Skeletal System Flashcards
Anatomical Position and Directional Terms
- Anatomical position = feet, face and palms forward
- Directional Terms:
1) Anterior (ventral) = looking at front of body
2) Posterior (Dorsal) = looking at back
3) Proximal
4) Distal
Skeletal System Overview
- Has 2 divisions:
1) Axial Skeleton (80 bones)
2) Appendicular Skeleton (126 bones) - Connections between bones = articulations (same thing as a joint)
Skull Groupings
1) Cranium- 8 bones (next to brain)
2) Facial bones - 14 bones
3) Auditory ossicles - 6 (3 bones on each side in the middle ears)
Cranium (Skull)
1) 1 frontal (forehead
2) 2 Parietal
3) 2 Temporal
4) 2 Sphenoid
5) 1 Ethmoid - forms superior and middle nasal chonchae
6) 1 Occipital
Facial Bones (Skull)
1) 2 Nasal
2) 2 Maxillae
3) 2 Zygomatic
4) 2 Lacrimal
5) Palatine (2 palatine + 2 maxillae = hard palate (top of mouth)
6) 2 inferior nasal chonchae
7) 1 Vomer
8) 1 Mandible
Auditory Ossicles (Skull)
1) Incus
2) Malleus
3) Stapes
Hyoid Bone
- NO articulations (joints/connections to other bones)
- Attaches muscles of torque and neck, assists in swallowing
Vertebral Column
- 26 vertebrae
- Separated into 5 regions
Body (Vertebrae Structure)
Thick anterior portion
Spinous Process (Vertebrae Structure)
(1) Median posterior projection
Transverse Process (Vertebrae Structure)
2- Lateral bony projections for muscle attachment
Lamina (Vertebrae Structure)
2- Connects the two processes
Pedicle (Vertebrae Structure)
2- Connects body to transverse process
Vertebral Foramen (Vertebrae Structure)
Hole for spinal cord
Superior + Inferior Articulate Facets (Vertebrae Structure)
Articulate with vertebrae above and below
Intervertebral Foramina (Vertebrae Structure)
Exit for spinal nerves
Cervical Vertebrae overview
- First section containing C1-C7
- C1, C2 = atypical
- C3- C7 = typical
C1 (cervical)
- C1 = atlas
- No body, no spinous process
- Articulates with occipital condyle of skull– allows nodding (‘yes”) motion
C2
- C2 = axis
- Dens (= odontoid process)
- Pivot joint around which atlas swivels – allows shaking (“no”) motion
C1-C7
-All have transverse foramina
Thoracic
- T1-T12
- Second section
- ALL articulate with ribs via costal facets
Lumbar
- L1-L5
- Third section
- Support upper body weight
- ALL have large bodies and rectangular spinous processes
Sacrum
- Located under Lumbar
- = 5 fused vertebrae
- Articulates with ilium (appendicular skeleton) and 5th lumbar vertebra (L5)
Coccyx
- Located under Sacrum
- = 3-5 fused vertebrae, usually 4
- = tailbone
Cervical and Lumbar Curvature
Curved convex anteriorly = concave posteriorly
Thoracic and Sacrum Curvature
Curved concave anteriorly = convex posteriorly
Scoliosis
- Abnormal curvature
- Spinal column curves laterally
Kyphosis
- Abnormal curvature
- Exaggerated thoracic curve (Hunchback)
Lordosis
- Abnormal curvature
- Exaggerated lumbar curve (Swayback)
Thoracic Cage
- Sternum (breast bone)
- Ribs
Sternum (Thoracic Cage)
- 3 Parts:
1) Manubrium - superior
2) Body - middle
3) Xiphoid Process - inferior
Ribs (Thoracic Cage)
- 12 pairs total (articulate posteriorly with T1-T12)
-7 pairs = true ribs
Attach directly to sternum via costal cartilage (hyaline cartilage) - 5 pairs = false ribs
Attach directly to sternum via costal cartilage (8-10) or not all = floating ribs (11,12 - embedded in muscle
Axial Skeleton
- Contains:
1) Skull
2) Hyoid Bone
3) Vertebral Column
4) Thoracic Cage
Appendicular Skeleton
- Contains:
1) Pectoral Girdle
2) Pelvic Girdle
3) Upper Limb
4) Lower Limb
Pectoral Girdle
1) Clavicle (collarbone)
- Articulates with sternum (manubrium) + Scapula (acromion process)
- Connects axial + appendicular skeletons
2) Scapula
- Spine (on posterior)
- Acromion process - Articulates with clavicle
- Glenoid Fossa/cavity - Articulates head of humerus
