The vastus medialis is an extensor muscle located medially in the thigh that extends the knee. The vastus medialis is part of the quadriceps muscle group; the vastus medialis is a muscle present in the anterior compartment of thigh, is one of the four muscles that make up the quadriceps muscle. The others are vastus intermedius and rectus femoris, it is the most medial of the "vastus" group of muscles. The vastus medialis arises medially along the entire length of the femur, attaches with the other muscles of the quadriceps in the quadriceps tendon; the vastus medialis muscle originates from a continuous line of attachment on the femur, which begins on the front and middle side on the intertrochanteric line of the femur. It continues down and back along the pectineal line and descends along the inner lip of the linea aspera and onto the medial supracondylar line of the femur; the fibers converge onto the inner part of the quadriceps tendon and the inner border of the patella. The obliquus genus muscle is the most distal segment of the vastus medialis muscle.
Its specific training plays an important role in maintaining patella position and limiting injuries to the knee. With no clear delineation, it is the most distal group of fibers of the vastus medialis; the vastus medialis is one of four muscles in the anterior compartment of the thigh. It is involved in knee extension, along with the other muscles the quadriceps muscle; the vastus medialis contributes to correct tracking of the patella. A division of the vastus medialis muscle into two groups of fibers has been hypothesized, a long and inline group of fibres with the quadriceps ligament, the vastus medialis longus. There is as yet insufficient evidence to conclusively deny this hypothesis. Knee pain is thought to be associated with specific quadriceps muscle weakness or fatigue in the vastus medialis obliquus, it is known that fatigue can be caused by many different mechanisms, ranging from the accumulation of metabolites within muscle fibers to the generation of an inadequate motor command in the motor cortex.
Characteristics of the vastus medialis, including its angle of insertion, correlate with presence of knee joint pain. However, this syndrome is complex and definitive evidence of causality has not yet been published. Misfiring and fatiguing of the VMO causes mal-tracking of the patella and subsequent damage to surrounding structures creating increased force on the knees resulting in injuries such as patellofemoral pain syndrome, anterior cruciate ligament rupture and tendinitis. Through the use of electromyography, researchers can evaluate and record the electrical activity produced by the skeletal muscle of the VMO to analyze the biomechanics and detect any possible abnormalities, weakness, or fatigue. With an analysis of muscle activity of the VMO through the use of electromyography, proper rehabilitative plans and goals can be established to not only correct the established abnormality, but prevent such injuries if tested sooner. Preventing injuries is crucial as well as teaching proper training techniques to ensure there are no valgus collapse forces causing unplanned stress on other structures of the knee, causing asymmetry, predisposing that individual for injury.
Medial patellofemoral ligament This article incorporates text in the public domain from page 471 of the 20th edition of Gray's Anatomy Cross section image: pembody/body18b—Plastination Laboratory at the Medical University of Vienna PTCentral
Biceps femoris muscle
The biceps femoris is a muscle of the thigh located to the posterior, or back. As its name implies, it has two parts, it has two heads of origin: the long head arises from the lower and inner impression on the posterior part of the tuberosity of the ischium. This is a common tendon origin with the semitendinosus muscle, from the lower part of the sacrotuberous ligament; the short head, arises from the lateral lip of the linea aspera, between the adductor magnus and vastus lateralis extending up as high as the insertion of the gluteus maximus, from the lateral prolongation of the linea aspera to within 5 cm. of the lateral condyle. The two muscle unite in an intricate fashion; the fibers of the long head form a fusiform belly, which passes obliquely downward and lateralward across the sciatic nerve to end in an aponeurosis which covers the posterior surface of the muscle and receives the fibers of the short head. Inferiorly, the aponeurosis condenses to form a tendon which predominantly inserts onto the lateral side of the head of the fibula.
