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.
A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is the stable outer shell of an organism, the endoskeleton, which forms the support structure inside the body, and the hydroskeleton, a flexible internal skeleton supported by fluid pressure. Vertebrates are animals with a vertebral column, and their skeletons are typically composed of bone and cartilage. Invertebrates are animals that lack a vertebral column. The skeletons of invertebrates vary, including hard exoskeleton shells, plated endoskeletons, or spicules. Cartilage is a rigid connective tissue that is found in the skeletal systems of vertebrates and invertebrates.
In biology, tissue is a historically derived biological organizational level between cells and a complete organ. A tissue is therefore often thought of as an assembly of similar cells and their extracellular matrix from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
The heel is the prominence at the posterior end of the foot. It is based on the projection of one bone, the calcaneus or heel bone, behind the articulation of the bones of the lower leg.
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme, derived from the mesoderm, the middle embryonic germ layer. Connective tissue is found in between other tissues everywhere in the body, including the nervous system. The three meninges, membranes that envelop the brain and spinal cord, are composed of connective tissue. Most types of connective tissue consists of three main components: elastic and collagen fibers, ground substance, and cells. Blood, and lymph are classed as specialized fluid connective tissues that do not contain fiber. All are immersed in the body water. The cells of connective tissue include fibroblasts, adipocytes, macrophages, mast cells and leucocytes.
Bone healing, or fracture healing, is a proliferative physiological process in which the body facilitates the repair of a bone fracture.
In anatomy, the meninges are the four membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, the SLYM and the pia mater. Cerebrospinal fluid is located in the subarachnoid space between the arachnoid mater and the pia mater. The primary function of the meninges is to protect the central nervous system.
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.
The suprahyoid muscles are four muscles located above the hyoid bone in the neck. They are the digastric, stylohyoid, geniohyoid, and mylohyoid muscles. They are all pharyngeal muscles, with the exception of the geniohyoid muscle. The digastric is uniquely named for its two bellies. Its posterior belly rises from the mastoid process of the cranium and slopes downward and forward. The anterior belly arises from the digastric fossa on the inner surface of the mandibular body, which slopes downward and backward. The two bellies connect at the intermediate tendon. The intermediate tendon passes through a connective tissue loop attached to the hyoid bone. The mylohyoid muscles are thin, flat muscles that form a sling inferior to the tongue supporting the floor of the mouth. The geniohyoids are short, narrow muscles that contact each other in the midline. The stylohyoids are long, thin muscles that are nearly parallel with the posterior belly of the digastric muscle.
The human musculoskeletal system is an organ system that gives humans the ability to move using their muscular and skeletal systems. The musculoskeletal system provides form, support, stability, and movement to the body.
The periosteum is a membrane that covers the outer surface of all bones, except at the articular surfaces of long bones. Endosteum lines the inner surface of the medullary cavity of all long bones.
The medullary cavity is the central cavity of bone shafts where red bone marrow and/or yellow bone marrow is stored; hence, the medullary cavity is also known as the marrow cavity.
Endochondral ossification is one of the two essential processes during fetal development of the mammalian skeletal system by which bone tissue is produced. Unlike intramembranous ossification, the other process by which bone tissue is produced, cartilage is present during endochondral ossification. Endochondral ossification is also an essential process during the rudimentary formation of long bones, the growth of the length of long bones, and the natural healing of bone fractures.
Intramembranous ossification is one of the two essential processes during fetal development of the gnathostome skeletal system by which rudimentary bone tissue is created. Intramembranous ossification is also an essential process during the natural healing of bone fractures and the rudimentary formation of bones of the head.
In osteology, the osteon or haversian system is the fundamental functional unit of much compact bone. Osteons are roughly cylindrical structures that are typically between 0.25 mm and 0.35 mm in diameter. Their length is often hard to define, but estimates vary from several millimeters to around 1 centimeter. They are present in many bones of most mammals and some bird, reptile, and amphibian species.
The metaphysis is the neck portion of a long bone between the epiphysis and the diaphysis. It contains the growth plate, the part of the bone that grows during childhood, and as it grows it ossifies near the diaphysis and the epiphyses. The metaphysis contains a diverse population of cells including mesenchymal stem cells, which give rise to bone and fat cells, as well as hematopoietic stem cells which give rise to a variety of blood cells as well as bone-destroying cells called osteoclasts. Thus the metaphysis contains a highly metabolic set of tissues including trabecular (spongy) bone, blood vessels, as well as Marrow Adipose Tissue (MAT).
Deep fascia is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments.
Panosteitis, sometimes shortened to pano among breeders, is an occasionally seen long bone condition in large breed dogs. It manifests with sudden, unexplained pain and lameness that may shift from leg to leg, usually between 5 and 14 months of age, earning the nickname "growing pains. " Signs such as fever, weight loss, anorexia, and lethargy can also be seen. The cause is unknown, but genetics, stress, infection, metabolism, or an autoimmune component may be factors. It has also been suggested that rapid growth and high-protein food are involved in the pathogenesis. Whole blood analysis may show an elevated white blood cell count; this finding lends support to the theory that panosteitis is due to an infection.
In the human body, the carpal tunnel or carpal canal is the passageway on the palmar side of the wrist that connects the forearm to the hand.
The vaginal support structures are those muscles, bones, ligaments, tendons, membranes and fascia, of the pelvic floor that maintain the position of the vagina within the pelvic cavity and allow the normal functioning of the vagina and other reproductive structures in the female. Defects or injuries to these support structures in the pelvic floor leads to pelvic organ prolapse. Anatomical and congenital variations of vaginal support structures can predispose a woman to further dysfunction and prolapse later in life. The urethra is part of the anterior wall of the vagina and damage to the support structures there can lead to incontinence and urinary retention.
