The latissimus dorsi () is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the

trapezius The trapezius is a large paired trapezoid-shaped surface muscle that extends longitudinally from 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 ...

on the back near the midline. The word latissimus dorsi (plural: ''latissimi dorsorum'') comes from

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

and means "broadest uscleof the back", from "latissimus" ( la, broadest)' and "dorsum" ( la, back). The pair of muscles are commonly known as "lats", especially among

bodybuilder Bodybuilding is the use of progressive resistance exercise to control and develop one's muscles (muscle building) by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerlifting because it focuses ...

s. The latissimus dorsi is the largest muscle in the upper body. The latissimus dorsi is responsible for

extension Extension, extend or extended may refer to: Mathematics Logic or set theory * Axiom of extensionality * Extensible cardinal * Extension (model theory) * Extension (predicate logic), the set of tuples of values that satisfy the predicate * E ...

adduction Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...

, transverse extension also known as horizontal abduction (or horizontal extension), flexion from an extended position, and (medial)

internal rotation Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...

of the

shoulder joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial 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 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.

Structure

Variations

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 Anatomical terminology is used to uniquely describe aspects of skeletal muscle, cardiac muscle, and smooth muscle such as their actions, structure, size, and location. Types There are three types of muscle tissue in the body: skeletal, smooth, a ...

, the axillary arch, varying from 7 to 10 cm in length, and from 5 to 15 mm in breadth, occasionally springs from 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 pectoralis major () is a thick, fan-shaped or triangular convergent muscle, situated at the chest of the human body. It makes up the bulk of the chest muscles and lies under the breast. Beneath the pectoralis major is the pectoralis minor, a ...

, the

coracobrachialis The coracobrachialis muscle is the smallest of the three muscles that attach to the coracoid process of the scapula. (The other two muscles are pectoralis minor and the short head of the biceps brachii.) It is situated at the upper and medial part ...

, or the fascia over the biceps brachii. This axillary arch crosses the

axillary artery In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla (armpit) and the upper limb. Its origin is at the lateral margin of the first rib, before which it is c ...

, just above the spot usually selected for the application of 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 the long head of the

triceps brachii The triceps, or triceps brachii (Latin for "three-headed muscle of the arm"), is a large muscle on the back of the upper limb of many vertebrates Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with ba ...

. This is occasionally muscular, and is the representative of the dorsoepitrochlearis brachii of

ape Apes (collectively Hominoidea ) are a clade of Old World simians native to sub-Saharan Africa and Southeast Asia (though they were more widespread in Africa, most of Asia, and as well as Europe in prehistory), which together with its sister g ...

s. 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 The scapula (plural scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on eithe ...

. A study found that, of 100 cadavers dissected: * 43% had "a substantial amount" of muscular fibers in the latissimus dorsi originating from the scapula. * 36% had few or no muscular fibers, but a "soft fibrous link" between the scapula and the latissimus dorsi * 21% had little or no connecting tissue between the two structures.

Triangles

* The lateral margin of the latissimus dorsi is separated below from the obliquus externus abdominis by a small triangular interval, the ''lumbar triangle of Petit'', the base of which is formed by the

iliac crest The crest of the ilium (or iliac crest) is the superior border of the wing of ilium and the superiolateral margin of the greater pelvis. Structure The iliac crest stretches posteriorly from the anterior superior iliac spine (ASIS) to the posterior ...

, and its floor by the obliquus internus abdominis. * Another triangle is situated behind the scapula. It is bounded above by the

, below by the latissimus dorsi, and laterally by the vertebral border of the scapula; the floor is partly formed by the

rhomboideus major The rhomboid major is a skeletal muscle on the back that connects the scapula with the vertebrae of the spinal column. In human anatomy, it acts together with the rhomboid minor to keep the scapula pressed against thoracic wall and to retract the ...

. If the

is drawn forward by folding the arms across the chest, and the trunk bent forward, parts of the sixth and seventh ribs and the interspace between them become subcutaneous and available for

auscultation Auscultation (based on the Latin verb ''auscultare'' "to listen") is listening to the internal sounds of the body, usually using a stethoscope. Auscultation is performed for the purposes of examining the circulatory and respiratory systems (hea ...

