Adductor magnus muscle
The adductor magnus is a large triangular muscle, situated on the medial side of the thigh. It consists of two parts; the portion which arises from the ischiopubic ramus is called the pubofemoral portion, adductor portion, or adductor minimus, the portion arising from the tuberosity of the ischium is called the ischiocondylar portion, extensor portion, or "hamstring portion". Due to its common embryonic origin and action the ischiocondylar portion is considered part of the hamstring group of muscles; the ischiocondylar portion of the adductor magnus is considered a muscle of the posterior compartment of the thigh while the pubofemoral portion of the adductor magnus is considered a muscle of the medial compartment. Those fibers which arise from the ramus of the pubis are short, horizontal in direction, are inserted into the rough line of the femur leading from the greater trochanter to the linea aspera, medial to the gluteus maximus; those fibers from the ramus of the ischium are directed downward and laterally with different degrees of obliquity, to be inserted, by means of a broad aponeurosis, into the linea aspera and the upper part of its medial prolongation below.
The medial portion of the muscle, composed principally of the fibers arising from the tuberosity of the ischium, forms a thick fleshy mass consisting of coarse bundles which descend vertically, end about the lower third of the thigh in a rounded tendon, inserted into the adductor tubercle on the medial condyle of the femur, is connected by a fibrous expansion to the line leading upward from the tubercle to the linea aspera. By its anterior surface the adductor magnus is in relation with the pectineus, adductor brevis, adductor longus, femoral artery and vein, profunda artery and vein, with their branches, with the posterior branches of the obturator artery, obturator vein and obturator nerve. By its posterior surface with the semitendinosus, semimembranosus and gluteus maximus muscle. By its inner border with the gracilis and sartorius. By its upper border with the obturator externus, quadratus femoris, it is a composite muscle as the adductor and hamstring portions of the muscle are innervated by two different nerves.
The adductor portion is innervated by the posterior division of the obturator nerve while the hamstring portion is innervated by the sciatic nerve. At the insertion of the muscle, there is a series of osseoaponeurotic openings, formed by tendinous arches attached to the bone; the upper four openings are small, give passage to the perforating branches of the profunda femoris artery. The lowest is large, transmits the femoral vessels to the popliteal fossa; the upper, lateral part of the adductor magnus is an incompletely separated division considered a separate muscle — the adductor minimus. These two muscles are separated by a branch of the superior perforating branch of the profunda femoris artery; the adductor magnus is a powerful adductor of the thigh, made active when the legs are moved from a wide spread position to one in which the legs parallel each other. The part attached to the linea aspera acts as a lateral rotator; the part which reaches the medial epicondyle acts as a medial rotator when the leg is rotated outwards and flexed, acts to extend the hip joint.
In other tetrapods, the adductor magnus crosses the knee joint and inserts into the tibia. In humans, the distal part of the tendon detaches and becomes the medial collateral ligament of the knee; because of this, the medial collateral ligament of the knee in humans may contain a few muscle fibres as an atavistic variation. Adductor hiatus This article incorporates text in the public domain from page 473 of the 20th edition of Gray's Anatomy Anatomy photo:14:st-0401 at the SUNY Downstate Medical Center PTCentral
Common peroneal nerve
The common fibular nerve is a nerve in the lower leg that provides sensation over the posterolateral part of the leg and the knee joint. It divides at the knee into two terminal branches: the superficial fibular nerve and deep fibular nerve, which innervate the muscles of the lateral and anterior compartments of the leg respectively; when the common fibular nerve is damaged or compressed, foot drop can be the end result. The common fibular nerve is the smaller terminal branch of the sciatic nerve; the common fibular nerve has root values of L4, L5, S1, S2. It arises from the superior angle of the popliteal fossa and extends to the lateral angle of the popliteal fossa, along the medial border of the biceps femoris, it winds around the neck of the fibula to pierce the fibularis longus and divides into terminal branches of superficial fibular nerve and deep fibular nerve. Before its division, the common fibular nerve gives off several branches in the popliteal fossa. Lateral sural cutaneous nerve - supplies the skin of the upper two-thirds of the lateral side of leg.
Sural communicating nerve - it runs on the posterolateral aspect of the calf and joins the sural nerve. Superior lateral genicular nerve - accompanies artery of the same name and lies above the lateral femoral condyle. Inferior lateral genicular nerve - accompanies artery of the same name and lies just above the head of the fibula. Recurrent genicular nerve - It arises from the point of division of the common fibular nerve. There is only one motor branch that arises directly from common fibular nerve, the nerve to the short head of the biceps femoris muscle; the common fibular nerve innervates the short head of the biceps femoris muscle via a motor branch that exits close to the gluteal cleft. The remainder of the fibular-innervated muscles are innervated by its branches, the deep fibular nerve and superficial fibular nerve, it provides sensory innervation to the skin over the upper third of the lateral aspect of the leg via the lateral sural cutaneous nerve. It gives the aural communicating nerve.
