Adductor Longus Anatomy

Origin

• A narrow, strong, flat tendon from the anterior surface of the body of the pubis, in the angle between the pubic crest and the pubic symphysis, immediately below the pubic tubercle.
• The origin footprint is small — commonly described as roughly 1-2 cm across — which concentrates load and explains the enthesial pathology.
• The tendon is continuous with the rectus abdominis aponeurosis across the anterior pubis, forming the aponeurotic plate, and blends with the pubic symphyseal disc and the superior and arcuate pubic ligaments.
• Distinguish the layers: an anterior superficial tendinous portion and a deeper, broader aponeurotic portion continuous with the plate. Selective partial release divides the former and preserves the latter.

Insertion

• Expands into a broad fleshy belly and inserts by an aponeurosis into the middle third of the medial lip of the linea aspera on the posteromedial femur.
• The insertion lies between the vastus medialis (anteriorly and laterally) and the adductor brevis and magnus (posteriorly).
• Distally the muscle's medial edge forms part of the posteromedial wall of the adductor canal.

Shape and plane

• Triangular: narrow proximally, broad distally — the opposite geometry to most muscles and a useful way to remember it.
• Lies anterior to the adductor brevis and medial to the pectineus, with the gracilis as the most medial and superficial strap of the compartment.

Named landmarks and measurements

Obturator nerve, anterior division

• Nerve: anterior division of the obturator nerve.
• Root values: L2, L3, L4 (anterior divisions of the ventral rami of the lumbar plexus).
• Course: the obturator nerve descends on the medial border of the psoas, crosses the pelvic brim behind the common iliac vessels, runs on the lateral pelvic wall above the obturator vessels, exits through the obturator canal, and divides into anterior and posterior divisions separated first by the obturator externus and then by the adductor brevis.
• The anterior division descends posterior to the pectineus and adductor longus and anterior to the adductor brevis, supplying adductor longus, adductor brevis, gracilis and pectineus, plus the cutaneous branch to the distal medial thigh and an articular branch to the hip joint.
• Motor entry: branches enter the posterior (deep) surface of the adductor longus in its proximal half.

Practical consequences

• Adductor tenotomy performed close to the pubic origin is proximal to the motor entry, so it does not denervate the muscle — the muscle simply loses its proximal attachment and scars to the adjacent tissue at a slightly longer resting length. This is the mechanical basis of the operation.
• Obturator nerve block anaesthetises the adductor longus completely. It is used diagnostically in suspected obturator neuropathy, therapeutically for adductor spasticity, and to prevent the adductor jerk during transurethral bladder resection.
• The anterior division is the marker for the safe plane in a medial approach to the hip: it lies on the anterior surface of the adductor brevis, so keeping it in view confirms you are anterior to the brevis and therefore away from the posterior division and the medial circumflex femoral artery.
• Obturator neuropathy in athletes is caused by fascial entrapment at the exit from the obturator canal, and presents as exertional medial thigh pain with adductor weakness and a small medial thigh sensory patch.

Root-value cross-check

• Hip adduction = L2/L3/L4.
• Distal medial thigh sensation is obturator; the anteromedial thigh is femoral; the medial leg and medial foot border is saphenous.
• Weak adduction plus medial thigh numbness localises to the obturator nerve. Add quadriceps weakness and the lesion is proximal — lumbar plexus, L2-L4 roots, or a retroperitoneal cause such as haematoma, abscess or tumour.

Supply

• Profunda femoris artery (deep femoral artery) — muscular branches, the dominant supply to the belly.
• Medial circumflex femoral artery — supplies the proximal muscle and the enthesial region.
• Obturator artery — anterior branch, contributing to the proximal muscle and the pubic enthesis.
• Perforating branches of the profunda femoris — segmental supply as they pass posteriorly.
• External pudendal and inferior epigastric territories contribute at the pubic enthesis via a fine periosteal plexus.

The enthesial vascular point

• The pubic enthesis has a relatively poor blood supply compared with the muscle belly — the typical enthesial pattern of a fibrocartilaginous insertion. This is one reason adductor-related groin pain is slow to resolve and why enthesial injury behaves like tendinopathy rather than like a muscle strain.
• After a complete proximal avulsion, the tendon retracts distally a short distance and heals by scar to the adjacent aponeurotic plate and periosteum — a functionally adequate result in most athletes, which is why non-operative management is the norm.

