A&P. Skeletal System
Terms
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- "osteo"
- = bone
- Ossification
- mineralization or hardening of bone
- Lacunae
- spaces in the ossified matrix that the osteoblasts become trapped in
- Canaliculi
- tiny channels through the matrix of bone
- Functions of Bones
-
Support: strength & structure
Protection: surrounds organs
Leverage: levers for skeletal muscles to move the body
Storage: minerals - Hematopoiesis
- blood cell production
- Cancellous Bone
-
light, spongy bone.
tiny spicules of bone, spaces full of bone marrow.
found in epiphyses of long bones - Compact Bone
-
heavy, dense, strong.
found in diaphyses of long bones & outside layer of all bones. - Haversian Canal
-
contains blood vessels, lymph vessels & nerves that supply the osteocytes.
run up & down in long bones - Osteology
- study of bones that make up the skeletal system
- Bone Matrix
-
organic = 1/3 bone composition.
- Support of Bones
- Ligaments & Tendons
- Protection of Bones
-
-CNS by skull & vertebral column
-heart & lungs by rib cage - Leverage of Bones
- attachments to muscle
- Storage
- Ca & P reservoir
- Periosteum
-
membrane that covers outer surfaces of bones except on articular surfaces.
outer layer = fibrous tissue
inner layer = osteoblasts - Endosteum
- membrane that lines the hollow interior surfaces (marrow cavity) of bones. contains osteoblasts.
- Osteoblasts
-
young bone cells.
cells that produce bone. - Osteocytes
-
adult/mature bone cells. ossified osteoblasts
- Osteoclasts
- remodel/remove bones
- Bone Cells
-
-increase bones diameter
-critical in healing fractures
-determines size of marrow cavity
-determine the thickness of the diaphyseal cortex - Volkmann Canals
- channels through bone matrix that contain blood vessels, run 90 degrees in bone (left & right)
- Nutrient Foramina
-
channels in many large bones.
contains large blood vessel, lymp vessles, nerves
carries blood in/out of the marrow. - Endochondral bone formation
- cartilage to bone. grows into & replaces cartilage.
- Intramembranous bone formation
- membrane. develops from fibrous tissue membranes
- Primary Growth Center
-
bones develop in diaphyses.
endochondral bone formation.
cartilage makes a template & is removed as bone is created. - Secondary Growth Center
-
develops in the epiphyses of the bone.
endochondral bone formation - how much can an adult bone be stretched before breaking?
- 0.5%
- what happens the bone reaches its full size?
- the epiphyseal plates completely ossify
- 4 types of bone shapes?
-
Long
Short
Flat
Irregular - Long Bones
-
proximal/distal end.
support & leverage.
limb bones - Short Bones
-
phalanges
metacarpals/metatarsals - Flat Bones
- ribs, skull, scapula
- Irregular Bones
- unpaired bones, vertebrae
- Bone Marrow
-
fills the spaces within bones.
red -> yellow -> white - Red Bone Marrow
-
forms blood cells.
majority of bone marrow in young animals.
only small portion in older animals.
specific locations in older animals. - Yellow Bone Marrow
-
primarily adipose connective tissue.
majority of bone marrow in adults.
can revert to red bone marrow only if animal is undergoing huge stress or hardship - White Marrow
- aged animals. nonfunctional. hard, fatty tissue. CANNOT revert back to yellow or red marrow.
- Articular Surfaces
-
joint surfaces.
condyle, head, facet. - condyle
- large, round articular surface
- head
- spherical articular surface on the proximal end of a long bone
- facet
- flat articular surface
- processes
- projections (lumps, bumps) off a bone surface. name of the process depends on the location.
- foramen
-
a hole in the bone.
may contain blood vessels & nerves. - Fossa
- a depressed/sunken area on the surface of a bone.
- axial skeleton
- skull. hyoid bone. spinal column. ribs. sternum.
- Skull
-
37-38 bones.
