Gastrocnemius muscle
The gastrocnemius muscle is a superficial two-headed muscle, in the back part of the lower leg of humans. It runs from its two heads just above the knee to a two joint muscle; the muscle is named via Latin, from Greek γαστήρ "belly or stomach" and κνήμη "leg". The gastrocnemius is located with the soleus in the posterior compartment of the leg; the lateral head originates from the lateral condyle of the femur, while the medial head originates from the medial condyle of the femur. Its other end forms a common tendon with the soleus muscle. Further, it is considered a superficial muscle as it is located directly under skin, so its shape is visible in a normal human being. Deep to the gastrocnemius is the soleus muscle; some anatomists consider both to be a single muscle, the triceps surae or "three-headed of the calf", since they share a common insertion via the Achilles tendon. The plantaris muscle and a portion of its tendon run between the two muscles, involved in "locking" the knee from the standing position.
Since the anterior compartment of the leg is lateral to the tibia, the bulge of muscle medial to the tibia on the anterior side is the posterior compartment. The soleus is superficial to the mid-shaft of the tibia. 10% to 30% of individuals have a sesamoid bone called the "fabella" in the lateral head of gastrocnemius muscle. Along with the soleus muscle, the gastrocnemius forms half of the calf muscle, its function is plantar flexing the leg at the knee joint. The gastrocnemius is involved in running and other "fast" movements of leg, to a lesser degree in walking and standing; this specialization is connected to the predominance of white muscle fibers present in the gastrocnemius, as opposed to the soleus, which has more red muscle fibers and is the primary active muscle when standing still, as determined by EMG studies. The plan to use the gastrocnemius in running, jumping and plantar flexing is created in the precentral gyrus in the cerebrum of the brain. Once a plan is produced, the signal is sent to and down an upper motor neuron.
The signal is passed through the internal capsule and decussates, or crosses, in the medulla oblongata in the lateral corticospinal tract. The signal continues down through the anterior horn of the spinal cord where the upper motor neuron synapses with the lower motor neuron. Signal propagation continues down the anterior rami of the sacral plexus; the sciatic nerve branches off of the sacral plexus in which the tibial and common fibular nerves are wrapped in one sheath. The tibial nerve separates from the sciatic nerve and innervates the gastrocnemius muscle. Thus, completing the plan the brain had started with, so that the actions of running and jumping could be executed; the gastrocnemius muscle is prone to spasms, which are painful, involuntary contractions of the muscle that may last several minutes. A severe ankle dorsiflexion force may result in an injury of the muscle referred to as a "torn" or "strained" calf muscle, acutely painful and disabling; the gastrocnemius muscle may become inflamed due to overuse.
Anti-inflammatory medications and physical therapy may be useful. Anatomical abnormalities involving the medial head of gastrocnemius muscle result in popliteal artery entrapment syndrome. In a 1967 EMG study and Bragin concluded that its most important role was plantar flexing in large contractions and in rapid development of tension. Anatomy photo:14:st-0405 at the SUNY Downstate Medical Center
Anatomical terminology
Anatomical terminology is a form of scientific terminology used by anatomists and health professionals such as doctors. Anatomical terminology uses many unique terms and prefixes deriving from Ancient Greek and Latin; these terms can be confusing to those unfamiliar with them, but can be more precise, reducing ambiguity and errors. Since these anatomical terms are not used in everyday conversation, their meanings are less to change, less to be misinterpreted. To illustrate how inexact day-to-day language can be: a scar "above the wrist" could be located on the forearm two or three inches away from the hand or at the base of the hand. By using precise anatomical terminology such ambiguity is eliminated. An international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the same prefixes and suffixes are used to add meanings to different roots; the root of a term refers to an organ or tissue. For example, the Latin names of structures such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for "two-headed", brachii as in the brachial region of the arm.
The first word describes what is being spoken about, the second describes it, the third points to location. When describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near; these landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, such as the midclavicular line from the centre of the clavicle. The cephalon or cephalic region refers to the head; this area is further differentiated into the cranium, frons, auris, nasus and mentum. The neck area is called cervical region. Examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body. For example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, is used when describing the skull.
