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Hinge Joint
A hinge joint (ginglymus or ginglymoid) is a bone joint in which the articular surfaces are molded to each other in such a manner as to permit motion only in one plane. According to one classification system they are said to be uniaxial (having one degree of freedom).Platzer, Werner (2008) ''Color Atlas of Human Anatomy', Volume 1p.28/ref> The direction which the distal bone takes in this motion is seldom in the same plane as that of the axis of the proximal bone; there is usually a certain amount of deviation from the straight line during flexion. The articular surfaces of the bones are connected by strong collateral ligaments. The best examples of ginglymoid joints are the Interphalangeal joints of the hand and those of the foot and the joint between the humerus and ulna. The knee joints and ankle joints are less typical, as they allow a slight degree of rotation or of side-to-side movement in certain positions of the limb. The knee is the largest hinge joint in the human b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ball And Socket Joint
The ball-and-socket joint (or spheroid joint) is a type of synovial joint in which the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. The distal bone is capable of motion around an indefinite number of axes, which have one common center. This enables the joint to move in many directions. An enarthrosis is a special kind of spheroidal joint in which the socket covers the sphere beyond its equator.Platzer, Werner (2008) ''Color Atlas of Human Anatomy'', Volume 1p.28/ref> Examples Examples of this form of articulation are found in the hip, where the round head of the femur (ball) rests in the cup-like acetabulum (socket) of the pelvis; and in the shoulder joint, where the rounded upper extremity of the humerus (ball) rests in the cup-like glenoid fossa (socket) of the shoulder blade.And the phalanges (toes, fingers)Introduction to Joints: Synovial Joints - Ball and Socket Joints (The shoulder also includes a sternoclavicular joint ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interphalangeal Articulations Of Foot
The interphalangeal joints of the foot are between the phalanx bones of the toes in the feet. Since the great toe only has two phalanx bones (proximal and distal phalanges), it only has one interphalangeal joint, which is often abbreviated as the "IP joint". The rest of the toes each have three phalanx bones (proximal, middle, and distal phalanges), so they have two interphalangeal joints: the proximal interphalangeal joint between the proximal and middle phalanges (abbreviated "PIP joint") and the distal interphalangeal joint between the middle and distal phalanges (abbreviated "DIP joint"). All interphalangeal joints are ginglymoid (hinge) joints, and each has a plantar (underside) and two collateral ligaments. In the arrangement of these ligaments, extensor tendons supply the places of dorsal ligaments, which is similar to that in the metatarsophalangeal articulations. Movements The only movements permitted in the joints of the digits are flexion and extension; these movem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synovial Joint
A synovial joint, also known as diarthrosis, joins bones or cartilage with a fibrous joint capsule that is continuous with the periosteum of the joined bones, constitutes the outer boundary of a synovial cavity, and surrounds the bones' articulating surfaces. This joint unites long bones and permits free bone movement and greater mobility. The synovial cavity/joint is filled with synovial fluid. The joint capsule is made up of an outer layer of fibrous membrane, which keeps the bones together structurally, and an inner layer, the synovial membrane, which seals in the synovial fluid. They are the most common and most movable type of joint in the body of a mammal. As with most other joints, synovial joints achieve movement at the point of contact of the articulating bones. Structure Synovial joints contain the following structures: * Synovial cavity: all diarthroses have the characteristic space between the bones that is filled with synovial fluid * Joint capsule: the fibrous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pivot Joint
In animal anatomy, a pivot joint (trochoid joint, rotary joint or lateral ginglymus) is a type of synovial joint whose movement axis is parallel to the long axis of the proximal bone, which typically has a convex articular surface. According to one classification system, a pivot joint like the other synovial joint —the hinge joint has one degree of freedom.Platzer, Werner (2008) ''Color Atlas of Human Anatomy'', Volume 1p.28/ref> Note that the degrees of freedom of a joint is not the same as the same as joint's range of motion. Movements Pivot joints allow for rotation, which can be external (for example when rotating an arm outward), or internal (as in rotating an arm inward). When rotating the forearm, these movements are typically called pronation and supination. In the standard anatomical position, the forearms are supinated, which means that the palms are facing forward, and the thumbs are pointing away from the body. In contrast, a forearm in pronation would have the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limb (anatomy)
A limb (from the Old English ''lim'', meaning "body part") or leg is a jointed, muscled appendage that tetrapod vertebrates use for weight-bearing and terrestrial locomotion such as walking, running and jumping, for paddle-swimming, or for grasping and climbing. The distalmost portion of a limb is known as its extremity. The limbs' bony endoskeleton, known as the appendicular skeleton, is homologous among all tetrapods. All tetrapods have four limbs that are organized into two bilaterally symmetrical pairs, with one pair at each end of the torso. The cranial pair are known as the forelimbs or ''front legs'', and the caudal pair the hindlimbs or ''back legs''. In animals with more upright posture (mainly hominid primates, particularly humans), the forelimbs and hindlimbs are often called upper and lower limbs, respectively. The fore-/upper limbs are connected to the thoracic cage via the shoulder girdles, and the hind-/lower limbs are connected to the pelvis via the hip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ankle Joint