There is a second small insertional attachment by a small tendon slip into the lateral condyle of the tibia. At its insertion the tendon divides into two portions, which embrace the fibular collateral ligament of the knee-joint. Together, this joining of tendons is referred to as the conjoined tendon of the knee. From the posterior border of the tendon a thin expansion is given off to the fascia of the leg; the tendon of insertion of this muscle forms the lateral hamstring. The short head may be absent; the tendon of insertion may be attached to the Iliotibial band and to retinacular fibers of the lateral joint capsule. A slip may pass to the gastrocnemius, it is a composite muscle as the short head of the biceps femoris develops in the flexor compartment of the thigh and is thus innervated by common fibular branch of the sciatic nerve, while the long head is innervated by the tibial branch of the sciatic nerve. The muscle's vascular supply is derived from the anastomoses of several arteries: the perforating branches of the profunda femoris artery, the inferior gluteal artery, the popliteal artery.
Both heads of the biceps femoris perform knee flexion. Since the long head originates in the pelvis it is involved in hip extension; the long head of the biceps femoris is a weaker knee flexor. For the same reason the long head is a weaker hip extender; when the knee is semi-flexed, the biceps femoris in consequence of its oblique direction rotates the leg outward. Avulsion of the biceps femoris tendon is common in sports that require explosive bending of the knee as seen in sprinting; this article incorporates text in the public domain from page 478 of the 20th edition of Gray's Anatomy Kumakura, Hiroo. "Functional analysis of the biceps femoris muscle during locomotor behavior in some primates". American Journal of Physical Anthropology. 79: 379–391. Doi:10.1002/ajpa.1330790314. PMID 2504047. Marshall, John L.. "The Biceps Femoris Tendon and Its Functional Significance". J Bone Joint Surg Am. 54: 1444–1450. Sneath, R. S.. "The insertion of the biceps femoris". J. Anat. 89: 550–553. PMC 1244747. PMID 13278305.
UWash - long head UWash - short head Anatomy photo:14:06-0100 at the SUNY Downstate Medical Center Anatomy photo:14:st-0402 at the SUNY Downstate Medical Center
The sartorius muscle is the longest muscle in the human body. It is a long, superficial muscle that runs down the length of the thigh in the anterior compartment; the sartorius muscle originates from the anterior superior iliac spine and part of the notch between the anterior superior iliac spine and anterior inferior iliac spine. It runs obliquely across the anterior part of the thigh in an inferomedial direction, it passes behind the medial condyle of the femur to end in a tendon. This tendon curves anteriorly to join the tendons of the gracilis and semitendinosus muscles in the pes anserinus, where it inserts into the superomedial surface of the tibia, its upper portion forms the lateral border of the femoral triangle, the point where it crosses adductor longus marks the apex of the triangle. Deep to sartorius and its fascia is the adductor canal, through which the saphenous nerve, femoral artery and vein, nerve to vastus medialis pass. Like the other muscles in the anterior compartment of the thigh, sartorius is innervated by the femoral nerve.
It may originate from the outer end of the inguinal ligament, the notch of the ilium, the ilio-pectineal line or the pubis. The muscle may be split into two parts, 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 in some people; the sartorius muscle can move the hip joint and the knee joint, but all of its actions are weak, making it a synergist muscle. At the hip, it can flex, weakly abduct, laterally rotate the thigh. At the knee, it can flex the leg. Turning the foot to look at the sole or sitting cross-legged demonstrates all four actions of the sartorius. One of the many conditions that can disrupt the use of the sartorius is pes anserine bursitis, an inflammatory condition of the medial portion of the knee; this condition occurs in athletes from overuse and is characterized by pain and tenderness.
