Anatomy and Physiology of the Skeletal System PDF

# Chapter 4: Musculoskeletal System ## Skeletal System at a Glance * **Functions of the skeletal system:** - internal framework of the body - supports the body - protects internal organs - point of attachment for muscles - produces blood cells - stores minerals * **Organs of the skeletal system...

# Chapter 4: Musculoskeletal System ## Skeletal System at a Glance * **Functions of the skeletal system:** - internal framework of the body - supports the body - protects internal organs - point of attachment for muscles - produces blood cells - stores minerals * **Organs of the skeletal system:** - bones of the skeleton - joints ## Skeleton - The skeleton has two divisions: - Axial skeleton - Appendicular skeleton ## Axial Skeleton - Includes bones in: - head - neck - spine - chest - trunk ## The Skull - It is divided into two parts: - cranium - facial bones - The skull: - protects the brain, eyes, ears, nasal cavity, and oral cavity - provides attachment for muscles of chewing and turning the head ### Cranial Bones - **Frontal:** forehead - **Parietal:** upper sides and roof of the skull - **Temporal:** sides and base of the skull ### Cranial Bones - **Ethmoid:** part of the eye orbit, nose, and floor of the skull - **Sphenoid:** part of the floor of the skull - **Occipital:** back and base of the skull ## Appendicular Skeleton - Includes bones of: - pectoral girdle - upper extremity - pelvic girdle - lower extremity ## Bones of the Pectoral Girdle - Attaches upper extremity to the axial skeleton - Articulates with: - sternum anteriorly - vertebral column posteriorly - Consists of: - clavicle (collar bone) - scapula (shoulder blade) ## Bones of the Upper Extremity ### Arm - Consists of: - humerus (upper arm) - ulna (part of forearm) - radius (part of forearm) - carpals (wrist bones) - metacarpals (hand bones) - phalanges (finger bones) ## Bones of the Pelvic Girdle - Also called os coxae, innominate bone, or hipbone - Attaches the lower extremity to the axial skeleton - Articulates with sacrum posteriorly - Consists of: - ilium - ischium - pubis ## Bones of the Lower Extremity ### Leg - Consists of: - femur (thigh bone) - patella (knee cap) - tibia (shin bone) - fibula (lower leg bone) - tarsals (ankle bones) - metatarsals (foot bones) - phalanges (toe bones) ## The Rib Cage - It consists of 12 pairs of ribs. - The ribs attach to the vertebral column at the back. - They also provide support for organs, such as the heart and lungs. ## True Ribs - 10 pairs in front attached to the sternum ## Floating Ribs - Inferior 2 pairs - No attachment in front ## The Vertebral Column ### Cervical - 7 vertebrae in the neck ### Thoracic - 12 vertebrae in the chest ### Lumbar - 5 vertebrae in the low back ### Sacrum - 5 fused vertebrae at the base of the spine ### Coccyx - 3-5 small vertebrae attached to the sacrum ## Bones - Also called **osseous tissue** - One of the **hardest materials** in the body - Formed from a gradual process before birth called **ossification** - Fetal skeleton is formed from a cartilage model ## Bones - Flexible tissue is gradually replaced by **osteoblasts** (immature bone cells). - In adult bones, **osteoblasts** mature into **osteocytes**. - The formation of strong bones depends on an adequate supply of minerals. ## Bone Structure | Bone Type | Description | Example | |---|---|---| | Long bones | Longer than wide | Femur, humerus | | Short bones | Roughly as long as wide | Carpals, tarsals | | Flat bones | Plate-shaped | Sternum, scapula, pelvis| | Irregular bones | Shape very irregular | Vertebrae | ## Hyoid Bone - A single U-shaped bone - It is located in the neck, between the mandible and the larynx. - It provides attachment for swallowing and speech muscles. ## The Trunk - The trunk is composed of: - vertebral column - sternum - rib cage ## The Vertebral Column - It is divided into five sections: - cervical - thoracic - lumbar - sacrum - coccyx ## Epiphysis - Are the wide ends of long bones (distal and proximal) - Articular cartilage covers the epiphysis, which prevents bone rubbing on bone. ## Periosteum - Covers the surface of the bone not covered by articular cartilage. - It is a thin connective tissue membrane that contains numerous nerves and lymphatic vessels ## Cancellous Bone - Also called spongy bone - Found inside bone - Has spaces containing red bone marrow - Manufactures blood cells ## Bone Projections and Depressions * **Projection:** a projection from the surface of a bone * **Rough processes:** provide places for muscle attachment. * **Smooth rounded processes** articulate with another bone in a joint. - **Named for shape and location** ## Facial Bones - **Mandible** (lower jawbone) - **Maxilla** (upper jawbone) - **Zygomatic:** cheek bones - **Vomer:** part of the nasal septum ## Facial Bones - **Palatine:** hard palate and floor of the nose - **Nasal:** part of the nasal septum and bridge of the nose - **Lacrimal:** inner corner of the eye ## Anatomy and Physiology of the Skeletal System - Bones are body organs with blood supply, nerves, and lymphatic vessels. - Bones are connected to each other to form the **skeleton**. - This provides a framework for the body. - There are 206 bones in the human body. ## Anatomy and Physiology of the Skeletal System - **Red bone marrow** within bones produces blood cells . - **Bones** also: - protect vital organs - store minerals ## Anatomy and Physiology of the Skeletal System * **Joint:** It is the place where two bones meet. - Joints are held together by ligaments. - They give flexibility to the skeleton.