Sutures: joints of the skull bones.
Mandible: connected to skull by synovial joint.
Maxilla: different in ruminant & monogastric - Suture
- joints of the skull bones
- Mandible
-
bottom portion of skull.
connected to skull by a synovial joint. - Upper Jaw
- Maxilla, incisive bones
- External Bone of Cranium
-
Frontal Bones = 2
big bone in front/on top of skull - Hyoid Bone
-
aka hyoid apparatus.
composed of several portions of bone united by cartilage - bones of ear
- = 6
- how many bones in the face?
- 11-12
- how many internal bones of the face?
- = 9
- Vertebrae
- consists of a body, an arch & processes
-
intervertebral disk
- cartilage separating bodies of adjacent vertebrae
- 3 types of vertebral processes?
- spinous, transvers, articular
- Cervical Verterbrae
-
C1 = atlas
C2 = axis - what are the vertebral regions?
-
cervical (C)
thoracic (T)
lumbar (L)
sacral (S)
coccygeal (Cd) - Ribs
-
flat bones, lateral walls of thorax.
dorsal heads of the ribs articulate with thoracic vertebrae - Costal Cartilage
- ventral ends of the ribs
- Xiphoid Process
- most caudal bone of the sternum
- Costochondral Junction
- area where costal cartilage meets bony rib
- Floating Ribs
- cartilage does not join anything at all
- Sternum
- breastbone. forms floor of throax. composed of sternebrae (fuse with age).
- Manubrium Sterni
- most cranial sternebra
- appendicular skeleton
-
bones of the limbs.
pectoral limb: thoracic limb or forelimb
pelvic limb: hind limb - Thoracic Limb
- scapula, humerus, radius, ulna, carpus, metacarpal, phalanges
- scapula
-
flat, triangular bone.
forms portion of shoulder joint. - Glenoid Cavity
- shallow, concave articular surface on scapula
- humerus
- long bone of brachium. forms parts of shoulder & elbow joints
- Tubercles
- processes where shoulder muscles attach
- Olecranon Fossa
- indentation above the condyle
- Epicondyles
- non-articular
- Ulna
- Olecranon process. point of elbow. site for tendon attachment of triceps brachii muscle.
- Trochlear Notch
- concave articular surface on ulna
- Radius
- main weight bearing bone of antebrachium. articulates with humerus & ulna
- Carpus
- 2 rows of carpal bones.
- metacarpal bones
-
extend distally from carpal bones to proximal phalanges.
dogs & cats = metacarpal 1: dewclaw - Splint Bones
- 2 smaller vestigial metacarpal bones on metacarpals of horse. non weight-bearing
- Metacarpal - cattle
- 2 fused metacarpal bones: bones 3 & 4
- long pastern bone =
- 1st or proximal phalanx
- short pastern bone =
- 2nd or middle phalanx
- coffin bone =
- 3rd or distal phalanx
- Pelvic Limb
-
pelvis (ilium, ischium, pubis), femur, tibia, fibula, tarsus, metatarsus, phalanges
-connected to axial skeleton at SI joing - Pelvis
- 3 fused bones: ilium, ischium, pubis
- pelvic symphysis
- carilaginous joint between the 2 halves of the pelvis
- ilium
-
dorsocranial direction.
forms SI (sacroiliac) joint with sacrum - ischium
-
caudal-most pelvic bone.
forms caudal portion of pelvic floor - pubis
- forms cranial portion of the pelvic floor
- Femur
- proximal ends form part of hip joint.
- Trochanters
- processes where hip & thigh muscles attach
- femur articular surfaces
- 2 condyles, trochlea
- trochlea
- articular groove containing the patella
- patella
- large sesamoid bone. protects tendon. formed in distal tendon of the quadriceps femoris muscle
- fabellae
- 2 small sesamoid bones in proximal gastrocnemius muscle tendons of dogs & cats. not in cattle or horses
- tibia
- weight bearing bone of lower limb. forms stifle joint
- fibula
- parallel to tibia. not weight bearing. muscle site attachment.
