DOCSLIB.ORG

The Anatomy of the Brachial Plexus As Displayed by Magnetic Resonance Imaging: Technique and Application

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Anatomy of the Brachial Plexus As Displayed by Magnetic Resonance Imaging: Technique and Application THE ANATOMY OF THE BRACHIAL PLEXUS AS DISPLAYED BY MAGNETIC RESONANCE IMAGING: TECHNIQUE AND APPLICATION James D. Collins, MD, Anthony C. Disher, MD, and Theodore Q. Miller, MD Los Angeles, California Full field of view coronal chest magnetic magnetic resonance angiography (MRA) se- resonance imaging (MRI) routinely displays quences were obtained in selected patients. bilateral images of the brachial plexus, surface Coronal, transverse, and sagittal sequences anatomy, and anatomic structures. Eighty pa- were reformatted for evaluation. Saline water tients had chest radiographs correlated with bags were placed between the neck and thorax surgery for thoracic outlet syndrome. The PA to enhance the signal-to-noise ratio. Compro- chest film findings correlated with the surgical mising abnormalities of the brachial plexus findings: smaller thoracic inlet on the concave were confirmed at surgery. Compromise of the side of the cervicothoracic spine scoliosis, neurovascular supply seemed to be one etiol- shorter distance between the dorsal spine of ogy that could be demonstrated. The clinical the second or third thoracic vertebral body to history, technique, and anatomic bilateral bra- the concavity of the first ribs, asymmetric chial plexus imaging is stressed to improve clavicles and coracoid processes, synchon- patient care. The cervical rib is one of the drosis of the first and second ribs, and muscle compromising brachial plexopathies selected atrophy on the side of the clinical complaints. for this presentation. (J Nat! Med Assoc. More than 235 patients were imaged. One 1 995;87:489-498.) hundred sixty-five of these were imaged with a 1.5-T unit and 3-D reconstruction MRI. Coronal, Key words * anatomy * brachial plexopathy transverse (axial), oblique transverse, and sag- * nerve model * MRI * pathology ittal plane Ti-weighted, selected T2-weighted, * 3-D color reconstruction and fast spine echo pulse sequences were obtained, 4- to 5-mm slice thickness, 40 to 45 Conventional roentgenography, linear tomography, cm full field of view, 512x256 matrix and 2 computerized tomography (CT), and magnetic reso- NEX. Two-dimensional time of flight (2D TOF), nance imaging (MRI) are radiographic modalities used to image the thorax, shoulder girdle, and soft tissues. I Vascular structures, surface anatomy, and From the Department of Radiological Sciences, UCLA School the soft tissues are incompletely imaged by conven- of Medicine, and the Department of Radiology, Charles R. Drew Postgraduate School of Medicine, Los Angeles, California. tional radiographic techniques. Computerized to- Presented at the 10th Annual Meeting of the American mography extends the capabilities of radiographic Association of Clinical Anatomists, June 17, 1993, Seattle, imaging to obtain detailed transverse (axial) ana- Washington; the 98th Annual Convention and Scientific Assem- bly of the National Medical Association, August 9, 1993, San tomic sections but CT does not definitively separate Antonio, Texas; and the Sunderland Society, September 22, tumors from vascular and neurovascular structures. 