The ankle, or the talocrural region, or the jumping bone (informal) is the area where the foot and the leg meet. The ankle includes three joints: the ankle joint proper or talocrural joint, the subtalar joint, and the inferior tibiofibular joint. The movements produced at this joint are dorsiflexion and plantarflexion of the foot. In common usage, the term ankle refers exclusively to the ankle region. In medical terminology, "ankle" (without qualifiers) can refer broadly to the region or specifically to the talocrural joint. The main bones of the ankle region are the talus (in the foot), and the tibia and fibula (in the leg). The talocrural joint is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus. The articulation between the tibia and the talus bears more weight than that between the smaller fibula and the talus. Structure Region The ankle region is found at the junction of the leg and the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Knee
In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the human body. The knee is a modified hinge joint, which permits flexion and extension as well as slight internal and external rotation. The knee is vulnerable to injury and to the development of osteoarthritis. It is often termed a ''compound joint'' having tibiofemoral and patellofemoral components. (The fibular collateral ligament is often considered with tibiofemoral components.) Structure The knee is a modified hinge joint, a type of synovial joint, which is composed of three functional compartments: the patellofemoral articulation, consisting of the patella, or "kneecap", and the patellar groove on the front of the femur through which it slides; and the medial and lateral tibiofemoral articulations linking the femur, or thigh bone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulna
The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of the forearm as the little finger. It runs parallel to the radius, the other long bone in the forearm. The ulna is usually slightly longer than the radius, but the radius is thicker. Therefore, the radius is considered to be the larger of the two. Structure The ulna is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. It is broader close to the elbow, and narrows as it approaches the wrist. Close to the elbow, the ulna has a bony process, the olecranon process, a hook-like structure that fits into the olecranon fossa of the humerus. This prevents hyperextension and forms a hinge joint with the trochlea of the humerus. There is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humerus
The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a rounded head, a narrow neck, and two short processes (tubercles, sometimes called tuberosities). The body is cylindrical in its upper portion, and more prismatic below. The lower extremity consists of 2 epicondyles, 2 processes (trochlea & capitulum), and 3 fossae (radial fossa, coronoid fossa, and olecranon fossa). As well as its true anatomical neck, the constriction below the greater and lesser tubercles of the humerus is referred to as its surgical neck due to its tendency to fracture, thus often becoming the focus of surgeons. Etymology The word "humerus" is derived from la, humerus, umerus meaning upper arm, shoulder, and is linguistically related to Gothic ''ams'' shoulder and Greek ''ōmos''. Structure Upper extremity The upper or pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interphalangeal Joints Of The Hand
The interphalangeal joints of the hand are the hinge joints between the phalanges of the fingers that provide flexion towards the palm of the hand. There are two sets in each finger (except in the thumb, which has only one joint): * "proximal interphalangeal joints" (PIJ or PIP), those between the first (also called proximal) and second (intermediate) phalanges * "distal interphalangeal joints" (DIJ or DIP), those between the second (intermediate) and third (distal) phalanges Anatomically, the proximal and distal interphalangeal joints are very similar. There are some minor differences in how the palmar plates are attached proximally and in the segmentation of the flexor tendon sheath, but the major differences are the smaller dimension and reduced mobility of the distal joint. Joint structure The PIP joint exhibits great lateral stability. Its transverse diameter is greater than its antero-posterior diameter and its thick collateral ligaments are tight in all positions duri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condyloid Joint
A condyloid joint (also called condylar, ellipsoidal, or bicondylar) is an ovoid articular surface, or condyle that is received into an elliptical cavity. This permits movement in two planes, allowing flexion, extension, adduction, abduction, and circumduction. Examples Examples include: * the * s * |
Ligaments
A ligament is the fibrous connective tissue that connects bones to other bones. It is also known as ''articular ligament'', ''articular larua'', ''fibrous ligament'', or ''true ligament''. Other ligaments in the body include the: * Peritoneal ligament: a fold of peritoneum or other membranes. * Fetal remnant ligament: the remnants of a fetal tubular structure. * Periodontal ligament: a group of fibers that attach the cementum of teeth to the surrounding alveolar bone. Ligaments are similar to tendons and fasciae as they are all made of connective tissue. The differences among them are in the connections that they make: ligaments connect one bone to another bone, tendons connect muscle to bone, and fasciae connect muscles to other muscles. These are all found in the skeletal system of the human body. Ligaments cannot usually be regenerated naturally; however, there are periodontal ligament stem cells located near the periodontal ligament which are involved in the adult regener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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