Skeletal System Hole's

Terms	Definitions
Skeletal system	Support, protection and movement Formation of blood cells in the marrow Inorganic ion homeostasis
bone classification according to shape	Long Bones: longitudinal axis is elongated, ends are expanded (forearm and thigh bones) Short Bones: same width as length (wrist and ankles) Flat Bones: plate like (ribs, scapulae, some skull bones) Irregular Bones: variety of shapes (vertebrae, many facial bones) Sesamoid (Round) Bones: inserted in tendons (kneecap)
Long Bones	longitudinalaxis is elongated, ends expanded - e.g. the femur
Short Bones	same width as length e.g. the bones of the wrist and ankles
Flat Bones	plate like e.g. scapula, ribs, some bones of the skull
Irregular Bones	Variety of shapese.g. vertebrae
Sesamoid Bone	(Round) Bones: inserted in tendons - e.g. the patella
Parts of long bone (verbal)	EPIPHYSIS DIAPHYSIS MEDULLARY CAVITY MARROW
epiphysis	enlarged ends distal proximal thin shell of compact bone spongy bone beneath covered by articular cartilage
diaphysis	shaft of long bone compact bone on the outside spongy bone on the inside covered by PERIOSTEUM contains blood vessels and nerves
medullary cavity	within the shaft which is lined by endosteum and bone forming cells
marrow	within the medullary cavity, red/yellow
parts of long bone (detail graphic)
Two types of bones	compact and spongy bone
compact bone	Compact [cortical] bone tightly packed extracellular matrix forms the walls of the diaphysis in thin layer on the surface of the epiphyses
spongy bone	Spongy [cancellous] bone composed of many branching plates [trabeculae] irregular spaces connect the trabeculae found in the epiphyses Compact bone overlays spongy bone in all bone types
compact bone (graphic)
spongy bone (graphic)
microscopic structure of compact bone	Osteocytes within lacunae form concentric circles around a longitudinal central canal [Haversian canal] Blood vessels Nerves Connective tissue
blood supply in bones
microscopic structure of compact bone	Volkman's canals (transverse perforating canals) are transversely oriented and contain larger blood vessels and nerves and connect Haversian canals with the bone surface osteon is the organizational unit of compact bone - a Haversian canal and the osteocytes that surround it
spongy bone	Osteocytes in trabeculae Extracellular matrix No central canal Diffusion through canaliculi
bone development	INTRAMEMBRANOUS OSSIFIACTION @ bones originate within sheetlike @ layers of connective tissues @ broad, flat bones @ skull bones (except mandible) @ intramembranous bones ENDOCHONDRIAL OSSIFICATION @ bones begin as hyaline cartilage @ form models for future bones @ most bones of the skeleton are of this type @ endochondral bones
intramembranous ossification	sheets of connective tissue appear at the site where the bone will form blood vessels form in the connective tissue cells within the connective tissue differentiate into osteoblasts [bone-forming cells] osteoblasts deposit extracellular matrix and when surrounded by the matrix [within lacunae] become osteocytes Cells of the CT outside become the periosteum
intramembranous ossification	bone forms in all directions within the connective tissue sheets outermost layer of connective tissue becomes the periosteum, with osteoblasts in its inner layer forming a layer of compact bone over the spongy bone beneath bones of the skull form in this manner
endochondral ossification	a cartilage model of the bone is formed cartilage cells degenerate and the model is surrounded by a periosteum connective tissue and osteoblasts invade the degenerating cartilage osteoblasts deposit spongy bone where the cartilage previously existed osteoblasts differentiate into osteocytes within lacunae, surrounded by bony matrix
endochondral ossification	a layer of compact bone forms beneath the periosteum in long bones, bone develops first from a primary ossification center in the center of the diaphysis [growing towards the ends] and later from secondary ossification centers in the epiphyses [growing in all directions] in long bones, a band of cartilage remains that separates the primary and secondary ossification centers - the epiphyseal plate
ossification begins at ...	Ossification begins at 3rd month of prenatal development By 23-23 years all bones are completely ossified
homeostasis of bone tissue	Old tissue is removed and new tissue is formed Bone Resorption - action of osteoclasts Bone Deposition - action of osteoblasts Bone remodeling Continues throughout life to keep bone mass at a constant level
Factors Affecting Bone Development, Growth, and Repair	Deficiency of Vitamin A - retards bone development Deficiency of Vitamin C - results in fragile bones Deficiency of Vitamin D - rickets, osteomalacia Insufficient Growth Hormone - dwarfism Excessive Growth Hormone - gigantism, acromegaly Insufficient Thyroid Hormone - delays bone growth Sex Hormones - promote bone formation; stimulate ossification of epiphyseal plates Physical Stress - stimulates bone growth, thicken and strengthen bone
