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The human skeleton has a variety of capabilities, similar to safety and supporting weight. Various kinds of bones have differing shapes associated to their specific perform.
So, what are the several types of bones? How are they categorized?
There are 5 forms of bones in the skeleton: flat, lengthy, quick, irregular, and sesamoid.
Let’s undergo every kind and see examples.
1. Flat Bones Shield Inside Organs
There are flat bones in the cranium (occipital, parietal, frontal, nasal, lacrimal, and vomer), the thoracic cage (sternum and ribs), and the pelvis (ilium, ischium, and pubis). The perform of flat bones is to guard inner organs similar to the mind, coronary heart, and pelvic organs. Flat bones are considerably flattened, and may present safety, like a defend; flat bones can even present massive areas of attachment for muscular tissues.
2. Lengthy Bones Assist Weight and Facilitate Motion
The lengthy bones, longer than they’re extensive, embrace the femur (the longest bone in the physique) in addition to comparatively small bones in the fingers. Lengthy bones perform to help the weight of the physique and facilitate motion. Lengthy bones are largely positioned in the appendicular skeleton and embrace bones in the decrease limbs (the tibia, fibula, femur, metatarsals, and phalanges) and bones in the higher limbs (the humerus, radius, ulna, metacarpals, and phalanges).
3. Brief Bones Are Dice-shaped
Brief bones are about so long as they’re extensive. Situated in the wrist and ankle joints, quick bones present stability and a few motion. The carpals in the wrist (scaphoid, lunate, triquetral, hamate, pisiform, capitate, trapezoid, and trapezium) and the tarsals in the ankles (calcaneus, talus, navicular, cuboid, lateral cuneiform, intermediate cuneiform, and medial cuneiform) are examples of quick bones.
4. Irregular Bones Have Advanced Shapes
Irregular bones range in form and construction and due to this fact don’t match into some other class (flat, quick, lengthy, or sesamoid). They usually have a pretty advanced form, which helps defend inner organs. For instance, the vertebrae, irregular bones of the vertebral column, defend the spinal twine. The irregular bones of the pelvis (pubis, ilium, and ischium) defend organs in the pelvic cavity.
5. Sesamoid Bones Reinforce Tendons
Sesamoid bones are bones embedded in tendons. These small, spherical bones are generally present in the tendons of the fingers, knees, and ft. Sesamoid bones perform to guard tendons from stress and put on. The patella, generally known as the kneecap, is an instance of a sesamoid bone.
An outline of forms of bones from the 1918 version of Grey’s Anatomy of the Human Physique.
Some extra bone fundamentals from Higher Well being Channel (a publication of the Division of Well being, State Authorities of Victoria, Australia).
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Bone, or osseous tissue, is a connective tissue that constitutes the endoskeleton. It comprises specialised cells and a matrix of mineral salts and collagen fibers.
The mineral salts primarily embrace hydroxyapatite, a mineral shaped from calcium phosphate. Calcification is the technique of deposition of mineral salts on the collagen fiber matrix that crystallizes and hardens the tissue. The method of calcification solely happens in the presence of collagen fibers.
The bones of the human skeleton are categorised by their form: lengthy bones, quick bones, flat bones, sutural bones, sesamoid bones, and irregular bones (Determine 1).
Determine 1. Proven are several types of bones: flat, irregular, lengthy, quick, and sesamoid.
Determine 2. The lengthy bone is roofed by articular cartilage at both finish and comprises bone marrow (proven in yellow on this illustration) in the marrow cavity.
Lengthy bones are longer than they’re extensive and have a shaft and two ends. The diaphysis, or central shaft, comprises bone marrow in a marrow cavity. The rounded ends, the epiphyses, are coated with articular cartilage and are full of pink bone marrow, which produces blood cells (Determine 2). Most of the limb bones are lengthy bones—for instance, the femur, tibia, ulna, and radius. Exceptions to this embrace the patella and the bones of the wrist and ankle.
Brief bones, or cuboidal bones, are bones which might be the identical width and size, giving them a cube-like form. For instance, the bones of the wrist (carpals) and ankle (tarsals) are quick bones (Determine 1).
Flat bones are skinny and comparatively broad bones which might be discovered the place intensive safety of organs is required or the place broad surfaces of muscle attachment are required. Examples of flat bones are the sternum (breast bone), ribs, scapulae (shoulder blades), and the roof of the cranium (Determine 1).
Irregular bones are bones with advanced shapes. These bones could have quick, flat, notched, or ridged surfaces. Examples of irregular bones are the vertebrae, hip bones, and several other cranium bones.
Sesamoid bones are small, flat bones and are formed equally to a sesame seed. The patellae are sesamoid bones. Sesamoid bones develop inside tendons and could also be discovered close to joints at the knees, fingers, and ft (see Determine 3).
Determine 3. The patella of the knee is an instance of a sesamoid bone.
Sutural bones are small, flat, irregularly formed bones. They might be discovered between the flat bones of the cranium. They range in quantity, form, measurement, and place.
The 4 Shapes of Bone and What They Do
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The skeleton is the physique’s body. It supplies the basis to which different buildings cling and helps to create our form. All 206 of the bones of the skeleton could be categorized into 4 sorts: lengthy, quick, flat, and irregular. Every kind of bone serves a specific goal and a few sorts have a couple of perform.
The skeleton of the legs and arms are made up of largely lengthy bones. Lengthy bones are so-called as a result of they’re longer than they’re extensive. Lengthy bones in the arm embrace the humerus, radius, ulna, metacarpals, and phalanges. Lengthy bones of the leg embrace the femur, tibia, fibula, metatarsals, and phalanges. The clavicles (collar bones) are additionally lengthy bones.
