; IJV: internal Jugular Vein; MCg: process of C3;” ferred from CT [17] viculae Middle Cervical Sympathetic Ganglion; NL: Nerve Loop; O, superior belly of the middle or lateral scans omohyoideus muscle; OT: Omohyoid Inter-Tendon; SCLnn: supraclavicular third of clavicle nerves; ST: Sympathetic Trunk; T: Trapezius muscle; THn: Nerve to thyrohyoid; atlas, axis; lateral XII, hypoglossal n. Scale bar, 10 mm. levator cla- third of clavicle, viculae posteriorly “from the medial detected by sonog- part of the neck to raphy levator cla- the middle portion (implicated in [18] viculae of the claviculae” thoracic outlet syn- drome) C3, posterior seen in conjunction levator cla- tubercle; poste- with a third head [19] viculae rior margin of the of sternocleido- clavicle mastoid m. transverse process innervated by a of the levator cla- small branch from C2-C3; middle [20] viculae the medial supra- third of the clavi- clavicular nerve cle. anterior to omohy- cleido-cervi- axis; middle third oid; omohyoid has calis or leva- of clavicle, poste- [21] two of origin for tor claviculae riorly superior belly C6, anterior tuber- cleido-cervi- cle of transverse [10] calis process; lateral clavicle C6, anterior tuber- cleido-cervi- cle of transverse [4] calis process; superior margin of clavicle Figure 2 Illustration of the dissection of the right cervical triangles in the male C3, C4 transverse similar to this human cadaver. cleidotrache- study, notes double [9] Abbreviations: ACi, ansa cervicalis, inferior root; C2, C3, C4: ventral rami lian to omohyoid innervation of cervical spinal nerves; C2-C4; CC: common carotid artery; GAn: greater process, superficial auricular nerve; H: hyoid bone; IJV: internal jugular vein; LC: longus coli cranial part with muscle; LCl: levator claviculae; muscle; L, M, lateral/medial belly; O: superior cleido-occip- trapezius; poste- [22] belly of the omohyoideus muscle; SCLnn: supraclavicular nerves; STn: nerve to italis riorly on lateral sternothyroid; THn: nerve to thyrohyoid; XII, hypoglossal n; third of clavicle *nerves to the levator claviculae Ann Vasc Med Res 8(1): 1125 (2021) 2/4 Bhatnagar KP, et al. (2021) Central The anomalous muscle was observed unilaterally in the Regarding the levator claviculae, it has been reported to posterior triangle of the neck on the right side (Figure 1). be remarkably well developed in some individuals, with viable Further careful dissection revealed the muscle had a branched nerve supply (as our observations also suggest), and thus is presumably functional Corner [7]. The muscle has been theorized clavicular attachments. to be a part of the sternomastoid. Indeed, any number of other configuration, with a single cervical attachment and two variant muscles occur in the region. There is a long history of The inferior belly of the omohyoid also split into two parts, sporadic reports of muscles including thecleidocervical (Tomo and is described below.The levator claviculae muscle (Figures et al., 19944; Nagashima et al., [10] tracheloclavicularis imus [11] , omocervicalis [12,13] levator claviculae Parsons [5] , attaching to the fascia of the longus capitis muscle at the level of omotrachelian [5] and musculus cucullaris (Myauchi and Kato, the1,2) transverse was lambda process (λ)- shapedof the fourth with cervicalits stem vertebra. oriented Thecranially, 9 mm 1983; = sternomastoid + omocervicalis,