Scapula

One thousand. Voss , ... P.Grand. Montavon , in Feline Orthopedic Surgery and Musculoskeletal Disease, 2009

27.5 Scapular avulsion

The scapula is connected to the body wall by both deep and superficial muscles. The deep muscle group holds the body up towards the scapula when the true cat is standing, and is composed of the serratus ventralis, trapezius, and rhomboideus muscles. These insert at the cranial angle and dorsal border of the scapula. Rupture of the deep muscle grouping causes the scapula to shift dorsally, and prevents the cat maintaining normal posture during weight-bearing. Jumps, falls, and seize with teeth wounds are common traumatic causes (6). At that place is i instance report of feline scapular avulsion in the literature (7). Fracture of the body of the scapula may coexist.

The characteristic dorsal displacement of the scapula is easily observed and palpable (Fig. 27-viii). The proximal office of the scapula displaces laterally if the distal limb is adducted. The part of the limb is initially impeded but with time the cats offset to use their leg again, although the scapula commonly remains dorsally dislocated without surgical treatment. A Velpeau sling may exist a successful treatment option for acute dislocation (eight).

The goal of surgery is temporarily to stabilize the scapular body to the trunk wall in its anatomic position until fibrous healing has occurred. Repair tin can be achieved by reattaching the bone to the serratus ventralis musculus with not-absorbable sutures secured through small holes in the scapula. If the soft-tissue repair is tenuous, a wire can be placed carefully around an adjacent rib (Box 27-4).

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Vertebrae, Ribs, Sternum, Pectoral and Pelvic Girdles, and Bones of the Limbs

Robert Lewis Maynard , Noel Downes , in Beefcake and Histology of the Laboratory Rat in Toxicology and Biomedical Enquiry, 2019

The Scapula

The scapula bears ii marked processes: the acromion and, rather less obvious, the coracoid. The acromion springs similar the head of a golf club from the spine of the scapula, extends anterior to the glenoid fossa and carries a small subsidiary procedure, the metacromion. The scapula provides the glenoid fossa (glenoid=socket): both the scapula and the coracoid procedure contribute to the articular surface.

The muscles of the scapula arise from the anterior and posterior spinous fossae on either side of the spine, and from the deep surface of the bone. The deep surface is ridged by the attachments of subscapularis and serratus anterior. The scapula ossifies from 2 major centres, one for the scapula and one for the coracoid process. In the rat, the borders of the scapula long remain cartilaginous.

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Anatomy of Muscle

P.D. Wilson , in Reference Module in Biomedical Sciences, 2014

Muscles that Motion the Shoulder

The scapula, a triangular bone, articulates solidly only with the pocket-size clavicle. Because the scapula is not held firmly in place, it is free to movement in several directions. The muscles that motion the scapulae are extrinsic muscles – they attach from the neck and/or shoulder to the limb ( Figures 11(a) and 11(b)). The trapezius is a large flat muscle that covers much of the upper back. Its fibers extend in several directions, and it elevates, retracts, and rotates the scapula freely. The rhomboideus and the levator scapulae muscles besides retract and elevate the scapula. Acting antagonistically to these muscles, the pectoralis modest and the serratus anterior protract the scapula forward, every bit when a person reaches for something. The subclavius muscle attaches to and acts indirectly through the clavicle to pull the scapula toward the sternum.

Figure xi. Muscles of the shoulder and brachium.

 Modified from Drake, R.Fifty., Vogel, West., Mitchell, A.W.M., 2005. Gray's Anatomy for Students. Elsevier, Philadelphia, Figures vii.9, 7.47, 7.63, seven.64, pp. 614, 651, 671, 673.

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Myofascial trigger point handling for headache and TMD

Kerrie Bolton , Peter Selvaratnam , in Headache, Orofacial Pain and Bruxism, 2009

Levator scapulae

Arises from transverse process of C1–C2, posterior tubercles of transverse processes of C3–C4 vertebrae and attaches to the superior part of medial edge of the scapula. It elevates and rotates the scapula ( Moore et al 2002).

Trigger signal location

Levator scapulae may have MTPs at its mid-belly or located merely superior to its attachment at the superior angle of the scapula ( Fig. 23.9). Both can refer pain ipsilaterally over the posterolateral angle of the cervix. The lower MTP may occasionally refer pain inferiorly along the medial border of the scapula or along the distal border of the spine of the scapula to the posterior aspect of the shoulder (Simons et al 1999).

