Muscle:Latissimus dorsi
Latissimus dorsi is a broad, fan-shaped muscle of the posterior trunk and a frequently overlooked myofascial source of mid-thoracic back pain. Its trigger points (TrPs) produce a constant aching pain centred on the inferior angle of the scapula that is distressingly unresponsive to positional change or stretching — a characteristic that routinely prompts negative investigations for intrathoracic disease before the muscular origin is recognised. When arm referral is present, the pattern extends down the medial arm and forearm to the ulnar hand including the ring and little fingers, closely mimicking C7–C8 radiculopathy and ulnar neuropathy. Because the latissimus dorsi is a long, slack muscle that rarely causes pain with partial stretch, patients are often unaware of any activity that aggravates their midback pain — and this clinical absence of a provocative movement is itself a pointer toward this muscle.
Anatomy
The latissimus dorsi is the broadest muscle of the back and links the upper and lower body through an extensive series of attachments.
Inferior (origin) attachments:
- Spinous processes of the lower six thoracic vertebrae (T7–T12)
- Spinous processes of all lumbar vertebrae (via the thoracolumbar/lumbar aponeurosis)
- Sacrum (via the lumbar aponeurosis)
- Posterior crest of the ilium
- Last three or four ribs (via muscular digitations that interdigitate with the lateral abdominal oblique)
The most vertical fibres, which attach to the ribs and iliac crest, hug the teres major within the axillary fold and attach most proximally on the humerus. The most horizontal (superior) fibres pass over or adhere to the inferior angle of the scapula and form the free posterior margin of the axillary fold, attaching more distally on the humerus. All fibres of the latissimus dorsi twist nearly 180° around the teres major muscle as they converge toward the humerus.
Superior (insertion) attachment:
- Floor of the intertubercular (bicipital) groove of the humerus — the tendons of the latissimus dorsi and teres major are partially united near their humeral attachments
The most anterior fibres form shorter digitations directly to the ribs; referred pain patterns from TrPs in these digitations have not been fully characterised.
Innervation: Thoracodorsal (long subscapular) nerve via the posterior cord; spinal levels C6, C7, and C8.
Primary actions:
- Extension of the arm at the shoulder
- Adduction of the arm
- Medial rotation of the arm
- Depression of the shoulder girdle and humerus
- Forceful elevation of the trunk toward the arms (e.g., swimming crawl, chinning, walking with crutches)
Referred Pain Patterns
Primary TrP location (posterior axillary fold)
The most clinically important TrPs lie in the midportion of the most cranial group of fibres, within the region of the posterior axillary fold at approximately the midscapular level. This is where the latissimus dorsi wraps around the lower border of the teres major.
Essential (solid) referral zone:
- Inferior angle of the scapula and surrounding midthoracic region — the patient centres the pain here and may have difficulty reaching behind to mark it
Spillover (stippled) referral zone:
- Posterior shoulder
- Medial arm and forearm
- Ulnar aspect of the hand, including the ring and little fingers
The patient usually describes the pain as a constant ache. Because it does not change with activity or position, it is commonly investigated as intrathoracic disease (bronchoscopy, coronary angiogram, myelogram, CT scan) before the myofascial source is identified.
Secondary TrP location (midregion of anterior fibres)
A less common TrP in the midregion of the longest, most anterior fibres refers pain to:
- Front of the shoulder
- Lower lateral trunk above the iliac crest
An intermediate TrP in the fibres attaching to the thoracolumbar region refers pain locally to the lower end of the posterior axillary fold, lateral to the scapula.
Clinical note on atypical referral
Where there is prior pain modification of central nervous system pathways (e.g., previous cholecystectomy, previous cardiac event), TrPs in the latissimus dorsi may refer to the site of previous pain rather than — or in addition to — the usual pattern. The more intense the earlier pain and associated emotion, the more likely this atypical referral becomes. A case of sharp stabbing right upper quadrant abdominal pain with radiation to the back, in a patient with a history of cholecystectomy, was fully reproduced by firm pressure over the latissimus dorsi and resolved with TrP treatment of that muscle alone.
Activation and Perpetuating Factors
The latissimus dorsi is unlikely to be activated by acute trauma or overload because of its long, slack nature. Activation is characteristically insidious and identified by analysis of activities involving forceful shoulder-girdle depression (weight bearing) or repetitive extension with adduction.
