The Skeletal System The Bodys Framework Definition The

The Skeletal System The Body’s Framework

Definition The adult skeletal system consists of: ◦ 206 bones ◦ The strong elastic tissue that forms ligaments, tendons, and cartilages These tie the bones together They also form the nose, larynx, trachea, bronchial tubes, and the outer ear

Functions of the Skeletal System 1. Provides a framework for the body 2. Gives the body it’s basic shape 3. Permits us to stand upright 4. Supports, restrains, and protects soft internal organs 5. Allows coordinated movement at it’s joints 6. Provide an anchor for skeletal muscles 7. Produce red blood cells within the bone marrow (hematopoiesis)

Bone Make-Up Bones are made up of 2 types of material ◦ Compact bone ◦ Spongy bone (cancellous bone)

Bone Make-Up – Compact Bone Very dense and hard Located near the surface of bones where strength is needed

Bone Make-Up – Spongy Bone A network of thin strands of bone and spaces The spaces are filled with bone marrow ◦ Red bone marrow – produces blood cells ◦ Yellow bone marrow – stores fat cells

Bone Classification 4 Classes of Bone

Bone Classification – Long Bones ◦ Strong shafts made of compact bone tissue Called the diaphysis ◦ Large ends made of spongy tissue covered with compact tissue Called the epiphyses At the joint ends, the epiphyses are covered with articular cartilage ◦ Covered by a layer of connective tissue called periosteum Produces bone cells Allows muscle attachment

Bone Classification – Long Bones Slightly curved to absorb shock Examples – leg, arm, clavicle, toe, and finger bones

Bone Classification – Short Bones Shaped like irregular cubes Spongy with a covering of compact tissue Examples – patella, carpal, and tarsal bones

Bone Classification – Flat Bones Broad, flat plates of spongy tissue sandwiched between 2 layers of compact tissue Examples – Skull, ribs, sternum, hips, and scapulae

Bone Classification – Irregular Bones Irregularly shaped Proportion of spongy to compact tissue varies from bone to bone Examples – Vertebrae and facial bones

Divisions of Skeletal System Axial skeleton – bones of the center (axis) of the body ◦ ◦ Skull Vertebral column Thorax Hyoid bone Appendicular skeleton – bones of the upper and lower extremities ◦ Upper extremity ◦ Lower extremity

Skull 2 main parts ◦ Cranium (brain case) ◦ Facial bones Number of bones ◦ 8 bones form the cranium The cranial bones are fused at lines called sutures ◦ 14 bones form the face ◦ 6 (tiny) bones that form the middle ear

Skull Bones of the cranium ◦ ◦ ◦ Frontal (1) Parietal (2) Sphenoid (1) Ethmoid (1) Temporal (2) Occipital (1)

Skull Bones of the face ◦ ◦ ◦ ◦ Nasal (2) Maxilla (2) Zygomatic (2) Mandible (1) Lacrimal (2) Palatine (2) Inferior concha (2) Nasal turbinates Part of ethmoid ◦ Vomer (1)

Skull Bones of the middle ear ◦ Malleus (2) ◦ Incus (2) ◦ Stapes (2)

Thorax The “chest” bones Includes: ◦ Ribs True ribs (14) thoracic vertebrae sternum False ribs (6) thoracic vertebrae cartilage of ribs above Floating ribs (4) thoracic vertebrae no anterior connection ◦ Sternum Manubrium Body Xiphoid process

Vertebral Column - Spine � Stack of 33 irregular bones � Separated by discs ◦ Shock absorption � Curved at each region ◦ Helps support body weight ◦ Provides balance ◦ Shock absorption � 5 ◦ ◦ ◦ regions Cervical (7) Thoracic (12) Lumbar (5) Sacrum (5 fused vertebrae) Coccyx (4)

Cervical Vertebrae – C 1 -C 7 Top 7 vertebrae Form the neck Support the skull Concave curvature Smallest of the vertebrae 1 st cervical vertebra – atlas 2 nd cervical vertebra - axis

Thoracic Vertebrae – T 1 -T 12 Next 12 vertebrae Convex curvature Attach to the 12 ribs ◦ Forms the thorax T 2

Lumbar Vertebrae – L 1 -L 5 Next 5 vertebrae Form the lower back Concave curvature Largest and thickest L 4

Sacrum – S 1 -S 5 5 fused vertebrae Triangular in shape Makes up part of the pelvis

Coccyx Bottom 4 vertebrae Fused Also called the tailbone

Upper Extremity - UE Appendicular skeleton Consists of: ◦ ◦ ◦ ◦ Scapula Clavicle Humerus Ulna Radius Carpals (8) Metacarpals (5) Phalanges (14)

Lower Extremity - LE � Appendicular � Consists of: skeleton ◦ Hip – Innominate or Coxal ◦ ◦ ◦ ◦ �Ilium �Ischium �Pubis Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges

Bones of the Lateral Skull

Bones of the Face

Bones of the Vertebral Column Atlas – C 1 Cervical vertebrae – C 1 -C 7 Axis – C 2 Thoracic vertebrae – T 1 -T 12 Lumbar vertebrae – L 1 -L 5 Sacrum – S 1 -S 5 Coccyx

Bones of the Thorax and Hips

Bones of the Upper Extremity

Bones of the Wrist and Hand

Bones of the Lower Extremity Ilium Pubis Ischium

Bones of the Foot