Skeletal System (EXAM #2) Flashcards
What are the 2 types of Bones?
- Compact Bone
- Spongy Bone
Bones
Subtype of connective tissue
Compact Bone
Covers external surfaces of ALL bones (Thin)
What is the structure of Compact Bone?
Composed of osteons
What does each Osteon contains?
- lamellae
- Lacunae (with osteocytes)
- Canaliculi
- Central Canal
- Perforating Canal
Lamellae
concentric circles of matrix
- Layers
Lacunae (with osteocytes)
- Between lamellae (space within matrix where osteocytes live)
- Empty space if taken out
Canaliculi
Small channels that connect osteocytes to blood supply and to each other
- Get nutrients
Central Canal
- Contains blood vessels and nerves
- Lined with endosteum
Perforating Canal
- Perpendicular to central canal
- Carry blood and nerve supply from periosteum (Surrounding the bone) to central canals and medullary cavity (middle cavity)
What is the structure of Spongy bone like?
- Inside
- NO osteons
- Have trabeculae (irregularly arranged lamellae)
- Canaliculi connect osteocytes in lacunae
- Found in:
- Flat & irregular bone (e.g. skull, ribs, vertebrae)
- Long bones
- Epiphyses (ends of the bone top and bottom)
- Lining medullary cavity
- Spaces contain bone marrow
- Red marrow produces blood cells
Anatomical Position
feet, face, & palms forward
Examples of Directional Terms
- Anterior/Ventral vs Posterior/Dorsal
- Proximal vs Distal
- Medial vs Lateral
- Superior vs Inferior
- Superficial vs Deep
Overview of the Skeletal System
- Know if the bones are paired
- 2 division:
- Axial Skeleton (80 bones)
- Appendicular Skeleton (126 bones)
Axial Skeleton (80 bones)
- Bones that form central core of body
- Skull
- Hyoid Bone
- Vertebral Column
- Thoracic cage (sternum and ribs)
Appendicular Skeleton (126 bones)
- Limbs and bones that attach them to axial skeleton (girdles)
- Pectoral girdle
- Pelvic girdle
- Upper limb (arm, forearm, and hand)
- Lower limb (thigh, leg, and foot)
ARTICULATIONS
- Connections between bones
- e.g. the humerus articulates with the scapula
What are the 3 main bone groups of the skull?
- Cranium
- 8 bones (next to brain)
- Facial Bones
- 14 Bones
- Auditory Ossicles
- 6 (3 bones on each side in the middle ears)
Cranium (Bones)
- 1 frontal (forehead)
- 2 parietal
- 2 temporal
- 1 sphenoid
- 1 ethmoid
- Forms superior and middle nasal chonchae
- 1 occipital
Facial Bones (Bones)
- 2 nasal
- 2 maxillae
- 2 zygomatic
- 2 lacrimal
- 2 palatine
- The two palatine boned and two maxillae form the hard palate
- 2 inferior nasal chonchae
- 1 vomer
- 1 mandible
Auditory Ossicles (Bones)
- For sound transmission
- 2 incus
- 2 malleus
- 2 stapes
Hyoid Bone
- No articulations (joints/connections to other bones)
- Attaches muscles of tongue and neck, assists in swallowing
Vertebral Column
- 26 vertebrae
- Separated into 5 regions:
- Cervical (7)
- Thoracic (12)
- Lumbar (5)
- Sacrum (1)
- Coccyx (1)
What is the general vertebrae structure?
- Body
- Spinous process (1)
- Transverse process (2)
- Lamina (2)
- Pedicle (2)
- Vertebral foramen
- Superior and inferior articular facets
- Intervertebral foramina
Body
Thick anterior portion
Spinous process (1)
Median posterior projection
Transverse process (2)
Lateral bony projections for muscle attachment
Lamina (2)
Connects the two processes
Pedicle (2)
Connects body to transverse process
Superior and Inferior Articular Facets
Articulates with vertebrae above and below
Intervertebral Foramina
Exit for spinal nerves
What are the characteristics of vertebrae by region?
- Cervical (C1-C7)
- Thoracic (T1-T12)
- Lumbar (L1-L5)
- Sacrum
- Coccyx
Cervical (C1-C7)
- C1-C7: All have a transverse foramen in each transverse process (for passage of vertebral arteries)
- C1, C2 do not follow general vertebral structure
C1 = Atlas
- No body, no spinous process
- Articulates with occipital bone of skull
- Allows flexion & extension of neck (nodding “yes” motion)
C2 = Axis
- Dens (= odontoid process)
- Pivot joint around which atlas swivels
- Allows rotation of head on neck (shaking head “no” motion)
C3-C7
Follow general vertebral structure
Thoracic (T1-T12)
ALL articulate with ribs via costal facets
Lumbar (L1-L5)
- Support upper body weight
- ALL have large bodies & rectangular spinous processes
Sacrum
- = 5 fused vertebrae
- Articulates with ilium (appendicular skeleton) and 5th lumbar vertebra (L5)
Coccyx
- = 3-5 fused vertebrae, usually 4
- = tailbone
Curvature of Spinal Column
- Based on S-shaped lateral view
- Cervical and Lumbar regions
- Thoracic and Sacrum regions
Cervical and Lumbar regions
Have a concave posterior curve
Thoracic and Sacrum regions
Have a convex posterior curve
What are the 3 abnormal curvature?