Activities that can eventually activate TrPs:
- Reaching overhead to exercise by pulling heavy weights (lat pulldowns, pull-ups, chinning)
- Throwing a baseball or similar overhead throwing activity
- Hanging from a swing or rope
- Pressing down to twist weeds out while gardening
- Repetitively pushing down with the hand beside the body
The patient typically becomes aware of a persistent midback ache some time after the activity has ended, and may not connect the two.
Perpetuating factors:
- Persistent compression from a tight brassiere (deep skin indentation from tight elastic) — the elastic can be weakened by dampening and heating with a hot iron
- Sleeping on the side of an active TrP, which activates it and disrupts function the next day
- Using the arm to push up from a low seat (loads the more vertical fibres)
- Sustained contraction to stabilise the scapula during sustained skill activities (e.g., playing the viola or similar instrument)
- Key TrPs in the serratus posterior superior can drive satellite TrPs in the latissimus dorsi; inactivation of the serratus key TrPs can resolve the latissimus satellites without direct treatment
Clinical Examination
Overview
Because of the latissimus dorsi's influence on the trunk and pelvis through its extensive attachments, patient examination must begin with an overall assessment of body symmetry and limb posture. Range of motion testing and joint play examination of the glenohumeral joint should be included routinely.
Postural Assessment
Active TrPs in the latissimus dorsi are associated with specific articular and postural findings that should be sought systematically:
| Finding | What to assess | Clinical significance |
|---|---|---|
| Segmental group dysfunction | Palpate spinal segments T7/T8 to L3/L4 | Group dysfunction spanning several segments in this range is characteristically associated with latissimus dorsi TrPs; sidebending of vertebrae toward the involved muscle with rotation away from it |
| Innominate upslip (ipsilateral) | Standing-flexion test; seated-flexion test | With latissimus dorsi TrPs: standing-flexion test positive, seated-flexion test negative — this combination rules out primary sacroiliac dysfunction and distinguishes from quadratus lumborum involvement (see #Differential Diagnosis) |
| Leg length discrepancy | Measure actual and apparent leg length | Ipsilateral innominate upslip from tension in latissimus fibres attaching to the iliac crest can produce concurrent leg length discrepancy |
| Shoulder depression asymmetry | Observe shoulder heights with patient standing | Shoulder girdle depression is a primary function of the latissimus; TrP tension may contribute to postural asymmetry |
Range of Motion Testing
Patients with latissimus dorsi TrPs are typically unaware of their slightly restricted range of motion. The following tests reveal the restriction:
Mouth Wrap-around Test (see Fig. 18.2 in Travell & Simons)
- Tests combined shoulder abduction, external rotation, and elbow flexion. Restriction indicates latissimus dorsi and/or teres major involvement.
Triceps Brachii Test (see Fig. 32.4 in Travell & Simons)
- The patient abducts the arm and, with the elbow held straight, brings the arm into firm contact with the ear and, if possible, behind the ear. Inability to hold the elbow straight in this position indicates additional involvement of the long head of the triceps brachii.
Hand-to-Shoulder-Blade Test (see Fig. 22.3 in Travell & Simons)
- Internal rotation and adduction behind the back; restriction points to latissimus dorsi and/or infraspinatus involvement.
Provocation Tests
Two positions selectively load or stretch the latissimus dorsi and can provoke referred pain in patients with active TrPs:
| Test | Technique | Response |
|---|---|---|
| Shoulder flexion with lateral rotation (stretch) | Patient reaches far forward and upward with the arm laterally rotated | Reproduces referred pain — the muscle is stretched by flexion and wrapped around the humerus |
| Bilateral iliac crest depression (loading) | Patient presses down hard on both iliac crests | Activates the muscle in its shortened position performing its shoulder depressor function; reproduces referred pain |
Trigger Point Examination
Positioning: Patient supine. Place the hand under the head or pillow with the arm laterally rotated and abducted to approximately 90° to put the muscle on half stretch.
Technique: The examiner grasps the latissimus dorsi with pincer palpation along the free border of the posterior axillary fold at the midscapular level, where the latissimus dorsi wraps around the teres major. While lifting the muscle away from the chest wall, taut bands and their points of maximal tenderness are rolled between fingers and thumb. TrPs typically lie a few centimetres (approximately one inch) below the top of the arch of the posterior axillary fold.
Distinguishing latissimus dorsi from teres major: Palpate the axillary border of the scapula. Include in the pincer grasp only those fibres that are inferior and not attached to the axillary border — these belong to the latissimus dorsi. The teres major fibres attach to the axillary (lateral) border of the scapula and lie more superiorly and medially within the axillary fold.