1993, Seattle, Washington. Address reprint requests to Dr tomography reconstructed imaging of James D. Collins, UCLA School of Medicine, Dept of Radiologi- Computed cal Sciences, 10833 Le Conte Ave, Los Angeles, CA 90024- soft-tissue anatomy is not satisfactory, and detailed 1721. peripheral nerve imaging is not possible. Magnetic JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 87, NO. 7 489 BRACHIAL PLEXUS The brachial plexus lies within the fascial planes of the neck and axilla, but is routinely displayed on MRI of the thorax and shoulder girdle.' Magnetic resonance multiplane imaging in the supine position allows bilateral sequential imaging of the thorax and the brachial plexus. This is the feature that gave us the opportunity to image the brachial plexus anatomy. construct 3-D color images, and present the anatomy and compromising abnormalities of the brachial plexus as displayed by MRI.2'7 Compromising abnormalities of the brachial plexus and brachial plexopathies result from disorders of the cervicothoracic levels of the vertebral column, the first rib, vascular supply, and soft tissues.8,9 The anterior and middle scalene muscles, through which the brachial plexus nerve roots pass and adhere to the subclavian artery, arise from the cervicothoracic levels of the me vertebral column. The muscles insert and, in part, support the first ribs. The first ribs are curved, flat, and slope obliquely to form most of the thoracic inlet. The slope that gives an anterosuperior directed upper surface changes with respiration and cervicothoracic spine scoliosis, and affects structures crossing the rib. The anterior scalene muscle and the posterior insertion of middle scalene muscle and the first ribs form the scalene triangle. The change in the slope of the first rib Figure 1. Cadaver dissection demonstrating the "M" or "W" of affects the interscalene triangle contents.2'5 The scalene the left brachial plexus. Legend: lateral cord (2 bar white are an arrows), brachial artery (BrA), median nerve (Me), musculo- muscles important visual anatomic landmark in cutaneous nerve (Mu), ulnar nerve (Ul), medial branch of the the understanding of brachial plexopathy displayed by lateral cord of Mu (black single bar arrow), and lateral branch of MRI. the medial cord forming the median nerve (Me). The upper nerve roots of the brachial plexus descend along the margin of the middle scalene muscle and join resonance imaging separates proton densities within the lower nerve roots to envelope the subclavian artery. organ systems and does not require reconstruction or The nerve roots bind to the artery within the scalene repositioning of the patient. The multi-planer MRI triangle to form a neurovascular bundle.'0 This bundle displays the anatomy of the brachial plexus and passes with sympathetic fibers unprotected over the peripheral nerves for investigation by sequential first rib through the scalene triangle, beneath the imaging of landmark anatomy according to proton clavicle and subclavius muscle, inferior to the coracoid density distribution.2 process and posterior to the tendon of the pectoralis The anatomy of the brachial plexus and peripheral minor muscle into the axilla. nerves are graphically displayed in classical text- The subclavian artery, similar to the artery within the books.3'4 Anatomic and clinicopathologic nerve studies femoral triangle, is unprotected4'8 but is not routinely allow investigative radiological studies using MRI to go cannulated for vascular studies. Different from the beyond textbook descriptions.5'6 Bilateral brachial femoral artery, a muscle (the anterior scalene muscle) plexus and peripheral nerve 3-D reconstruction imaging separates the subclavian vein from the subclavian makes possible demonstration of the relationship of artery. This makes the anterior scalene muscle an nerves to their surrounding landmark anatomy (Figure important anatomic landmark in determining compres- 1). The knowledge of peripheral nerve and brachial sion (effacement) of the scalene triangle contents. plexus anatomic imaging offers new avenues for Enlargements of the anterior scalene muscle or atrophy teaching medical students, residents, and health profes- of the anterior scalene muscle increases or decreases the sionals. I distance between the subclavian artery and the sub- 490 JOURNAL OF THE NATIONAL MEDICAL ASSOCIATION, VOL. 87, NO. 7 BRACHIAL PLEXUS clavian vein as demonstrated on transverse MRI The signal-to-noise ratio