Bone Function	Support, Movement & Protection (gives shape to head, etc./supports body's weight/protects lungs, etc./bones and muscles interact when limbs or body parts move Blood Cell Formation (hematopoiesis/red marrow) Inorganic Salt Storage (calcium/phosphate/magnesium/sodium/potassium)
Bone Marrow	Red and yellow Red marrow --- hematopoiesis Yellow marrow - adipose tissue In adults red marrow in the spongy bone of skull, ribs, sternum, vertebrae, clavicles and hip bone If blood supply is low , yellow marrow turns to red
Bone Function (Salts)	Inorganic salt storage 70% of extracellular matrix of bone is mineral salts, mostly hydroxyapatite [calcium phosphate] these salts are an important reservoir of minerals needed for body metabolism and are actively stored in and released from bone when blood calcium is low, parathyroid hormone is released from the parathyroid gland and osteoclasts are stimulated to break down bone matrix and release calcium into the bloodstream when blood calcium is high, osteoclast activity is inhibited and calcitonin is released from the thyroid gland, which stimulates osteoblasts to form bone matrix
Regulatori of calcium levels (graphic)
Osteopenia and Osteoporosis	Bone tissue is remodeled, by a balance of resorption and deposition. With time more bone tissue is lost then replaced. In women past menopause this results in low bone mass or osteopenia. Eventually to porous bones which is osteoporosis Bones develop spaces and canals which fill with fibrous and fatty tissue. Bones can fracture easily, sometimes spontaneously,vertebrae collapse. Most common type of fracture is hip fracture
Sutural Bones
Skeletal organization	Axial Skeleton (red) head neck trunk Appendicular Skeleton (green) upper limbs lower limbs pectoral girdle pelvic girdle
part of axial skeleton is the ...	@ Skull cranium facial bones @ Hyoid bone below the jaw and above the larynx does not articulate with other bones supports the tongue and muscles of swallowing
more parts of the axial skeleton	@ Vertebral column 24 vertebrae [7 cervical, 12 thoracic, 5 lumbar] sacrum coccyx - tailbone @ Thoracic cage ribs [24 total - 12 on each side] sternum [breastbone; to which most ribs are attached]
Axial skeleton shown in red
Skeletal Organization: Appendicular skeleton part 1	@ Pectoral girdle scapula [shoulder blade] clavicle [collar bone] connects the bones of the upper limb to the axial skeleton @ Upper limbs humerus - arm bone radius and ulna - forearm bones humerus, radius and ulna articulate at the elbow carpals - wrist bones [8] metacarpals - palm bones [5] phalanges - finger bones [14]
Skeletal Organization: Appendicular skeleton part 2	@ Pelvic girdle hipbones connect to sacrum connect bones of the lower limbs to axial skeleton with the sacrum and coccyx, form the pelvis @ Lower limbs femur - thigh bone tibia and fibula - lower leg femur and tibia articulate with the patella [kneecap]Terms of the Skeletal Structures tarsals - ankle bones [7] metatarsals - foot bones [5] phalanges - toe bones [14]
Terms of the skeletal Structures
Skull	21 bones joined by sutures [immovable joints] (8 in cranium 13 in facial skeleton) Mandible is freely moving at its joint with the cranium
Cranium	Houses and protects the brain Some bones have air filled cavities called sinuses 8 cranial bones
Skull (graphic)	Frontal bone (1) Parietal bones (2) Occipital bone (1) Temporal (2) Sphenoid bone Ethmoid bone
Infantile skull	Incompletely developed at birth Fibrous membranes ( Fontanels ) connect the bones. Important for the infant's head when passing through the birth canal Close between 2 months to 2 years Small face, prominent forehead and large orbits Bones thin and flexible
Facial Skeleton	14 bones 13 immovable and 1 movable ( lower jaw) Shapes face Provides attachments for muscles of facial expression and muscle that move the jaw
Facial Bones	Maxillary bones ( upper jaw) Palatine bones ( floor of the nasal cavity ) Zygomatic bones ( Cheek bones ) Lacrimal bones ( In the medial wall of the orbit ) Nasal bones ( Bridge of the nose ) Vomer bone ( Nasal septum ) Nasal conchae ( attached to the lateral walls of the nasal cavity ) Mandible ( lower jaw bone )
Sinuses	Inside the Maxilla, lateral to the nasal cavity are maxillary sinuses. Largest of sinuses. part of facial skeleton
Vertebral Column	@ Extends from the skull to the pelvis, forming the vertical axis of the skeleton @ Composed of vertebrae connected by ligaments separated by intervertebral dics [fibrocartilage] @ Supports the head and trunk but is flexible, permitting bending and turning; also protect the spinal cord within the vertebral canal
Vertebral Column: Curvatures	@ Primary curves Thoracic curvature Sacral curvature Both are concave anteriorly @ Secondary curves Cervical curvature - develops when a child begins to hold up its head Lumbar curvature - develops when a child begins to stand Both are convex anteriorly
vertebral view posterior and sagital
Features of a typical vertebra	Body - thick, anterior portion, with intervertebral discs between them Pedicles - project posteriorly from the body and form the sides of the vertebral foramen Laminae - form the back of the vertebral foramen Spinous process - fusion of laminae, projects dorsally from posterior wall of vertebral arch; ligaments attach here
