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Actions of Dopamine on the Skin and the Skeleton
Published in Nira Ben-Jonathan, Dopamine, 2020
The human skeleton provides the internal framework of the human body and is divided into the axial skeleton and appendicular skeleton. The axial skeleton is composed of the vertebral column, rib cage, skull, and other associated bones. The appendicular skeleton is attached to the axial skeleton and is composed of the shoulder and pelvic girdles, and upper and lower limbs. The bone mass in the skeleton reaches its maximal density around age 21, followed by progressive loss of bone tissue with advanced age. The aging bone has reduced mineral content, and is prone to osteoporosis—a condition in which bones are less dense, more fragile, and predisposed to fractures [53].
Disc Structure and Function
Published in Peter Ghosh, The Biology of the Intervertebral Disc, 2019
It is the combination of the mechanical properties of all its parts which leads to mechanical stability of the spine. Nevertheless, the discs are the major structures of the intervertebral joints, which are mainly responsible for conferring flexibility along most of the spinal column. They enable the spine to adopt the wide range of postures essential for it to function satisfactorily as the main component of the axial skeleton.
Fundamentals
Published in Clare E. Milner, Functional Anatomy for Sport and Exercise, 2019
The axial skeleton consists of the vertebral column and skull plus the ribs and associated bones of the thorax. It is the central part of the skeleton and the appendicular skeleton attaches to it through the shoulder and pelvic girdles. The vertebral column contains 33 vertebrae in four regions; moving distally from the head, these are the 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae. Vertebrae within a region are numbered in ascending order in a proximal to distal direction. The sacrum and coccyx are made up of fused vertebrae, whereas the vertebrae in the other regions are movable. The vertebral column is not simply a stack of vertebrae, but has four curved regions. The cervical curve is convex anteriorly, followed by the thoracic curve, which is concave anteriorly, the anteriorly convex lumbar curve, and the anteriorly concave pelvic curve. Since the vertebrae protect the spinal cord, injuries to this region are potentially very severe. Depending on the vertebral level at which the spinal cord is damaged, more or less of the body may be paralyzed. As a result, most sports have rules that are designed to minimize the risk of spinal cord damage. For example, American football bans tackles made with the head of the tackler as the first point of contact with the opponent. This rule was introduced after changes to protective headgear led to a large increase in cervical spine injuries because of an increase in the use of this tackling technique.
Advances in pharmacotherapies for axial spondyloarthritis
Published in Expert Opinion on Pharmacotherapy, 2023
Spondyloarthritis (SpA) corresponds to a group of inflammatory rheumatic diseases that share common clinical, genetic, and imaging characteristics. This group includes axial SpA (axSpA), reactive arthritis, arthritis associated with inflammatory bowel diseases (IBD), psoriatic arthritis (PsA), juvenile and late onset SpA, and undifferentiated SpA. These diseases mainly affect the axial skeleton, i.e. the spine and sacroiliac joints (SIJ). Peripheral joints may also be involved with arthritis predominantly located in the lower limbs. According to the main clinical presentation, SpA may be subclassified as axial or peripheral SpA. Spondyloarthritis also presents with specific musculoskeletal manifestations, i.e. dactylitis and inflammation of entheseal structures, the sites where tendons or ligaments are attached to the bone. Specific extra-musculoskeletal organs such as the skin, eye, and gut may also be affected in SpA, with respectively psoriasis, acute anterior uveitis, and IBD as the main manifestations [1].
Drug treatment strategies for paget’s disease: relieving pain and preventing progression
Published in Expert Opinion on Pharmacotherapy, 2023
Daniela Merlotti, Domenico Rendina, Guido Cavati, Veronica Abate, Alberto Falchetti, Christian Mingiano, Ranuccio Nuti, Luigi Gennari
Paget’s disease of bone (PDB) is a focal skeletal disorder exhibiting a markedly increased bone remodeling in one or more skeletal sites, depending on whether it is a mono- or polyostotic form [1–3]. The most affected sites are mainly at the level of the axial skeleton, including the pelvis, femur, tibia, lumbar spine, and skull (one or more of these five sites are involved in up to 95% of patients). Bone affected by PDB is increased in volume, hyper-vascularized, structurally weak, and therefore at risk for deformities and fractures (Figure 1a,b). These alterations in bone composition and shape may result in the occurrence of pain at the affected bones, at adjacent joints or even arising from nerve compression syndromes. However, in view of the decrease of both prevalence (currently estimated to be below 1%) and clinical severity of PDB reported over the past 30–50 years, most patients are actually asymptomatic or only present mild symptoms, especially during the early stages of the disorder, so that frequently the disease is occasionally found during biochemical or radiological investigations for other diseases [3,4].
Long-term effects of mTBIs includes a higher dependency on visual inputs to control vertical posture
Published in Brain Injury, 2023
Alessander Danna-Dos-Santos, Patricia Driusso, Adriana Menezes Degani
Disproportionate deterioration of body postural control in medial-lateral direction has been described in postural studies conducted in other populations (48,49). However, its driving mechanisms remain unclear. We speculate this effect may be driven by a combination of anatomical aspects of the axial skeleton and the segmental distribution of its postural muscles. Specifically, the presence of two lower limbs positioned side-by-side and the reduced range-of motion of the knee joints in the frontal plane allow for relatively better medial-lateral stability. The parallel positioning of the two lower limbs increases the size of our base of support in the medial-lateral direction while allowing an effective transmission of reactive forces to partially counter-act the tendency of the body to lean on its side. As a result of this mechanical stability, the number of muscles dedicated to control medial-lateral balance can be reduced, therefore, making the muscular system dedicated to this type of control less redundant. Even though this less redundant system functions well in health, it might reduce the ability of the CNS to adapt its neuromechanisms of control when the controller itself is compromised by pathologies. Instability will then follow.