decreases with FSE imag- sequences.2 This distance may be measured on the first ing, causing decreased contrast and resolution of the image or raw data of the magnetic resonance angiogra- images. The low-signal intensities of flowing blood and phy (MRA) 2-D time of flight (TOF) of the brachial the high-signal intensities of myelin combine to vary plexus.' the high signal intensity of nerves. The signal intensity A thin layer of deep fascia envelopes the neurovascu- of nerves then may depend on the imaging axis of that lar bundle of the upper limb. Four spaces are formed nerve.' The combination of a rich blood supply to the from the root of the neck to the lower part of the axilla. spinal cord and cerebral spinal fluid results in the The spaces that may have clinical problems that intermediate-signal intensity of the spinal cord. Nerve compromise the brachial plexus8 include the interverte- roots may have high-signal intensities after they exit bral foramina, scalene triangle, costoclavicular, costo- from the subarachnoid space. The low-signal intensity coracoid, and the axilla. In most individuals, the fascial vertical bands of nutrient vessels may interrupt the plane spacing between soft tissues and osseous struc- high-signal intensity of nerves.2,10,14.15 Compression tures is adequate to perform routine functions without injuries of nerves involve an ischemic component and compromising the nerves and the artery that combine to alter blood supply. Ischemia initiates inflammatory form the neurovascular bundle. Pathology involving changes causing edema and fibrosis. Inflammation and peripheral nerves alters fascial planes. Acute or perma- edema diminishes the signal intensity of nerves and nent changes may alter the adjacent tissues, thereby alters their architecture when compromised in autoim- compromising the vascular supply that nourishes the mune disease.12 peripheral nerves.2 5 6 This results in patients presenting Bilateral imaging of the brachial plexus
Load more

Recommended publications
  • Respiratory Function of the Rib Cage Muscles
    Copyright @ERS Journals Ltd 1993 Eur Respir J, 1993, 6, 722-728 European Respiratory Journal Printed In UK • all rights reserved ISSN 0903 • 1936 REVIEW Respiratory function of the rib cage muscles J.N. Han, G. Gayan-Ramirez, A. Dekhuijzen, M. Decramer Respiratory function of the rib cage muscles. J.N. Han, G. Gayan-Ramirez, R. Respiratory Muscle Research Unit, Labo­ Dekhuijzen, M. Decramer. ©ERS Journals Ltd 1993. ratory of Pneumology, Respiratory ABSTRACT: Elevation of the ribs and expansion of the rib cage result from the Division, Katholieke Universiteit Leuven, co-ordinated action of the rib cage muscles. We wished to review the action and Belgium. interaction of the rib cage muscles during ventilation. Correspondence: M. Decramer The parasternal intercostal muscles appear to play a predominant role during Respiratory Division quiet breathing, both in humans and in anaesthetized dogs. In humans, the para­ University Hospital sternal intercostals act in concert with the scalene muscles to expand the upper rib Weligerveld 1 cage, and/or to prevent it from being drawn inward by the action of the diaphragm. B-3212 Pellenberg The external intercostal muscles are considered to be active mainly during inspira­ Leuven tion, and the internal intercostal muscles during expiration. Belgium The respiratory activity of the external intercostals is minimal during quiet breathing both in man and in dogs, but increases with increasing ventilation. In­ Keywords: Chest wall mechanics contractile properties spiratory activity in the external intercostals can be enhanced in anaesthetized ani­ rib cage muscles mals and humans by inspiratory mechanical loading and by col stimulation, rib displacement suggesting that the external intercostals may constitute a reserve system, that may be recruited when the desired expansion of the rib cage is increased.