. The space is therefore known as the ''

triangle of auscultation The triangle of auscultation is a relative thinning of the Muscle, musculature of the Human back, back, situated along the medial border of the scapula which allows for improved auscultation, listening to the lungs. Boundaries It has the followi ...

''. *The latissimus dorsi can be remembered best for insertion as "A Miss Between Two Majors". As the latissimus dorsi inserts into the floor of the intertubercular groove of the

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

it is surrounded by two major muscles. The teres major inserts medially on the medial lip of the intertubercular groove and the pectoralis major inserts laterally onto the lateral lip.

Nerve supply

The latissimus dorsi is innervated by the sixth, seventh, and eighth cervical nerves through the thoracodorsal (long subscapular) nerve.

Electromyography Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyog ...

suggests that it consists of six groups of muscle fibres that can be independently coordinated by the

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all par ...

Function

The latissimus dorsi assists in depression of the arm with the

teres major The teres major muscle is a muscle of the upper limb. It attaches to the scapula and the humerus and is one of the seven scapulohumeral muscles. It is a thick but somewhat flattened muscle. The teres major muscle (from Latin ''teres'', meaning ...

and

. It adducts, extends, and internally rotates the shoulder. When the arms are in a fixed overhead position, 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

, posterior fibres of the deltoid, long head of the

, among numerous other stabilizing muscles. Compound exercises for the 'lats' typically involve elbow flexion and tend to recruit the biceps brachii, brachialis, and

brachioradialis The brachioradialis is a muscle of the forearm that flexes the forearm at the elbow. It is also capable of both pronation and supination, depending on the position of the forearm. It is attached to the distal styloid process of the radius by ...

for this function. Depending on the line of pull, the

muscles can be recruited as well; horizontal pulling motions such as rows recruit both latissimus dorsi and trapezius heavily.

Training

The power/size/strength of this muscle can be

trained Training is teaching, or developing in oneself or others, any skills and knowledge or fitness that relate to specific useful competencies. Training has specific goals of improving one's capability, capacity, productivity and performance. I ...

with a variety of different exercises. Some of these include: * Vertical pulling movements such as pull-downs and pull-ups (including

chin-up A pull-up is an upper-body strength exercise. The pull-up is a closed-chain movement where the body is suspended by the hands, gripping a bar or other implement at a distance typically wider than shoulder-width, and pulled up. As this happens, ...

s) * Horizontal pulling movements such as

bent-over row A bent-over row (or barbell row) is a weight training exercise that targets a variety of back muscles. Which ones are targeted varies on form. The bent over row is often used for both bodybuilding and powerlifting. Implements There are several va ...

, T-bar row and other

rowing exercise In strength training, rowing (or a row, usually preceded by a qualifying adjective — for instance a ''seated row'') is an exercise where the purpose is to strengthen the muscles that draw the rower's arms toward the body ( latissimus dorsi) a ...

s * Shoulder extension movements with straight arms such as straight-arm lat pulldowns and Pull-overs *

Deadlift The deadlift is a weight training exercise in which a loaded barbell or bar is lifted off the ground to the level of the hips, torso perpendicular to the floor, before being placed back on the ground. It is one of the three powerlifting exercises, ...

Clinical significance

Tight latissimus dorsi has been shown to be a contributor to chronic shoulder pain and chronic back pain.Arnheim, D.D., Prentice, W.E., Principles of athletic training. 9th ed. McGraw Hill, pp 570-574, 1997. Because the latissimus dorsi connects the spine to the

, tightness in this muscle can manifest as either sub-optimal

glenohumeral joint The shoulder joint (or glenohumeral joint from Greek ''glene'', eyeball, + -''oid'', 'form of', + Latin ''humerus'', shoulder) is structurally classified as a synovial ball-and-socket joint and functionally as a diarthrosis and multiaxial joint. ...

