Adductor Brevis Anatomy

Origin

• Outer (anterior) surface of the body of the pubis and the inferior pubic ramus.
• Positioned between the origin of the gracilis below and medially and the origin of the obturator externus above and laterally.
• The origin is broader and more inferior than that of the adductor longus, whose narrow tendon lies immediately above and lateral to it on the pubic body.

Insertion

• The upper third of the medial lip of the linea aspera and the adjacent pectineal line of the femur, by an aponeurosis.
• The insertion is proximal to that of the adductor longus (which takes the middle third of the medial lip) and anterior to the adductor magnus insertion.
• Because insertion is proximal and the muscle is short, its fibres are relatively transverse, giving it a favourable adduction moment arm but very little excursion.

Shape and plane

• Triangular and short (hence brevis), broad at its femoral insertion.
• Occupies the middle plane of the compartment: deep to pectineus and adductor longus, superficial to adductor magnus, with the gracilis medial and superficial to the whole group.
• Its superior border relates to the obturator externus and the hip joint capsule; its inferior border to the adductor magnus.

Named landmarks and measurements

Obturator nerve — and a genuine variation

• Principal supply: the anterior division of the obturator nerve (L2, L3, L4).
• Additional supply: the posterior division also contributes to the adductor brevis in a substantial proportion of individuals. This dual contribution is described in anatomical studies and is a legitimate variation to mention.
• Root values: L2, L3, L4 (anterior divisions of the ventral rami).
• Motor entry: branches from the anterior division enter the anterior surface of the muscle; branches from the posterior division, where present, enter the posterior surface.

Practical consequences

• The nerve divisions define the muscle, not the other way round. In a medial approach, finding the anterior division running distally on the anterior surface of adductor brevis confirms both that you have identified the correct muscle and that you are in the safe plane.
• Selective anterior branch obturator neurectomy for adductor spasticity: the anterior division is accessible on the anterior surface of the brevis, which is why it can be divided selectively. However, because the brevis may also receive posterior division fibres, an anterior neurectomy does not necessarily denervate it completely.
• Obturator nerve block for chronic adductor spasticity, for diagnostic purposes in suspected neuropathy, and to prevent the adductor jerk during transurethral bladder resection. The block is performed at or just distal to the obturator canal, roughly 2-3 cm inferolateral to the pubic tubercle, ideally under ultrasound guidance with the interfascial plane between the adductor muscles as the target.
• Incomplete block is common and has three anatomical explanations: an accessory obturator nerve (present in a minority, crossing over the superior pubic ramus rather than through the canal), the femoral nerve contribution to the pectineus, and a distal division of the nerve requiring separate injections for each division.
• Obturator nerve entrapment in athletes occurs at the fascia overlying the short adductor (adductor brevis) at the exit from the obturator canal, producing exertional medial thigh pain and adductor weakness. Fascial release at that point has been reported to restore sport.

Root-value cross-check

• Hip adduction = L2/L3/L4 (obturator).
• Distal medial thigh sensation is the obturator cutaneous branch (from the anterior division).
• The posterior division supplies the knee joint via an articular branch through the adductor hiatus — the anatomical basis of referred medial knee pain in hip pathology.
• Weak adduction with a medial thigh sensory patch localises to the obturator nerve; add quadriceps weakness and the lesion is proximal (lumbar plexus, L2-L4 roots, retroperitoneal haematoma, abscess or tumour).

Supply

• Obturator artery — its anterior and posterior branches supply the proximal muscle, entering close to the nerve after emerging from the obturator canal. The anterior branch also gives the acetabular branch running in the ligamentum teres.
• Medial circumflex femoral artery — supplies the proximal muscle as it passes deep to the pectineus and adductor brevis.
• Profunda femoris artery — muscular branches, the dominant supply to the body of the muscle.
• Perforating branches of the profunda femoris — these pass through the adductor brevis and the adductor magnus to reach the posterior compartment. This is a genuinely useful point: the perforators pierce the adductors, so dividing the adductor brevis blindly bleeds.