    [Show full text]
  • Relation of Roots and Trunks of Brachial Plexus to Scalenus Anterior Muscle and Its Clinical Significance
    IOSR Journal of Dental and Medical Sciences (IOSR-JDMS) e-ISSN: 2279-0853, p-ISSN: 2279-0861. Volume 11, Issue 4 (Nov.- Dec. 2013), PP 03-05 www.iosrjournals.org Relation of roots and trunks of brachial plexus to scalenus anterior muscle and its clinical significance Yogesh1, Viveka S2, Sudha M J3, Santosh Kumar S.C4, Sanjay Revankar5 1Assistant Professor, Department of Anatomy, Shridevi Institute of Medical Sciences & Research Hospital, Tumkur 2Assistant Professor, Department of Anatomy, Azeezia Institute of Medical Sciences, Kollam 3Assistant Professor, Department of Pharmacology, Azeezia Institute of Medical Sciences, Kollam 4 Department of Pharmacology, Shridevi Institute of Medical Sciences & Research Hospital, Tumkur 5Post graduate, Department of Anatomy, A J Institute of Medical Sciences, Mangalore. Abstract: Variations in the structures at the root of neck are important in understanding many clinical and surgical conditions. Scalenus anterior, the key muscle in the neck, usually related to the roots of brachial plexus in its posterior aspect. This study was designed to evaluate the relations of roots of brachial plexus to the scalene muscles. Posterior triangles of neck on both sides were studied in 24 cadavers. In two cases C5 and C6 pierced scalenus anterior muscle and emerged from its anterior surface. In other specimen roots of C5, C6 and C7 entered scalenus muscle and exited anterolateraly in a sequential manner. Knowledge of such variations is important for anaesthetists and surgeons. Key words: Scalenus anterior; Scalenus medius; roots of brachial plexus; variations I. Introduction Brachial plexus is formed by union of ventral rami of lower four cervical nerves and first thoracic nerve.
    [Show full text]
  • Hyperfunctional Laryngeal Conditions: Muscle Tension
    Karen Drake MA, CCC-SLP Linda Bryans MA, CCC-SLP Jana Childes MS, CCC-SLP Identify disorders that can be classified as hyperfunctional laryngeal conditions Describe how laryngeal hyperfunction can contribute to dysphonia, chronic cough and paradoxical vocal fold motion (PVFM) Describe how treatment may be modified to better address these interrelationships 2 3 “MTD can be described as the pathological condition in which an excessive tension of the (para)laryngeal musculature, caused by a diverse number of etiological factors, leads to a disturbed voice.” ◦ Van Houtte, Van Lierde & Claeys (2011) Descriptive label Multiple etiological factors Diagnosed by specific findings on videostroboscopy Voice therapy is the treatment of choice – supported by a joint statement of the AAO and ASHA in 2005 Hoarseness Poor vocal quality Vocal fatigue Increase voicing effort/strain Difficulty with projection Inability to be understood over background noise or the telephone Voice breaks Periods of voice loss Sore throat Globus sensation Throat clearing Pressure, tightness or tension Tenderness Difficulty getting a full breath Running out of air with speaking Difficulty swallowing secretions Disturbed Altered tension of Changed position inclination of extrinsic muscles of larynx in neck cartilaginous structures Tension of intrinsic Voice disturbance musculature Van Houtte, Van Lierde & Claeys (2011) Excess jaw tension Lingual posture and/or tension Altered resonance focus Breath holding Poor coordination of breath and voice Pharyngeal
    [Show full text]
  • Muscular and Skeletal Changes in Cervical Dysphonic in Women
    Original Article Muscular and Skeletal Changes in Cervical Dysphonic in Women Alterações Musculares e Esqueléticas Cervicais em Mulheres Disfônicas Laiza Carine Maia Menoncin*, Ari Leon Jurkiewicz**, Kelly Cristina A. Silvério***, Paulo Monteiro Camargo****, Nathália Martii Monti Wolff*****. * Master in Communication Disorders at the University Tuiuti. Physiotherapist. ** PhD, UNIFESP. Professor of the Masters Program in Communication Disorders at the University Tuiuti. *** Doctor Unicamp. Professor, Master’s and Doctoral Program in Communication Disorders at the University Tuiuti. **** PhD in Clinical - Surgical UFPR. Head of the Department of Laryngology of the Hospital Angelina Caron. ***** Medical. ENT resident. Institution: University of Tuiuti Curitiba. Curitiba / PR - Brazil. Mail Address: Nathan Wolff Monti Martini - Sector Master Program in Communication Disorders - Rua Sydnei A. Rangel Santos, 238 - Curitiba / PR - Brazil - Zip code: 82010-330 - Telephone: (+55 41) 3331-7700 - E-mail: [email protected] Article received on June 14, 2010. Approved on 1 October 2010. SUMMARY Introduction: The vocal and neck are associated with the presence of tension and cervical muscle contraction. These disorders compromise the vocal tract and musculoskeletal cervical region and, thus, can cause muscle shortening, pain and fatigue in the neck and shoulder girdle. Objective: To evaluate and identify cervical abnormalities in women with vocal disorders, and neck pains comparing them to women without vocal complaints independent of the neck. Method: This prospective study of 32 subjects studied in the dysphonic group and 18 subjects in the control group, aged between 25 and 55 year old female. The subjects underwent assessments, ENT, orthopedic, physical therapy and voice recording. Results: At Rx cervical region more patients in the control group had this normal, however, with regard to the reduction of spaces interdiscal dysphonic patients prevailed.