Expected responses:
- Snapping palpation of a taut band elicits a strong local twitch response, visible along the scapular margin or over the lower thoracic and lumbar regions depending on which fibres are involved
- A large simultaneous twitch of several bands may cause the arm to jerk visibly
Inter-rater reliability for TrP characteristics of the latissimus dorsi (spot tenderness, taut band, referred pain, symptomatic pain reproduction, local twitch response) has been confirmed as high (P < 0.001) in experienced clinicians with adequate training.
Glenohumeral Joint Assessment
Uncompensated tension from the latissimus dorsi tends to displace the head of the humerus anteriorly in the glenoid cavity. Test the glenohumeral joint for normal joint play in all cases where latissimus dorsi TrPs are suspected.
Differential Diagnosis
Cardinal differentiating features of latissimus dorsi TrP pain
The following features, taken together, constitute the clinical profile that should direct suspicion toward the latissimus dorsi:
| Feature | Present / Absent / Variable |
|---|---|
| Constant midthoracic ache centred on inferior scapular angle | Must be present |
| Pain unchanged by positional change or active stretch | Must be present (distinguishes from postural or disc-related pain which typically has a relieving position) |
| No activity immediately aggravates or relieves the midback pain | Must be present — absence of a provocative movement is the signature characteristic |
| History of negative intrathoracic investigations (angiogram, bronchoscopy, CT, myelogram) | Commonly present — negative workup heightens suspicion |
| Previous treatment applied to the referred pain zone (back) rather than the muscle itself | Commonly present |
| Medial arm and forearm pain to ulnar hand (ring and little fingers) | Variable — present when TrPs are sufficiently active; essential to differentiate from radicular sources |
| Onset insidious, not acute | Must be present — the long slack nature of the muscle means acute overload does not activate it |
Differentiating Latissimus Dorsi TrPs from Nerve Entrapment and Radiculopathy
| Condition | Key differentiating features |
|---|---|
| Suprascapular nerve entrapment at the spine of the scapula | Deep aching in the supraspinous and infraspinous fossae; weakness and atrophy of supraspinatus and infraspinatus; confirmatory electrodiagnostic studies (nerve conduction, EMG) |
| C7 radiculopathy | Dermatomal sensory deficit (middle finger primarily); triceps reflex depression or absence; weakness in C7 myotome (elbow extension, wrist flexion); neuroimaging confirms disc or foraminal pathology. Latissimus dorsi TrP pain does not produce reflex change, dermatome-specific sensory loss, or myotomal weakness. |
| Ulnar neuropathy | Sensory deficit strictly in the ulnar nerve distribution (dorsal and palmar ulnar hand including both aspects of little finger and ulnar half of ring finger); Tinel's sign at the cubital tunnel or Guyon's canal; confirmatory nerve conduction studies. Latissimus dorsi referral to the ulnar hand does not produce objective sensory deficit. |
| Bicipital tendinitis | Tenderness specifically at the biceps tendon in the bicipital groove; positive Speed's test and Yergason's test; pain reproduced by resisted elbow flexion and supination. Often associated with TrPs in the long head of biceps brachii. |
Articular Dysfunction Differentiation (Innominate and Sacroiliac)
Both latissimus dorsi and quadratus lumborum TrPs are associated with innominate dysfunction. These are distinguished by a specific combination of clinical tests:
| Test | Latissimus Dorsi TrPs | Quadratus Lumborum TrPs |
|---|---|---|
| Referred pain pattern | Inferior scapular angle, midthoracic back, medial arm/forearm/ulnar hand | Ipsilateral lower quadrant, posterior iliac crest, lateral hip — does not extend to arm |
| Standing-flexion test | Positive (ipsilateral) | Positive (ipsilateral) |
| Seated-flexion test | Negative — rules out primary sacroiliac dysfunction | Positive — confirms sacroiliac involvement |
| Innominate finding | Ipsilateral upslip — tension in latissimus fibres attaching to the iliac crest | Sacroiliac dysfunction (not upslip) |
| Leg length discrepancy | May be present (secondary to innominate upslip) | Less specific |
Clinical implication: A positive standing-flexion test with a negative seated-flexion test in a patient with midback pain pointing to the inferior scapular angle is a combination that implicates the latissimus dorsi, not a primary sacroiliac or quadratus lumborum problem.