The vascular fact that dominates the surgical anatomy

• The medial circumflex femoral artery (MCFA) arises from the profunda femoris (occasionally directly from the femoral artery), passes posteriorly between the pectineus and the psoas major, then continues between the obturator externus and the quadratus femoris to reach the posterior aspect of the hip. Its deep branch and the terminal retinacular (lateral epiphyseal) vessels entering the posterosuperior head-neck junction are the dominant blood supply to the adult femoral head.
• The MCFA therefore lies deep and posterior to the pectineus and adductor brevis in the proximal medial thigh. Dissection carried posterior to the adductor brevis in a medial approach risks it, and its injury causes avascular necrosis of the femoral head.

Not a flap

• The adductor brevis has no single dominant pedicle and a short, broad, low-excursion architecture. It is not used as a muscle flap or as a tendon transfer donor — a negative worth stating explicitly in a viva, alongside the fact that the useful medial thigh flap and graft donor is the gracilis (on the ascending branch of the medial circumflex femoral artery, with a long tendon and a single dominant nerve).

Anterior (superficial) to adductor brevis

• Pectineus proximally and adductor longus distally.
• Anterior division of the obturator nerve, running distally on its anterior surface — the key relation.
• Femoral vessels further anteriorly, in the femoral triangle on the floor formed by iliopsoas and pectineus.

Posterior (deep) to adductor brevis

• Posterior division of the obturator nerve, on the anterior surface of the adductor magnus.
• Adductor magnus.
• Perforating branches of the profunda femoris passing through toward the posterior compartment.

Superior

• Obturator externus and the hip joint capsule — the depth limit of a medial approach and the target in open reduction of a dislocated hip.
• Medial circumflex femoral artery passing posteriorly, deep to the pectineus.

Inferior and medial

• Adductor magnus inferiorly.
• Gracilis medially and superficially — the most medial strap of the compartment and the only biarticular adductor.

Structures at risk in the adductor brevis territory

The medial (Ludloff) approach — and why the brevis defines it

Purpose: direct access to the inferomedial hip capsule and the structures blocking reduction of a dislocated hip. Principally used for open reduction of developmental dysplasia of the hip in the infant (commonly quoted as most suitable under about 12-18 months), and occasionally for psoas release or biopsy of a medial lesion.

Positioning and incision

• Supine with the hip flexed, abducted and externally rotated (the frog-leg position).
• Incision: transverse or short longitudinal over the adductor longus, beginning roughly 1-2 cm distal to the pubic tubercle and extending 4-6 cm distally and posteriorly.

The two described intervals — know both and know which is safer

Sequence using the safer plane

1. Identify and tenotomise the adductor longus close to its origin.
2. Identify the anterior division of the obturator nerve on the anterior surface of the adductor brevis — this confirms the plane.
3. Develop the interval anterior to the adductor brevis, retracting the pectineus anteriorly (which also shields the femoral vessels lying on its anterior surface in the iliopectineal groove).
4. Identify and release the iliopsoas tendon at the level of the lesser trochanter — a major block to reduction.
5. Perform the capsulotomy, excise the ligamentum teres and the pulvinar, and divide the transverse acetabular ligament.
6. Reduce concentrically without force, and immobilise in the human position (approximately 100 degrees of flexion, 45-55 degrees of abduction).

Limitations to state

• Capsulorrhaphy is not possible through this approach — a genuine and important limitation.
• A concurrent pelvic osteotomy is not possible.
• Residual acetabular dysplasia is common and may require later surgery.
• Avascular necrosis is the feared complication, with rates varying widely between series.