    [Show full text]
  • Levator Scapulae Muscle Asymmetry Presenting As a Palpable Neck Mass: CT Evaluation
    Levator Scapulae Muscle Asymmetry Presenting as a Palpable Neck Mass: CT Evaluation Barry A. Shpizner1 and Roy A . Hollida/ PURPOSE: To define the normal CT anatomy of the levator scapulae muscle and to report on a series of five patients who presented with a palpable mass in the posterior triangle due to asymmetry of the levator scapulae muscles. PATIENTS AND METHODS: The contrast-enhanced CT examinations of the neck in 25 patients without palpable masses were reviewed to es tablish the normal CT appearance of the levator scapulae muscle. We retrospectively reviewed the contrast-enhanced CT examinations of the neck in five patients who presented with a palpable mass secondary to asymmetric levator scapulae muscles . RESULTS: In three patients who had undergone unilateral radical neck dissection, hypertrophy of the ipsi lateral levator scapulae muscle was found. In one patient, the normal levator scapulae muscle produced a fa ctitious "mass" due to atrophy of the contralateral levator scapulae muscle. One patient had an intramuscular neoplasm of the levator scapulae. CONCLUSION: Asymmetry of the levator scapulae muscles , an unusual cause of a posterior triangle mass, can be diagnosed using CT. Index terms: Neck, muscles; Neck, computed tomography AJNR 14:461-464, Mar/ Apr 1993 The levator scapulae muscle can be identified between January 1987 and March 1991 were reviewed. A ll readily on axial images by its characteristic ap­ patients presented with a palpable mass in the posterior pearance and its relationship to the other muscles triangle of the infrahyoid neck. The patients, three men forming the boundaries of the posterior triangle.
    [Show full text]
  • Prevertebral Muscles (A, B) Scalene Muscles (A, B)
    80 Trunk Prevertebral Muscles (A, B) lift the first two pairs of ribs and thus the superior part of the thorax. Their action is The prevertebral muscles include the rec- increased when the head is bent backward. tus capitis anterior, longus capitis, and lon- Unilateral contraction tilts the cervical gus colli. column to one side. Occasionally there is a The rectus capitis anterior (1) extends scalenus minimus which arises from the from the lateral mass of the atlas (2) to the seventh cervical vertebra and joins the basal part of the occipital bone (3). It helps scalenus medius. It is attached to the apex to flex the head. of the pleura. Nerve supply: cervical plexus (C1). The scalenus anterior (17) arises from the The longus capitis (4) arises from the ante- anterior tubercles of the transverse Trunk rior tubercles of the transverse processes of processes of the (third) fourth to sixth cervi- the third to sixth cervical vertebrae (5). It cal vertebrae (18) and is inserted on the runs upward and is attached to the basal anterior scalene tubercle (19) of the first rib. part of the occipital bone (6). The two longi Nerve supply: brachial plexus (C5 –C7). capitis muscles bend the head forward. The scalenus medius (20) arises from the pos- Unilateral action of the muscle helps to tilt terior tubercles of the transverse processes the head sideways. of the (first) second to seventh cervical Nerve supply: cervical plexus (C1 –C4). vertebrae (21). It is inserted into the 1st rib The longus colli (7) is roughly triangular in behind the subclavian artery groove and shape because it consists of three groups of into the external intercostal membrane of fibers.
