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Carpal Bones
The carpal bones are the eight small bones that make up the wrist (carpus) that connects the hand to the forearm. The terms "carpus" and "carpal" are derived from the Latin wikt:carpus#Latin, carpus and the Greek language, Greek wikt:καρπός#Ancient Greek, καρπός (karpós), meaning "wrist". In human anatomy, the main role of the carpal bones is to joint, articulate with the radius (bone), radial and ulnar heads to form a highly mobile condyloid joint (i.e. wrist joint),Kingston 2000, pp 126-127 to provide attachments for thenar and hypothenar muscles, and to form part of the rigid carpal tunnel which allows the median nerve and tendons of the anterior compartment of the forearm, anterior forearm muscles to be transmitted to the hand and fingers. In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius (bone), radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers (or toes in quadrupeds), whereas those ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility. Bones come in a variety of shapes and sizes and have complex internal and external structures. They are lightweight yet strong and hard and serve multiple functions. Bone tissue (osseous tissue), which is also called bone in the uncountable sense of that word, is hard tissue, a type of specialised connective tissue. It has a honeycomb-like matrix internally, which helps to give the bone rigidity. Bone tissue is made up of different types of bone cells. Osteoblasts and osteocytes are involved in the formation and mineralisation of bone; osteoclasts are involved in the resorption of bone tissue. Modified (flattened) osteoblasts become the lining cells that form a protective layer on the bone surface. The mine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Median Nerve
The median nerve is a nerve in humans and other animals in the upper limb. It is one of the five main nerves originating from the brachial plexus. The median nerve originates from the lateral and medial cords of the brachial plexus, and has contributions from ventral roots of C6-C7 (lateral cord) and C8 and T1 (medial cord). The median nerve is the only nerve that passes through the carpal tunnel. Carpal tunnel syndrome is the disability that results from the median nerve being pressed in the carpal tunnel. Structure The median nerve arises from the branches from lateral and medial cords of the brachial plexus, courses through the anterior part of arm, forearm, and hand, and terminates by supplying the muscles of the hand. Arm After receiving inputs from both the lateral and medial cords of the brachial plexus, the median nerve enters the arm from the axilla at the inferior margin of the teres major muscle. It then passes vertically down and courses lateral to the brac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pisiform Bone
The pisiform bone ( or ), also spelled pisiforme (from the Latin ''pisiformis'', pea-shaped), is a small knobbly, sesamoid bone that is found in the wrist. It forms the ulnar border of the carpal tunnel. Structure The pisiform is a sesamoid bone, with no covering membrane of periosteum. It is the last carpal bone to ossify. The pisiform bone is a small bone found in the proximal row of the wrist ( carpus). It is situated where the ulna joins the wrist, within the tendon of the flexor carpi ulnaris muscle. It only has one side that acts as a joint, articulating with the triquetral bone. It is on a plane anterior to the other carpal bones and is spheroidal in form. The pisiform bone has four surfaces: # The ''dorsal surface'' is smooth and oval, and articulates with the triquetral: this facet approaches the superior, but not the inferior border of the bone. # The ''palmar surface'' is rounded and rough, and gives attachment to the transverse carpal ligament, the flexor carpi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triquetral Bone
The triquetral bone (; also called triquetrum, pyramidal, three-faced, and formerly cuneiform bone) is located in the wrist on the medial side of the proximal row of the carpus between the lunate and pisiform bones. It is on the ulnar side of the hand, but does not directly articulate with the ulna. Instead, it is connected to and articulates with the ulna through the Triangular fibrocartilage discManaster, B. J., Julia Crim "Imaging Anatomy: Musculoskeletal E-Book" Elsevier Health Sciences, 2016, p. 326. and ligament, which forms part of the ulnocarpal joint capsule. It connects with the pisiform, hamate, and lunate bones. It is the 2nd most commonly fractured carpal bone. Structure The triquetral is one of the eight carpal bones of the hand. It is a three-faced bone found within the proximal row of carpal bones. Situated beneath the pisiform, it is one of the carpal bones that form the carpal arch, within which lies the carpal tunnel. The triquetral bone may be distingui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunate Bone
The lunate bone (semilunar bone) is a carpal bone in the human hand. It is distinguished by its deep concavity and crescentic outline. It is situated in the center of the proximal row carpal bones, which lie between the ulna and radius and the hand. The lunate carpal bone is situated between the lateral scaphoid bone and medial triquetral bone. Structure The lunate is a crescent-shaped carpal bone found within the hand. The lunate is found within the proximal row of carpal bones. Proximally, it abuts the radius. Laterally, it articulates with the scaphoid bone, medially with the triquetral bone, and distally with the capitate bone. The lunate also articulates on its distal and medial surface with the hamate bone. The lunate is stabilised by a medial ligament to the scaphoid bone and a lateral ligament to the triquetral bone. Ligaments between the radius and carpal bone also stabilise the position of the lunate, as does its position in the lunate fossa of the radius. Bone Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scaphoid Bone
