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30-537: The latissimus dorsi ( / l ə ˈ t ɪ s ɪ m ə s ˈ d ɔːr s aɪ / ) is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline. The word latissimus dorsi (plural: latissimi dorsi ) comes from Latin and means "broadest [muscle] of the back", from "latissimus" ( Latin : broadest ) and "dorsum" ( Latin : back ). The pair of muscles are commonly known as " lats ", especially among bodybuilders . The latissimus dorsi

60-484: A ligature, and may mislead a surgeon. It is present in about 7% of the population and may be easily recognized by the transverse direction of its fibers. Guy et al. extensively described this muscular variant using MRI data and positively correlated its presence with symptoms of neurological impingement. A fibrous slip usually passes from the upper border of the tendon of the Latissimus dorsi, near its insertion, to

90-415: A portion of the analogous muscle. The superior or upper (or descending) fibers of the trapezius originate from the spinous process of C7, the external occipital protuberance , the medial third of the superior nuchal line of the occipital bone (both in the back of the head), and the ligamentum nuchae . From this origin, they proceed downward and laterally to be inserted into the posterior border of

120-431: A procedure called cardiomyoplasty may support the failing heart. This procedure involves wrapping the latissimus dorsi muscles around the heart and electrostimulating them in synchrony with ventricular systole. Injuries to the latissimus dorsi are rare. They occur disproportionately in baseball pitchers. Diagnosis can be achieved by visualization of the muscle and movement testing. MRI of the shoulder girdle will confirm

150-412: A variety of different exercises. Some of these include: Tight latissimus dorsi has been shown to be a contributor to chronic shoulder pain and chronic back pain. Because the latissimus dorsi connects the spine to the humerus , tightness in this muscle can manifest as either sub-optimal glenohumeral joint (shoulder) function which leads to chronic pain or tendinitis in the tendinous fasciae connecting

180-439: Is connected to the bone by a thin fibrous lamina, firmly adherent to the skin. The superficial and deep epimysia are continuous with an investing deep fascia that encircles the neck and also contains both sternocleidomastoid muscles. At the middle, the muscle is connected to the spinous processes by a broad semi-elliptical aponeurosis , which reaches from the sixth cervical to the third thoracic vertebræ and forms, with that of

210-418: Is innervated by the radial nerve . Of the muscles that receive innervation from the radial nerve, it is one of only four that receive input directly from the radial nerve. The other three are the triceps , anconeus , and extensor carpi radialis longus . (All other posterior compartment muscles that receive radial innervation are supplied by the deep branch of the radial nerve .) The brachioradialis flexes

240-403: Is one of the commonly affected muscles in facioscapulohumeral muscular dystrophy (FSHD). The lower and middle fibers are affected initially, and the upper fibers are commonly spared until late in the disease. Although rare, underdevelopment or absence of the trapezius has been reported to correlate to neck pain and poor scapular control that are not responsive to physical therapy . Absence of

270-404: Is responsible for extension , adduction , transverse extension also known as horizontal abduction (or horizontal extension), flexion from an extended position, and (medial) internal rotation of the shoulder joint . It also has a synergistic role in extension and lateral flexion of the lumbar spine. Due to bypassing the scapulothoracic joints and attaching directly to the spine, the actions

300-420: The acromion and inferior angles move up and the medial border moves down (upward rotation). The upper and lower fibers work in tandem with serratus anterior to upwardly rotate the scapulae, and work in opposition to the levator scapulae and the rhomboids , which effect downward rotation. An example of trapezius function is an overhead press . When activating together, the upper and lower fibers also assist

330-453: The occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of the scapula . It moves the scapula and supports the arm . The trapezius has three functional parts: The trapezius muscle resembles a trapezium , also known as a trapezoid, or diamond-shaped quadrilateral . The word "spinotrapezius" refers to the human trapezius, although it is not commonly used in modern texts. In other mammals, it refers to

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360-402: The thoracodorsal (long subscapular) nerve. Electromyography suggests that it consists of six groups of muscle fibres that can be independently coordinated by the central nervous system . The latissimus dorsi assists in depression of the arm with the teres major and pectoralis major . It adducts, extends, and internally rotates the shoulder. When the arms are in a fixed overhead position,

390-464: The triceps brachii , among numerous other stabilizing muscles. Compound exercises for the 'lats' typically involve elbow flexion and tend to recruit the biceps brachii , brachialis , and brachioradialis for this function. Depending on the line of pull, the trapezius muscles can be recruited as well; horizontal pulling motions such as rows recruit both latissimus dorsi and trapezius heavily. The power/size/strength of this muscle can be trained with

420-411: The biceps brachii is in a mechanical disadvantage. With the insertion of the muscle so far from the fulcrum of the elbow, the brachioradialis does not generate as much joint torque as the brachialis or the biceps. It is effective mainly when those muscles have already partially flexed at the elbow. The brachioradialis flexes the forearm at the elbow, especially when quick movement is required and when

450-481: The diagnosis. Muscle belly injuries are treated with rehabilitation while tendon avulsion injuries can be treated surgically, or with rehab. Regardless of treatment, patients tend to return to play without any functional losses. [REDACTED] This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) Trapezius The trapezius is a large paired trapezoid -shaped surface muscle that extends longitudinally from