    [Show full text]
  • Levator Claviculae: a Case Report and Review of the Literature
    Folia Morphol. Vol. 67, No. 4, pp. 307–310 Copyright © 2008 Via Medica C A S E R E P O R T ISSN 0015–5659 www.fm.viamedica.pl Levator claviculae: a case report and review of the literature M. Loukas1, A. Sullivan1, R.S. Tubbs2, M.M. Shoja3 1Department of Anatomical Sciences, School of Medicine, St. George’s University, Grenada, West Indies 2Section of Pediatric Neurosurgery, Children’s Hospital, Birmingham, AL, USA 3Tuberculosis and Lung Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran [Received 3 April 2008; Accepted 29 August 2008] The levator claviculae is an uncommon anatomical variant found in the poste- rior cervical triangle. In this report we present a 78-year-old man with this muscular variation, which was found during gross anatomical dissection. While sites of insertion and origin have been variable, in the present case the muscle originated from the left transverse processes of C3 and C4, and inserted onto the lateral third of the ipsilateral clavicle. Clinical considerations of this variant anatomy are of interest, as they may present in patients as a supraclavicular mass and may also mimic pathology on cross-sectional imaging. (Folia Morphol 2008; 67: 307–310) Key words: anatomy, neck, cervical, clavicle INTRODUCTION reports have been documented as well, although The levator claviculae is a very rare variation of these are much less common [3, 14]. The nerve sup- the cervical musculature, although it is observed reg- ply of the levator claviculae has been described as ularly in certain mammalian species [7, 14, 17]. It arising from a branch of the fourth cervical nerve lies in the posterior cervical triangle of the neck, usually and its blood supply as stemming from the ascend- arising from the transverse processes of the upper ing cervical artery [8, 11].
    [Show full text]
  • Seventh Cervical Nerve Perforating the Middle Scalene Muscle: a Possible Clinical and Surgical Application
    Original article http://dx.doi.org/10.4322/jms.ao041013 Seventh cervical nerve perforating the middle scalene muscle: a possible clinical and surgical application SILVA, A. T.1*, GAMA, H. V. P.1, SIQUEIRA, S. L.2, SALES, M. C.3, FRANCO, A. G.1 and CASAGRANDE, M. M.3 1Acadêmico do 5º ano de Medicina da Faculdade de Ciências Médicas de Minas Gerais, Monitor da disciplina de Anatomia, Departamento de Anatomia, Faculdade de Ciências Médicas de Minas Gerais – FCMMG, Alameda Ezequiel Dias, 275, Santa Efigênia, CEP 30130-110, Belo Horizonte, MG, Brazil 2Pós-doutor em Ciências e Técnicas Nucleares pela Universidade Federal de Minas Gerais – UFMG, Mestre e Doutor em Cirurgia pela UFMG, Professor Assistente da Disciplina de Anatomia da Faculdade de Ciências Médicas de Minas Gerais – FCMMG, Professor Adjunto de Cirurgia da Universidade Federal de Ouro Preto – UFOP, Departamento de Anatomia, Faculdade de Ciências Médicas de Minas Gerais – FCMMG, Alameda Ezequiel Dias, 275, Santa Efigênia, CEP 30130-110, Belo Horizonte, MG, Brazil 3Acadêmico do 4º ano de Medicina da Faculdade de Ciências Médicas de Minas Gerais, Monitor da disciplina de Anatomia, Departamento de Anatomia, Faculdade de Ciências Médicas de Minas Gerais – FCMMG, Alameda Ezequiel Dias, 275, Santa Efigênia, CEP 30130-110, Belo Horizonte, MG, Brazil *E-mail: [email protected] Abstract Introduction: In most of cases, the emergency of the nervous roots of the brachial plexus in the posterior cervical triangle occur between the anterior and middle scalene muscles. However, anatomic variations in the brachial plexus are not rare. Methods: In the laboratory of Human Anatomy of the “Faculdade de Ciências Médicas de Minas Gerais” 106 cadavers were dissected.