Vessels at risk in the region

• The profunda femoris and its perforating branches lie deep and posterior to the muscle; blind dissection posterior to the adductor longus in the proximal thigh risks them.
• The medial circumflex femoral artery lies deep to the pectineus and adductor brevis, more proximally and posteriorly — the vessel of concern in the medial approach to the hip.
• Corona mortis, the anastomosis between obturator and external iliac or inferior epigastric systems, crosses the superior pubic ramus typically within 3-6 cm lateral to the symphysis, just deep to the adductor and pectineus origins.

Anterior (superficial) to adductor longus

• Fascia lata and subcutaneous tissue in the proximal medial thigh — the tendon is essentially subcutaneous at its origin, which is why it is so easily palpated and so precisely localised.
• Femoral vessels cross anterior to the muscle in the femoral triangle; more distally the sartorius overlies the interval between adductor longus and vastus medialis, roofing the adductor canal.
• Great saphenous vein and the superficial external pudendal artery in the subcutaneous plane proximally.

Posterior (deep) to adductor longus

• Anterior division of the obturator nerve, on the anterior surface of the adductor brevis.
• Adductor brevis proximally and adductor magnus distally.
• Profunda femoris artery and vein and their perforating branches.
• Posterior division of the obturator nerve deeper still, behind the adductor brevis.

Lateral

• Pectineus proximally, then the femoral vessels in the femoral triangle, then the vastus medialis distally.

Medial

• Gracilis — the most medial and superficial of the compartment.

The femoral triangle and the adductor canal

• Femoral triangle boundaries: inguinal ligament superiorly, medial border of sartorius laterally, medial border of adductor longus medially. Floor: iliopsoas laterally, pectineus medially, adductor longus most medially. Roof: fascia lata and cribriform fascia.
• Apex of the femoral triangle: where the medial border of sartorius crosses the medial border of adductor longus — this is where the adductor canal begins.
• Adductor canal (subsartorial, Hunter's canal): from the apex of the femoral triangle to the adductor hiatus in adductor magnus.
  • Anterolateral wall: vastus medialis.
  • Posteromedial wall: adductor longus proximally and adductor magnus distally.
  • Roof: the vastoadductor membrane, deep to the sartorius.
  • Contents: femoral artery, femoral vein, saphenous nerve, nerve to vastus medialis, and the descending genicular artery arising within it.

Structures at risk in the adductor longus territory

Adductor-related groin pain — the Doha framework

The Doha agreement established a clinical classification that examiners expect you to use.

The essential message: these entities coexist in a large proportion of athletes, because of the aponeurotic plate. A complete examination names all entities present, and treatment addresses all of them.

Acute adductor injury

• Mechanism: eccentric loading during change of direction, a sliding tackle, a reach or a kick — hip abducted and extended with explosive adduction.
• Location: almost always at or near the proximal enthesis, not in the muscle belly. Clinical examination localises the injury well.
• Grading on MRI: by whether the tendon is intact with oedema, partially detached, or completely avulsed, and by the degree of retraction and the extent of muscle involvement.
• Management: criteria-based rehabilitation. Relative rest and analgesia for a few days, then early graded active loading with progressive eccentric adduction work, then sport-specific progression. Return to play by criteria, not calendar.
• Complete proximal avulsion: manage non-operatively as the default. Comparative series in professional athletes show return-to-play times and outcomes comparable with surgical repair, so surgery is not routinely indicated.

Longstanding adductor-related groin pain

• Presentation: insidious exertional medial groin pain over months, often with a history of recurrent minor injuries and inadequate rehabilitation.
• Treatment: an active physical training programme is the intervention with the strongest evidence — substantially more effective than passive modalities such as physiotherapy without active strengthening, massage, stretching or electrotherapy. Recovery takes months, and the athlete must be counselled accordingly.
• Components: progressive adduction strengthening including eccentric work, core and hip stabiliser strengthening, control of dynamic movement patterns, load management, and correction of contributing factors such as reduced hip range or poor abductor strength.
• Adjuncts: image-guided injection into the enthesis has limited and inconsistent evidence and does not replace loading; it may facilitate rehabilitation in a selected athlete.

