Sartorius muscle
Encyclopedia
The Sartorius muscle – the longest muscle in the human body – is a long thin muscle
that runs down the length of the thigh
. Its upper portion forms the lateral border of the femoral triangle
.
, running obliquely across the upper and anterior part of the thigh
in an inferomedial direction.
It descends as far as the medial side of the knee
, passing behind the medial condyle of the femur
to end in a tendon.
This tendon curves anteriorly to join the tendons of the gracilis
and semitendinous muscles which together form the pes anserinus
, finally inserting into the proximal part of the tibia
on the medial surface of its body.
word sartor, meaning tailor, and it is sometimes called the tailor's muscle.
There are four hypotheses as to the genesis of the name:
One is that this name was chosen in reference to the cross-legged position in which tailors once sat. Another is that it refers to the location of the inferior portion of the muscle being the "inseam" or area of the inner thigh tailors commonly measure when fitting a pant. A third is that the muscle closely resembles a tailor's ribbon. Additionally, antique sewing machines required continuous cross body pedalling. This combination of lateral rotation and flexion of the hip and flexion of the knee gave tailors particularly enlarged sartorius muscles.
(AORN Journal, J. Murauski). The femoral nerve is responsible for both sensory and motor components in the sartorius and provides proprioceptive feedback for the muscle (Anatomy and Physiology 5th edition, K. Saladin)
, an inflammatory condition of the medial portion of the knee. This condition usually occurs in athletes from overuse and is characterized by pain, swelling and tenderness. The pes anserinus
is made up from the tendons of the gracilis
, semitendinosus, and sartorius muscles; these tendons attach on to the anteromedial proximal tibia. When inflammation of the bursa underlying the tendons occurs they separate from the head of the tibia (eMedicine, MD. M. Glencross).
, the notch of the ilium
, the ilio-pectineal line or the pubis
occur.
The muscle may be split into two parts, and one part may be inserted into the fascia lata
, the femur
, the ligament of the patella or the tendon of the Semitendinosus.
The tendon of insertion may end in the fascia lata
, the capsule of the knee-joint, or the fascia of the leg.
The muscle may be absent ( p.606).
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
that runs down the length of the thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
. Its upper portion forms the lateral border of the femoral triangle
Femoral triangle
The femoral triangle is an anatomical region of the upper inner human thigh.-Boundaries:It is bounded by:* the inguinal ligament* the medial border of the adductor longus muscle...
.
Origin and insertion
The sartorius muscle arises by tendinous fibres from the anterior superior iliac spineAnterior superior iliac spine
The anterior superior iliac spine is an important landmark of surface anatomy. It refers to the anterior extremity of the iliac crest of the pelvis, which provides attachment for the inguinal ligament, and the sartorius muscle...
, running obliquely across the upper and anterior part of the thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
in an inferomedial direction.
It descends as far as the medial side of the knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...
, passing behind the medial condyle of the femur
Medial condyle of femur
The medial condyle is one of the two projections on the lower extremity of femur.The medial condyle is larger than the lateral condyle due to more weight bearing caused by the center of gravity being medial to the knee. On the posterior surface of the condyle the linea aspera turns into the...
to end in a tendon.
This tendon curves anteriorly to join the tendons of the gracilis
Gracilis muscle
The gracilis is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.-Origin and insertion:...
and semitendinous muscles which together form the pes anserinus
Pes anserinus (leg)
The pes anserinus is the insertion of the conjoined tendons of three muscles onto the anteromedial surface of the proximal extremity of the tibia.-Anatomy:The three muscles are :* sartorius...
, finally inserting into the proximal part of the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
on the medial surface of its body.
Etymology
Sartorius comes from the LatinLatin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
word sartor, meaning tailor, and it is sometimes called the tailor's muscle.
There are four hypotheses as to the genesis of the name:
One is that this name was chosen in reference to the cross-legged position in which tailors once sat. Another is that it refers to the location of the inferior portion of the muscle being the "inseam" or area of the inner thigh tailors commonly measure when fitting a pant. A third is that the muscle closely resembles a tailor's ribbon. Additionally, antique sewing machines required continuous cross body pedalling. This combination of lateral rotation and flexion of the hip and flexion of the knee gave tailors particularly enlarged sartorius muscles.
Actions
Assists in flexion, abduction and lateral rotation of hip, and flexion of knee. Looking at the bottom of one's foot, as if checking to see if one had stepped in gum, demonstrates all four actions of sartorius.Innervation
Situated in the anterior fascial compartment of the thigh, the sartorius is innervated via the anterior (or superficial) branch of the femoral nerveFemoral nerve
The femoral nerve, the largest branch of the lumbar plexus, arises from the dorsal divisions of the ventral rami of the second, third, and fourth lumbar nerves...
(AORN Journal, J. Murauski). The femoral nerve is responsible for both sensory and motor components in the sartorius and provides proprioceptive feedback for the muscle (Anatomy and Physiology 5th edition, K. Saladin)
Pathology
One of the many conditions that can disrupt the use of the sartorius is pes anserine bursitisPes Anserine Bursitis
Pes anserine bursitis is an inflammatory condition of the medial knee at the bursa of the pes anserinus.- Pathology :The pes anserinus is the anatomic term used to identify the insertion of the conjoined tendons Sartorius, Gracilis, and Semitendinosus into the anteromedial proximal tibia...
, an inflammatory condition of the medial portion of the knee. This condition usually occurs in athletes from overuse and is characterized by pain, swelling and tenderness. The pes anserinus
Pes anserinus
Pes anserinus is the anatomic term used to describe two different structures:* Pes anserinus * Pes anserinus...
is made up from the tendons of the gracilis
Gracilis muscle
The gracilis is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.-Origin and insertion:...
, semitendinosus, and sartorius muscles; these tendons attach on to the anteromedial proximal tibia. When inflammation of the bursa underlying the tendons occurs they separate from the head of the tibia (eMedicine, MD. M. Glencross).
Variations
Slips of origin from the outer end of the inguinal ligamentInguinal ligament
The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...
, the notch of the ilium
Ilium (bone)
The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
, the ilio-pectineal line or the pubis
Pubis (bone)
In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....
occur.
The muscle may be split into two parts, and one part may be inserted into the fascia lata
Fascia lata
-Thickness:It is an investment for the whole of the thigh, but varies in thickness in different parts.Thus, it is thicker in the upper and lateral part of the thigh, where it receives a fibrous expansion from the Glutæus maximus, and where the Tensor fasciæ latæ is inserted between its layers; it...
, the femur
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, the ligament of the patella or the tendon of the Semitendinosus.
The tendon of insertion may end in the fascia lata
Fascia lata
-Thickness:It is an investment for the whole of the thigh, but varies in thickness in different parts.Thus, it is thicker in the upper and lateral part of the thigh, where it receives a fibrous expansion from the Glutæus maximus, and where the Tensor fasciæ latæ is inserted between its layers; it...
, the capsule of the knee-joint, or the fascia of the leg.
The muscle may be absent ( p.606).