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
Rectus femoris muscle
The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius, the vastus lateralis. All four parts of the quadriceps muscle attach to the patella by the quadriceps tendon; the rectus femoris is situated in the middle of the front of the thigh. Its functions are to extend the leg at the knee joint, it arises by two tendons: the anterior or straight, from the anterior inferior iliac spine. The two unite at an acute angle and spread into an aponeurosis, prolonged downward on the anterior surface of the muscle, from this the muscular fibers arise; the muscle ends in a broad and thick aponeurosis that occupies the lower two-thirds of its posterior surface, becoming narrowed into a flattened tendon, is inserted into the base of the patella. The neurons for voluntary thigh contraction originate near the summit of the medial side of the precentral gyrus; these neurons send a nerve signal, carried by the corticospinal tract down the brainstem and spinal cord.
The signal starts with the upper motor neurons carrying the signal from the precentral gyrus down through the internal capsule, through the cerebral peduncle, into the medulla. In the medullary pyramid, the corticospinal tract decussates and becomes the lateral corticospinal tract; the nerve signal will continue down the lateral corticospinal tract until it reaches spinal nerve L4. At this point, the nerve signal will synapse from the upper motor neurons to the lower motor neurons; the signal will travel through the anterior root of L4 and into the anterior rami of the L4 nerve, leaving the spinal cord through the lumbar plexus. The posterior division of the L4 root is the Femoral nerve; the femoral nerve innervates the quadriceps femoris, a fourth of, the rectus femoris. When the rectus femoris receives the signal that has traveled all the way from the medial side of the precentral gyrus, it contracts, extending the knee and flexing the thigh at the hip; the rectus femoris and iliopsoas are the flexors of the thigh at the hip.
The rectus femoris is a weaker hip flexor when the knee is extended because it is shortened and thus suffers from active insufficiency. The rectus femoris is not dominant in knee extension when the hip is flexed since it is shortened and thus suffers from active insufficiency. In essence: the action of extending the knee from a seated position is driven by the vastus lateralis, vastus medialis, vastus intermedius, less by the rectus femoris. In the other extreme, the muscle's ability to flex the hip and extend the knee can be compromised in a position of full hip extension and knee flexion, due to passive insufficiency; the rectus femoris is a direct antagonist at the hip and at the knee. Rectus femoris strain, referred to as hip flexor strain, is an injury at the tendon that attaches to the patella or in the muscle itself; the injury is a partial tear but could be a full tear. The injury is caused by a forceful movement related to sprinting, jumping, or kicking and is common in sports like football or soccer.
The rectus femoris is prone to injury since it crosses both the hip. Symptoms include a sudden sharp pain at the front of the hip or in the groin and bruising, an inability to contract the rectus femoris with a full tear; this article incorporates text in the public domain from page 470 of the 20th edition of Gray's Anatomy PTCentral
Quadratus femoris muscle
The quadratus femoris is a flat, quadrilateral skeletal muscle. Located on the posterior side of the hip joint, it is a strong external rotator and adductor of the thigh, but acts to stabilize the femoral head in the acetabulum, it originates on the lateral border of the ischial tuberosity of the ischium of the pelvis. From there, it passes laterally to its insertion on the posterior side of the head of the femur: the quadrate tubercle on the intertrochanteric crest and along the quadrate line, the vertical line which runs downward to bisect the lesser trochanter on the medial side of the femur. Along its course, quadratus is aligned edge to edge with the inferior gemellus above and the adductor magnus below, so that its upper and lower borders run horizontal and parallel. At its origin, the upper margin of the adductor magnus is separated from it by the terminal branches of the medial femoral circumflex vessels. A bursa is found between the front of this muscle and the lesser trochanter. Sometimes absent.