- Tarsus
- hock. 2 rows of tarsal bones.
- calcaneal tuberosity
- point of attachment for the tendon of the gastrocnemius muscle
- metatarsal in animals
-
dogs & cats = 4 bones (2,3,4,5)
horses = 1 large (cannon), 2 small (splint) - visceral skeleton
- bones that form in organs
- 3 types of Joints
-
1. fibrous - immovable
2. cartilaginous - slightly movable
3. synovial - freely movable - Fibrous Joints
- synarthroses, united by fibrous tissue. ex: skull sutures, splint bones
- Cartilaginous Joints
- amphiarthroses. slight rocking movement. ex: pubic symphysis, intervertebral disks
- Synovial Joints
- diarthroses. freely movalbe, articular surfaces on bones covered by articular cartilage (hyaline), fluid filled joint cavity enclosed by joint capsule
- synovial joint movements
- flexion, extension, adduction, abduction, rotation, circumduction
- Flexion
- decrease angle b/w 2 bones
- Extension
- increase angle of 2 bones
- Adduction
- come together, towards medial plane
- Abduction
- opposite, apart
- Rotation
- twisting movement of a part on its own axis
- Circumduction
- movement of an extremity so that the distal end moves in a circle
- Synovial Joints (4 types)
- hinge, gliding, pivot, ball & socket
- Hinge Joints
-
ginglymus joints,2 joint surface swivels around another.
only flexion & extension. ex: elbow
- Gliding Joints
- arthrodial joints. rocking motion of 1 joint surface on the other. primarily flexion & extension. abduction & adduction possible. ex: carpus
- Pivot Joints
- trochoid joints. 2 bone pivots (rotates) on another. only rotation. ex: atlantoaxial joint
- Ball & Socket Joints
- spheroidal joints. all joint movements. ex: shoulder/hip joints
- Fracture
- a break in the continuity of a bone
- Simple Fracture
- skin over the fracture site is unbroken
- Open/Compound Fracture
- wound from exterior contacts the bone at the point of the fracture
- Greenstick Fracture
- 1 side of bone is broken/splintered. other side is bent. typically young animals
- Complete Fracture
- bone is broken entirely across
- Episyseal Fracture
- at junction of the epiphysis & diaphysis of a bone. typically young animals. dangerous because of growth plates
- Comminuted Fracture
- bone was splintered or crushed producing small fragments
- What causes pathologic conditions of bones?
- infections, tumors, endocrine disturbances, nutritional imbalances, genetic abnormalities
- Osteomyelitis
- inflammation of the bone & bone marrow. usually caused by bacteria (staphylococcus or streptococcus)
- Osteoma
- bone tumors. benign = slow growing, not harmful. malignant = grow rapidly, harmful.
- Rickets
- nutritional imbalance. disease of young bones that affects the growing areas of bone
- Osteomalacia
- adult rickets. affects entire bone. due to lack of vitamin D and/or imbalance or lack of calcium and/or phosphorus
- what type of tissue is red bone marrow?
- Hematopoietic Tissue
- Foramen Magnum
- the center of the occipital bone, where the spinal cord exits the skull
- Occipital Bone
- base of skull
- Frontal Bones
- forehead region of the skull.
- Pituitary fossa
- houses the pituitary gland. in the sphenoid bone
- Intervertebral disk
- cartilaginous disk located between the bodies of adjacent vertebrae. shock absorber for vertebrae
- Brachium =
- upper arm
- antebrachium =
- "forearm" (ulna & radius)
- what are digits made of?
- phalanges (singular bones)
- Obturator foramina
- 2 large holes in the pelvis, purpose is to lighten it
- acetabulum
- socket portion of the ball & socket hip joint. formed at junction of ilium ,ischium & pubis.