Palpatory examination

Direct palpation of levator scapulae is hard due to the overlying upper trapezius. The levator scapulae may be palpated in the prone or side-lying position with the affected side uppermost. In order to relax upper trapezius, the clinician supports the patient's ipsilateral elbow with one hand (while the patient's elbow is flexed to 90°), then passively elevates the shoulder girdle. Following this, the alphabetize or middle finger of the other hand palpates anteriorly under the border of the upper trapezius just above the superior bending of the scapula to place the distal attribute of the levator scapulae. The muscle is then followed superiorly until it disappears under the overlying muscles.

Additional considerations

In the authors' experience myofascial pain from levator scapulae tin can often reproduce pain in the subacromial region and limit shoulder summit. Similarly it can limit cervical rotation. If left untreated, MTPs in levator scapulae tin can go precursors for associated MTPs in the SCM and may pb to poor scapula command (Simons et al 1999). The shoulder girdle stabilizers also need to be assessed and treated to reduce the presence of chronic MTPs in levator scapulae.

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Winged Scapula Syndrome

Steven D. Waldman Doc, JD , in Atlas of Uncommon Hurting Syndromes (Third Edition), 2014

The Clinical Syndrome

Winged scapula syndrome is an uncommon cause of musculoskeletal pain of the shoulder and posterior breast wall. Caused by paralysis of the serratus anterior musculus, winged scapula syndrome begins as a painless weakness of the musculus with the resultant pathognomonic finding of winged scapula. As a upshot of dysfunction secondary to paralysis of the muscle, musculoskeletal hurting often results. Winged scapula syndrome is often initially misdiagnosed equally strain of the shoulder groups and muscles of the posterior breast wall because the onset of the syndrome oftentimes occurs afterwards heavy exertion, most usually subsequently carrying heavy backpacks. The syndrome may coexist with entrapment of the suprascapular nerve.

Trauma to the long thoracic nervus of Bong is almost often responsible for the development of winged scapula syndrome. Arising from the fifth, sixth, and seventh cervical nerves, the nervus is susceptible to stretch injuries and directly trauma. The nerve is often injured during first rib resection for thoracic outlet syndrome. Injuries to the brachial plexus or cervical roots as well may cause scapular winging, but usually in conjunction with other neurological findings.

The hurting of winged scapula syndrome is aching and is localized to the muscle mass of the posterior breast wall and scapula. The hurting may radiate into the shoulder and upper arm. The intensity of the hurting of winged scapula syndrome is mild to moderate, but information technology may produce meaning functional disability, which, if untreated, continues to exacerbate the musculoskeletal component of the pain.

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Supraglenoid Tubercle Fracture

Nick Carlson , in Comparative Veterinary Anatomy, 2022

Scapula (Fig. xiv.2-3)

The scapula is a wide, flat bone bisected on the lateral surface by the scapular spine. Noteworthy anatomic landmarks include the scapular cartilage, scapular spine, supraglenoid tubercle, coracoid process, and glenoid cavity. Unlike cats and dogs, the clavicle is absent-minded in the equus caballus. Horses likewise lack an acromion on the distal role of the scapula.

Image 1

The scapula has 4 centers of ossification: the torso of the scapula and the scapular cartilage (fused at birth), the cranial portion of the glenoid cavity of the scapula (fused at v months), and the supraglenoid tubercle (fused between 12 and 24 months).

Figure 14.2-3

Figure fourteen.2-three. Bones, joints, and bursae of the equine shoulder region: (A) lateral view and (B) cranial view.
Image 2

The virtually common fracture of the scapula is through the supraglenoid tubercle, commonly seen in younger animals (<

 

 ii years one-time) associated with directly trauma and a concurrent avulsion injury from the biceps. The goal of surgery to repair supraglenoid tubercle fractures is to restore congruity of the glenoid crenel. Depending on the size of the fragment, it tin be removed or repaired with cortical os screws. The supraglenoid tubercle is the origin of the biceps tendon and can place considerable tensile forces on fixations of these fractures. Other fractures seen are stress fractures of the body of the scapula in young racehorses, complete scapular trunk fractures, and fractures of the scapular spine.

