Skeletal System

Skeletal System Functions Provides shape and support. Video Notes Anatomy Skeletal System Support

Skeletal System Functions Enables you to move. Skeletal muscles, which are attached to bones by tendons, pull on the bones to produce movement.

Skeletal System Jobs Protects your internal organs. Your heart and lungs are shielded by your ribs. Your brain is protected by your skull. Your spinal cord is protected by your vertebral column. Video Notes Anatomy Skeletal System Bones Protect

Skeletal System Jobs Produces blood cells. Some of your bones are filled with special material that makes red and white blood cells. Video Notes Anatomy Skeletal System Bones Make Blood

Skeletal System Jobs Stores minerals, fats, and other substances.

Types of Bone Compact bone: has no visible open spaces and provides most of the strength and support for a bone.

Types of Bone Spongy bone: has many open spaces which makes the bone light, but strong.

Bone Marrow Bone marrow is a soft tissue found inside the bones that makes red blood cells and stores fat. Video Notes Anatomy Skeletal System Bone Types

Cartilage Cartilage- soft, flexible tissue that is part of the skeletal system. Makes up the nose and ears, and helps cushion the area where two bones meet. Video Notes Anatomy Skeletal System Cartilage

Joints Joints- the place where two or more bones connect and allow for movement. Video Notes Anatomy Skeletal System Types of Joints

Joints or “Articulations” Articulation = place where two bones come together Classification methods: Function: Synarthrosis (non-movable) Amphiarthrosis (slightly movable) Diarthrosis (freely movable) Structure (connective tissue type): Fibrous (fibrous tissue) Cartilaginous (cartilage) Synovial (synovial fluid)

Fibrous joints Cartilaginous joints Synovial joints No movement Sutures in fetal skull Cartilaginous joints Slight movements Epiphyseal plates, costal cartilage Synovial joints Free movements Most joints (wrist, knee, shoulder, hip, etc.)

Fibrous Joints

Synovial Joints

Ball and Socket Joint Ball and Socket Joint: allow the greatest range of motion, like your shoulder and hip.

Hinge Joint Hinge Joint: like the hinge of a door, allows forward or backward motion. Knee Joint Elbow Joint

Pivot Joint Pivot Joint: allows one bone to rotate around another, neck and head.

Sliding Joint Sliding Joint: allows one bone to slide over another, wrist and ankles.

Types of Joint Movements Flexion vs. extension Plantar flexion vs. dorsiflexion Abduction vs. adduction Pronation vs. supination Eversion vs. inversion Rotation Protraction vs. retraction Elevation vs. depression Circumduction Excursion (mandible moving side to side) Opposition vs. reposition (thumb & pinky together, then apart)

Bone to Bone Ligaments- connects bone to bone.

Bone to Muscle Tendons- connects muscle to bone.

Divisions of the Skeleton Axial skeleton Skull Hyoid bone Vertebral column Thoracic (rib) cage Appendicular skeleton Limbs Girdles 7-27 27

Axial skeleton 1. Skull (28 bones including auditory ossicles) 2. Hyoid bone (1 bone) 3. Vertebral column (26 bones) a. Cervical (7 vertebrae) b. Thoracic (12 vertebrae) c. Lumbar (5 vertebrae) d. Sacrum (1 – 5 fused vertebrae) e. Coccyx (1 -~4 fused vertebrae) 4. Thoracic Cage (25 bones) a. Ribs (24) b. Sternum (1 – 3 parts) 80 total bones in axial skeleton

The Skull – 28 bones Braincase – encloses cranial cavity Surrounds & protects brain 6 bones, 8 when paired Facial bones – forms facial structure 8 bones, 14 when paired Auditory ossicles – form the middle ear These bones transmit vibration to eardrum Malleus, incus, & stapes

Hyoid bone U-shaped Not part of skull No direct bony attachment to skull (attached by muscles & ligaments) Attachment site for tongue & larynx muscles (speech & swallowing)

Vertebral Column “Backbone” Central axis of skeleton 5 regions: Cervical vertebrae (neck + to turn) (C1-C7) Thoracic vertebrae (T1-T12) Lumbar vertebrae (L1-L5) Sacral (S) Coccygeal bone (CO) 4 curves: Cervical curves anteriorly Thoracic curves posteriorly Lumbar curves anteriorly Sacral & coccygeal curve posteriorly

Functions of Vertebral Column Supports weight of head & trunk Protects spinal cord Allows spinal nerves to exit spinal cord Site for muscle attachment Permits head & trunk movement

Vertebral Column “Backbone” Central axis of skeleton 5 regions: Cervical vertebrae (neck + to turn) (C1-C7) Thoracic vertebrae (T1-T12) Lumbar vertebrae (L1-L5) Sacral (S) Coccygeal bone (CO) 4 curves: Cervical curves anteriorly Thoracic curves posteriorly Lumbar curves anteriorly Sacral & coccygeal curve posteriorly

Vertebral Column Defects Lordosis – abnormal anterior curvature Lumbar Swayback Kyphosis – abnormal posterior curvature Usually upper thoracic Hunchback Scoliosis – abnormal lateral curvature

Vertebral Column Damage Herniated disk Compresses nerves “Broken Tailbone” Fractured coccyx Can occur during childbirth and from falls

Thoracic Cage “Rib cage” Functions: Consists of: Protects vital organs in thorax Prevents collapse of thorax during respiration Consists of: Thoracic vertebrae Ribs + associated cartilages Sternum

Ribs & Costal Cartilages 12 pairs (24 total) Articulate with thoracic vertebrae True ribs – (1-7) superior 7 attach to sternum via cartilage False ribs – (8-12) inferior 5 do not directly attach to sternum Floating ribs – (11-12) inferior 2 not attached to sternum at all

Sternum “Breastbone” Three parts: Manubrium (handle) Body Jugular notch – superior to manubrium; between clavicular articulations Body Sternal angle – at junction of manubrium & body; locates 2nd rib & used to find apex of heart Xiphoid process (sword) Used in CPR alignment

Appendicular Skeleton Girdles Pectoral or shoulder Pelvic Upper Limbs Arm Forearm Wrist Hand Lower Limbs Thigh Leg Foot 7-41 41

Pectoral Girdle 2 scapulae 2 clavicles Articulates with humerus Articulates with sternum & scapula

Pelvic Girdle 2 coxae Coxa formed by 3 fused bones: ilium, ischium, pubis Sex differences: larger pelvic inlet and outlet in females, broader pelvis in females, greater subpubic angle in females (childbirth)

Comparison of the Male and Female Pelvis 7-44 44

Upper Limb Arm Forearm Wrist Hand

Upper Limb: Arm Humerus – region between shoulder and elbow

Upper Limb: Forearm Radius (lateral or thumb side) & Ulna (medial or little finger side)

Upper Limb: Wrist & Hand Wrist – region between forearm and hand 8 carpals Hand – attached to carpals 5 metacarpals 5 digits 3 phalanges per finger (2 on thumb)

Lower Limb Thigh Leg Ankle Foot

Lower Limb: Thigh Femur – region between hip and knee Patella Articulates with coxa and tibia Patella

Lower Limb: Leg Tibia (shin) and fibula

Lower Limb: Foot & Ankle Ankle = 7 tarsals; articulates with tibia & fibula; calcaneus forms heel Foot = 5 metatarsals; 3 phalanges per digit (except great toe – has 2)