Skeleton System

Classification of bone Based on Location Based on Location Axial and Appendicular Axial and Appendicular Based on Shape Based on Shape Long, short, flat, Sesamoid, irregular Long, short, flat, Sesamoid, irregular Based on Ossification Based on Ossification Endochondral and Intramembranous Endochondral and Intramembranous

Based on location Axial Formed from ~80 named bones Formed from ~80 named bones Consists of skull, vertebral column, and bony thorax Consists of skull, vertebral column, and bony thorax Appendicular Appendicular Remaining ~126 bones of Thoracic girdle Thoracic girdle Pelvic girdle Pelvic girdle Attached limbs Attached limbs

5 classes based on shape A. Long B. Short C. Flat bones- D. Irregular bone E- Sesamoids bone

Classification of Bones Long bones – Long bones – Longer than wide Longer than wide a shaft plus two ends a shaft plus two ends primarily compact bone primarily compact bone Short bones – Short bones – roughly cube-shaped roughly cube-shaped - mostly spongy bone - mostly spongy bone

Classification of Bones Flat bones Flat bones thin and flattened, usually curved thin and flattened, usually curved contain two roughly parallel compact bone surfaces with a layer of spongy bone between them contain two roughly parallel compact bone surfaces with a layer of spongy bone between them Irregular bones Irregular bones various shapes, do not fit into other categories – complicated shapes various shapes, do not fit into other categories – complicated shapes consist mainly of spongy bone enclosed by thin layers of compact bone consist mainly of spongy bone enclosed by thin layers of compact bone Sesamoid bone-usually small, round, flat, associated with tendons, patella, proximal/distal sesamoid bones

Anatomy of a long bone- 1. diaphysis (dy-AF-I-sis)- 2. epiphysis (e-PIF-I-sis)- 3. Epiphyseal cartilage (physis, growth plate)- plate of cartilage between diaphysis and epiphysis of immature long bones, where lengthening of long bones occurs 4. metaphysis (me-TAF-I-sis)- The joining point of the diaphysis and epiphysis in growing bone; the part of the epiphyseal cartilage being replace by bone.

5. nutrient foramen- 6. periosteum- connective tissue surrounding the bone that is not covered by articular cartilage; necessary for bone growth, repair, and attachment of ligaments/tendons. 7. articular surface- smooth layer of hyaline cartilage covering the epiphysis, involved in joint formation. 8. medullary cavity- 9. endosteum- 10. compact bone- gross term for the part of the bone that looks solid 11. spongy bone - gross term for the part of the bone with visible spaces

Based on Ossification- Two types of Ossification: 1. Intramembranous Ossification- 2. Endochondral Ossification- I.B.1. I.B.2. I.B.3 I.B.3.b I.B.3 (cont.)

Axial vs. Appendicular Skull Skull Vertebral column Vertebral column Thoracic cage Thoracic cage Remaining bones of Thoracic girdle Pelvic girdle Attached limbs

Appendicular skeleton Consists of: Consists of: Thoracic girdles Thoracic girdles Clavicle Clavicle Scapula Scapula Attached limbs Attached limbs Pelvic girdles Pelvic girdles Pelvic bones Pelvic bones Attached limbs Attached limbs

The shoulder girdle and upper limb Clavicle Clavicle Scapula Scapula Each upper extremity: Each upper extremity: Humerus Humerus Radius Radius Ulna Ulna Carpal bones Carpal bones Metacarpal Metacarpal Phalanges Phalanges

Scapula Is a flat triangular-shaped bone Is a flat triangular-shaped bone Have Have 3 borders 3 borders Cranial, caudal, Dorsal Cranial, caudal, Dorsal 3 angles 3 angles Cranial, caudal, Ventral Cranial, caudal, Ventral 3 fossae 3 fossae Supraspinous, infraspinous, subscapular Supraspinous, infraspinous, subscapular

The humerus Long bone Long bone It is consist of It is consist of Proximal end (head) Proximal end (head) Neck Neck Shaft Shaft Distal end Distal end

The ulna and Radius The two bones of the forearm The two bones of the forearm The proximal Ext. of ulna is medial to the radius The proximal Ext. of ulna is medial to the radius The distal Ext. of ulna is lateral to the radius The distal Ext. of ulna is lateral to the radius Ulna Ulna Proximal end, shaft, distal end (head) Proximal end, shaft, distal end (head) Proximal end Proximal end Olecranon process Olecranon process Trochlear notch Trochlear notch

The Carpal bones (bones of the wrist) The carpal bones (are Seven in number). The carpal bones (are Seven in number). Proximal row Proximal row Ulnar, accessory, Intermedioradial Carpal Ulnar, accessory, Intermedioradial Carpal Distal row Distal row 1 th, 2 nd, 3 rd, 4 th Carpal 1 th, 2 nd, 3 rd, 4 th Carpal

The metacarpal Five in the number Five in the number

The Phalanges There are 14 phalanges There are 14 phalanges Each finger have 3 phalanges Each finger have 3 phalanges Thumb (have two) Thumb (have two)