The Skeletal System Part 1: The Axial Skeleton

Warm-up Read the handout from bench 8 The History of the Skeleton and record 5 things you learned from this reading.

The Skeletal System Parts of the Skeletal System Bones (skeleton) Joints Cartilages Ligaments (bone to bone) Divided into two divisions Axial Skeleton Appendicular Skeleton (limbs and girdle)

Functions of Bones Support of the body Protection of soft organs Movement due to attached skeletal muscles Storage of minerals and fats Blood cell formation

The Axial Skeleton Forms the longitudinal part of the body Divided into 3 parts: Skull Vertebral Column Rib Cage

The Skull Two sets of bones Cranium Facial bones Bones are joined by sutures Only the mandible is attached by a freely movable joint

The Skull

Human Skull, Superior View

Human Skull, Inferior View

Paranasal Sinuses Hollow portions of bones surrounding the nasal cavity

Paranasal Sinuses Functions: Lighten the skull Give resonance and amplification to voice

The Hyoid Bone The only bone that does not articulate with another bone Serves as a moveable base for the tongue

The Fetal Skull Fontanelles: Fibrous membranes connecting the cranial bones Allow the brain to grow Convert to bone within 24 months

The Vertebral Column Vertebrae separated by intervertebral discs The spine has a normal curvature Each vertebrae is given a name according to its location Cervical (C1-C7) Thoracic (T1-T12) Lumbar (L1-L5)

The Vertebral Column Sacrum: 5 fused vertebrae Intersects with the hip bones Supports weight of upper body Coccyx: 4 fused vertebrae Smallest bone in spine Remnant of tail in most mammals Bears body weight while sitting and anchors muscles

The Bony Thorax 12 pairs of ribs Made up of 3 parts Sternum Manubrium Body Xiphoid Process Thoracic Vertebrae Posterior point of attachment Ribs

The Bony Thorax Ribs True Ribs: a rib that is attached directly to the sternum Ribs 1-7 False Ribs: ribs that do NOT directly attach to the sternum. They are connected by the costal cartilage of the ribs above Ribs 8-10 Floating Ribs: Does NOT attach to the sternum or another rib Ribs 11 & 12