The Appendicular skeleton 126 bones Upper Extremities Arms

The Appendicular skeleton • 126 bones • Upper Extremities – Arms, Shoulders(pectoral girdle), Hands • Lower Extremities – Legs, Feet, Hips(pelvic girdle)

Appendicular Skeleton The pelvic girdle is made up of the hip bones. The “hip bones” – Coxal bones - are composed of three pair of fused bones – the ilium, ischium, and pubic bone.

Axial Skeleton

Axial Skeleton • • Consists of 80 bones Skull Face Inner Ear Hyoid Spinal Column Ribs

Spinal Column • Vertebral, or spinal column forms longitudinal axis of the skeleton • Flexible due to segmentation of vertebrae • 24 vertebrae plus sacrum and coccyx

How important? • • • Head is balanced above Ribs are suspended in front Lower extremities below Spinal cord enclosed within it. Literally the “Backbone” of the body.

Spinal Cord • Divided into three sections • Cervical – 1 -7 (ie. C 1, C 2…) – neck • Thoracic – 1 -12 (ie. T 1, T 2…) – Chest • Lumbar – 1 - 5 (ie. L 1, L 2…) – Lower back

• Sacrum – – Single bone formed from fusion of 5 vertebrae • Coccyx – Single bone formed from fusion of 4 or 5 vertebrae

• All have similar structures • Flat, rounded body placed anteriorly and centrally • Sharp or blunt spinous process projecting inferiorly on poster aspect • Two transverse processes projecting laterally

Movement of vertebrae • Articulation Everywhere – Ribs – Iliac(pelvis) – Head – Each vertebrae articulate with eachother

Vertebral Development • When born spinal column forms one continuous posterior convexity from head to coccyx • As a child learns to sit and stand secondary posterior convexities form to maintain balance – cervical and lumbar regions.

Problems with Convexity

The bony thorax is made up of three parts: 1)Sternum 2)Ribs(24) 3)Thoracic vertebrae

Sternum • Xiphoid Process

Ribs 12 pairs You have three different types of ribs • True ribs are the first seven pairs of ribs. True ribs attach directly to the sternum by costal cartilages. • False ribs are the next five pairs. They either attach indirectly to the sternum or not at all. – Floating ribs are the last two pairs of false ribs. They lack sternal attachments.

Bones of the Cranium • • • Parietal(2) Occipital Temporal(2) Sphenoid Ethmoid

Bones of the Face • • Nasal(2) Maxillary(2) Zygomatic(2) Mandible Lacrimal(2) Palatine(2) Inferior nasal conchae(2) Vomer