which cranial nerve controls the trapezius and sternocleidomastoid muscles?

Dissection should be carried out until the eleventh nerve trunk is identified. Lorenzo Crumbie MBBS, BSc Oxford, England (6th edition): Churchill Livingstone. Cranial Nerves This assesses the power of the sternocleidomastoid muscle. 3 Which cranial nerves affect swallowing? Contraction of the muscle gives rise to a condition called torticollis or wry neck, and this can have a number of causes. Once you've finished editing, click 'Submit for Review', and your changes will be reviewed by our team before publishing on the site. This article was most recently revised and updated by, https://www.britannica.com/science/cranial-nerve, University of Washington - Cranial Nerves, Verywell Health - The Anatomy of the Cranial Nerves, National Library of Medicine - Neuroanatomy, Cranial Nerve. The t-tubule meets with the sarcoplasmic reticulum at locations throughout the muscle fiber, at these locations the sarcoplasmic reticulum releases calcium ions that results in the movement of troponin and tropomyosin on thin filaments. The accessory nerve (Fig. Oculomotor nerve: Ability to move and blink your eyes. It is classified as the eleventh of twelve pairs of cranial nerves because part of it was formerly believed to originate in the brain. Actions Lateral flexion and rotation of the neck when acting unilaterally, and extension of the neck at the atlanto-occipital joints when acting bilaterally. This nerve supplies the sternocleidomastoid and trapezius muscles, which have the following functions: Rotation of head away from the side of the contracting sternocleidomastoid muscle. Furthermore, patients may have trouble performing basic activities of daily living that require elevation of the shoulder, as they experience varying degree of weakness depending on the extent of the injury. Once the nerve is found, we dissect the surrounding tissue distally and proximally to expose the nerve trunk completely. As the trapezius muscle has an extensive vascular supply, it can be used as a site for musculocutaneous tissue flap harvesting for reconstructive purposes in other areas of the body, such as for breast reconstruction. Key Points The cranial nerves serve functions such as smell, sight, eye movement, and feeling in the face. Sternocleidomastoid muscle To find out more, read our privacy policy. You also have the option to opt-out of these cookies. Other causes are diabetes, vitamin B12 deficiency, and tumours. nerve Updates? The sternocleidomastoid muscle is generally considered to have nerve supply from the accessory nerve. Although the accessory nucleus receives bilateral cortical projection, they still can present with unique symptoms following hemispheric injuries. The joint may become stiff and difficult to mobilize with both active and passive maneuvers. Nerve Spinal Portion: Travels upwards as the C1-C5/6 spinal root section join together and exit out the jugular foramen, with the cranial portion. Cranial nerve Copyright Assessment of the accessory nerve in the clinical setting can be quickly conducted by checking the muscle bulk, tone, and power. Palastanga, N., Field, D., & Soames, R. (1989). Get rid of shoulder and scapular pain by flossing. Cranial nerve XI innervates the motor function of the trapezius. Injury to the SAN causes varying degrees of disfunction to the Trapezius muscle and the Sternocleidomastoid muscle. Fig 2 Lateral view of the neck. This process involves a series of inductive events associated with progressive proliferation, differentiation, and migration of primitive nerve tissue. The function of the trapezius is to stabilize and move the scapula. However, it is more common to observe the nerve passing anterolaterally with respect to the internal jugular vein. The cookies is used to store the user consent for the cookies in the category "Necessary". In the original Bertrands technique, the peripheral main trunk of the eleventh nerve is completely exposed by sectioning the SCM with a large skin incision along the direction of the eleventh nerve. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. But opting out of some of these cookies may affect your browsing experience. These branches should be checked with electrical stimulation. These cookies will be stored in your browser only with your consent. Trapezius muscle (Musculus trapezius) -Yousun Koh, Superficial muscles of the back -Yousun Koh. Contraction of the stenocleidomastoid fibres turns the head to the opposite side, the net effect meaning that the head is turned to the side of the brain receiving visual information from that area. Instead, these fibers go on to join the upper fibers from the nucleus ambiguus that form CN X. The trapezius has many attachment points, extending from the skull and vertebral column to the shoulder girdle. Mediates sensation of sound, rotation, and gravity (essential for balance and movement). This cookie is set by GDPR Cookie Consent plugin. 