The gracilis muscle (; Latin for "slender") is the most superficial muscle on the medial side of the

thigh In human anatomy, the thigh is the area between the hip ( pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of ...

. It is thin and flattened, broad above, narrow and tapering below.

Structure

It arises by a thin aponeurosis from the anterior margins of the lower half of the symphysis pubis and the upper half of the

pubic arch The pubic arch, also referred to as the ''ischiopubic arch'', is part of the pelvis. It is formed by the convergence of the inferior rami of the ischium and pubis on either side, below the pubic symphysis. The angle at which they converge is kno ...

. The muscle's fibers run vertically downward, ending in a rounded tendon. This tendon passes behind the medial condyle of the

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates with ...

, curves around the medial condyle of the tibia where it becomes flattened, and inserts into the upper part of the medial surface of the body of the

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

, below the condyle. For this reason, the muscle is a lower limb adductor. At its insertion the tendon is situated immediately above that of the

semitendinosus muscle The semitendinosus () is a long superficial muscle in the back of the thigh. It is so named because it has a very long tendon of insertion. It lies posteromedially in the thigh, superficial to the semimembranosus. Structure The semitendinosus, r ...

, and its upper edge is overlapped by the tendon of the

sartorius muscle The sartorius muscle () is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the Anterior compartment of thigh, anterior compartment. Structure The sartorius muscle originates f ...

, which it joins to form the pes anserinus. The pes anserinus is separated from the

medial collateral ligament The medial collateral ligament (MCL), or tibial collateral ligament (TCL), is one of the four major ligaments of the knee. It is on the medial (inner) side of the knee joint in humans and other primates. Its primary function is to resist out ...

of the

knee-joint In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

by a

bursa ( grc-gre, Προῦσα, Proûsa, Latin: Prusa, ota, بورسه, Arabic:بورصة) is a city in northwestern Turkey and the administrative center of Bursa Province. The fourth-most populous city in Turkey and second-most populous in the ...

. A few of the fibers of the lower part of the tendon are prolonged into the deep fascia of the leg.

Relations

By its inner or superficial surface gracilis is in relation with the fascia lata, and below with the sartorius and internal

saphenous nerve The saphenous nerve (long or internal saphenous nerve) is the largest cutaneous branch of the femoral nerve. It is a strictly sensory nerve, and has no motor function. Structure It is purely a sensory nerve. The saphenous nerve is the largest ...

; the internal saphenous vein crosses it lying superficially to the fascia lata. By its outer or deep surface with the

adductor longus In the human body, the adductor longus is a skeletal muscle located in the thigh. One of the adductor muscles of the hip, its main function is to adduct the thigh and it is innervated by the obturator nerve. It forms the medial wall of the fem ...

, brevis, and

magnus Magnus, meaning "Great" in Latin, was used as cognomen of Gnaeus Pompeius Magnus in the first century BC. The best-known use of the name during the Roman Empire is for the fourth-century Western Roman Emperor Magnus Maximus. The name gained wid ...

, and the internal lateral ligament of the knee-joint, from which it is separated by a synovial bursa common to the tendons of the gracilis and

semitendinosus The semitendinosus () is a long superficial muscle in the back of the thigh. It is so named because it has a very long tendon of insertion. It lies posteromedially in the thigh, superficial to the semimembranosus. Structure The semitendinosus, r ...

Nerve supply

The obturator nerve innervates the gracilis muscle via the lumbar spinal vertebrae.

Function

The muscle adducts, medially rotates (with hip flexion), laterally rotates, and flexes the hip as above, and also aids in flexion of the knee.

Clinical significance

The gracilis muscle is commonly used as a

flap Flap may refer to: Arts, entertainment, and media * ''Flap'' (film), a 1970 American film * Flap, a boss character in the arcade game ''Gaiapolis'' * Flap, a minor character in the film '' Little Nemo: Adventures in Slumberland'' Biology and he ...

microsurgery Microsurgery is a general term for surgery requiring an operating microscope. The most obvious developments have been procedures developed to allow anastomosis of successively smaller blood vessels and nerves (typically 1 mm in diameter) whic ...

. According to the classification of Mathes and Nahai, it presents a type II blood supply, allowing it to be transferred on its artery derived from the medial circumflex femoral artery. This artery enters the muscle about 10 cm from the pubic symphysis. At this point (or 1 cm proximal) the nerve also enters. Gracilis muscle is widely used in reconstructive surgery (graciloplasty), either as a pedicled flap or as a free microsurgical flap. Both pedicled and free flaps can be muscular or musculocutaneous (the so- called "composite flaps"). As a pedicled flap, gracilis muscle can be used in perineal and vaginal reconstruction, after oncological surgery, in the treatment of recurrent anovaginal and rectovaginal fistulas as well in the coverage of the neurovascular bundle after vascular surgery. As a functioning pedicled flap, the gracilis muscle can be transferred for the treatment of anal incontinence. This technique called graciloplasty was described in the 1950s by Pickrell and was revolutionized in the late 1980s by the introduction of chronic muscle electro-stimulation. The gracilis microsurgical free flap is commonly used in the reconstruction of upper and lower limbs, in breast reconstruction and – as a free functioning flap – to restore forearm function or in dynamic reconstruction of facial paralysis.

Transplantation sites

The muscle may be split to reduce bulk for facial reanimation, as well as to repair hand muscles. It can be used to fashion an

external anal sphincter The external anal sphincter (or sphincter ani externus ) is a flat plane of skeletal muscle fibers, elliptical in shape and intimately adherent to the skin surrounding the margin of the anus. Anatomy The external anal sphincter measures about 8 ...

Additional images

File:Gray235.png, Right hip bone. External surface. File:Gray344.png, Structures surrounding right hip-joint. File:Gray430.png, Muscles of the iliac and anterior femoral regions. File:Gray434.png, Muscles of the gluteal and posterior femoral regions. File:Gray549.png, The left femoral triangle. File:Gray827.png, Nerves of the right lower extremity. Front view. File:Anatomical dissection6.JPG, Gracilis muscle File:Slide3rrr.JPG, Gracilis muscle File:Slide3www.JPG, Gracilis muscle File:Slide8CCCC.JPG, Gracilis muscle File:Slide4FFFFF.JPG, Gracilis muscle File:Slide6LLLL.JPG, Gracilis muscle File:Slide3WWWW.JPG, Gracilis muscle File:Slide11WWWW.JPG, Gracilis muscle File:Slide2DADE.JPG, Muscles of thigh. Lateral view. File:Slide2EA.JPG, Muscles of thigh. Cross section.

References

External links

* - "Muscles of the anterior (extensor) compartment of the

." * - "Muscles that form the superficial boundaries of the

popliteal fossa The popliteal fossa (also referred to as hough, .html" ;"title="/sup>">/sup> or kneepit in analogy to the cubital fossa) is a shallow depression located at the back of the knee joint. The bones of the popliteal fossa are the femur and the tibia ...

." * {{DEFAULTSORT:Gracilis Muscle Hip adductors Hip flexors Thigh muscles Medial compartment of thigh