The pes anserinus is made up from the tendons of the gracilis and sartorius muscles. When inflammation of the bursa underlying the tendons occurs they separate from the head of the tibia. Sartorius comes from the Latin word sartor, meaning tailor, it is sometimes called the tailor's muscle; this name was chosen in reference to the cross-legged position. In French, the muscle name itself "couturier" comes from this specific position, referred to as "sitting as a tailor". There are other hypotheses as to the genesis of the name. One is that it refers to the location of the inferior portion of the muscle being the "inseam" or area of the inner thigh that tailors measure when fitting trousers. Another is that the muscle resembles a tailor's ribbon. Additionally, antique sewing machines required continuous cross body pedaling; this combination of lateral rotation and flexion of the hip and flexion of the knee gave tailors enlarged sartorius muscles. The sartorius is called the honeymoon muscle; this article incorporates text in the public domain from page 470 of the 20th edition of Gray's Anatomy Anatomy photo:14:st-0407 at the SUNY Downstate Medical Center Cross section image: pembody/body15a—Plastination Laboratory at the Medical University of Vienna Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna
Vastus lateralis muscle
The vastus lateralis called the"vastus externus" is the largest and most powerful part of the quadriceps femoris, a muscle in the thigh. Together with other muscles of the quadriceps group, it serves to extend the knee joint, moving the lower leg forward, it arises from a series of flat, broad tendons attached to the femur, attaches to the outer border of the patella. It joins with the other muscles that make up the quadriceps in the quadriceps tendon, which travels over the knee to connect to the tibia; the vastus lateralis is the recommended site for intramuscular injection in infants less than 7 months old and those unable to walk, with loss of muscular tone. The vastus lateralis muscle arises from several areas of the femur, including the upper part of the intertrochanteric line; these form a broad flat tendon that covers the upper three-quarters of the muscle. From the inner surface of the aponeurosis, many muscle fibers originate; some additional fibers arise from the tendon of the gluteus maximus muscle, from the septum between the vastus lateralis and short head of the biceps femoris.
The fibers form a large fleshy mass, attached to a second strong aponeurosis, placed on the deep surface of the lower part of the muscle. This lower aponeurosis becomes contracted and thickened into a flat tendon that attaches to the outer border of the patella, subsequently joins with the quadriceps femoris tendon, expanding the capsule of the knee-joint; the vastus lateralis muscle is innervated by the muscular branches of the femoral nerve. Notes This article incorporates text in the public domain from page 470 of the 20th edition of Gray's Anatomy Cross section image: pembody/body18b—Plastination Laboratory at the Medical University of Vienna Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna PTCentral
The gluteus minimus, the smallest of the three gluteal muscles, is situated beneath the gluteus medius. It is fan-shaped, arising from the outer surface of the ilium, between the anterior and inferior gluteal lines, behind, from the margin of the greater sciatic notch; the fibers converge to the deep surface of a radiated aponeurosis, this ends in a tendon, inserted into an impression on the anterior border of the greater trochanter, gives an expansion to the capsule of the hip joint. It is a local stabilizer for the hip. A bursa is interposed between the greater trochanter. Between the gluteus medius and gluteus minimus are the deep branches of the superior gluteal vessels and the superior gluteal nerve; the deep surface of the gluteus minimus is in relation with the reflected tendon of the rectus femoris and the capsule of the hip joint. The gluteus medius and gluteus minimus abduct the thigh, when the limb is extended, are principally called into action in supporting the body on one limb, in conjunction with the tensor fasciæ latæ.