Pseudothoracic Outlet Syndrome
The latissimus dorsi is one of four muscles constituting the myofascial pseudothoracic outlet syndrome — the others are the pectoralis major, teres major, and subscapularis. When at least three of these four muscles carry active TrPs simultaneously, their composite referred pain pattern is strongly suggestive of thoracic outlet syndrome and is commonly misdiagnosed as such. These muscles cause no actual compression of neurovascular structures in the thoracic outlet.
Clinically distinguish from true thoracic outlet syndrome by:
- Absence of objective neurological deficit in the ulnar nerve distribution (thoracic outlet compression typically involves T1; the lower trunk)
- Absence of vascular signs (diminished radial pulse with arm position, supraclavicular bruit)
- Absence of positive Adson's, costoclavicular, or hyperabduction manoeuvre with vascular obliteration
- Presence of identifiable TrPs in these four muscles with referred pain patterns collectively producing the composite presentation
- Resolution of symptoms with TrP treatment rather than surgical decompression
Other muscles referring to the midthoracic back
When midback pain does not resolve with latissimus dorsi treatment, consider:
| Muscle | Distinguishing features |
|---|---|
| Lower trapezius | Essential zone at the high cervical paravertebral region and mastoid; spillover to suprascapular ridge and acromion; no arm referral |
| Rhomboids | Superficial aching along the medial scapular border between the scapula and the spine; not at the inferior angle; no arm referral; pain worse at rest, not with activity |
| Serratus posterior superior | Can be a key TrP driving latissimus satellite; deep posterior shoulder and upper scapular pain; pain on deep breathing |
| Iliocostalis thoracis | Pain in the same thoracic segment but more paravertebral; associated with spinal segmental dysfunction; can be a satellite of latissimus dorsi |
| Scalenes | Anterior chest and medial border of scapula; arm referral to radial (not ulnar) forearm and hand; associated with upper rib restriction |
| Upper rectus abdominis | Bilateral band across the midback; epigastric referral; associated with abdominal guarding and visceral mimicry |
| Subscapularis | Posterior shoulder; wrist band; part of the pseudothoracic outlet quadrad |
Entrapment
No nerve entrapment attributable to TrP activity in the latissimus dorsi has been identified.
Treatment
Trigger Point Release
Because the latissimus dorsi is a long, slack muscle, full use of augmentation techniques is especially important during stretch release. Partial stretch alone is rarely sufficient.
Supine position (Fig. 24.4):
- Patient supine; arm abducted and laterally rotated
- Vapocoolant spray applied cephalad from the pelvis, covering the length of the muscle and the full posterior axillary fold, then continuing down the posterior arm and forearm over the referred pain region, including the fourth and fifth digits
- Operator continuously takes up any slack that develops
- Full spray pattern repeated as the muscle is passively elongated
- Following spray, apply moist heat and then active full range of motion
Sidelying position for full posterior stretch (Fig. 24.5):
- Patient lies on the opposite (uninvolved) side
- Painful arm brought slowly overhead, then posteriorly, until it reaches tightly behind the ear
- Vapocoolant sweeps start at the TrP area, covering all posterior thoracic zones of referred pain, then directed from the TrP area to the fingertips
Stretch for horizontal fibres: When TrPs are in the nearly horizontal superior fibres, stretch by placing the patient's arm anteriorly across the chest and pulling it into full adduction to take up the slack.
Augmentation techniques:
- Slow exhalation during passive elongation
- Contract-relax (postisometric relaxation): patient inhales and presses the humerus lightly against the operator's hand, then exhales slowly and relaxes
- Reciprocal inhibition: voluntary contraction of antagonists (shoulder flexors and external rotators)
A lower rib release technique (Fig. 45.11) is also effective for releasing the latissimus dorsi. An interscapular and shoulder-girdle release technique illustrated in Figure 18.3 incorporates the latissimus dorsi within a broader shoulder-girdle release.
Following vapocoolant, apply moist heat immediately, then active full range of motion is essential.
Trigger Point Injection
TrPs in the posterior axillary fold are readily and effectively injected.
Technique:
- Patient supine; TrPs located by pincer palpation as described under #Trigger Point Examination
- TrP fixed between the operator's digits for precise needle insertion
- A strong local twitch response is usually both seen and felt when the needle penetrates a latissimus dorsi TrP
- Both superficial and deep axillary portions of the muscle should be probed — TrPs tend to occur in clusters
- Immediate haemostasis maintained by the palpating hand both during probing and after injection
The teres major often also harbours active TrPs, which can be injected through the same skin puncture by sliding the skin and repositioning the needle tip subcutaneously.