Prevention

• Eccentric adduction strength and the adduction to abduction strength ratio are modifiable risk factors.
• The Copenhagen adduction exercise (a partner-assisted or bench-supported side-lying adduction exercise) increases eccentric adduction strength, and prevention programmes incorporating it have reduced the prevalence of groin problems in randomised trials in football.
• Practical prevention answer: an in-season programme including the Copenhagen adduction exercise, appropriate load progression, and screening of adductor strength.

Adductor tenotomy in the athlete

Indication

• Refractory adductor-related groin pain in an athlete who has completed an adequate active rehabilitation programme (generally at least three to six months) without resolution, with clinical findings and imaging confirming an enthesial problem.
• Not an early or first-line intervention, and not a substitute for rehabilitation.

Selective partial adductor release — the technique to describe

• The rationale is anatomical: the adductor longus enthesis has an anterior superficial tendinous portion and a deeper aponeurotic portion continuous with the plate. Dividing the superficial anterior portion selectively relieves the enthesial load while preserving the deep aponeurotic continuity and therefore the stability of the pubic plate.
• Approach: a short transverse or longitudinal incision over the palpable adductor longus tendon, immediately below and medial to the pubic tubercle.
• Steps: expose the tendon, identify the superficial anterior tendinous fibres, divide them selectively under direct vision, preserving the deeper aponeurosis, and avoid dissection posteriorly where the anterior division of the obturator nerve lies on the adductor brevis.
• Rehabilitation: early mobilisation with graded loading, with reported return to sport typically in the region of a few months.
• Reported outcomes: series of professional athletes undergoing selective partial adductor release for chronic adductor-related groin pain report a high rate of return to play at the previous level.

Complete adductor tenotomy

• Divides the whole tendon at the pubis. Effective for pain but with a greater risk of measurable adduction weakness and, theoretically, of destabilising the aponeurotic plate.
• Reserved for cases where a selective release has failed, or where a complete release is being performed for a different indication (spasticity, contracture).

Adductor release for spastic hip displacement (cerebral palsy)

• Adductor longus tenotomy is the primary and first release. It is performed close to the pubic origin, followed if needed by gracilis release, then adductor brevis, then pectineus.
• Indication: a young child with a migration percentage of roughly 30-50 percent, reduced passive abduction and a still-adequate acetabulum, detected through a hip surveillance programme because displacement is painless until late.
• Target: approximately 40-45 degrees of abduction per side intraoperatively.
• Combine with intramuscular iliopsoas lengthening at the pelvic brim rather than a tenotomy at the lesser trochanter, to preserve hip flexion power in an ambulant child.
• Avoid complete anterior branch obturator neurectomy — it risks an abduction contracture, which is functionally worse, and it cannot abolish adduction anyway because the pectineus retains a femoral supply and the ischiocondylar adductor magnus a sciatic supply.
• If the migration percentage exceeds roughly 50-60 percent, or the acetabulum is deficient, soft-tissue release alone will fail and the operation becomes a varus derotation femoral osteotomy with a pelvic osteotomy (Dega, San Diego, Pemberton) and capsulorrhaphy as required.

Adductor tenotomy before hip arthroplasty

• A fixed adductor contracture in a long-standing arthritic or ankylosed hip prevents adequate positioning, dislocation and limb manipulation.
• Perform the adductor tenotomy first, before the arthrotomy, so that the limb can be moved freely for the rest of the procedure.
• Also relevant for perineal hygiene and catheterisation in a non-ambulant adult with adductor spasticity, where the sequence is obturator nerve block (diagnostic and therapeutic), then botulinum toxin, then tenotomy with or without limited neurectomy for a fixed problem.

The adductor canal and the block

Boundaries — state them precisely

• Extent: from the apex of the femoral triangle (where the medial border of sartorius crosses the medial border of adductor longus) to the adductor hiatus in the adductor magnus, where the femoral vessels become the popliteal vessels.
• Anterolateral wall: vastus medialis.
• Posteromedial wall: adductor longus proximally, adductor magnus distally.
• Roof: the vastoadductor membrane, deep to the sartorius.
• Contents: femoral artery, femoral vein (posterior to the artery), saphenous nerve (anterolateral to the artery), nerve to vastus medialis, and the descending genicular artery, which arises from the femoral artery within the canal just before the hiatus.
• Exits: the saphenous nerve and the saphenous branch of the descending genicular artery leave by piercing the vastoadductor membrane; the femoral artery and vein leave through the adductor hiatus.