Groin pain can be a disabling ailment with many potential root causes: one such cause overlooked, is quadratus femoris tendinitis. Magnetic resonance imaging can show abnormal signal intensity at the insertion of the right quadratus femoris tendon, which suggests inflammation of the area. Since the muscle works to laterally rotate and adduct the femur, actions involving the lower body can strain the muscle. In addition, patients present with hip pain and an increased signal intensity of the MRI of the quadratus femoris have been shown to have a narrower ischiofemoral space compared to the general populace; the ischiofemoral impingement may be a cause of the hip pain associated with quadratus femoris tendinitis. This article incorporates text in the public domain from page 477 of the 20th edition of Gray's Anatomy Mcminn, R. M. H.. Last's Applied. Elsevier Australia. ISBN 0-7295-3752-8. Platzer, Werner. Color Atlas of Human Anatomy, Vol 1: Locomotor system. Thieme. ISBN 3-13-533305-1. Thieme Atlas of Anatomy.
Thieme. 2006. ISBN 978-1-60406-062-1. PTCentral Anatomy photo:13:st-0409 at the SUNY Downstate Medical Center
The gluteal muscles are a group of three muscles which make up the buttocks: the gluteus maximus, gluteus medius and gluteus minimus. The three muscles insert on the femur; the functions of the muscles include extension, external rotation and internal rotation of the hip joint. The gluteus maximus is the most superficial of the three gluteal muscles, it makes up a large portion of the appearance of the hips. It is a narrow and thick fleshy mass of a quadrilateral shape, forms the prominence of the nates; the gluteus medius is a broad, radiating muscle, situated on the outer surface of the pelvis. It lies profound to the gluteus maximus and its posterior third is covered by the gluteus maximus, its anterior two-thirds by the gluteal aponeurosis, which separates it from the superficial fascia and integument; the gluteus minimus is the smallest of the three gluteal muscles and is situated beneath the gluteus medius. The bulk of the gluteal muscle mass contributes only to shape of the buttocks; the other major contributing factor is that of the panniculus adiposus of the buttocks, well developed in this area, gives the buttock its characteristic rounded shape.
The gluteal muscle bulk and tone can be improved with exercise. However, it is predominantly the disposition of the overlying panniculus adiposus which may cause sagging in this region of the body. Exercise in general which can contribute to fat loss can lead to reduction of mass in subcutaneal fat storage locations on the body which includes the panniculus, so for leaner and more active individuals, the glutes will more predominantly contribute to the shape than someone less active with a fattier composition; the degree of body fat stored in various locations such as the panniculus is dictated by genetic and hormonal profiles. The gluteus maximus arises from the posterior gluteal line of the inner upper ilium, the rough portion of bone including the crest above and behind it; the fibers are lateralward. Its action is to extend and to laterally rotate the hip, to extend the trunk; the gluteus medius muscle originates on the outer surface of the ilium between the iliac crest and the posterior gluteal line above, the anterior gluteal line below.
The fibers of the muscle converge into a strong flattened tendon that inserts on the lateral surface of the greater trochanter. More the muscle's tendon inserts into an oblique ridge that runs downward and forward on the lateral surface of the greater trochanter; the gluteus minimus 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; the functions of muscles includes extension, lateral rotation and medial rotation of the hip joint. The gluteus maximus supports the extended knee through the iliotibial tract. Sitting for long periods can lead to the gluteal muscles atrophying through constant pressure and disuse; this may be associated with lower back pain, difficulty with some movements that require the gluteal muscles, such as rising from the seated position, climbing stairs.