- Coracoid process - attaches muscles for arm and chest
Pelvic Girdle
- Composed of 2 os coxae (hipbones) each with 3 bones
- Joints:
1) Pubic symphysis
2) Sacroiliac joint - sacrum + ilium
3) Acetabulum - articulates with head of femur (ALL 3 bones of os coxae join here
Ilium (Os coxae bone)
Articulates with sacrum
Ischium (Os coxae bone)
Most inferior part = ischial tuberosity
Pubis (OS coxae bone)
Left and right joined by pubic symphysis
Upper Limb (in anatomical position)
1) Humerus
2) Radius (lateral) / Ulna (medial)
3) Carpals (8) = wrist
4) Metacarpals (5) = palm
5) Phalanges (14) = fingers and thumb
NOTE: All are LONG bones (except carpals)
Lower Limb (in anatomical position)
1) Femur
2) Patella (Knee Cap)
3) Tibia (medial)/ Fibula (lateral)
4) Tarsals (7)
- Talus - articulates with tibia
-Calcaneus = heal bone
5) Metatarsals (5) = sole
6) Phalanges (14) = digits (toes)
NOTE: All are Long bones (except patella and tarsals)
Bone overview
-In general consists of: Cells + Matrix - 2 Types of bone: Compact Bone Spongy Bone
Bone cells
Consists of:
1) Osteoblasts
2) Osteocytes
3) Osteoclasts
Bone Matrix (intercellular substance)
Consists of:
1) Ground Substances (Hydroxyapatite= insoluble Ca2+ phosphate salts (Strength)
2) Collagen Fibres (flexibility)
3) Water
Compact Bone
- Covers external surfaces of ALL bones
- Composed of Osteons
- Each Osteon contains:
1) Lamellae
2) Lacunae
3) Canaliculi
4) Central Canal
5) Perforating Canal
Lamellae (Osteon)
Concentric circles of matrix
Lacunae (Osteon)
- with osteocytes
- Between lamellae (space within matrix where osteocytes live)
Canaliculi (Osteon)
- Small channels that connect osteocytes to blood supply and to each other
Central Canal (Osteon)
- Contains blood vessels and nerves
- Lined with endosteum
Perforating Canal (Osteon)
- Perpendicular to central canal
- Carry blood supply from periosteum to central canals and medullary cavity (which makes bones highly vascular)
Spongy Bone
-NO osteons
-Have trabecular (irregularly arranged lamellae)
- Canaliculi connect osteocytes in lacunae
-Found in:
Flat + irregular bone ( Skull, ribs, vertebrae)
Long bones (epiphyses + lining medullary cavity)
- Spaces contain bone marrow (red marrow produces blood cells)
Cartilage (CT)
- Organ level of organization
- Hyaline Cartilage contains:
1) Chondrocytes in lacunae
2) Matrix ( Shiny ground substance chondroitin sulphate + hyaluronic acid, Collagen Fibres and Water)
3) Non-vascular
Structural Classification on Articulations/ joints
-Based on: Presence/absence of joint cavity Type of CT - 3 Types of structural joints: Fibrous Cartilaginous Synovial
Fibrous (Joint)
- No joint cavity
- Fibrous CT
- E.g. structures in skull (fontanels in a newborn)
Catilaginous (Joint)
- No joint cavity
- Cartilage attaches bones
- E.g. public symphysis, costal cartilages of ribs
Synovial (Joint)
-E.g. shoulder, elbow, hip, knee
-Structure:
1) Articular cartilage (hyaline)
2) Joint Cavity (contains synovial fluid)
3) Articular/ joint capsule
Outer layer = fibrous capsule
-Attaches to periosteum
-Ligaments within (Capsule = thickened) or separate
Inner layer = synovial membrane (CT only)
-Secretes synovial fluid
Types of Synovial Joint
- Grouped according to shape of articulating bones
1) Plane/Gliding - Flat surfaces (E.g. sacroiliac)
2) Hinge - Concave/ Convex surfaces( E.g. Elbow, knee)
3) Pivot - Projection in ring (e.g. dens (on axis) in atlas
4) Ball + Socket - Great freedom of movement (e.g. humerus in glenoid fossa. e.g. femur in acetabulum (hip))
Functional Classification of articulations/ joints
-Based on: Degree of movement -Types of functional joints: 1) Synarthotic -Immovable (Skull structure) 2) Amphiarthrotic -Slightly moveable (Pubic symphysis 3) Diarthrotic -Freely moveable (hip, shoulder)