Lengthy bones present the leverage we’d like for shifting our our bodies and for manipulating our surroundings. All lengthy bones have two most important components: diaphysis and epiphysis.
The diaphysis is the shaft of the lengthy bone, the most important physique. The diaphysis is a tube with a hole heart referred to as the medullary cavity (or marrow cavity). The wall of the diaphysis is made up of compact bone, which is dense and really onerous. For many of the lifetime of a lengthy bone, the heart of the diaphysis is full of yellow bone marrow. Yellow bone marrow is principally fats, also called adipose tissue.
Every finish of a lengthy bone known as an epiphysis. Every epiphysis is formed to suit its connecting bone at a junction that known as a joint and the form of the epiphysis relies on the job of the joint. The proximal (nearer to the physique) epiphysis of the humerus and the proximal epiphysis of the femur are formed in a rounded method, referred to as the head, and look a bit like half of a ball. This form permits these two lengthy bones to rotate in a number of instructions. The pinnacle of the femur suits into a socket in the pelvis. The pinnacle of the humerus suits into a socket in the shoulder. That kind of joint known as a ball-and-socket joint. Joints that solely permit motion alongside one axis are referred to as hinge joints.
The wall of the epiphysis is made from compact bone like the diaphysis and the heart comprises spongy bone. Spongy bone is made from many small cavities (additionally referred to as medullary cavities) full of pink bone marrow. Purple bone marrow manufactures pink blood cells and may be very properly linked to the circulatory system. There may be a lot blood movement by way of the spongy bone, that needles inserted into the spongy bone of the humerus, of the femur, or of the sternum (not a lengthy bone as you will see beneath) can be utilized to manage fluid or drugs identical to an intravenous line.
There may be a line that may be seen on photos of the epiphysis and known as the epiphyseal plate. That’s the place new bone is added to extend the size of the lengthy bone throughout improvement (referred to as ossification). It’s generally generally known as the progress plate. Fractures (breaks and cracks in the bone) that embrace the epiphyseal plate can interrupt correct bone improvement in children.
Brief bones are referred to as that as a result of they about as extensive as they’re lengthy. There is no such thing as a diaphysis on a quick bone. It’s made up of spongy bone surrounded by compact bone identical to the epiphysis. Brief bones additionally include pink bone marrow.
There are 32 quick bones in the human skeleton. Usually, quick bones facilitate motion and power in the advanced joints of the wrist and ankles by sliding and shifting in opposition to one another.
The carpals (wrist bones), tarsals (ankle and heel bones), and the patella (kneecap) are all quick bones. Some consultants take into account the patella a sesamoid bone (mentioned beneath) as a result of it primarily supplies an anchor level for tendons and ligaments. Nevertheless, the patella is widespread to everybody whereas sesamoid bones develop in another way between particular person individuals.
Flat bones are the armor of the physique. Flat bones present construction, similar to the form of the head and torso, and the basis of the shoulder and hip. Flat bones can even present safety of sentimental tissues beneath. Like quick bones, flat bones have partitions which might be made from compact bone and a heart of spongy bone (with pink bone marrow) that varieties one thing like a sandwich.
The cranial bones, scapula (shoulder blade), sternum (breast bone), ribs, and iliac bone (hip) are all flat bones. Of those, the scapula, sternum, ribs, and iliac bone all present robust insertion factors for tendons and muscular tissues.
The bones of the skull are the a part of the cranium that encapsulates the mind. The bones of the skull are linked collectively by way of joints referred to as sutures, which appear like they’re stitched. Typically, further small bones can develop between sutured bones of the skull alongside the suture traces. These small bones are referred to as sutural bones. They develop randomly and will not be named bones.
Bones which might be neither lengthy, quick, nor flat are thought-about irregular bones. The shapes of those bones present very particular capabilities. The facial bones and the bones of the spinal column, the vertebrae, are all irregular bones. These bones have sophisticated shapes which might be distinctive to their perform. Most of the irregular bones seem solely as soon as in the physique alongside the midline, similar to every of the vertebrae. A few of the bones of the face seem in mirror picture, similar to the zygomatic bones (cheekbones).
Irregular bones usually have sophisticated shapes which might be used as insertion factors for muscular tissues, tendons, and ligaments. The commonest form known as a course of that appears like a protrusion. The vertebrae every have three processes: the spinous course of alongside the posterior (again) in the heart (midline), and transverse processes on both facet of the spinous course of.
Typically, bones will develop because of friction alongside tendons or ligaments. Often, these are very small bones and develop randomly between people. They aren’t named. Some anatomists take into account the patella an instance of sesamoid bone.
Equally, you might ask, is the pelvis a flat or irregular bone?
Irregular bones range in form and construction and due to this fact don’t match into some other class (flat, quick, lengthy, or sesamoid). For instance, the vertebrae, irregular bones of the vertebral column, defend the spinal twine. The irregular bones of the pelvis (pubis, ilium, and ischium) defend organs in the pelvic cavity.
One may ask, how are flat bones and lengthy bones related? Lengthy bones, similar to the femur, are longer than they’re extensive. Brief bones, similar to the carpals, are roughly equal in size, width, and thickness. Flat bones are skinny, however are sometimes curved, similar to the ribs. Irregular bones similar to these of the face don’t have any attribute form.
Secondly, what kind of bone is the hip bone?
The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a massive irregular bone, constricted in the heart and expanded above and beneath. In some vertebrates (together with people earlier than puberty) it’s composed of three components: the ilium, ischium, and the pubis.
Is the mandible a flat bone?
No, the mandible will not be a flat bone. It’s characterised as an irregular bone. Different irregular bones in the human skeleton embrace the vertebrae, sacrum, coccyx, temporal, sphenoid, ethmoid, zygomatic, maxilla, mandible, palatine, inferior nasal concha, and hyoid.