4 What happens if cranial nerve 11 is damaged? Revisions: 18. Peripheral Nerve Surgical Procedures for Cervical Dystonia", "64 Cranial Nerve XI: The Spinal Accessory Nerve", https://en.wikipedia.org/w/index.php?title=Sternocleidomastoid_muscle&oldid=1159834521, Wikipedia articles incorporating text from the 20th edition of Gray's Anatomy (1918), Short description is different from Wikidata, Articles with unsourced statements from July 2021, Creative Commons Attribution-ShareAlike License 4.0. Muscle [caption id="attachment_9762" align="aligncenter" width="596"], [caption id="attachment_9763" align="aligncenter" width="457"]. What cranial nerve is responsible for shoulder shrug? Dimitrios Mytilinaios MD, PhD Available from: I give my consent to Physiopedia to be in touch with me via email using the information I have provided in this form for the purpose of news, updates and marketing. Gray's Anatomy: The anatomical basis of clinical practice (41tst ed.). A thorough medical and objective history should be carried out to determine the reasons for damage and the extent of the damage. According to their study, there are three main types of variations of innervation pattern to the SCM (Figure 28.13). The rootlets eventually coalesce to form a solitary nerve fiber known as the spinal accessory nerve. Along their course, all fibers of the trapezius converge laterally on the superior angle of the scapula to attach on their respective insertion points. These injuries can also be localized because there are specific symptoms associated with different segmental injuries. G.B.-12 is located directly posterior and inferior to the mastoid; S.I.-17 is also located on the level of the mandibular angle, but on the anterior border of the sternocleidomastoid muscle. The sternocleidomastoid muscle tilts and rotates the head, while the trapezius muscle, connecting to the scapula, acts to shrug the shoulder. Torticollis gives the appearance of a tilted head on the side involved. Laura Jean Shipley MD, in Pediatric Clinical Advisor (Second Edition), 2007, Tight SCM muscle, often with palpable, hard, olivelike mass in the midsection of the cervical muscle, Typically regresses by 4 to 6 months, leaving only contracture and fibrotic thickening of the involved muscle, Head tilt in the direction of the muscle involved with chin turned away from the contracted side, Later findings include facial asymmetry and plagiocephaly (flattening on affected side), Assess for other orthopedic abnormalities that may be associated with torticollis (e.g., congenital hip dysplasia), Assess for associated ophthalmologic and neurologic abnormalities, In Pediatric Clinical Advisor (Second Edition), 2007. The vagus nerve enervates the gut (gastrointestinal tract), heart and larynx. [7], Injury to the spinal accessory nerve commonly occurs during neck surgery, including neck dissection and lymph node excision. To learn more on the ways that nerves heal after injury watch the great 8 minutes video clip below, Get Top Tips Tuesday and The Latest Physiopedia updates, The content on or accessible through Physiopedia is for informational purposes only. There are usually 3 to 4 branches from the main trunk to the SCM. Grounded on academic literature and research, validated by experts, and trusted by more than 2 million users. Register now The sternocleidomastoid muscle originates from two locations: the manubrium of the sternum and the clavicle. Also while standing behind the patient, ask that they shrug their shoulders as the examining hands apply opposing downwards pressure. Attachments - Runs from the base of the skull and the spinous processes of the C7-T12 vertebrae tolateral third of the clavicle and the acromion of the scapula. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. glossopharyngeal nerve The clavicular origin of the sternocleidomastoid varies greatly: in some cases the clavicular head may be as narrow as the sternal; in others it may be as much as 7.5 millimetres (0.30in) in breadth. Reviewer: The ascending (lower) fibers are responsible for depression of the medial part of the scapula, and thus lowering the shoulder. This article incorporates text in the public domain from page 390 ofthe 20th edition of Gray's Anatomy (1918). Several researchers have published data that contradicts the existence of the cranial nuclei of the accessory nerve. The middle fibers adduct (retract) the scapula. This cookie is set by GDPR Cookie Consent plugin. Congenital torticollis can have an unknown cause or result from birth trauma that gives rise to a mass or tumor that can be palpated within the muscle. Access over 1700 multiple choice questions. Simply observing the patient may also reveal signs of muscle wasting in the sternocleidomastoid and trapeziusin cases of long-standing nerve damage. The spinal accessory nerve