Their anterior fibers flex the hip, by drawing the greater trochanter forward, rotate the thigh inward, in which action they are assisted by the Tensor fasciæ latæ. Additionally, with the hip flexed, the gluteus minimus internally rotate the thigh. With the hip extended, the gluteus gluteus minimus externally rotate the thigh; the attachment to the superior capsule of the hip may serve to retract the capsule away from the joint during motion. This mechanism may prevent capsular impingement similar to the role of the articularis genus in the knee; the muscle may be divided into an anterior and a posterior part, or it may send slips to the piriformis, the superior gemellus or the outer part of the origin of the vastus lateralis. Paralysis of this muscle or gluteus medius, such as may be caused by the superior gluteal nerve palsy, can lead to difficulty abducting the leg. Patients will compensate for their difficulty walking by adopting a Trendelenburg gait; this article incorporates text in the public domain from page 475 of the 20th edition of Gray's Anatomy PTCentral Anatomy photo:13:st-0406 at the SUNY Downstate Medical Center
Inferior gemellus muscle
The inferior gemellus muscle is a muscle of the human body. The Gemelli are two small muscular fasciculi, accessories to the tendon of the Obturator internus, received into a groove between them; the Gemellus inferior arises from the upper part of the tuberosity of the ischium below the groove for the Obturator internus tendon. It blends with the lower part of the tendon of the Obturator internus, is inserted with it into the medial surface of the greater trochanter. Absent. Like the obturator internus muscle, the gemellus superior and gemellus inferior help to steady the femoral head in the acetabulum. Both muscles help to laterally rotate the extended thigh and abduct the flexed thigh at the hip Superior gemellus muscle This article incorporates text in the public domain from page 477 of the 20th edition of Gray's Anatomy PTCentral Anatomy photo:13:st-0401 at the SUNY Downstate Medical Center
Tensor fasciae latae muscle
The tensor fasciae latae is a muscle of the thigh. It is related to the gluteus maximus in function and structure and is continuous with the iliotibial tract, which attaches to the tibia; the muscle assists in walking, or running. It arises from the anterior part of the outer lip of the iliac crest, it is inserted between the two layers of the iliotibial tract of the fascia lata about the junction of the middle and upper thirds of the thigh. The tensor fasciae latae tautens the iliotibial tract and braces the knee when the opposite foot is lifted; the terminal insertion point lies on the lateral condyle of the tibia. Tensor fasciae latae is innervated by the superior gluteal nerve, L5 and S1. At its origins of the anterior rami of L4, L5, S1 nerves, the superior gluteal nerve exits the pelvis via greater sciatic foramen superior to the piriformis; the nerve courses between the gluteus medius and minimus. The superior gluteal artery supplies the tensor fasciae latae; the superior gluteal nerve arises from the sacral plexus and only has muscular innervation associated with it.
There is no cutaneous innervation for sensation. The tensor fasciae latae is a tensor of the fascia lata; the fascia lata is a fibrous sheath that encircles the thigh like a subcutaneous stocking and binds its muscles. On the lateral surface, it combines with the tendons of the gluteus maximus and tensor fasciae latae to form the iliotibial tract, which extends from the iliac crest to the lateral condyle of the tibia. In the erect posture, acting from below, it will serve to steady the pelvis upon the head of the femur; the basic functional movement of tensor fasciae latae is walking. The tensor fasciae latae is utilized in horse riding and water skiing; some problems that arise when this muscle is tight or shortened are pelvic imbalances that lead to pain in hips, as well as pain in the lower back and lateral area of knees. Because of its insertion point on the lateral condyle of the tibia, it aids in the lateral rotation of the tibia; this lateral rotation may be initiated in conjunction with hip abduction and medial rotation of the femur while kicking a soccer ball.
The tensor fasciae latae works in synergy with the gluteus medius and gluteus minimus muscles to abduct and medially rotate the femur. The TFL is a hip abductor muscle. To stretch the tensor fasciae latae, the knee may be brought medially across the body. If one leans against a wall with crossed legs and pushes the pelvis away from the wall sidebending the lumbar spine should be avoided as it stretches the lumbar region rather than the tensor fasciae latae and other muscles which cross the hip rather than the spine; because it is used for so many movements and is in a shortened position when seated, the TFL becomes tight easily. TFL stretches lengthen this important muscle. A small case notes that “it seems possible that a sloped or banked surface could predispose an individual to a TFL strain.” In such a case, “treatment consists of rest and flexibility exercises”, such as lliotibial band stretching. "Tensor fasciae latae" translates from Latin to English as "stretcher of the side band". "Tensor" is an agent noun that comes from the past participle stem "tens-" of the Latin verb "tendere", meaning "to stretch".
"Fasciae" is in the singular genitive case. "Latae" is the respective singular, feminine form of the Latin adjective "latus" meaning "side". This article incorporates text in the public domain from page 476 of the 20th edition of Gray's Anatomy Cross section image: pelvis/pelvis-e12-15—Plastination Laboratory at the Medical University of Vienna Muscles/TensorFasciaeLatae at exrx.net Coachr