Chronic fibular neuropathy can result from, among other conditions, bed rest of long duration, hyperflexion of the knee, peripheral neuropathy, pressure in obstetric stirrups, conditioning in ballet dancers. The most common cause is habitual leg crossing that compresses the common fibular nerve as it crosses around the head of the fibula. Transient trauma to the nerve can result from peroneal strike. Damage to this nerve results in foot drop, where dorsiflexion of the foot is compromised and the foot drags during walking. A common yoga kneeling exercise, the Vajrasana, has been linked to a variant called yoga foot drop. Surgical procedures involving the nerve involve: Fibular nerve decompression To surgically decompress the common fibular nerve, an incision is made over the neck of the fibula. Fascia surrounding the nerves to the lateral side of the leg is released. Deep fibular nerve decompression In the surgical treatment of deep peroneal nerve entrapment in the foot, a ligament from the extensor digitorum brevis muscle that crosses over the deep peroneal nerve, putting pressure on it and causing pain, is released.
Deep fibular nerve Peroneal strike Peroneal vein Peroneus muscles This article incorporates text in the public domain from page 964 of the 20th edition of Gray's Anatomy Anatomy photo:14:st-0501 at the SUNY Downstate Medical Center Peroneal_nerve at the Duke University Health System's Orthopedics program latleg at The Anatomy Lesson by Wesley Norman arteries-nerves%20LE/nerves4 at the Dartmouth Medical School's Department of Anatomy Overview at okstate.edu
Anatomical terms of muscle
Muscles are described using unique anatomical terminology according to their actions and structure. There are three types of muscle tissue in the human body: skeletal and cardiac. Skeletal striated muscle, or "voluntary muscle" joins to bone with tendons. Skeletal muscle maintains posture. Smooth muscle tissue is found in parts of the body; the majority of this type of muscle tissue is found in the digestive and urinary systems where it acts by propelling forward food and feces in the former and urine in the latter. Other places smooth muscle can be found are within the uterus, where it helps facilitate birth, the eye, where the pupillary sphincter controls pupil size. Cardiac muscle is specific to the heart, it is involuntary in its movement, is additionally self-excitatory, contracting without outside stimuli. As well as anatomical terms of motion, which describe the motion made by a muscle, unique terminology is used to describe the action of a set of muscles. Agonist muscles and antagonist muscles refer to muscles that inhibit a movement.
Agonist muscles cause a movement to occur through their own activation. For example, the triceps brachii contracts, producing a shortening contraction, during the up phase of a push-up. During the down phase of a push-up, the same triceps brachii controls elbow flexion while producing a lengthening contraction, it is still the agonist, because while resisting gravity during relaxing, the triceps brachii continues to be the prime mover, or controller, of the joint action. Agonists are interchangeably referred to as "prime movers," since they are the muscles considered responsible for generating or controlling a specific movement. Another example is the dumbbell curl at the elbow; the "elbow flexor" group is the agonist. During the lowering phase the "elbow flexor" muscles lengthen, remaining the agonists because they are controlling the load and the movement. For both the lifting and lowering phase, the "elbow extensor" muscles are the antagonists, they shorten during the dumbbell lowering phase.
Here it is important to understand that it is common practice to give a name to a muscle group based on the joint action they produce during a shortening contraction. However, this naming convention does not mean; this term describes the function of skeletal muscles. Antagonist muscles are the muscles that produce an opposing joint torque to the agonist muscles; this torque can aid in controlling a motion. The opposing torque can slow movement down - in the case of a ballistic movement. For example, during a rapid discrete movement of the elbow, such as throwing a dart, the triceps muscles will be activated briefly and to accelerate the extension movement at the elbow, followed immediately by a "burst" of activation to the elbow flexor muscles that decelerates the elbow movement to arrive at a quick stop. To use an automotive analogy, this would be similar to pressing your gas pedal and immediately pressing the brake. Antagonism is not an intrinsic property of a particular muscle group. During slower joint actions that involve gravity, just as with the agonist muscle, the antagonist muscle can shorten and lengthen.