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Musculoskeletal Diseases

Greg L.Chiliad. Harasen , Susan Due east. Little , in The Cat, 2012

Dorsal Scapular Luxation

The scapula is attached to the thoracic body wall by the serratus ventralis, rhomboideus, and trapezius muscles. Trauma incurred by falling from a height can cause partial or complete rupture of these muscles, which will displace the scapula, especially during weight-begetting activities. If these cats are presented acutely at that place will exist a not–weight-begetting lameness accompanied by pain and swelling betwixt the dorsal scapula and the body wall. Afterward a few days, this inflammation volition subside and the true cat volition brainstorm bearing weight. This produces an unusual gait considering the scapula is dorsally displaced with each footstep. Nearly cats will regain a reasonable degree of mobility, and if the true cat is non especially active, no further treatment need be undertaken. The true cat will, of course, retain the distinctive gait abnormality. If the owner is unsettled by the gait or feels that it represents a disability for the true cat, surgical stabilization can be undertaken. This consists of exploration of the dorsal attribute of the scapula and primary suturing of the torn muscles, where possible. In addition, 2 holes are drilled in the dorsocaudal area of the scapula and the scapula is attached in a normal position to an adjacent rib with nonabsorbable suture or surgical wire. Care must be taken that the thoracic cavity is not entered while passing the wire. The limb is then bandaged against the chest so it cannot be used for 2 weeks. 48

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Upper Limb

South. Jacob MBBS MS (Anatomy) , in Human Anatomy, 2008

Scapula – anterior aspect

The scapula ( Fig. 2.xiv), whose mobility is essential to facilitate the wide range of movements of the shoulder, is rarely fractured as the os is virtually completely encased in muscles. From the inductive attribute of the scapula (the costal surface) which covers the thoracic cage the subscapularis muscle originates. The surface is marked by ridges for the attachment of gristly septae of this multipennate muscle. The serratus inductive muscle which moves the scapula forward (protraction of scapula) is inserted on the medial margin on the costal surface. The glenoid fossa, seen at the lateral aspect in the upper part, faces frontward also as laterally. Higher up this is the acromion which is the uppermost bony point in the shoulder region. The coracoid process projecting anteriorly receives the attachments of 3 muscles, i.eastward. brusque head of biceps, coracobrachialis and the pectoralis small-scale. The coracoclavicular and the coracoacromial ligaments are also fastened to the coracoid process.

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Organ Evolution

Mariel Young , ... Terence D. Capellini , in Current Topics in Developmental Biology, 2019

2.ane Embryonic and fetal scapula evolution

The scapula is forms from multiple progenitor cell populations from different tissue layers—a rare characteristic amongst appendicular bones, most of which derive from only i tissue layer or progenitor cell population. The scapula has contributions from the dermomyotome (a dorsolateral derivative of the somite), somatopleure (somatopleuric derivative of the lateral plate mesoderm plus inner ectoderm), and neural crest (migratory pluripotent cells delaminated from the dorsal neural tube) ( Durland, Sferlazzo, Logan, & Burke, 2008; Huang, Christ, & Patel, 2006; Huang, Zhi, Patel, Wilting, & Christ, 2000; Matsuoka et al., 2005). The dermomyotome gives ascension to the scapula blade and proximal scapula spine, whereas the somatopleure gives rise to the glenoid fossa, coracoid, acromion, structures of the scapula neck, head, and spine, although the extent to which each of these progenitor tissues contribute to the scapula varies across species (Durland et al., 2008; Ehehalt, Wang, Christ, Patel, & Huang, 2004; Huang et al., 2000; Malashichev, Christ, & Pröls, 2008; Valasek et al., 2010). Matsuoka et al. (2005) additionally demonstrated in mice that post-otic neural crest cells contribute to the scapular blade's superior edge, spine/acromion, and coracoid process.