Different terminology is used in the arms, in part to reduce ambiguity as to what the "front", "back", "inner" and "outer" surfaces are. For this reason, the terms below are used: Radial referring to the radius bone, seen laterally in the standard anatomical position. Ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet, other structures such as the eye. International morphological terminology is used by the colleges of medicine and dentistry and other areas of the health sciences, it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research and medical care. The international morphological terminology refers to morphological sciences as a biological sciences' branch. In this field, the form and structure are examined as well as the changes or developments in the organism, it is functional.
It covers the gross anatomy and the microscopic of living beings. It involves the anatomy of the adult, it includes comparative anatomy between different species. The vocabulary is extensive and complex, requires a systematic presentation. Within the international field, a group of experts reviews and discusses the morphological terms of the structures of the human body, forming today's Terminology Committee from the International Federation of Associations of Anatomists, it deals with the anatomical and embryologic terminology. In the Latin American field, there are meetings called Iberian Latin American Symposium Terminology, where a group of experts of the Pan American Association of Anatomy that speak Spanish and Portuguese and studies the international morphological terminology; the current international standard for human anatomical terminology is based on the Terminologia Anatomica. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998.
It supersedes Nomina Anatomica. Terminologia Anatomica contains terminology for about 7500 human gross anatomical structures. For microanatomy, known as histology, a similar standard exists in Terminologia Histologica, for embryology, the study of development, a standard exists in Terminologia Embryologica; these standards specify accepted names that can be used to refer to histological and embryological structures in journal articles and other areas. As of September 2016, two sections of the Terminologia Anatomica, including central nervous system and peripheral nervous system, were merged to form the Terminologia Neuroanatomica; the Terminologia Anatomica has been perceived with a considerable criticism regarding its content including coverage and spelling mistakes and errors. Anatomical terminology is chosen to highlight the relative location of body structures. For instance, an anatomist might describe one band of tissue as "inferior to" another or a physician might describe a tumor as "superficial to" a deeper body structure.
Anatomical terms used to describe location
Gluteal muscles
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
Muscles of the hip
In human anatomy, the muscles of the hip joint are those muscles that cause movement in the hip. Most modern anatomists define 17 of these muscles, although some additional muscles may sometimes be considered; these are divided into four groups according to their orientation around the hip joint: the gluteal group. The muscles of the hip consist of four main groups The gluteal muscles include the gluteus maximus, gluteus medius, gluteus minimus, tensor fasciae latae, they cover the lateral surface of the ilium. The gluteus maximus, which forms most of the muscle of the buttocks, originates on the ilium and sacrum and inserts on the gluteal tuberosity of the femur as well as the iliotibial tract, a tract of strong fibrous tissue that runs along the lateral thigh to the tibia and fibula; the gluteus medius and gluteus minimus originate anterior to the gluteus maximus on the ilium and both insert on the greater trochanter of the femur. The tensor fasciae latae shares its origin with the gluteus maximus at the ilium and shares the insertion at the iliotibial tract.
The adductor brevis, adductor longus, adductor magnus and gracilis make up the adductor group. The adductors all originate on the pubis and insert on the medial, posterior surface of the femur, with the exception of the gracilis which inserts just below the medial condyle of the tibia; the iliacus and psoas major comprise the iliopsoas group. The psoas major is a large muscle that runs from the bodies and disc of the L1 to L5 vertebrae, joins with the iliacus via its tendon, connects to the lesser trochanter of the femur; the iliacus originates on the iliac fossa of the ilium. Together these muscles are referred to as the "iliopsoas"; this group consists of the externus and internus obturators, the piriformis, the superior and inferior gemelli, the quadratus femoris. These six originate at or below the acetabulum of the ilium and insert on or near the greater trochanter of the femur. Additional muscles, such as the rectus femoris and the sartorius, can cause some movement in the hip joint; however these muscles move the knee, not classified as muscles of the hip.