    [Show full text]
  • Suprahyoid and Infrahyoid Neck Overview
    Suprahyoid and Infrahyoid Neck Overview Imaging Approaches & Indications by space, the skull base interactions above and IHN extension below are apparent. Neither CT nor MR is a perfect modality for imaging the • PPS has bland triangular skull base abutment without extracranial H&N. MR is most useful in the suprahyoid neck critical foramen involved; it empties inferiorly into (SHN) because it is less affected by oral cavity dental amalgam submandibular space (SMS) artifact. The SHN tissue is less affected by motion compared • PMS touches posterior basisphenoid and anterior with the infrahyoid neck (IHN); therefore, the MR image basiocciput, including foramen lacerum; PMS includes quality is not degraded by movement seen in the IHN. Axial nasopharyngeal, oropharyngeal, and hypopharyngeal and coronal T1 fat-saturated enhanced MR is superior to CECT mucosal surfaces in defining soft tissue extent of tumor, perineural tumor • MS superior skull base interaction includes zygomatic spread, and dural/intracranial spread. When MR is combined with CT of the facial bones and skull base, a clinician can obtain arch, condylar fossa, skull base, including foramen ovale (CNV3), and foramen spinosum (middle meningeal precise mapping of SHN lesions. Suprahyoid and Infrahyoid Neck artery); MS ends at inferior surface of body of mandible CECT is the modality of choice when IHN and mediastinum are • PS abuts floor of external auditory canal, mastoid tip, imaged. Swallowing, coughing, and breathing makes this area including stylomastoid foramen (CNVII); parotid tail a "moving target" for the imager. MR image quality is often extends inferiorly into posterior SMS degraded as a result. Multislice CT with multiplanar • CS meets jugular foramen (CNIX-XI) floor, hypoglossal reformations now permits exquisite images of the IHN canal (CNXII), and petrous internal carotid artery canal; unaffected by movement.
    [Show full text]
  • Anatomy Module 3. Muscles. Materials for Colloquium Preparation
    Section 3. Muscles 1 Trapezius muscle functions (m. trapezius): brings the scapula to the vertebral column when the scapulae are stable extends the neck, which is the motion of bending the neck straight back work as auxiliary respiratory muscles extends lumbar spine when unilateral contraction - slightly rotates face in the opposite direction 2 Functions of the latissimus dorsi muscle (m. latissimus dorsi): flexes the shoulder extends the shoulder rotates the shoulder inwards (internal rotation) adducts the arm to the body pulls up the body to the arms 3 Levator scapula functions (m. levator scapulae): takes part in breathing when the spine is fixed, levator scapulae elevates the scapula and rotates its inferior angle medially when the shoulder is fixed, levator scapula flexes to the same side the cervical spine rotates the arm inwards rotates the arm outward 4 Minor and major rhomboid muscles function: (mm. rhomboidei major et minor) take part in breathing retract the scapula, pulling it towards the vertebral column, while moving it upward bend the head to the same side as the acting muscle tilt the head in the opposite direction adducts the arm 5 Serratus posterior superior muscle function (m. serratus posterior superior): brings the ribs closer to the scapula lift the arm depresses the arm tilts the spine column to its' side elevates ribs 6 Serratus posterior inferior muscle function (m. serratus posterior inferior): elevates the ribs depresses the ribs lift the shoulder depresses the shoulder tilts the spine column to its' side 7 Latissimus dorsi muscle functions (m. latissimus dorsi): depresses lifted arm takes part in breathing (auxiliary respiratory muscle) flexes the shoulder rotates the arm outward rotates the arm inwards 8 Sources of muscle development are: sclerotome dermatome truncal myotomes gill arches mesenchyme cephalic myotomes 9 Muscle work can be: addacting overcoming ceding restraining deflecting 10 Intrinsic back muscles (autochthonous) are: minor and major rhomboid muscles (mm.