The complication of the dermomyotomal origin of the scapula blade is underscored by the complex system of the dermomyotome itself, and how information technology is pre-patterned and differentiates during somitogenesis. Early in somitogenesis, a partially overlapping three′ Hox expression domain is suggested to pre-pattern or specify (scapula) pre-dermomyotomal cells in the undifferentiated somite to become blade progenitors (Huang et al., 2006). Indeed, information technology appears that just specific hypaxial dermomyotomal cells of the brachio-thoracic region (somites 17–24 in chick) give rise to superior/inferior domains of the scapula bract and spine (Huang et al., 2006, 2000) and that such cells patently do not mix from 1 axial level to the next (Ehehalt et al., 2004; Huang et al., 2000). When these somites are ablated the scapula blade is also absent-minded (Malashichev et al., 2008). Importantly, at this stage, dermomyotomal cells from the cervical region likewise appear incapable of forming scapular elements, indicating that the brachio-thoracic dermomyotome is pre-patterned with the intrinsic ability to grade the scapula blade (Ehehalt et al., 2004). These findings support a pre-patterning mechanism, although evidence for a straight role of a Hox code is weak (run across beneath) and needs further testing.

Presently later on this pre-patterning stage, the dermomyotome proper forms as a dorsal subdivision of the somite (Gilbert, 2000) and further subdivides into an epaxial domain situated dorsal-medially and a hypaxial domain located ventral-laterally (Burke & Nowicki, 2003; Cheng, Alvares, Ahmed, El-Hanfy, & Dietrich, 2004). Here, dermomyotomal differentiation occurs nether distinct regulatory inputs: in the epaxial domain, regulatory signals arise from the notochord and neural tube, whereas in the hypaxial region signals arise from the adjacent and more lateral plate mesoderm (Chiang et al., 1996; Ehehalt et al., 2004; Huang et al., 2006, 2000; Rong, Teillet, Ziller, & Le Douarin, 1992; Teillet, Lapointe, & Le Douarin, 1998). The hypaxial region appears important for blade differentiation since ablation of epaxial tissues results in normally patterned scapula blades (Teillet et al., 1998), whereas inhibition of signaling from the lateral plate mesoderm blocks scapula germination (Wang et al., 2005).

Once hypaxial dermomyotomal cells take been specified as scapular progenitors, additional signaling from the ectoderm and somatopleure is critical for dermomyotomal maturation, migration, and differentiation into prechondrogenic scapular mesenchyme. Based on the work of Moeller (2003), Rodríguez-Niedenführ, Dathe, Jacob, Pröls, and Christ (2003), and Ehehalt et al. (2004), Wang et al. (2005) argued that ectodermal WNT signaling into the hypaxial dermomyotome is disquisitional for keeping cells in an undifferentiated epithelial country and that the cessation of such signals, which occurs normally in a cranial-to-caudal sequence during somitogenesis, leads to their differentiation into mesenchyme, an initial step into forming scapula cartilages. However, while Huang et al. (2000) demonstrated that only brachio-thoracic dermomyotome cells are capable of forming scapula bract condensations, Ehehalt et al. (2004) found that the ectoderm overlying the cervical region is able to back up ectopic brachio-thoracic dermomyotome to form scapular mesenchymal and cartilage condensations. This finding suggests that signaling by the ectoderm (e.thou., possibly by WNTs) might exist responsible for inducing later, scapular mesenchymal- and/or cartilage-like fates, or that information technology plays an earlier, unappreciated role in pre-patterning cells to become scapular bract tissues. Additionally, during the transition to dermomyotomal mesenchyme, bone morphogenetic poly peptide (BMP) signaling from the somatopleure facilitates the expression of early scapula progenitor marking genes, such as Pax1 (Wang et al., 2005), while blocking or inhibiting BMP signaling in this domain in chick results in the downregulation of Pax1 and the absence of the scapula blade.

The extent to which the dermomyotome contributes to the scapula blade across tetrapods remains quite unclear. In mice, fate-mapping experiments using Prx1-Cre/Z/AP and Pax3-Cre/R26RYFP reveal that dermomyotome cells give ascension to but the vertebral border of the scapula bract and minor parts of the spine and acromion (Durland et al., 2008; Valasek et al., 2010). Almost blade regions are formed from the somatopleure, every bit is most of the head and neck, while the spine and acromion take been shown to have a neural crest cell contribution (run across below) (Durland et al., 2008; Huang et al., 2006; Matsuoka et al., 2005; Valasek et al., 2010). This departure betwixt chick and mouse appears to reflect the differential growth of the somatopleuric portion of the blade during mouse scapulogenesis (Shearman, Tulenko, & Shush, 2011; Valasek et al., 2010).