then leaves the posterior border of the sternocleidomastoid to enter the posterior triangle of the neck. WebThe spinal accessory nerve ( also called accessory nerve) is the eleventh cranial nerve (CN XI). Sternocleidomastoid Muscle The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. [7] The trapezius muscle controls the action of shrugging the shoulders, and the sternocleidomastoid the action of turning the head. Get instant access to this gallery, plus: Introduction to the musculoskeletal system, Nerves, vessels and lymphatics of the abdomen, Nerves, vessels and lymphatics of the pelvis, Infratemporal region and pterygopalatine fossa, Meninges, ventricular system and subarachnoid space. Cranial Nerves With a fine monopolar stimulation (1-5V, 5Hz, 0.2-0.5ms), the location of the eleventh nerve trunk is roughly confirmed by strong contractions of the trapezius muscle. The sternocleidomastoid muscle is tested by asking the patient to turn their head to the left or right against resistance. [5][6] It supplies only motor fibres. The accessory nerve is derived from the basal plate of the embryonic spinal segments C1C6. The patient's upper extremities should be otherwise relaxed. For this reason, the cranial part of the accessory nerve is considered as part of the vagus nerve. 1), named after Thomas Willis (Willis, 1965) cranial nerve XI, innervates the sternocleidomastoid (SCM) and trapezius muscles. These cookies ensure basic functionalities and security features of the website, anonymously. Others consider the spinal accessory nerve to carry general somatic efferent (GSE) information. As the spinal accessory nerve leaves the jugular foramen to enter the posterior triangle of the neck, it has a variable relationship to the internal jugular vein. two components). Reviewer: It then separates into ventral and dorsal thickened areas known as basal and alar plates. SCM: (i) ask the patient to flex the neck and resist the movement with a hand against the forehead; (ii) place a hand on the patient's right temple and ask the patient to turn the head to the right watch the left SCM. What would happen if there were nerve damage to the sternocleidomastoid? They write new content and verify and edit content received from contributors. After a signal reaches the accessory nerve nucleus in the anterior horn of the spinal cord, the signal is conveyed to motor endplates on the muscle fibers located at the clavicle. [9] The nerve is intentionally removed in "radical" neck dissections, which are attempts at exploring the neck surgically for the presence and extent of cancer. These are raised parts of the muscle that can be painful. Benign fibrosis of sternocleidomastoid (SCM) muscle, Most common cervical mass of infancy: Postulated to be muscular response to birth trauma or peripartum injury, Often diagnosed clinically without imaging, Ultrasound modality of choice when imaging required, Process entirely intramuscular (contained within SCM), without local invasion or inflammatory changes, Thick & short compared to contralateral SCM, Variable heterogeneity of lesion with loss of normal muscle architecture, Ranges from nearly homogeneous to markedly heterogeneous on US/CECT/MR, Variable internal vascularity within/about mass, No associated adenopathy or fluid collection, Contralateral occipital flattening (plagiocephaly), Treatment: Self-limited, usually resolves by 6 months of age, 90% fully recover with conservative treatment & physiotherapy, Surgery only in unusual cases when craniofacial asymmetry or refractory torticollis persists after 1 year, Jean-Pierre Barral, Alain Croibier, in Manual Therapy for the Cranial Nerves, 2009. Damage to the muscles may also result in an asymmetrical neckline. Trochlear nerve: Ability to move your eyes up and down or back and forth. After it exits from the skull through the jugular foramen, the accessory nerve runs along the deep surface of the sternocleidomastoid. Symptoms will depend on at what point along its length the nerve was severed. Lesions of the spinal root cause paralysis of the sternocleidomastoid and trapezius muscles. [5], Injury to the accessory nerve can result in neck pain and weakness of the trapezius muscle. This portion of the nucleus ambiguus is referred to as the cranial nucleus of the accessory nerve. The throwing action is a common manoeuvre in which the trapezius muscle is active, along with the deltoid muscle and the rotator cuff muscles. The formed nerve enters the skull through the foramen magnum, the large opening at the skull's base. Trigger points can develop for many reasons, including from exercise, inactivity, or working for prolonged periods with a poor posture or with your head down. Concepts about the course, function, and examination of the nerve will be addressed. Copyright Flexion of the neck by both sternocleidomastoid muscles. Peripheral Nerve Surgical Procedures for Cervical