Obturator nerve block

• Indications: prevention of the adductor jerk during transurethral resection of a lateral bladder wall tumour (the obturator nerve runs adjacent to the lateral bladder wall and is stimulated by the resectoscope current); diagnostic block in suspected obturator neuropathy or in assessing whether adductor spasticity is the source of a problem; therapeutic block for chronic adductor spasticity; and as a component of analgesia for hip and knee surgery in some regimens.
• Technique: classically a landmark technique at the obturator canal, approximately 2-3 cm inferolateral to the pubic tubercle; now more commonly ultrasound-guided, either at the canal (proximal, blocking the common nerve) or distally in the thigh, injecting into the interfascial planes between pectineus and adductor brevis (anterior division) and between adductor brevis and adductor magnus (posterior division).
• Why the distal technique needs two injections: the divisions are separated by the adductor brevis, so a single interfascial injection anterior to the brevis blocks only the anterior division.
• Reasons for an incomplete block:
  • Accessory obturator nerve (present in a minority), which passes over the superior pubic ramus rather than through the canal.
  • Femoral nerve contribution to the pectineus, which is not blocked.
  • Failure to block both divisions when the distal approach is used.
  • Note also that the ischiocondylar part of adductor magnus is supplied by the tibial division of the sciatic nerve and is never blocked by an obturator block.

Selective obturator neurectomy

• Anterior branch neurectomy was formerly combined with adductor release for spastic adduction. It is now generally avoided or limited, because a complete neurectomy risks an abduction contracture — a functionally worse deformity for seating and perineal care.
• It also cannot abolish adduction, for the reasons above.
• Where a neural procedure is desired, botulinum toxin to the adductor group or a diagnostic then therapeutic block are the graded alternatives before any irreversible step.

Obturator neuropathy

• Causes: pelvic and acetabular surgery, pelvic fracture, obstetric compression during labour, gynaecological and urological surgery, tumour or lymphadenopathy, pelvic haematoma, obturator hernia, and in athletes fascial entrapment at the exit from the obturator canal over the short adductor.
• Presentation: exertional medial thigh pain beginning after minutes of activity, adductor weakness, and a small patch of altered sensation on the distal medial thigh. Not tender at the adductor enthesis — which is the discriminator from adductor-related groin pain.
• Investigation: MRI of the pelvis to exclude a mass, haematoma or hernia; electromyography of the adductors, ideally after exercise provocation, which is the most useful confirmatory test; a diagnostic obturator nerve block.
• Treatment: address the cause. For fascial entrapment in the athlete, surgical release of the fascia over the short adductor at the obturator canal exit has been reported to allow return to sport.
• MRI denervation pattern: oedema and later fatty atrophy in adductor longus, brevis, gracilis and the adductor part of magnus, with relative sparing of pectineus and of the ischiocondylar adductor magnus — a pattern that localises the lesion to the obturator nerve.

Referred knee pain — the paediatric trap

• The posterior division of the obturator nerve gives an articular branch to the knee, descending with the popliteal artery through the adductor hiatus to the posterior capsule.
• Consequence: hip pathology refers pain to the medial knee. A child presenting with knee pain and a normal knee examination must have the hip examined and imaged — slipped upper femoral epiphysis, Perthes disease and septic arthritis of the hip are all missed this way.

Adductor release for spastic hip displacement

Context and surveillance

• Hip displacement is common in cerebral palsy and its prevalence rises steeply with GMFCS level, approaching the majority in non-ambulant children (GMFCS IV-V). It is painless until late, which is why radiographic surveillance rather than symptom-driven review is the standard of care.
• Migration percentage (Reimers index) on a standardised AP pelvis with the legs neutral: the proportion of femoral head width lateral to Perkins' line.
• Surveillance schedules are stratified by GMFCS level, with more frequent radiographs at higher levels.

Where adductor brevis fits

• The brevis is the third structure released, after adductor longus and gracilis, and only if abduction remains restricted. Because its fibres are short and relatively transverse, it is frequently the residual restraint after the longus and gracilis have gone.
• Divide it under direct vision. Behind it lie the posterior division of the obturator nerve and the adductor magnus; passing through it are the perforating branches of the profunda femoris.
• Partial rather than complete release of the brevis is often sufficient to reach the target.

