4 Axial Skeleton different bones & location
- 1. SKELETAL SYSTEM Mrs. Samruddhi S.Vyawahare (M.Pharm Pharmacology) Assistant Professor Sudhakarrao Naik Institute of Pharmacy Pusad
- 2. SKELATAL SYSTEM • Bone tissues makes up about 18% of the total human body weight. • The skeletal system supports and protects the body while giving it shape and form. • Osteology: It is the branch of science that deals with the study of the skeletal system, their structure and functions.
- 3. SKELETAL SYSTEM • COMPOSED OF: -Bones -Cartilage -Joints -Ligaments
- 4. FUNCTIONS OF SKELETAL SYSTEM • SUPPORT: Hard framework that supports and anchors the soft organs of the body. • PROTECTION: Surrounds organs such as the brain and spinal cord. • MOVEMENT: Allows for muscle attachment therefore the bones are used as levers. • STORAGE: Minerals and lipids are stored within bone material. • BLOOD CELL FORMATION: The bone marrow is responsible for blood cell production.
- 5. DIVISIONS OF THE SKELETAL SYSTEM • The human skeleton consists of 206 named bones • Bones of the skeleton are grouped into two principal divisions: – Axial skeleton • Skull bones, auditory ossicles (ear bones), hyoid bone, ribs, sternum (breastbone), and bones of the vertebral column – Appendicular skeleton • Consists of the bones of the upper and lower limbs (extremities), plus the bones forming the girdles that connect the limbs to the axial skeleton
- 6. DIVISIONS OF THE SKELETAL SYSTEM
- 7. CLASSIFICATION OF BONE BASED ON SHAPE • Bones can be classified into five types based on shape: • Long • Short • Flat • Irregular • Sesamoid
- 8. CLASSIFICATION OF BONE BASED ON SHAPE • Long Bones – Greater length than width and are slightly curved for strength – Femur, tibia, fibula, humerus, ulna, radius, phalanges • Short bones – Cube-shaped and are nearly equal in length and width – Carpal, tarsal • Flat bones – Thin and composed of two nearly parallel plates of compact bone tissue enclosing a layer of spongy bone tissue – Cranial, sternum, ribs, scapulae • Irregular bones – Complex shapes and cannot be grouped into any of the previous categories – Vertebrae, hip bones, some facial bones, calcaneus • Sesamoid bones – Protect tendons from excessive wear and tear – Patellae, foot, hand
- 9. THE AXIAL SKELETON The axial skeleton consists of : 1. Skull. 2. Vertebral column (spinal column). 3. Thoracic cage. 4. Sternum.
- 10. THE AXIAL SKELETON Skull • The skull is situated on the upper end of vertebral column and its bony structure is divided into 2 parts. 1. The cranium 2. The face
- 11. THE AXIAL SKELETON A. Cranium: • It is formed by flat and irregular bones that provides a bony protection to the brain. • 1 Frontal Bone – It forms the forehead, It forms parts of eye sockets – The coronal suture joins the frontal and parietal bones. • 2 Parietal Bones – It form the sides and roof of the cranial cavity, it articulates with each other at the sagittal suture. – It joins the frontal bone with coronal suture and occipital bone with lambdoidal suture and the temporal bones at the squamous suture. • 3 Temporal Bones – These bones lie one on each side of the head and form immovable joints with the parietal, occipital, sphenoid and zygomatic bones.
- 12. THE AXIAL SKELETON • 4 Occipital Bone – It forms back of head and most of the base of the skull. – It has immovable joints with the parietal, temporal and sphenoid bones. • 5 Sphenoid Bone – It occupies the middle portion of base of skull and it articulates with the occipital, temporal, parietal and frontal bones. • 6 Ethmoid Bone – It occupies the anterior part of base of the skull and helps to form the orbital cavity, the nasal septum and the lateral walls of the nasal cavity. – It is very delight bone containing many air sinuses that opens into the nasal cavity.
- 14. THE AXIAL SKELETON B. The Face (Facial bones) • Nasal Bones – Form the bridge of the nose • Maxillae – Form the upper jawbone – Form most of the hard palate • Separates the nasal cavity from the oral cavity • Zygomatic Bones – commonly called cheekbones, form the prominences of the cheeks • Lacrimal Bones – Form a part of the medial wall of each orbit • Palatine Bones – Form the posterior portion of the hard palate • Inferior Nasal Conchae – Form a part of the inferior lateral wall of the nasal cavity
- 15. THE AXIAL SKELETON • Vomer – Forms the inferior portion of the nasal septum • Mandible – Lower jawbone – The largest, strongest facial bone – The only movable skull bone • Nasal Septum – Divides the interior of the nasal cavity into right and left sides – “Broken nose,” in most cases, refers to septal damage rather than the nasal bones themselves • Orbits – Eye socket • Foramina – Openings for blood vessels , nerves , or ligaments of the skull
- 18. THE AXIAL SKELETON • The vertebral column: • Also called the spine, backbone, or spinal column • Functions to: – Protect the spinal cord – Support the head – Serve as a point of attachment for the ribs, pelvic girdle, and muscles • The vertebral column is curved to varying degrees in different locations – Curves increase the column strength – Help maintain balance in the upright position – Absorb shocks during walking, and help protect the vertebrae from fracture
- 20. THE AXIAL SKELETON • The vertebral column: • Composed of a series of bones called vertebrae (Adult=26) – 7 cervical are in the neck region – 12 thoracic are posterior to the thoracic cavity – 5 lumbar support the lower back – 1 sacrum consists of five fused sacral vertebrae – 1 coccyx consists of four fused coccygeal vertebrae
- 21. THE AXIAL SKELETON • Intervertebral Discs: • Found between the bodies of adjacent vertebrae • Functions to: – Form strong joints – Permit various movements of the vertebral column – Absorb vertical shock • Vertebrae typically consist of: – A Body (weight bearing) – A vertebral arch (surrounds the spinal cord) – Several processes (points of attachment for muscles)
- 23. THE AXIAL SKELETON • Thorax: (Thoracic cage) • Thoracic cage is formed by the: – Sternum – Ribs – Costal cartilages – Thoracic vertebrae • Functions to: – Enclose and protect the organs in the thoracic and abdominal cavities – Provide support for the bones of the upper limbs – Play a role in breathing
- 24. THE AXIAL SKELETON • Sternum – “Breastbone” located in the center of the thoracic wall – Consists of the manubrium, body, xiphoid process • Ribs – Twelve pairs of ribs give structural support to the sides of the thoracic cavity • Costal cartilages – Costal cartilages contribute to the elasticity of the thoracic cage
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