The hamstring muscles, which originate from the ischial tuberosity inserting on the tibia/fibula, have a large moment assisting with hip extension. Movements of the hip occur. Most muscles are responsible for more than one type of movement. Movements of the hip are described in anatomical terminology using anatomical terms of motion; the movement that brings the thighs close to the abdomen is called "flexion". When the legs open, such as in the lotus posture of yoga, this is called "lateral rotation", with the opposite movement called "medial rotation". Hip abduction occurs when the femur moves outward as in taking the thighs apart. Hip adduction occurs. Many muscles contribute to these movements: The psoas is the primary hip flexor, assisted by the iliacus; the pectineus, the adductors longus and magnus, as well as the tensor fasciae latae are involved in flexion. The gluteus maximus is the main hip extensor, but the inferior portion of the adductor magnus plays a role; the adductor group is responsible for hip adduction.
Medial rotation is performed by the gluteus medius and gluteus minimus, as well as the tensor fasciae latae and assisted by the adductors brevis and longus and the superior portion of the adductor magnus. Each muscle of the lateral rotator group causes lateral rotation of the thigh; these muscles are aided by the inferior portion of the adductor magnus. Hips muscles play a role in maintaining the standing posture; these muscles work in an integrated system with muscles of the shoulder, core, lower leg, supporting muscles of the spine, to provide the ability to stand with good posture. These muscles include the gluteus medius and gluteus minimus which abduct the thigh, prevent swaying of hips, stabilize pelvic region while keeping hips level, shift an individual’s weight in order to adjust body placement to increase one's overall body stability. Calais-Germain, Blandine. "Anatomy of Movement", Eastland Press, 1993. ISBN 0-939616-17-3 Martini, Frederic. "Human Anatomy", 3rd Edition, Prentice-Hall, 2000.
ISBN 0-13-010011-0 Marieb, Elaine. "Essentials of Human Anatomy and Physiology", 6th Edition. Addison Wesley Longman, 2000. ISBN 0-8053-4940-5 Netter, Frank H. "Atlas of Human Anatomy", 2nd Edition, Icon Learning Systems, 2001. ISBN 0-914168-81-9
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
Plantar fascial rupture
A plantar fascial rupture often called a plantar fascial tear, is a painful tear in the plantar fascia. The plantar fascia is a connective tissue; the condition plantar fasciitus may increase the likelihood of rupture. A plantar fascial rupture may be mistaken for plantar fasciitus or a calcaneal fracture. To allow for proper diagnosis, an MRI is needed. Complete tears of the plantar fascia are due to sudden trauma or injury; the rupture will be accompanied by a popping sound and painful snapping sensation. The bottom of the foot bruises and swells. Former NFL athlete Peyton Manning suffered a complete rupture in 2015; the surgical procedure known as a plantar fascia release involves the purposeful infliction of a complete tear of the plantar fascia. This is intended to relieve plantar fasciitus symptoms when the tissue recovers by building more tissue, elongating the tight plantar fascia. Partial tears are even less common than complete tears, they are more to arise from overuse from activities like daily running.
The bottom of the foot may be bruised. Full recovery from both complete and partial tears takes 12 weeks or more. However, activities may resume after 6-8 weeks when the plantar fascia will be recovered. Surgery is a last resort. At home, it might be advisable to follow the RICE method to ease pain. For the first 2-4 weeks after diagnosis, patients are instructed to use a walking boot to immobilize and protect the foot. During the immobilization period, it is important to keep the foot flexible by stretching the foot and calf regularly; as the plantar fascia recovers, physical therapy exercises help stabilize the ankle and correct gait patterns that may have contributed to the tear. Stretching and strengthening exercises decrease the chance of reinjury. Platelet-Rich Plasma injections may be used to help accelerate recovery and decrease the chance of reinjury. Cortisone injections may ease pain
Biomechanics
Biomechanics is the study of the structure and motion of the mechanical aspects of biological systems, at any level from whole organisms to organs and cell organelles, using the methods of mechanics. The word "biomechanics" and the related "biomechanical" come from the Ancient Greek βίος bios "life" and μηχανική, mēchanikē "mechanics", to refer to the study of the mechanical principles of living organisms their movement and structure. Biological fluid mechanics, or biofluid mechanics, is the study of both gas and liquid fluid flows in or around biological organisms. An studied liquid biofluids problem is that of blood flow in the human cardiovascular system. Under certain mathematical circumstances, blood flow can be modelled by the Navier–Stokes equations. In vivo whole blood is assumed to be an incompressible Newtonian fluid. However, this assumption fails. At the microscopic scale, the effects of individual red blood cells become significant, whole blood can no longer be modelled as a continuum.
