Download Organization of the skeletal system

Organization of the skeletal system
Adam Koleśnik, MD
Department of Descriptive and Clinical Anatomy
Center of Biostructure Research
Medical University of Warsaw
Function of the skeleton
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movement
protection
haemopoiesis (bone marrow)
calcium reservoir
hearing
moisturizing and warming the inhaled air
The skeletal system
• axial skeleton
– skull
– vertebral column
– ribs and sternum
• appendicular skeleton
– skeleton of the girdle
– skeleton of the free limb
The skeletal system
Clinically Oriented Anatomy, 6th Edition
Tissues forming the skeleton
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bone
cartilage
fibrous connective tissue (most of ligaments)
elastic connective tissue (ligamenta flava)
Structure of the bone
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compact bone
spongy (cancellous, trabecular) bone
medullary cavity
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organic material (collagen, glycoproteins)
inorganic (mineral) material –
hydroxiapatite: Ca10(PO4)6(OH)2
Clinically Oriented Anatomy, 6th Edition
Structure of the bone
• woven (bundle) bone
– fetal bone
– rapid remodelling
– repair of fractures
• lamellar bone
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osteons (Haversian systems)
lamellae
osteocytes
canaliculi
central Haversian canals
Volkmann’s canals
Gray’s Anatomy, 39th Edition
Structure of the bone
• periosteum
– outer surface of the bone
– thick fibrocollagenous layer
– tethered to the bone by
Sharpey’s fibres
– important for repair of fractures
• endosteum
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inner surface of the bone
thinner and more cellular
remodelling and repair
calcium homeostasis
Gray’s Anatomy, 39th Edition
Cells of the bone
• osteoblasts
– derived from osteoprogenitor (stem) cells
– synthesis and secretion of organic matrix (osteoid)
– role in mineralization of osteoid – osteocalcin, alkaline
phosphatase, pyrophosphatase
– regulation of bone resorption (osteoclasts activity)
– endosteum, periosteum, vascular canals within osteons
• osteocytes
– major cell type of mature bone
– do not divide
• osteoclasts
– local removal and remodelling of bone
– respond to cytokines, parathormon, 1,25(OH)2 vitamin D
Bone marrow
• red marrow
– haemopoietic organ
– all bones in fetus and children <5th year
– in adults: vertebrae, sternum, ribs, clavicles,
scapulae, pelvis, cranial bones, proximal ends of
femur and humerus
• yellow marrow
– blood vessels and adipocytes (fat cells)
– may be reactivated when necessary
Cartilage
• cells (chondroblasts, chondrocytes)
• matrix (collagen – type II, proteoglycans,
glycosaminoglycans – chondroitin sulphate,
keratan sulphate)
• perichondrium
Cartilage
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hyaline cartilage
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homogenous, glassy, bluish opalescent
costal, nasal, some laryngeal, tracheobronchial, most articular cartilages
cell nests (mostly pairs of cells) surrounded by the matrix
poor regenerative capacity
prone to calcification in adults
fibrocartilage
– dense, fasciculated, opaque, white
– fibroblasts and small groups of chondrocytes
– intervertebral discs, articular discs, glenoid labra, cartilaginous lining of bony
grooves, some articular cartilages
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elastic cartilage
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typical chondrocytes
yellow elastic fibers
external ear, laryngeal cartilages
vibrational functions
Ossification
• intramembranous
– mesenchymal models of bones form during the
embryonic period and ossify directly
• endochondral
– cartilage models of bones form from mesenchyme
during the fetal period and ossify subsequently
Ossification
Langman’s Medical Embryology, 10th Edition
Clinically Oriented Anatomy, 6th Edition
Bone age
Adult vs fetal skull
material of the Department of Descriptive and Clinical Anatomy, MUW
Clinically Oriented Anatomy, 6th Edition
Bone formations
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Capitulum: small, round, articular
head
Condyle: rounded, knuckle-like
articular area, often occurring in pairs
Crest: ridge of bone
Epicondyle :eminence superior to a
condyle
Facet: smooth flat area, usually
covered with cartilage, where a bone
articulates with another bone
Foramen: passage through a bone
Fossa: hollow or depressed
Groove: elongated depression or
furrow
Head (L. caput): large, round articular
end
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Line: linear elevation
Malleolus: rounded process
Notch: indentation at the edge of a
bone
Protuberance: projection of bone
Spine: thorn-like process
Spinous process: projecting spine-like
part
Trochanter: large blunt elevation
Trochlea: spool-like articular process
or process that acts as a pulley
Tubercle: small raised eminence
Tuberosity: large rounded elevation
Pneumatization
Fatu C, Puisoru M, Rotaru M, Truta AM. Ann Anat 2006;188:275-280
Fracture healing
Clinically Oriented Anatomy, 6th Edition
Development of the skeleton
Langman’s Medical Embryology, 10th Edition
Development of the vertebrae
Langman’s Medical Embryology, 10th Edition
Bifid spine and myelomeningocele
Langman’s Medical Embryology, 10th Edition
Perinatology and Prenatal Cardiology Clinic, MUW
Department of Descriptive and Clinical Anatomy, MUW
Development of the limbs
Langman’s Medical Embryology, 10th Edition
Development of the limbs
AER – apical ectodermal ridge
Langman’s Medical Embryology, 10th Edition
Limb anomalies
• meromelia – partial absence of the limb
• amelia – complete absence of the limb
• phocomelia – rudimentary hands attached to the trunk
by small, irregurarly shaped bones
• micromelia – all segments present, but short
• brachydactyly – shortened digits
• syndactyly – fused digits
• polydactyly – extra digits
• ectrodactyly – absence of digits (usually the thumb)
• lobster claw deformity - cleft hand and foot
Development of the skull
red – paraaxial mesoderm
blue – neural crest
yellow – lateral plate mesoderm
Langman’s Medical Embryology, 10th Edition
Development of the skull
material of the Department of Descriptive and Clinical Anatomy, MUW
Development of the face
Langman’s Medical Embryology, 10th Edition
Development of the face
Langman’s Medical Embryology, 10th Edition
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