Any exercise that works and/or stretches the buttocks is suitable, for example lunges, hip thrusts, climbing stairs, bicycling, squats, arabesque and various specific exercises for the bottom. Weight training exercises which are known to strengthen the gluteal muscles include the squat, leg press, any other movements involving external hip rotation and hip extension. Gluteal crease McMinn, RMH Last applied. London: Churchill Livingstone. ISBN 0-443-04662-X 8b; the Muscles and Fasciæ of the Thigh Bartleby.com, Henry Gray, Anatomy of the Human Body, 1918
Quadriceps femoris muscle
The quadriceps femoris is a large muscle group that includes the four prevailing muscles on the front of the thigh. It is the great extensor muscle of the knee, forming a large fleshy mass which covers the front and sides of the femur; the name derives from Latin four-headed muscle of the femur. It is subdivided into four separate portions or'heads', which have received distinctive names: Rectus femoris occupies the middle of the thigh, covering most of the other three quadriceps muscles, it originates on the ilium. It is named from its straight course; the other three lie deep to rectus femoris and originate from the body of the femur, which they cover from the trochanters to the condyles: Vastus lateralis is on the lateral side of the femur. Vastus medialis is on the medial side of the femur. Vastus intermedius lies between vastus lateralis and vastus medialis on the front of the femur, but deep to the rectus femoris, it cannot be seen without dissection of the rectus femoris. All four parts of the quadriceps muscle insert into the tuberosity of the tibia via the patella, where the quadriceps tendon becomes the patellar ligament.
There is a fifth muscle of the quadriceps complex, forgotten and taught called articularis genus. In addition, recent cadaver studies have confirmed the presence of a sixth muscle, the tensor vastus intermedius. While the muscle has variable presentations, it originates at the proximal femur, runs between the vastus lateralis and vastus intermedius muscles, inserts distally at the medial aspect of the patellar base. Considered a part of the vastus lateralis, the tensor vastus intermedius muscle is innervated by an independent branch of the femoral nerve and its tendinous belly can be separated from the vasti lateralis and intermedius muscles in most cases. Femoral nerve. All four quadriceps are powerful extensors of the knee joint, they are crucial in walking, running and squatting. Because the rectus femoris attaches to the ilium, it is a flexor of the hip; this action is crucial to walking or running as it swings the leg forward into the ensuing step. The quadriceps the vastus medialis, play the important role of stabilizing the patella and the knee joint during gait.
In strength training, the quadriceps are trained by several leg exercises. Effective exercises include the leg press; the isolation movement is the leg extension exercise. In body building communities, this muscle is colloquially referred to as the "leg triceps"; the proper Latin plural form of the adjective quadriceps would be quadricipites. In modern English usage, quadriceps is used in both plural; the singular form quadricep, produced by back-formation, is used. Hamstring Quadriceps_muscle at the Duke University Health System's Orthopedics program Muscles/Quadriceps at exrx.net "Anatomy diagram: 39960.000-1". Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2014-01-01
The iliacus is a flat, triangular muscle which fills the iliac fossa. It forms the lateral portion of iliopsoas, providing flexion of the thigh and lower limb at the acetabulofemoral joint; the iliacus arises from the iliac fossa on the interior side of the hip bone, from the region of the anterior inferior iliac spine. It joins the psoas major to form the Iliopsoas as which it proceeds across the iliopubic eminence through the muscular lacuna to its insertion on the lesser trochanter of the femur, its fibers are inserted in front of those of the psoas major and extend distally over the lesser trochanter. The iliopsoas is innervated by direct branches from the lumbar plexus. In open-chain exercises, as part of the iliopsoas, the iliacus is important for lifting the femur forward. In closed-chain exercises, the iliopsoas bends the trunk forward and can lift the trunk from a lying posture because the psoas major crosses several vertebral joints and the sacroiliac joint. From its origin in the lesser pelvis the iliacus acts on the hip joint.
Platzer, Werner. Color Atlas of Human Anatomy, Vol. 1: Locomotor System. Thieme. ISBN 3-13-533305-1. Thieme Atlas of Anatomy: General Anatomy and Musculoskeletal System. Thieme. 2006. ISBN 1-58890-419-9. PTCentral Anatomy figure: 40:07-05 at Human Anatomy Online, SUNY Downstate Medical Center - "Muscles and nerves of the posterior abdominal wall." Pelvis at The Anatomy Lesson by Wesley Norman
Anatomical terms of motion
Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints and specific sections of the body; the terminology used describes this motion according to its direction relative to the anatomical position of the joints. Anatomists use a unified set of terms to describe most of the movements, although other, more specialized terms are necessary for describing the uniqueness of the movements such as those of the hands and eyes. In general, motion is classified according to the anatomical plane. Flexion and extension are examples of angular motions, in which two axes of a joint are brought closer together or moved further apart. Rotational motion may occur at other joints, for example the shoulder, are described as internal or external. Other terms, such as elevation and depression, describe movement above or below the horizontal plane. Many anatomical terms derive from Latin terms with the same meaning. Motions are classified after the anatomical planes they occur in, although movement is more than not a combination of different motions occurring in several planes.