The block

• Adductor canal block is widely used for analgesia after total knee arthroplasty and after knee arthroscopic surgery. It anaesthetises the saphenous nerve (medial knee and leg sensation), the nerve to vastus medialis, and variably the articular branches to the knee.
• It is more quadriceps-sparing than a femoral nerve block but is not motor-neutral, because the nerve to vastus medialis is a motor nerve within the canal.
• Level matters. Ultrasound and anatomical studies show that a large proportion of injections labelled adductor canal blocks are actually placed proximal to the apex of the femoral triangle, in the distal femoral triangle. A more proximal injection reaches more motor branches and produces greater quadriceps weakness.
• Practical safeguard: identify the apex sonographically (the crossing of sartorius over adductor longus), know which block you are performing, and assess quadriceps power before the first mobilisation regardless of the block used, with a knee immobiliser or supervised ambulation as required.

The adductor hiatus

• The opening in the aponeurotic insertion of the adductor magnus through which the femoral artery and vein pass to become the popliteal vessels.
• Clinical relevance: it is a fixed point of arterial tethering, which makes it a site of arterial injury in distal femoral fractures and knee dislocations, a site of entrapment in the rare popliteal artery entrapment variants, and a landmark in vascular surgical exposure of the distal femoral and proximal popliteal artery.
• The descending genicular artery arises just proximal to the hiatus.

Medial (Ludloff) approach to the hip

• The adductor longus is the first structure identified and tenotomised in the medial approach, used principally for open reduction of developmental dysplasia of the hip in the infant.
• Interval: classically between adductor longus and gracilis superficially and adductor brevis and adductor magnus deeply. The Ferguson modification works anterior to the adductor brevis, which is the safer plane.
• Why the plane matters: the anterior division of the obturator nerve lies anterior to adductor brevis and the posterior division behind it; the medial circumflex femoral artery lies posteriorly, deep to pectineus and adductor brevis, and is the dominant blood supply to the femoral head. Working anterior to adductor brevis keeps you away from both.
• Blocks to reduction released: the iliopsoas tendon at the lesser trochanter, the ligamentum teres, the pulvinar and the transverse acetabular ligament.
• Limitations: capsulorrhaphy is not possible, residual acetabular dysplasia is common, and avascular necrosis is the feared complication. Immobilise in the human position (roughly 100 degrees of flexion, 45-55 degrees of abduction), not extreme abduction.

Adolescent apophyseal avulsion

• The pubic and ischiopubic apophyses can avulse at the adductor origin in the skeletally immature athlete, presenting exactly like an adductor enthesial injury but with a bony fragment on radiograph or apophyseal oedema on MRI.
• Management is almost always non-operative with protected weight-bearing and graded rehabilitation.
• Always radiograph an adolescent with adductor-origin pain rather than assuming a soft-tissue injury.

Osteitis pubis and pubic-related groin pain

• Chronic overload of the symphysis and the aponeurotic plate, presenting with midline and paramedian pubic pain, tenderness over the symphysis, and radiographic and MRI changes (sclerosis, irregularity, marrow oedema, symphyseal widening).
• Very frequently coexists with adductor-related pain, for the mechanical reasons described.
• Treatment is load management and progressive strengthening; surgery (symphyseal debridement, curettage, arthrodesis) is a last resort with limited evidence.

Obturator neuropathy

• Exertional medial thigh pain with adductor weakness and a small patch of medial thigh numbness, caused by fascial entrapment at the exit from the obturator canal in athletes, or by pelvic pathology.
• Post-exercise electromyography of the adductors is the most useful confirmatory test; MRI excludes a mass or hernia; a diagnostic obturator nerve block supports it.
• Fascial release at the obturator canal exit has been reported to allow return to sport.

Myositis ossificans and heterotopic ossification

• Follows a direct blow or a large enthesial haematoma; presents with a firm tender mass and progressive loss of abduction.
• Radiographs show centripetal (zonal) maturation — peripheral mature bone with an immature centre, the opposite of osteosarcoma.
• Manage conservatively, avoid deep massage and early excision, and excise only a mature lesion causing mechanical restriction.