    [Show full text]
  • Download the ECA VA 101 Handouts Here
    Vocal Anatomy 101 Handouts Why study vocal anatomy? “Because singing is movement, singers need and deserve training that creates an accurate body map, a fine-tuned kinesthetic sense, and the conscious use of inclusive awareness” -MaryJean Allen, from “What Every Singer Needs to Know About the Body” (Plural Publishing) Our vocal instruments are made up of 4 main elements: 1. Power Source (Breath/Airflow) This is what makes the parts of the instrument move. 2. Vibration Source (Vocal Folds) As air passes through our vocal folds, they vibrate, creating sound waves! This is where we control pitch. 3. Resonator Tube (Vocal Tract - throat, mouth, nose) The shape of our vocal tract affects the quality of sound we make (bright, dark, pointy, muted, round, warm, brassy, nasal, etc.) 4. Articulators (tongue/lips) These form the sounds to distinguish words. (Vowels and consonants!) POWER SOURCE: BREATH ● The primary muscle of breathing is the diaphragm, which is attached to the bottom of our rib cage. It is an involuntary muscle, and works all the time, without us even thinking about it! It engages and descends every time we inhale. It relaxes and ascends when we exhale. ● In addition to the diaphragm, upon inhalation, we use our external intercostal muscles to open the ribcage and increase volume in the thoracic cavity. ● The sternocleidomastoid and scalene muscles are secondary muscles of inhalation, but should probably be used sparingly while singing (avoid stress breath and neck tension!) ● The primary muscles of exhalation include the transverse abdominis (abs), the internal and external obliques(abs), the rectus abdominis (abs), the pelvic floor, and the internal intercostal muscles (ribs).
    [Show full text]
  • Positional Anomaly Between the Brachial Plexus and the Scalene Muscles, Concomitant with an Anomalous Path of the Musculocutaneous Nerve
    Int. J. Morphol., 38(4):845-852, 2020. Positional Anomaly Between the Brachial Plexus and the Scalene Muscles, Concomitant with an Anomalous Path of the Musculocutaneous Nerve. Case Report and Clinical Implication Anomalía Posicional entre el Plexo Braquial y el Músculo Escaleno Anterior, Concomitante con un Trayecto Anómalo del Nervio Musculocutáneo. Reporte de un Caso e Implicancia Clínica Emilio Farfán C.; Mark Echeverría M.; Verónica Inostroza R.; Daniela Schneeberger L. & Oscar Inzunza H. FARFÁN, C. E.; ECHEVERRÍA, M. M.; INOSTROZA, R. V.; SCHNEEBERGER, L. D. & INZUNZA, H. O. Positional anomaly between the brachial plexus and the scalene muscles, concomitant with an anomalous path of the musculocutaneous nerve. Case report and clinical implication. Int. J. Morphol., 38(4):845-852, 2020. SUMMARY: Anatomical variations of the scalene muscles are frequent, as are those of the brachial plexus and its terminal nerves. Nonetheless, these variations are reported separately in the literature. The aim of this work is to present a variation of scalene muscles, concomitant with an abnormal path of the musculocutaneous nerve. During a routine dissection of the cervical region, axilla and right anterior brachial region in an adult male cadaver, a supernumerary muscle fascicle was located in the anterior scalene muscle, altering the anatomical relations of C5 and C6 ventral branches of the brachial plexus. This variation was related to an anomalous path of the musculocutaneous nerve that did not cross the coracobrachialis muscle. It passed through the brachial canal along with the median nerve. It then sent off muscular branches to the anterior brachial region and likewise, communicating branches to the median nerve.
    [Show full text]