more Features of a typical vertebra	Vertebral foramen - spinal cord passes through this Vertebral arch - composed of pedicles, laminae and spinous process, surrounds the vertebral canal Transverse process - projects laterally, between the pedicles and laminae; ligaments attach here Articulating processes - superior and inferior - where the vertebrae articulate with each other
Cervical Vertebrae	Cervical Vertebrae [7] !!! Transverse foramina within the transverse processes - contain arteries Spinous processes are forked [but these are usually broken off in lab specimens......] on vertebrae 2-6 Vertebra prominens - vertebra 7 - has a long spinous process - can be felt through the skin
Cervical Vertebrae: Atlas and Axis	@ Atlas - 1st cervical vertebra supports head - articulates with occipital condyles Bony ring - no body or spine @ Axis - 2nd cervical vertebra Dens process projects up and lies within the ring of the atlas. Allows the head to pivot
Cervical Vertebrae
Thoracic Vertebrae	Thoracic Vertebrae [12] Transverse processes projects sharply posteriorly Spinous processes are long, pointed and project downward Facets which articulate with ribs are on transverse processes Bodies of increasing size
Thoracic Vertebrae (graphic)
Lumbar Vertebrae	Lumbar Vertebrae [5] Specialized for support of body weight Thinner transverse processes Spinous process is short, thick and nearly horizontal Body is large
Sacrum	at the base of the vertebral column Composed of 5 fused vertebrae - fully fused between age 18-30 Articulates with the coxae [hipbones] at the sacroiliac joints [fibrocartilage] Forms posterior wall of the pelvic cavity
Coccyx	tailbone four fused vertebrae - fuse by end of 25th year
Thoracic Cage	The thoracic cage includes the ribs, the thoracic vertebrae, the sternum, and the costal cartilages that attach the ribs to the sternum.
Thoracic Cage (details)	Ribs (12) Sternum Thoracic vertebrae (12) Costal cartilages Supports shoulder girdle and upper limbs Protects viscera Role in breathing
ribs	* sternum o manubrium (1) o sternal angle (2) o body (3) o xiphoid process (4) * 12 pairs of ribs o 7 pairs of true ribs (5) o 5 pairs of false ribs (6) o 2 pairs of floating ribs (7) * thoracic inlet (superiorly) (8) * thoracic outlet (inferiorly) (9) * thoracic vertebrae, posteriorly
Rib Structure	Shaft Head - posterior end; articulates with vertebrae Costal cartilage - hyaline cartilage
Sternum	Three (3) parts of the sternum: Manubrium Body Xiphoid process
Pectoral Girdle	Also known as the shoulder girdle Clavicles Scapulae Supports upper limbs True shoulder joint is simply the articulation of the humerus and scapula
Clavicles	Articulate with manubrium Articulate with scapulae (acromion process)
Scapulae	Spine Supraspinous fossa Infraspinous fossa Acromion process Coracoid process Glenoid fossa or cavity
Right Upper Limb	Humerus Radius Ulna Carpals Metacarpals Phalanges
Humerus	Head Greater tubercle Lesser tubercle Anatomical neck Surgical neck Deltoid tuberosity Capitulum Trochlea Coronoid fossa Olecranon fossa
Radius	Lateral forearm bone Head Radial tuberosity Styloid process
Ulna	Medial forearm bone Trochlear notch Olecranon process Coronoid process Styloid process
Wrist and Hand	@ Carpal Bones (16 total bones) Scaphoid Lunate Triquetral Pisiform Hamate Capitate Trapezoid Trapezium @ Metacarpal Bones (10) @ Phalangeal Bones (28) Proximal phalanx Middle phalanx Distal phalanx
Pelvic Girdle	Coxal Bones (2) Supports trunk of body Protects viscera Forms pelvic cavity
Coxae
Differences Between Male Female Pelvis	Female pelvis Iliac bones more flared Broader hips Pubic arch angle greater More distance between ischial spines and ischial tuberosities Sacral curvature shorter and flatter Lighter bones
Lower Limb	Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges
Femur	Longest bone of body Head Fovea capitis Neck Greater trochanter Lesser trochanter Linea aspera Condyles Epicondyles
Patella	a.k.a. kneecap Anterior surface of the knee joint Flat sesamoid bone located in the quadriceps tendon
Foot	@ Tarsal Bones (14) Calcaneus Talus Navicular Cuboid Lateral (3rd) cuneiform Intermediate (2nd) cuneiform Medial (1st) cuneiform @ Metatarsal Bones (10) @ Phalanges (28) Proximal Middle Distal
more of the Foot
differences between male and female skeleton	Skull: Male, larger and heavier, more attachments for muscles. Forehead is shorter, facial area is less round. Jaws larger supra orbital processes more prominent. Pelvis: Male coxae are heavier, thicker, more muscular attachments. Pelvic cavity is narrower less roomy Sacrum : male sacrum is narrower Coccyx: Male is less movable than female
Lifespan Changes	Decrease in height at about age 30 Calcium levels fall Bones become brittle Osteoclasts outnumber osteoblasts Spongy bone weakens before compact bone Bone loss rapid in menopausal women Hip fractures common Vertebral compression fractures common
skeletal system