- Scoliosis
- Kyphosis
- Lordosis
Scoliosis
Spinal column curves laterally
Kyphosis
Exaggerated thoracic curve
Lordosis
Exaggerated lumbar curve
Thoracic Cage
- Protects thoracic organs
- Sternum
- Ribs
Sternum
- Breast Bone
- A fusion of 3 bones:
- Manubrium - superior
- Body - middle
- Xiphoid Process - inferior
- A fusion of 3 bones:
Ribs
- 12 pairs total (articulate with T1-T12)
- 7 pairs
- 5 pairs
7 Pairs (Ribs)
- True ribs (superior)
- Attach directly to sternum via costal cartilage (hyaline cartilage)
5 Pairs (Ribs)
- False ribs (inferior)
- Ribs 8-10 attach indirectly to sternum via the costal cartillage for rib 7; ribs 11-12 are not attached to sternum = floating ribs
Appendicular Skeleton
- Pectoral Girdle
- Pelvic Girdle
- Upper Limb
- Lower Limb
Bones of Pectoral Girdle
- Clavicle (collarbone)
- Scapula (shoulder blades)
Clavicle
- Articulates with sternum (manubrium) & scapula (acromion process)
- Connects axial & appendicular skeletons
What are the parts of Scapula?
- Spine
- Acromion Process
- Glenoid Cavity
- Coracoid Process
Spine
Runs along posterior surface of scapula
Acromion Process
Articulates with clavicle
Glenoid Cavity
Articulates with head of humerus
Coracoid Process
Attachment point for muscles of arm and chest
What is Pelvic Girdle composed of?
2 os coxae (hip bones) formed by the fusion of 3 bones:
1. ilium
2. Ischium
3. Pubis
Ilium
- Superior
- Articulates with sacrum
Ischium
Posterior
Pubis
- Anterior
- Left and right joined by pubic symphysis
What are the Pelvic Girdle Joints?
- Pubic Symphysis
- Sacroiliac Joint
- Acetabulum
Pubic Symphysis
Cartilaginous joint between the pubic bones
Sacroiliac Joint
Sacrum and ilium
Acetabulum
Articulates with head of femur
Bones in Upper Limb?
- Humerus
- Radius & Ulna
- Carpals
- Metacarpals
- Phalanges
Humerus
Shoulder to Elbow
Radius & Ulna
- Radius:
- Lateral
- Ulna:
- Medial
Carpals
- 8
- Wrist
Metacarpals
- 5
- Palm
Phalanges
- 14
- Digits
- Fingers and thumb
Bones in the Lower Limb?
- Femur
- Patella
- Tibia & Fibula
- Tarsals
- Metatarsals
- Phalanges
Femur
Thigh
Patella
Knee cap
Tibia & Fibula
- Tibia:
- Medial
- Fibula:
- Lateral
Tarsals
- 7
- Talus:
- Articulates with tibia
- Calcaneus:
- Heel bone
Metatarsals
- 5
- Sole
Phalanges
- 14
- Digits
- Toes
What are the Long Bone Components?
- Diaphysis
- Epiphyses
- Epiphyseal Plate
- Epiphyseal Line
- Medullary Cavity
- Periosteum
- Endosteum
- Articular Cartilage
Diaphysis
Shaft (body)
Epiphyses
Proximal and distal extremities
Epiphyseal Plate
- Hyaline cartilage
- used for bone growth (length)
Epiphyseal Line
- Replaces plate with bone when growth completed
- Plate/line - where the diaphysis and epiphyses meet
Medullary Cavity
Red marrow in child, yellow marrow in adult
Periosteum
- External surface
- 2 layers of connective tissue
- Outer = dense irregular
- Ineer = mainly osteoblasts and osteoclasts
- Allows bone to grow in diameter
Endosteum
Lines medullary cavity AND canals (contains osteoblasts and osteoclasts)
Articular Cartilage
- Hyaline (only at articulation points)
- Prevents friction between bones (no periosteum here)
What are Articulations and Joints?
- Point of contact between 2 or more bones
- 2 classes
- Structural
- Functional
Structural Classification
- Anatomical
- Based on:
- Presence/absence of joint cavity
- Type of connective tissue that joint the bones
What are the types of Structural Joints?
- Fibrous
- Cartilaginous
- Synovial
Fibrous
- No joint cavity
- Fibrous connective tissue
- E.g. sutures in skull (fontanels in a newborn)
Cartilaginous
- No joint cavity
- Cartilage attaches bones
- E.g. pubic symphysis, costal cartilages of ribs
Synovial
E.g. shoulder, elbow, hip, knee
What are the Synovial structure?
- Articulating bones are connected by the joint capsule and ligament
- Articular cartilage (hyaline) of bone
- Space between bones is the joint cavity
- Contains synovial fluid
- Articular/joint capsule encloses the joint cavity
Outer Layer
- Fibrous capsule
- Attaches to periosteum
Inner Layer
- Synovial membrane (CT only)
- Secretes synovial fluid
What are the types of Synovial Joints?
- Grouped according to shape of articulating bones
- Plane/Gliding
- Hinge
- Pivot
- Ball & Socket
Plane/Gliding
- Flat surfaces
- e.g. sacroiliac
Hinge
- Concave/convex surfaces
- e.g. elbow, knee
Pivot
- Projection in ring
- e.g. dens (on axis) in atlas
Ball & Socket
- Great freedom of movement
- e.g.1: humerus in glenoid fossa
- e.g.2: femur in acetabulum (hip)
Functional Classification
- Physiological
- Based on:
- Degree of movement
What are the types of Functional Joints?
- Synarthrotic
- Amphiarthrotic
- Diarthrotic
Synarthrotic
- Immovable
- e.g skull sutures
Amphiarthrotic
Slightly moveable
- e.g. pubic symphysis
Diarthrotic
- Freely movable
- e.g. hip, shoulder