Motions can be split into categories relating to the nature of the joints involved: Gliding motions occur between flat surfaces, such as in the intervertebral discs or between the carpal and metacarpal bones of the hand. Angular motions occur over synovial joints and causes them to either increase or decrease angles between bones. Rotational motions move a structure in a rotational motion along a longitudinal axis, such as turning the head to look to either side. Apart from this motions can be divided into: Linear motions, which move in a line between two points. Rectilinear motion is motion in a straight line between two points, whereas curvilinear motion is motion following a curved path. Angular motions occur when an object is around another object decreasing the angle; the different parts of the object do not move the same distance. Examples include a movement of the knee, where the lower leg changes angle compared to the femur, or movements of the ankle; the study of movement is known as kinesiology.
A categoric list of movements of the human body and the muscles involved can be found at list of movements of the human body. The prefix hyper- is sometimes added to describe movement beyond the normal limits, such as in hypermobility, hyperflexion or hyperextension; the range of motion describes the total range of motion. For example, if a part of the body such as a joint is overstretched or "bent backwards" because of exaggerated extension motion it can be described as hyperextended. Hyperextension increases the stress on the ligaments of a joint, is not always because of a voluntary movement, it may be other causes of trauma. It may be used in surgery, such as in temporarily dislocating joints for surgical procedures; these are general terms. Most terms have a clear opposite, so are treated in pairs. Flexion and extension describe movements; these terms come from the Latin words with the same meaning. Flexion describes a bending movement that decreases the angle between a segment and its proximal segment.
For example, bending the elbow, or clenching a hand into a fist, are examples of flexion. When sitting down, the knees are flexed; when a joint can move forward and backward, such as the neck and trunk, flexion refers to movement in the anterior direction. When the chin is against the chest, the head is flexed, the trunk is flexed when a person leans forward. Flexion of the shoulder or hip refers to movement of the leg forward. Extension is the opposite of flexion, describing a straightening movement that increases the angle between body parts. For example, when standing up, the knees are extended; when a joint can move forward and backward, such as the neck and trunk, extension refers to movement in the posterior direction. Extension of the hip or shoulder moves the leg backward. Abduction is the motion of a structure away from the midline while adduction refer to motion towards the center of the body; the centre of the body is defined as the midsagittal plane. These terms come from Latin words with similar meanings, ab- being the Latin prefix indicating "away," ad- indicating "toward," and ducere meaning "to draw or pull".
Abduction refers to a motion that pulls a part away from the midline of the body. In the case of fingers and toes, it refers to spreading the digits apart, away from the centerline of the hand or foot. Abduction of the wrist is called radial deviation. For example, raising the arms up, such as when tightrope-walking, is an example of abduction at the shoulder; when the legs are splayed at the hip, such as when doing a star jump or doing a split, the legs are abducted at the hip. Adduction refers to a motion that pulls a structure or part toward the midline of the body, or towards the midline of a limb. In the case of fingers and toes, it refers to bringing the digits together, towards the centerline of the hand or foot. Adduction of the wrist is called ulnar deviation. Dropping the arms to the sides, bringing the knees together, are examples of adduction. Ulnar deviation is the hand moving towards the ulnar styloid. Radial deviation is the hand moving towards the radial styloid; the terms elevation and depression refer to movement below the horizontal.
They derive from the Latin terms with similar meaningsElevation refers to movement in a superior direction. For example