Using the example above of the triceps brachii during a push-up, the elbow flexor muscles are the antagonists at the elbow during both the up phase and down phase of the movement. During the dumbbell curl, the elbow extensors are the antagonists for both the lifting and lowering phases. Antagonist and agonist muscles occur in pairs, called antagonistic pairs; as one muscle contracts, the other relaxes. An example of an antagonistic pair is the triceps. "Reverse motions" need antagonistic pairs located in opposite sides of a joint or bone, including abductor-adductor pairs and flexor-extensor pairs. These consist of an extensor muscle, which "opens" the joint and a flexor muscle, which does the opposite by decreasing the angle between two bones. However, muscles don't always work this way. Sometimes during a joint action controlled by an agonist muscle, the antagonist will be activated, naturally; this occurs and is not considered to be a problem unless it is excessive or uncontrolled and disturbs the control of the joint action.
This serves to mechanically stiffen the joint. Not all muscles are paired in this way. An example of an exception is the deltoid. Synergist muscles help perform, the same set of joint motion as the agonists. Synergists muscles act on movable joints. Synergists are sometimes referred to as "neutralizers" because they help cancel out, or neutralize, extra motion from the agonists to make sure that the force generated works within the desired plane of motion. Muscle fibers can only contract up to 40% of their stretched length, thus the short fibers of pennate muscles are more suitable where power rather than range of contraction is required. This limitation in the range of contraction affects all muscles, those that act over several joints may be unable to shorten sufficiently to produce
Anatomical terms of location
Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. All vertebrates have the same basic body plan – they are bilaterally symmetrical in early embryonic stages and bilaterally symmetrical in adulthood; that is, they have mirror-image left and right halves if divided down the middle. For these reasons, the basic directional terms can be considered to be those used in vertebrates. By extension, the same terms are used for many other organisms as well. While these terms are standardized within specific fields of biology, there are unavoidable, sometimes dramatic, differences between some disciplines. For example, differences in terminology remain a problem that, to some extent, still separates the terminology of human anatomy from that used in the study of various other zoological categories. Standardized anatomical and zoological terms of location have been developed based on Latin and Greek words, to enable all biological and medical scientists to delineate and communicate information about animal bodies and their component organs though the meaning of some of the terms is context-sensitive.
The vertebrates and Craniata share a substantial heritage and common structure, so many of the same terms are used for location. To avoid ambiguities this terminology is based on the anatomy of each animal in a standard way. For humans, one type of vertebrate, anatomical terms may differ from other forms of vertebrates. For one reason, this is because humans have a different neuraxis and, unlike animals that rest on four limbs, humans are considered when describing anatomy as being in the standard anatomical position, thus what is on "top" of a human is the head, whereas the "top" of a dog may be its back, the "top" of a flounder could refer to either its left or its right side. For invertebrates, standard application of locational terminology becomes difficult or debatable at best when the differences in morphology are so radical that common concepts are not homologous and do not refer to common concepts. For example, many species are not bilaterally symmetrical. In these species, terminology depends on their type of symmetry.
Because animals can change orientation with respect to their environment, because appendages like limbs and tentacles can change position with respect to the main body, positional descriptive terms need to refer to the animal as in its standard anatomical position. All descriptions are with respect to the organism in its standard anatomical position when the organism in question has appendages in another position; this helps avoid confusion in terminology. In humans, this refers to the body in a standing position with arms at the side and palms facing forward. While the universal vertebrate terminology used in veterinary medicine would work in human medicine, the human terms are thought to be too well established to be worth changing. Many anatomical terms can be combined, either to indicate a position in two axes or to indicate the direction of a movement relative to the body. For example, "anterolateral" indicates a position, both anterior and lateral to the body axis. In radiology, an X-ray image may be said to be "anteroposterior", indicating that the beam of X-rays pass from their source to patient's anterior body wall through the body to exit through posterior body wall.
There is no definite limit to the contexts in which terms may be modified to qualify each other in such combinations. The modifier term is truncated and an "o" or an "i" is added in prefixing it to the qualified term. For example, a view of an animal from an aspect at once dorsal and lateral might be called a "dorsolateral" view. Again, in describing the morphology of an organ or habitus of an animal such as many of the Platyhelminthes, one might speak of it as "dorsiventrally" flattened as opposed to bilaterally flattened animals such as ocean sunfish. Where desirable three or more terms may be agglutinated or concatenated, as in "anteriodorsolateral"; such terms sometimes used to be hyphenated. There is however little basis for any strict rule to interfere with choice of convenience in such usage. Three basic reference planes are used to describe location; the sagittal plane is a plane parallel to the sagittal suture. All other sagittal planes are parallel to it, it is known as a "longitudinal plane".