Injections are followed by stretch and spray, then hot packs to the axillary region, and then full active range of motion.
Note on satellite resolution: Release of key latissimus dorsi TrPs may resolve satellite TrPs in other muscles (iliocostalis thoracis, lower trapezius, triceps brachii, flexor carpi ulnaris) without direct treatment to those muscles.
Note on Satellite TrP Relationships
The latissimus dorsi occupies a central position in a bidirectional satellite network:
Latissimus dorsi as satellite (driven by key TrPs elsewhere):
- Serratus posterior superior — inactivation of the key serratus TrPs can inactivate latissimus dorsi satellites without further treatment
Latissimus dorsi as key TrP (driving satellites in other muscles):
- Triceps brachii — synergistic/antagonistic overload depending on arm position; especially in chronic cases
- Lower trapezius — within the referred pain zone
- Iliocostalis thoracis — within the referred pain zone
- Flexor carpi ulnaris — within the referred ulnar forearm/hand zone
In some cases a satellite TrP does not clear with inactivation of the key TrP and must be identified and inactivated individually.
Patient Education
Activity Modification
- When pulling down on something: keep the arm vertical (not forward of the abdomen) and the elbow beside the body
- Step up on a stool to avoid reaching high for heavy objects — overhead reach with a loaded arm is the most consistent activating mechanism
- Avoid hanging from a swing, rope, or bar during the active treatment phase
Sleep Position
- Do not sleep on the side of an active latissimus dorsi TrP — direct body pressure on the TrP activates it and disrupts function the following day
- At night, keep a pillow in the axilla between the elbow and the chest to prevent prolonged shortening of the muscle at rest (see Fig. 26.7 in Travell & Simons)
Brassiere Fit
Persistent compression from a tight brassiere can activate and perpetuate TrPs in the latissimus dorsi. If deep skin indentation is present from tight elastic, the elasticity can be reduced by dampening the elastic section and heating it briefly with a hot iron.
Home Stretching
- Mouth Wrap-around Test position (see Fig. 18.2) — used as a daily home stretch
- In-doorway stretch, upper hand position (see Fig. 42.9C): the low back must be hyperextended and the hips swung forward through the doorway; the patient should feel the tension in the latissimus dorsi. Release the stretch with slow exhalation and advance the hands slightly higher in successive repetitions.
- Quadruped self-stretch (Greenman technique): upper limb reach with pelvic shift to lengthen the muscle
Stretching should be done smoothly without jerking, for a few repetitions daily, followed by 15–20 minutes of moist heat.
Tennis ball self-release: Patient lies on the affected side with a pillow supporting head and shoulders, arm flexed to take up slack. Body position adjusted over a tennis ball to locate TrP tenderness. Gentle non-painful pressure applied while alternately contracting and relaxing the muscle, exhaling during each relaxation phase, until tenderness fades.
Satellite Trigger Points
- Triceps brachii (long head) — most common satellite; synergistic/antagonistic overload; address after latissimus key TrP
- Lower trapezius — within the referred pain zone
- Iliocostalis thoracis — within the referred pain zone
- Flexor carpi ulnaris — ulnar forearm; within the referred arm/hand zone
- Teres major — anatomically and functionally closely related; almost always develops active TrPs in association with latissimus dorsi; shares the posterior axillary fold; treat together
Related Pages
- Pain:Midback Pain — Diagnostic algorithm for midthoracic back pain
- Muscle:Teres Major — anatomically and functionally inseparable companion; shares posterior axillary fold
- Muscle:Trapezius/Lower — commonly co-active; satellite relationship
- Muscle:Iliocostalis Thoracis — satellite of latissimus dorsi; shares midback referral zone
- Muscle:Serratus Posterior Superior — can be key TrP driving latissimus satellite TrPs
- Muscle:Triceps Brachii — common satellite; synergistic overload
- Muscle:Subscapularis — pseudothoracic outlet quadrad member
- Muscle:Pectoralis Major — pseudothoracic outlet quadrad member
- Muscle:Quadratus Lumborum — differential diagnosis: innominate/sacroiliac dysfunction
References
- Travell JG, Simons DG. Myofascial Pain and Dysfunction: The Trigger Point Manual, Volume 1: The Upper Half of Body. 2nd ed. Baltimore: Williams & Wilkins; 1999. Chapter 24.