When the diameter of the blood vessel is just larger than the diameter of the red blood cell the Fahraeus–Lindquist effect occurs and there is a decrease in wall shear stress. However, as the diameter of the blood vessel decreases further, the red blood cells have to squeeze through the vessel and can only pass in single file. In this case, the inverse Fahraeus -- the wall shear stress increases. An example of a gaseous biofluids problem is that of human respiration. Respiratory systems in insects have been studied for bioinspiration for designing improved microfluidic devices; the main aspects of Contact mechanics and tribology are related to friction and lubrication. When the two surfaces come in contact during motion i.e. rub against each other, friction and lubrication effects are important to analyze in order to determine the performance of the material. Biotribology is a study of friction and lubrication of biological systems human joints such as hips and knees. For example and tibial components of knee implant rub against each other during daily activity such as walking or stair climbing.
If the performance of tibial component needs to be analyzed, the principles of biotribology are used to determine the wear performance of the implant and lubrication effects of synovial fluid. In addition, the theory of contact mechanics becomes important for wear analysis. Additional aspects of biotribology can include analysis of subsurface damage resulting from two surfaces coming in contact during motion, i.e. rubbing against each other, such as in the evaluation of tissue engineered cartilage. Comparative biomechanics is the application of biomechanics to non-human organisms, whether used to gain greater insights into humans or into the functions and adaptations of the organisms themselves. Common areas of investigation are Animal locomotion and feeding, as these have strong connections to the organism's fitness and impose high mechanical demands. Animal locomotion, has many manifestations, including running and flying. Locomotion requires energy to overcome friction, drag and gravity, though which factor predominates varies with environment.
Comparative biomechanics overlaps with many other fields, including ecology, developmental biology and paleontology, to the extent of publishing papers in the journals of these other fields. Comparative biomechanics is applied in medicine as well as in biomimetics, which looks to nature for solutions to engineering problems. Computational biomechanics is the application of engineering computational tools, such as the Finite element method to study the mechanics of biological systems. Computational models and simulations are used to predict the relationship between parameters that are otherwise challenging to test experimentally, or used to design more relevant experiments reducing the time and costs of experiments. Mechanical modeling using finite element analysis has been used to interpret the experimental observation of plant cell growth to understand how they differentiate, for instance. In medicine, over the past decade, the Finite element method has become an established alternative to in vivo surgical assessment.
One of the main advantages of computational biomechanics lies in its ability to determine the endo-anatomical response of an anatomy, without being subject to ethical restrictions. This has led FE modeling to the point of becoming ubiquitous in several fields of Biomechanics while several projects have adopted an open source philosophy; the mechanical analysis of biomaterials and biofluids is carried forth with the concepts of continuum mechanics. This assumption breaks down when the length scales of interest approach the order of the micro structural details of the material. One of the most remarkable characteristic of biomaterials is their hierarchical structure. In other words, the mechanical characteristics of these materials rely on physical phenomena occurring in multiple levels, from the molecular all the way up to the tissue and organ levels. Biomaterials are classified in two groups and soft tissues. Mechanical deformation of hard tissues may be analysed with the theory of linear elasticity.
On the other hand, soft tissues undergo large deformations and thus their analysis rely on the finite strain theory and computer simulations. The interest in continuum biomechanics is spurred by the need for realism in the development of medical simulation