The scaphoid bone is one of the carpal bones of the wrist. It is situated between the hand and forearm on the thumb side of the wrist (also called the lateral or radial side). It forms the radial border of the carpal tunnel. The scaphoid bone is the largest bone of the proximal row of wrist bones, its long axis being from above downward, lateralward, and forward. It is approximately the size and shape of a medium cashew nut. Structure The scaphoid is situated between the proximal and distal rows of carpal bones. It is located on the radial side of the wrist, adjacent to the styloid process of the radius. It articulates with the radius, lunate, trapezoid, trapezium, and capitate. Over 80% of the bone is covered in articular cartilage. Bone The palmar surface of the scaphoid is concave, and forming a distal tubercle, giving attachment to the transverse carpal ligament. The proximal surface is triangular, smooth and convex. The lateral surface is narrow and gives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flexor Retinaculum Of The Hand
The flexor retinaculum (transverse carpal ligament or anterior annular ligament) is a fibrous band on the palmar side of the hand near the wrist. It arches over the carpal bones of the hands, covering them and forming the carpal tunnel. Structure The flexor retinaculum is a strong, fibrous band that covers the carpal bones on the palmar side of the hand near the wrist. It attaches to the bones near the radius and ulna. On the ulnar side, the flexor retinaculum attaches to the pisiform bone and the hook of the hamate bone. On the radial side, it attaches to the tubercle of the scaphoid bone, and to the medial part of the palmar surface and the ridge of the trapezium bone. The flexor retinaculum is continuous with the palmar carpal ligament, and deeper with the palmar aponeurosis. The ulnar artery and ulnar nerve, and the cutaneous branches of the median and ulnar nerves, pass on top of the flexor retinaculum. On the radial side of the retinaculum is the tendon of the flexor car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tarsus (skeleton)
In the human body, the tarsus (: tarsi) is a cluster of seven articulating bones in each foot situated between the lower end of the tibia and the fibula of the lower leg and the metatarsus. It is made up of the midfoot (Cuboid bone, cuboid, medial, intermediate, and lateral cuneiform bone, cuneiform, and navicular) and hindfoot (Talus bone, talus and calcaneus). The tarsus articulates with the bones of the metatarsus, which in turn articulate with the proximal phalanges of the toes. The joint between the tibia and fibula above and the tarsus below is referred to as the ankle, ankle joint proper. In humans the largest bone in the tarsus is the calcaneus, which is the weight-bearing bone within the heel of the foot. Human anatomy Bones The talus bone or ankle bone is connected superiorly to the two bones of the lower leg, the tibia and fibula, to form the ankle, ankle joint or talocrural joint; inferiorly, at the subtalar joint, to the calcaneus or heel bone. Together, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foot
The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up of one or more segments or bones, generally including claws and/or nails. Etymology The word "foot", in the sense of meaning the "terminal part of the leg of a vertebrate animal" comes from Old English ''fot'', from Proto-Germanic *''fot'' (source also of Old Frisian ''fot'', Old Saxon ''fot'', Old Norse ''fotr'', Danish ''fod'', Swedish ''fot'', Dutch ''voet'', Old High German ''fuoz'', German ''Fuß'', Gothic ''fotus'', all meaning "foot"), from PIE root *''ped-'' "foot". The plural form ''feet'' is an instance of i-mutation. Structure The human foot is a strong and complex mechanical structure containing 26 bones, 33 joints (20 of which are actively articulated), and more than a hundred muscles, tendons, and ligaments.Podiatry Chan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacarpus
In human anatomy, the metacarpal bones or metacarpus, also known as the "palm bones", are the appendicular skeleton, appendicular bones that form the intermediate part of the hand between the phalanges (fingers) and the carpal bones (wrist, wrist bones), which joint, articulate with the forearm. The metacarpal bones are homologous to the metatarsal bones in the foot. Structure The metacarpals form a transverse arch to which the rigid row of distal carpal bones are fixed. The peripheral metacarpals (those of the thumb and little finger) form the sides of the cup of the palmar gutter and as they are brought together they deepen this concavity. The index metacarpal is the most firmly fixed, while the thumb metacarpal articulates with the trapezium and acts independently from the others. The middle metacarpals are tightly united to the carpus by intrinsic interlocking bone elements at their bases. The ring metacarpal is somewhat more mobile while the fifth metacarpal is semi-indepen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulna
The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long bone. Longer and thinner than the radius, the ulna is considered to be the smaller long bone of the lower arm. The corresponding bone in the Human leg#Structure, lower leg is the fibula. Structure The ulna is a long bone found in the forearm that stretches from the elbow to the wrist, and when in standard anatomical position, is found on the Medial (anatomy), 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 (anatomy), 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 also a radial notch for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
A tetrapod (; from Ancient Greek :wiktionary:τετρα-#Ancient Greek, τετρα- ''(tetra-)'' 'four' and :wiktionary:πούς#Ancient Greek, πούς ''(poús)'' 'foot') is any four-Limb (anatomy), limbed vertebrate animal of the clade Tetrapoda (). Tetrapods include all Neontology#Extant taxa versus extinct taxa, extant and Extinction, extinct amphibians and amniotes, with the latter in turn Evolution, evolving into two major clades, the Sauropsida, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (extinct pelycosaur, "pelycosaurs", therapsids and all extant mammals, including Homo sapiens, humans). Hox gene mutations have resulted in some tetrapods becoming Limbless vertebrate, limbless (snakes, legless lizards, and caecilians) or two-limbed (cetaceans, sirenians, Bipedidae, some lizards, kiwi (bird), kiwis, and the extinct moa and elephant birds). Nevertheless, they still qualify as tetrapods through their ancestry, and some retain a pair of ves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