Dystonia, Caliot, Bousquet, Midy, & Cabanie, 1989; Caliot, Cabani, Bousquet, & Midy, 1984, nerve). This would leave no posterior triangle. Syringomyelia, brainstem tumors, or infarctions can give rise to these lesions. The main function of the trapezius is stabilizing the scapula in its anatomical place, as well as controlling it during movements of the shoulder and upper limb. Curated learning paths created by our anatomy experts, 1000s of high quality anatomy illustrations and articles. It is often ipsilateral to the lesion and may radiate along the upper back and neck. Anatomy and human movement: Structure and function. For completion, the other two columns form the nucleus of the hypoglossal nerve(general somatic efferent; CN XII) medially, and the special somatic efferent nuclei that innervate the derivatives of the derivatives of the pharyngeal arches. More rarely, the adjoining margins of the sternocleidomastoid and trapezius are in contact. Outside the cranium, the spinal part descends along the internal carotid arteryto reach the sternocleidomastoid muscle, which it innervates. Further points regarding lesions of the accessory nerve will also be included here. You need our trunk wall muscle anatomy chart! By continuing you agree to the use of cookies. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Anatomy, Head and Neck, Scalenus Muscle - StatPearls - NCBI Bookshelf. The parts of the trapezius include: Along with latissimus dorsi, the trapezius is the most superficial of the superficial extrinsic back muscles. The cervical plexus is a network of nerve fibres that supplies innervation to some of the structures in the neck and trunk. This means that the sternocleidomastoid is controlled by the brain on the same side of the body. What are the jumps called in show jumping? The cranial part , along with the cranial nerves 9 and 10, supplies innervation to the soft palate, larynx and pharynx. Reading time: 10 minutes. Read more. Click on the study unit below to continue learning and testing yourself! Some studies demonstrate that the rootlets that originate from the caudal part of the nucleus ambiguus do not join those of the spinal nucleus. Linea nuchalis superior ossis occipitalis. This makes it easier to identify all the motor nerves going to the SCM. The accessory nerve, also known as the eleventh cranial nerve, cranial nerve XI, or simply CN XI, is a cranial nerve that supplies the sternocleidomastoid and trapezius muscles. Contraction or contracture of the muscles of the neck causes the head to be tilted to one side. The most common cause of accessory nerve damage is iatrogenic. This cookie is set by GDPR Cookie Consent plugin. Cranial Nerves [4] Injury can cause wasting of the shoulder muscles, winging of the scapula, and weakness of shoulder abduction and external rotation.[5]. We use cookies to help provide and enhance our service and tailor content and ads. It begins in the central nervous system (CNS) and exits the cranium through a foramen. By visiting this site you agree to the foregoing terms and conditions. If you believe that this Physiopedia article is the primary source for the information you are refering to, you can use the button below to access a related citation statement. The 12 cranial nerves are pairs of nerves that start in different parts of your brain. What is accessory nerve disorder. While every effort has been made to follow citation style rules, there may be some discrepancies. The sternocleidomastoid muscles are responsible for turning the head while the trapezius muscles control the action of The following conditions may affect nerve function eg Pharyngo-cervical-brachial variant of Guillain-Barre-syndrome, Sandifer syndrome, Eagle-syndrome, Diphtheria (infection), Poliomyelitis or Tetanus (both situations that rarely can affect the XI nerve), botulism, and sarcoidosis. Use of acute brief low frequency electrostimulation eg TENS, has been found in some studies to be beneficial in axonal growth, Sling use several hours a day to help with pain management, Cervical PNF patterns extension to flexion with rotation and, Strengthening exercises for whole shoulder girdle with particular focus on Trapezius and SCM, Stretching of muscles, nerves and soft tissues in the shoulder and neck deemed necessary, Home exercise program individually tailored, Nerve surgery, nerve grafting, nerve regeneration, Tendon of muscle transfers to stabilise scapular eg scapulothoracic fusion. Figure 28.13. It can be felt on each side of the neck when a person moves their head to the opposite side. 6 Where does the cranial nerve XI originate from? The patient's upper extremities should be otherwise relaxed. This technique can be used as an adjunct to other peripheral surgical procedures in patients with marked laterocollis and dystonic elevation and anteversion of the shoulder.

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