480-438: The forearm at the elbow. When the forearm is pronated, the brachioradialis tends to supinate as it flexes. In a supinated position, it tends to pronate as it flexes. This also assists the biceps brachii . The brachioradialis is a stronger elbow flexor when the forearm is in a midposition between supination and pronation at the radioulnar joint . When pronated, the brachioradialis is more active during elbow flexion since

510-416: The forearm. It originates proximally on the lateral supracondylar ridge of the humerus . It inserts distally on the radius , at the base of its styloid process . Near the elbow, it forms the lateral limit of the cubital fossa , or elbow pit. Despite the bulk of the muscle body being visible from the anterior aspect of the forearm, the brachioradialis is a posterior compartment muscle and consequently

540-452: The lateral third of the clavicle . The middle fibers, or transverse of the trapezius arise from the spinous process of the seventh cervical (both in the back of the neck), and the spinous processes of the first, second, and third thoracic vertebrae . They are inserted into the medial margin of the acromion , and into the superior lip of the posterior border of the spine of the scapula . The inferior or lower (or ascending) fibers of

570-473: The latissimi dorsi have on moving the arms can also influence the movement of the scapulae, such as their downward rotation during a pull up . The number of dorsal vertebrae, to which it is attached, varies from four to eight; the number of costal attachments varies; muscle fibers may or may not reach the crest of the ilium. A muscle slip , the axillary arch , varying from 7 to 10 cm in length, and from 5 to 15 mm in breadth, occasionally springs from

600-426: The latissimus dorsi pulls the trunk upward and forward. It has a synergistic role in extension (posterior fibers) and lateral flexion (anterior fibers) of the lumbar spine, and assists as a muscle of both forced expiration (anterior fibers) and an accessory muscle of inspiration (posterior fibers). Most latissimus dorsi exercises concurrently recruit the teres major , posterior fibres of the deltoid , long head of

630-462: The latissimus dorsi to the thoracic and lumbar spine . The latissimus dorsi is a potential source of muscle for breast reconstruction surgery after mastectomy (e.g., Mannu flap) or to correct pectoral hypoplastic defects such as Poland's syndrome . An absent or hypoplastic latissimus dorsi can be one of the associated symptoms of Poland's syndrome. For heart patients with low cardiac output and who are not candidates for cardiac transplantation,

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660-451: The long head of the triceps brachii . This is occasionally muscular, and is the representative of the dorsoepitrochlearis brachii of apes . This muscular form is found in ~5% of humans and is sometimes termed the latissimocondyloideus. The latissimus dorsi crosses the inferior angle of the scapula . A study found that, of 100 cadavers dissected: The latissimus dorsi is innervated by the sixth, seventh, and eighth cervical nerves through

690-403: The middle fibers (along with other muscles such as the rhomboids ) with scapular retraction/adduction. The trapezius also assists in abduction of the shoulder above 90 degrees by rotating the glenoid upward. Injury to cranial nerve XI will cause weakness in abducting the shoulder above 90 degrees. When the scapulae are stable, a co-contraction of both sides can extend the neck. Dysfunction of

720-411: The opposite muscle, a tendinous ellipse. The rest of the muscle arises by numerous short tendinous fibers. It is possible to feel the muscles of the superior trapezius as they become active by holding a weight in one hand in front of the body and, with the other hand, touching the area between the shoulder and the neck. Motor function is supplied by the accessory nerve . Sensation, including pain and

750-417: The sense of joint position ( proprioception ), travel via the ventral rami of the third (C3) and fourth (C4) cervical spinal nerves . Since it is a muscle of the upper limb, the trapezius is not innervated by dorsal rami , despite being placed superficially in the back. Contraction of the trapezius muscle can have two effects: movement of the scapulae when the spinal origins are stable, and movement of

780-407: The spine when the scapulae are stable. Its main function is to stabilize and move the scapula. The upper fibers elevate the scapulae, the middle fibers retract the scapulae, and the lower fibers depress the scapulae. In addition to scapular translation, the trapezius induces scapular rotation. The upper and lower fibers tend to rotate the scapula around the sternoclavicular articulation so that

810-401: The trapezius arise from the spinous processes of the remaining thoracic vertebrae (T4–T12). From this origin, they proceed upward and laterally to converge near the scapula and end in an aponeurosis , which glides over the smooth triangular surface on the medial end of the spine, to be inserted into a tubercle at the apex of this smooth triangular surface. At its occipital origin, the trapezius

840-544: The trapezius can result in winged scapula , sometimes further specified as "lateral winging" and in an abnormal mobility or function of the scapula (scapular dyskinesia). There are multiple causes of trapezius dysfunction. Trapezius palsy , due to damage of the spinal accessory nerve , is characterized by difficulty with arm adduction and abduction , and associated with a drooping shoulder, and shoulder and neck pain . Intractable trapezius palsy can be surgically managed with an Eden–Lange procedure . The trapezius muscle

870-403: The trapezius has been reported in association with Poland syndrome . It is mainly used in throwing, with the deltoid muscle and rotator cuff . [REDACTED] This article incorporates text in the public domain from page 432 of the 20th edition of Gray's Anatomy (1918) Brachioradialis The brachioradialis is a superficial, fusiform muscle on the lateral side of

900-402: The upper edge of the latissimus dorsi about the middle of the posterior fold of the axilla, and crosses the axilla in front of the axillary vessels and nerves, to join the under surface of the tendon of the pectoralis major , the coracobrachialis , or the fascia over the biceps brachii . This axillary arch crosses the axillary artery , just above the spot usually selected for the application of

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