5Long Bones Microscopic Anatomy Osteocytes – mature bone cellsLacunae – cavitiesLamellae – circles of lacunaeHaversian canals – cavity with blood supplyOsteon – canal and matrix ringsCanaliculi – connect cells to haversian canalsPerforating canals – canals at right angles
6Bone Formation, Growth and Remodeling Ossification has two major phasesHyaline model is covered with bone cells (osteoblasts)Hyaline model digested away, making medullary cavity.Hyaline stays in the articular cartilages and epiphyseal platesBone remodeling:Osteoclasts – activated by PTH to destroy bone and release calcium into the blood stream
7Homeostatic Imbalance Rickets:Childhood disease in which bones fail to calcify. Lack of vitamin D or of calcium. Milk, bread and others are fortified with Vit D. Sun.
8Bone FracturesSimple fracture – bone breaks cleanly and does not penetrate skinCompound fracture – broken bone ends penetrate skinFracture treated by reductionClosed reduction: bone ends are put back into normal position by doctorOpen reduction: surgery is performed to secure them with pins/plates/wires
10Fracture Healing Four events: 1. Hematoma formed by ruptured blood vessels2. Break splinted by fibrocartilage callus (cartilage matrix, bony matrix and collagen fibers). “Splints” the bone, closing the gap3. Bony callus formed (spongy bone)4. Bony callus remodeled over months time
11Axial Skeleton Skull: Cranium and Facial Bones Cranium bones: Frontal (forehead)Parietal (superior & lateral. Paired… form sagittal suture and coronal suture)Temporal (inferior to parietal… form squamous sutures. External auditory meatus, styloid process, zygomatic process, mastoid process, jugular foramen)Occipital (most posterior. Forms lambdoid suture. Opening called foramen magnum. Occipital condyles)Sphenoid (floor of cranial cavity. Sella turcica, foramen ovale, sphenoid sinuses)Ethmoid (roof of nasal cavity. Crista galli, cribiform plates)Facial Bones:Maxillae (paired and fuse to form upper jaw. Palantine process, paranasal sinuses)Palantine (paired. Posterior part of hard palate. Cleft palate)Zygomatic (paired. Cheekbones)Lacrimal (paired. Medial walls of orbit)Nasal (paired. Bridge of nose)Vomer (single bone. Nasal septum)Inferior Conchae (paired. Inside nasal cavity)Mandible (single bone. Largest, strongest bone in face)Hyoid BoneClosely related to mandible and temporal bones. Suspended midneck above larynx. Movable base for tongue and attaches neck muscles)
31Synovial Joints Based on Shape Plane JointNonaxialIntercarpal joints of wristHinge JointUniaxialElbow, ankle, joints between phalangesPivot JointProximal radioulnar jointCondyloid joint“knuckle-like”, biaxialMetacarpophalangeal jointsSaddle jointBiaxialCarpometacarpal joints in thumbBall-and-socket jointMultiaxialShoulder, hip