Regardless of the extent to which diverse embryonic tissues contribute to the scapula, the resulting jail cell populations become integrated into one mesenchymal condensation by embryonic day (Due east) eleven.5 in mice (homo E43), and into a conspicuously recognizable pre-cartilaginous scapula past E12.5 (homo E44) located adjacent to the forelimb bud at the brachio-thoracic-axial level (Durland et al., 2008; Hita-Contreras et al., 2018; Huang et al., 2006, 2000; Young & Capellini, 2015). Recent analysis by Hita-Contreras et al. (2018) has shown that this mesenchymal condensation has multiple outgrowths: ane each for the scapular body, coracoid process, and the acromion and spine. These findings concur with Capellini et al. (2010) assessment using 3D Optimal Projection Tomography of the boundaries of Sox9 expression, a marker of mesenchymal condensation formation. Subsequently, this mass shifts caudally to its final position posterior at the thorax, such that by human embryonic solar day 44 (E12.5–13 in mouse) it is positioned lateral to or behind the ribs, depending on the species (Bardeen & Lewis, 1901; O'Rahilly & Gardner, 1972).

Following this patterning stage, the chondrogenesis phase of bone formation begins at E12.v in mice or the 6th gestational calendar week in humans (Monkhouse, 1996). Like nearly all appendicular elements, the scapula forms via endochondral ossification (Karsenty & Wagner, 2002), in which the mesenchymal condensation that prefigures scapular morphology begins to differentiate into chondrocytes by secreting a collagen matrix consisting of types 2, Nine, and Xi collagen, equally well as proteoglycans (Long & Ornitz, 2013). The chondrocytes dissever and differentiate, forming growth plates that ultimately elongate to course a well-nigh complete chondrocyte replica of the osseous scapula. During later on embryonic gestation in mice (E15.five) or the second gestational calendar month in humans (Andersen, 1963; Mall, 1906; Monkhouse, 1996; unpublished results from the Capellini laboratory), this cartilaginous scapula is invaded past blood vessels and osteoblasts assuasive for the appearance of a single primary ossification heart in the scapular neck region, which then facilitates bone formation (Long & Ornitz, 2013). Ossification typically extends bidirectionally across the blade medially and toward the glenohumeral articulation laterally (Scheuer, Black, & Christie, 2000), reaching the base of operations of the spine by gestational week 9 in humans (equivalent to E18.5 in mice) and the glenoid by gestational week 12 (P02 in mice) (Andersen, 1963; Ogden & Phillips, 1983).

During this flow, mail-otic neural crest cells likewise contribute to the scapula, specifically to endochondral and perichondrial tissues of the superior border, spine/acromion, and coracoid process, likewise equally to the connective tissues of the muscles inserting into these structures (Matsuoka et al., 2005). Sox10-Cre ROSA GFP   + cells contribute specifically the endochondral and perichondrial tissues of these structures and past doing and so they provide, and help anchor, major attachment regions for the branchial muscles (e.g., the trapezius). This process occurs later on the initial patterning of scapula progenitors in early on fetal development.

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The True cat

Gerardo De Iuliis PhD , Dino Pulerà MScBMC, CMI , in The Autopsy of Vertebrates (Third Edition), 2019

Scapula

The scapula , or shoulder bract (Figure 7.17a–b), is a flat, triangular bone. Its medial surface is nearly apartment, whereas its lateral surface has a prominent scapular spine. Examine a mounted skeleton, and note that the apex of the scapula is directed ventrally. Place the scapula's anterior, dorsal, and posterior borders. The glenoid fossa is the smooth, concave surface at the apex for articulation with the humerus. The frail coracoid process projects medially from the anterior margin of the glenoid fossa and is the site of origin for the coracobrachialis muscle.

The medial surface bears the subscapular fossa. It is relatively flat, with a few prominent scar ridges indicating tendinous muscular insertions. Notation the prominent ridge near the posterior border that demarcates a narrow, slightly concave surface for muscular zipper. On the lateral surface, the scapular spine rises prominently and separates the supraspinous fossa anteriorly from the infraspinous fossa posteriorly, both of which are fairly smooth surfaces. Ventrally the spine ends in the acromion procedure. Just dorsal to the acromion process is the posteriorly projecting metacromion process.

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