Axial Skeleton PDF

Nursing Grade: First year Lecture no. 3 Axial skeleton Skeletal system Consists of cartilage and bone. A. Cartilage is a special type of connective tissue nonvascular, Three types: 1. Hyaline cartilage (articular surface). 2. Firous cartilage (discs). 3. Elastic cartilage (au...

Nursing Grade: First year Lecture no. 3 Axial skeleton Skeletal system Consists of cartilage and bone. A. Cartilage is a special type of connective tissue nonvascular, Three types: 1. Hyaline cartilage (articular surface). 2. Firous cartilage (discs). 3. Elastic cartilage (auricle). B. Bone Hard calcified type of Connective Tissue, its function: 1. Protects organs. 2. Offers support, protection and flexibility to organisms. 3. Forms blood cells. 4. Stores calcium. Gross types of bones 1. Long bones: have two ends and shaft. e.g. humerus and femur. Each long bone consists of: I. Epiphysis. II. Metaphysis = includes epiphyseal plate in growing bones. III. Diaphysis = shaft. Gross types of bones 2. Short bones: have no epiphyses and shaft. e.g. carpal and tarsal bones. 3. Flat bones: bones with two surfaces. e.g. cranial bones, scapula, ribs, sutural bones. Gross types of bones 4. Irregular bones: bones with no definite shape. e.g. vertebrae, face bones. 5. Sesamoid bones: associated with tendons of upper and lower limbs. Patella is the largest sesamoid bone. Gross types of bones 6. Pneumatic bones: certain bones of skull containing air cavities, such as; frontal, sphenoid, ethmoid, mastoid part of temporal and maxillae. Bone markings Surface features of bones: 1. Sites of attachments for muscles, tendons, and ligaments. 2. Passages for nerves and blood vessels. Bone markings Depression and Openings: Processes: Fissure Condyle Foramen Facet Fossa Head Sulcus Crest Meatus Epicondyle Line Spinous process Trochanter Tubercle Tuberocity Clinical notes Fractures of the bones  Bone fractures A break in a bone. Types of bone fractures: Closed (simple) fracture – break that does not penetrate the skin Open (compound) fracture – broken bone penetrates through the skin Greenstick- frays, hard to repair, breaks like a green twig. Bone fractures Open fracture Closed fracture Bone fractures Greenstick fracture Skeleton system axial and appendicular systems Skeleton system Axial skeleton: (80 bones) in skull, vertebrae, ribs, sternum, hyoid bone Appendicular Skeleton: (126 bones)- upper & lower extremities plus two girdles Axial skeleton Includes: 1. Skull. 2. Mandible. 3. Hyoid bone. 4. Sternum. 5. Ribs. 6. Vertebral column. Skull upper cranium and lower facial skeleton Skull The skull is formed by 22 bones, and descriptively divided into: a. Upper cranium and, b. lower facial skeleton. The cranium consists of 8 cranial bones, and contains large cranial cavity that lodges the brain and its covering meninges. Skull The facial skeleton is formed by 14 bones, and contains small cavities, including oral, nasal, and orbital cavities. The nasal and orbital cavities lodges organs of special sensation (smell, vision). All bones of the skull, except mandible, are firmly joined together by immobile, false fibrous joints called sutures. Skull The mandible is the only mobile bone of skull which articulates with temporal bones in temporo- mandibular joints (TMJ). The cranium bones Includes 1 2 1. Frontal 2. Parietal (2) 3. Temporal (2) 6 5 3 4 4. Occipital 5. Sphenoid 6. Ethmoid (gray)  The cranium bones 6. Ethmoid bone The facial bones Includes: 1. Zygomatic bones: 2 2. Maxillae: 2 3. Nasal bones: 2 4 3 4. Lacrimal bones: 2 1 1 5. Vomer: 1 2 7 5 2 6. Palatine bones: 2 7. Inferior conchae: 2 8. Mandible: 1 8 The facial bones 6. Palatine bones: 2 Cranial sutures 1. Sagittal suture: between the parietal bones. 2. Coronal suture: between the frontal bone and the parietal bones. 3. Lambdoid suture: between the occipital bone and the parietal bones.  Anterior fontanelle Cranial sutures Frontal bone Coronal suture Parietal bone Sagittal suture Posterior fontanelle Lambdoid suture Lambda Occipital bone Cranial sutures Lambdoid suture Coronal suture Pterion Squmaous suture Clinical notes  The pterion Is an important area because it overlies the middle meningeal artery. Fracture to the pterion can rupture the anterior branch of this artery resulting in hematoma which exerts pressure on the underlying cerebral cortex. An untreated meningeal artery can cause hemorrhage which can lead to death in few hours. The pterion Mandible Condylar process Coronoid process Ramus Body Hyoid bone U-shape located in the neck. Has body, greater and lesser horns. Does not articulate with any bone and suspended in place by membranes, muscles and ligaments. Important for movements of tongue, pharynx and larynx. The vertebral column cervical, thoracic, lumber, fused sacrum, fused coccygeal The vertebral column There are 33 vertebrae divided into five groups: 1. Seven cervical. 2. Twelve thoracic. 3. Five lumber. 4. Five fused sacrum. 5. Four fused coccygeal. Normal curves of vertebral column 1. Cervical curve. 2. Thoracic curve. 3. Lumber curve. Clinical notes Abnormal curvatures  Kyphosis (hump back) Kyphosis (hump back) increase in the thoracic curvature.  Lordosis Increase in the lumber curvature.  Scoliosis Abnormal lateral curvature of the vertebral column Typical vertebrae Body Vertebral arch: a. pedicles b. Laminae Vertebral foramen Seven processes a. 2 transverse b. 1 spinous c. 4 articular Typical vertebrae Cervical vertebrae There are seven cervical vertebrae. The 3rd to 6th are typical. The 1st to 2nd are modified to permit movement of the head The 7th shows some features of the thoracic vertebrae. Cervical vertebrae Atlas – 1st; supports head Axis – 2nd; dens pivots to turn head Cervical vertebrae Atlas – 1st Axis – 2nd; dens pivots Cervical vertebrae Cervical vertebrae Typical cervical vertebrae C3-C7. Smaller bodies. Larger vertebral foramen Bifid spinous process Thoracic vertebrae T1-T12. All articulate with ribs. Have heart-shaped bodies. Each side of the body bears demi facets for articulation with ribs. Each typical rib articulates with vertebral bodies and tubercle of transverse process. Lumbar vertebrae Bodies are thick and strong. Allows flexion, extension, and rotation Vertebral foramina are triangular. Sacrum and coccygeal Sacrum Sacrum foramen coccygeal Intervertebral disc Anulus fibrosus Nucleus pulposus Thoracic cage The thoracic cage Function 2 1 1. Sternum 2. Ribs 3 3. Costal cartilage 4. Thoracic vertebrae 4 Clinical notes Thoracic outlet syndrome Thoracic outlet syndrome Ribs 12 pairs of ribs Ribs 1-7 are true ribs. Ribs 8-10 are false ribs. Ribs 11-12 are floating. Clinical notes Cervical rib Cervical rib Sternum Made up of: 1- Manubrium 2- Body 3- Xiphoid process Typical rib Posterior end 1. Head 2. Neck 3. Tubercle Anterior end Typical rib thank you