Endpoint and adjuncts

• Target: approximately 40-45 degrees of abduction per side intraoperatively.
• Intramuscular iliopsoas lengthening at the pelvic brim rather than a tenotomy at the lesser trochanter, preserving hip flexion power in an ambulant child.
• Avoid a complete anterior branch obturator neurectomy — abduction contracture risk, and adduction cannot be abolished anyway.

When release alone will not work

• Migration percentage greater than about 50-60 percent, an established acetabular deficiency, marked coxa valga and femoral anteversion, or an older child.
• Then the operation is a varus derotation osteotomy of the proximal femur with a pelvic osteotomy (Dega, San Diego, Pemberton), open reduction and capsulorrhaphy as required, with adductor release as part of the same procedure.
• Salvage for the painful dislocated hip in a non-ambulant adolescent — proximal femoral resection (Castle or McHale), valgus osteotomy, or arthroplasty in selected cases — has limited and variable outcomes, which is the argument for effective surveillance.

Adductor release in the adult

• Adductor spasticity after stroke, brain injury or spinal cord injury causing scissoring, hygiene difficulty or problems with catheterisation: graded management with obturator nerve block (diagnostic then therapeutic), then botulinum toxin, then adductor tenotomy with or without limited neurectomy for a fixed problem.
• Fixed adductor contracture before total hip arthroplasty: perform the adductor tenotomy before the arthrotomy so that the limb can be manipulated and dislocated freely.

The adductor compartment

• Contents: adductor longus, adductor brevis, adductor magnus, gracilis, obturator externus, and (by convention) pectineus; the obturator nerve and vessels; and the profunda femoris with its perforating branches.
• Boundaries: the medial intermuscular septum separates it from the anterior compartment; the posterior intermuscular septum from the posterior compartment; the femur and the fascia lata complete it.
• Adductor compartment syndrome is rare but recognised, most often after a crush injury, a large adductor haematoma (particularly in an anticoagulated patient), reperfusion, or prolonged compression. It presents with a tense tender medial thigh, pain out of proportion, and pain on passive hip abduction (which stretches the adductors). Treatment is a medial thigh fasciotomy through a longitudinal medial incision, added to the lateral incision when the anterior compartment also requires decompression.

Perforating branches of the profunda femoris

• Typically three to four perforators pass from the anterior to the posterior compartment, piercing the adductor brevis and the adductor magnus and also the intermuscular septa.
• Relevance here: dividing the adductor brevis or magnus without vision bleeds from a vessel that then retracts into muscle. Control under direct vision, and never chase a retracted vessel blindly toward the posterior compartment.
• The same vessels are the ones divided in the lateral approach to the femur when the vastus lateralis is elevated off the lateral intermuscular septum.

Obturator hernia

• Herniation through the obturator canal, classically in an elderly, thin, multiparous woman, presenting with small bowel obstruction.
• Howship-Romberg sign: medial thigh pain on hip extension, adduction and internal rotation, from obturator nerve compression by the hernia.
• Hannington-Kiff sign: absent adductor reflex with a preserved patellar reflex.
• Diagnosis: CT. Treatment: surgical repair, usually urgently.
• Orthopaedic relevance: it is a cause of medial thigh and knee pain that will be missed if the differential stops at the musculoskeletal system.

Corona mortis

• An anastomotic vessel between the obturator and external iliac or inferior epigastric systems, crossing the superior pubic ramus typically within 3-6 cm lateral to the symphysis pubis, deep to the adductor and pectineus origins.
• Present in a substantial proportion of individuals, venous more often than arterial.
• Relevance: torrential and difficult-to-control bleeding during anterior pelvic (Stoppa, ilioinguinal) approaches, acetabular fracture fixation and pelvic ring surgery. Inspect and ligate deliberately.

Heterotopic ossification

• Occurs in the adductor group after acetabular fracture surgery, hip arthroplasty, and head or spinal cord injury, and can bridge the pubis to the femur producing a fixed adduction deformity.
• Management: prophylaxis in high-risk patients; excision only when mature, with recurrence prophylaxis.