(shoulder) function which leads to chronic pain or

tendinitis Tendinopathy, a type of tendon disorder that results in pain, swelling, and impaired function. The pain is typically worse with movement. It most commonly occurs around the shoulder (rotator cuff tendinitis, biceps tendinitis), elbow (tennis elbo ...

in the tendinous fasciae connecting the latissimus dorsi to the thoracic and

lumbar spine The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse p ...

.Francis, P., Applied anatomy and kinesiology, supplemental materials. KB Books., p 19-25, 1999. The latissimus dorsi is a potential source of muscle for

breast reconstruction Breast reconstruction is the surgical process of rebuilding the shape and look of a breast, most commonly in women who have had surgery to treat breast cancer. It involves using autologous tissue, prosthetic implants, or a combination of both wit ...

surgery after mastectomy (e.g. Mannu flap) or to correct pectoral

hypoplastic Hypoplasia (from Ancient Greek :wikt:ὑπό, ὑπo- ''hypo-'' 'under' + πλάσις ''plasis'' 'formation'; adjective form ''hypoplastic'') is underdevelopment or incomplete development of a tissue or organ.Poland's syndrome Poland syndrome is a birth defect characterized by an underdeveloped chest muscle and short webbed fingers on one side of the body. There may also be short ribs, less fat, and breast and nipple abnormalities on the same side of the body. Typical ...

. An absent or hypoplastic latissimus dorsi can be one of the associated symptoms of Poland's syndrome.

Cardiac support

For heart patients with low cardiac output and who are not candidates for cardiac transplantation, a procedure called ''

cardiomyoplasty Cardiomyoplasty is a surgical procedure in which healthy muscle from another part of the body is wrapped around the heart to provide support for the failing heart. Most often the latissimus dorsi muscle is used for this purpose. A special pacemake ...

'' may support the failing heart. This procedure involves wrapping the latissimus dorsi muscles around the heart and electrostimulating them in synchrony with ventricular systole.

Injury

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 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.

Additional images

File:Latissimus dorsi muscle animation.gif, Position of the latissimus dorsi muscle (shown in red). Animation. File:Latissimus dorsi muscle animation3.gif, Animation.

Rib cage The rib cage, as an enclosure that comprises the ribs, vertebral column and sternum in the thorax of most vertebrates, protects vital organs such as the heart, lungs and great vessels. The sternum, together known as the thoracic cage, is a semi- ...

is not shown, except for 10th rib, 11th rib and 12th rib. File:LumbarTriangle.jpg, Lumbar triangle File:Slide9111.JPG, Latissimus dorsi File:2019-05-24 Budapest Cup training pommel horse (Martin Rulsch) 466.jpg, Clearly visible ''latissimus dorsi muscle'' of an

artistic gymnast Artistic gymnastics is a discipline of gymnastics in which athletes perform short routines on different apparatuses. The sport is governed by the Fédération Internationale de Gymnastique (FIG), which designs the Code of Points and regulates ...

pommel horse The pommel horse is an artistic gymnastics apparatus. Traditionally, it is used by only male gymnasts. Originally made of a metal frame with a wooden body and a leather cover, the modern pommel horse has a metal body covered with foam rubber and ...

. File:Deutsche Jugendmeisterschaften Gerätturnen männlich Training at Internationales Deutsches Turnfest Berlin 2017 (Martin Rulsch) 0857.jpg,

Contraction Contraction may refer to: Linguistics * Contraction (grammar), a shortened word * Poetic contraction, omission of letters for poetic reasons * Elision, omission of sounds ** Syncope (phonology), omission of sounds in a word * Synalepha, merged ...

of the ''latissimus dorsi muscle'' of another artistic gymnast on

still rings The rings, also known as still rings (in contrast to flying rings), is an artistic gymnastics apparatus and the event that uses it. It is traditionally used only by male gymnasts, due to its extreme upper body strength requirements. Gymnasts oft ...

References

External links

* - "Superficial layer of the extrinsic muscles of the back." * {{DEFAULTSORT:Latissimus Dorsi Muscle Muscles of the upper limb Shoulder adductors Shoulder extensors Shoulder medial rotators Shoulder flexors Spine lateral flexors