Gracilis Flap

May 1, 2021 4 min read
Gracilis Flap

This article details the anatomy, technique, indications, benefits and disadvantages of the gracilis flap.

5 Key Points

1. Workhorse flap for facial reanimation, limb trauma, perineal recon.
2. Pedicle is medial femoral circumflex artery and venae comitantes.
3. Thin muscle in medial thigh located ~2 fingers below adductor longus.
4. Benefits are reliable anatomy with thin volume.
5. Disadvantaged by strength and a variable skin supply.


Gracilis Flap Anatomy

Essentials
· Location: 2-3 fingers posterior to adductor longus.
· Muscle: pubic symphysis to medial condyle of the knee.
· Artery: medial femoral circumflex system
· Nerve: branch of the obturator nerve.

Gracilis Muscle

The gracilis muscle is a flat and thin muscle located superficially in the medial thigh. Here are some key points:

  • Location: 2-3 fingers medial and posterior to adductor longus
  • Origin is Broad: pubic symphysis, inferior pubic ramus, ischium.
  • Insertion is Thin: medial condyle of the tibia and medial tibial surface
  • Innervation: branch of obturator nerve
  • Function: thigh adduction and knee flexion

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Anatomy of the Gracilis Muscle Flap

Blood Supply to Gracilis Flap

The gracilis flap is a Mathes and Nahai Type II. It has one dominant and several minor vascular pedicles arising from the medial femoral circumflex (same blood supply as adductor longus).

Pedicle

  • Measurements: ~ 7cm long and ~2mm diameter.
  • Origin: medial femoral circumflex artery (branch of profunda femoris)
  • Course: travels laterally deep to adductor longus on adductor magnus
  • Entry: enters muscle ~10cm inferior to pubic tubercle as several branches.
  • Minor pedicles are usually proximal & distal (variations do exist1).

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Blood supply to the Gracilis Muscle Flap

Perforators

  • Musculocutaneous: more prominent proximally, more variable distally.
  • Septocutaneous: direct from pedicle between adductor longus & gracilis.

Veins

  • Number: Usually, two venae comitantes travel with the artery.
  • Dimensions: ~6cm length and ~2mm diameter

Innervation of Gracilis Muscle

Motor Nerve to Muscle

  • This is the anterior branch of the obturator nerve
  • It is the motor innervation to the Gracilis Muscle

Sensory Nerve

  • This is the medial cutaneous nerve of the thigh
  • It is a branch of the obturator nerve
  • It courses on the undersurface of the adductor longus muscle as a separate branch, following the course of the motor branch to the gracilis muscle.


How to Perform a Gracilis Flap

The gracilis flap technique is performed under a general anaesthetic in a frog-leg position. It is designed relative to the adductor longus. Harvesting requires the identification of gracilis and its pedicle between the adductor muscles.

Frog-leg Position

  • Supine
  • Thigh abducted
  • Knee slightly flexed.

Position and Skin Markings for Gracilis Flap

Skin Markings of Gracilis Flap

💡
Design Tip: mycocutaneous skin paddles can be designed laterally to overly the posterior edge of adductor longus/intermuscular septum.

The following technique should be considered when designing a gracilis flap:

  1. Identify adductor longus tendon on the proximal aspect of medial thigh
  2. Measure 2-3 fingers below the adductor longus tendon
  3. Draw a line along an axis towards the medial tibial condyle
  4. Mark the expected location of the pedicle ~10cm distal to the groin crease

Myocuntaenous flaps require anterior (lateral) & posterior (medial) incisions.

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Surface Markings for the Gracilis Muscle

Harvesting a Myocutaenous Gracilis Flap

  1. Incise anteriorly to identify adductor longus.
  2. Protect the great saphenous vein.
  3. Retract the adductor longus to visualize pedicle & nerve in the septum.
  4. Incise posteriorly through subcutaneous tissue to gracilis
  5. Dissect pedicle b/w adductor longus & magnus until adductor longus branch.
  6. Mobilize proximally (muscle) and distally (tendon)
  7. Transect nerve (protect nerve if functional flap)
  8. Closure in layers with drain.

💡
Technique Tip: intermuscular septum should be included with the flap as it contains septocutaneous perforators supplying the overlying skin.

Gracilis Flap Harvesting - Video


Indications for Gracilis Flap

The gracilis muscle or musculocutaneous flap is a workhorse flap. It can be used for functional restoration and wound coverage.

Functional Flap (Motor Nerve Protected)

  • Facial reanimation
  • Anal sphincter reconstruction

Pedicled Flap

  • Myocutaneous flap for vagina, perineum, ischium
  • Medial Knee Defects (Less Common)

Free Flap

  • Lower Limb Trauma
  • Breast Reconstruction (Less Common)
  • Head and Neck Reconstruction (Less Common)


Advantages and Disadvantages

There is no such thing as a "perfect flap". There are benefits and pitfalls to the Gracilis flap. 

Advantages of Gracilis Flap

  • Reproducible anatomy
  • Long and reliable pedicle
  • Dimensions and volume are ideal for specific areas (e.g facial reanimation)
  • Ergonomics allows for two teams (1 preparing, 1 elevation)
  • Minimal donor site morbidity or functional issues.

Disadvantages of Gracilis Flap

  • Skin blood supply is not constant
  • Thin muscle results in less strength.


References

  1. Mathes SJ, Nahai F. Clinical atlas of muscle and musculocutaneous flaps.
    CV Mosby, St Louis, 1979.
  2. Mathes SJ, Nahai F. Classification of the vascular anatomy of muscles: experimental and clinical correlation. Plast Reconstr Surg 1981; 67(2): 177–187
  3. Chuang DCC, Mardini S, Lin SH, Chen HC. Free proximal gracilis muscle and its skin paddle compound flap transplantation for complex facial paralysis. Plast Reconstr Surg 2004; 113: 126–132
  4. Chwei-Chin Chuang, D. (2009). Gracilis flap. Flaps and Reconstructive Surgery, 397–410.doi:10.1016/b978-0-7216-0519-7.00029-0.
  5. Azizzadeh B, Pettijohn KJ. The Gracilis Free Flap. Facial Plast Surg Clin North Am. 2016 Feb;24(1):47-60. doi: 10.1016/j.fsc.2015.09.002. PMID: 26611701.
  6. Lyons ME, Goldman JJ. Gracilis Tissue Transfer. 2021 Jul 6. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 32644472.
  7. Garcia RM, Ruch DS. Free Flap Functional Muscle Transfers. Hand Clin. 2016 Aug;32(3):397-405. doi: 10.1016/j.hcl.2016.03.009. PMID: 27387083.


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