The plane is perpendicular to the ground. The median plane or midsagittal plane is in the midline of the body, divides the body into left and right portions; this passes through the head, spinal cord, and, in many animals, the tail. The term "median plane" can refer to the midsagittal plane of other structures, such as a digit; the frontal plane or coronal plane divides the body into ventral portions. For post-embryonic humans a coronal plane is vertical and a transverse plane is horizontal, but for embryos and quadrupeds a coronal plane is horizontal and a transverse plane is vertical. A longitudinal plane is any plane perpendicular to the transverse plane; the coronal plane and the sagittal plane are examples of longitudinal planes. A transverse plane known as a cross-section, divides the body into cranial and caudal portions. In human anatomy: A transverse plane is an X-Z plane, parallel to the ground, which s
Quadrupedalism
Quadrupedalism or pronograde posture is a form of terrestrial locomotion in animals using four limbs or legs. An animal or machine that moves in a quadrupedal manner is known as a quadruped, meaning "four feet"; the majority of quadrupeds are vertebrate animals, including mammals such as cattle and cats, reptiles such as lizards. Few other animals are quadrupedal, though a few birds like the shoebill sometimes use their wings to right themselves after lunging at prey. Although the words quadruped and tetrapod are both derived from terms meaning "four-footed", they have distinct meanings. A tetrapod is any member of the taxonomic unit Tetrapoda whereas a quadruped uses four limbs for locomotion. Not all tetrapods are quadrupeds and not all quadrupeds are tetrapods; the distinction between quadrupeds and tetrapods is important in evolutionary biology in the context of tetrapods whose limbs have adapted to other roles. All of these animals are tetrapods. Snakes, whose limbs have become vestigial or lost are tetrapods.
Most quadrupedal animals are tetrapods but there are a few exceptions. For instance, among the insects, the praying mantis is a quadruped. In July 2005, in rural Turkey, scientists discovered five Kurdish siblings who had learned to walk on their hands and feet. Unlike chimpanzees, which ambulate on their knuckles, the Kurdish siblings walked on their palms, allowing them to preserve the dexterity of their fingers. Many people practitioners of parkour and freerunning and Georges Hébert's Natural Method, find benefit in quadrupedal movements to build full body strength. Kenichi Ito is a Japanese man famous for speed running on four limbs. Quadrupedalism is sometimes referred to as being on all fours, is observed in crawling by infants. BigDog is a dynamically stable quadruped robot created in 2005 by Boston Dynamics with Foster-Miller, the NASA Jet Propulsion Laboratory, the Harvard University Concord Field Station. By NASA JPL, in collaboration with University of California, Santa Barbara Robotics Lab, is RoboSimian, with emphasis on stability and deliberation.
It has been demonstrated at the DARPA Robotics Challenge. Bipedalism Orthograde posture Family may provide evolution clue - BBC News
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
Linea aspera
The linea aspera is a ridge of roughened surface on the posterior surface of the shaft of the femur, to which are attached muscles and intermuscular septum. Its margins diverge below; the linea aspera is a prominent longitudinal ridge or crest, on the middle third of the bone, presenting a medial and a lateral lip, a narrow rough, intermediate line. It is an important insertion point for the adductors and the lateral and medial intermuscular septa that divides the thigh into three compartments; the tension generated by muscle attached to the bones is responsible for the formation of the ridges. Above, the linea aspera is prolonged by three ridges; the lateral ridge is rough, runs vertically upward to the base of the greater trochanter. It is termed the gluteal tuberosity, gives attachment to part of the gluteus maximus: its upper part is elongated into a roughened crest, on which a more or less well-marked, rounded tubercle, the third trochanter, is developed; the intermediate ridge or pectineal line is continued to the base of the lesser trochanter and gives attachment to the pectineus.
Below, the linea aspera is prolonged into two ridges, enclosing between them a triangular area, the popliteal surface, upon which the popliteal artery rests. Of these two ridges, the lateral is the more prominent, descends to the summit of the lateral condyle; the medial is less marked at its upper part, where it is crossed by the femoral artery. It ends below at the summit of the medial condyle, in a small tubercle, the adductor tubercle, which affords insertion to the tendon of the adductor magnus; the tension generated by muscle attached to the bones is responsible for the formation of the ridges. A number of muscles attach to the linea aspera: From the medial lip of the linea aspera and its prolongations above and below, the vastus medialis originates. From the lateral lip and its upward prolongation, the vastus lateralis takes origin; the adductor magnus is inserted into the linea aspera, to its lateral prolongation above, its medial prolongation below. Between the vastus lateralis and the adductor magnus two muscles are attached: the gluteus maximus inserted above, the short head of the biceps femoris originating below.
Between the adductor magnus and the vastus medialis four muscles are inserted: the iliacus and pectineus above. The linea aspera is perforated a little below its center by the nutrient canal, directed obliquely upward; this article incorporates text in the public domain from page 246 of the 20th edition of Gray's Anatomy University of Washington DartmouthAnatomy
