Anatomy & Physiology :Anatomy & Physiology Skeletal System “Connecting Them Bones” Mr. Mullins


CLASSIFICATION OF BONES :CLASSIFICATION OF BONES


Classification of Bones :Classification of Bones 206 bones in the adult skeleton composed of two basic kinds of osseous (bone) tissue that differ in their texture: Compact bone looks smooth and homogeneous Spongy bone Composed of small trabeculae (bar) of bone and lots of open space


Slide 4:Bones are further classified on the basis of their relative gross anatomy into four groups Long bones Femur Are much longer then they are wide Usually consisting of a shaft with heads at either end Short bones Carpals and tarsals Are typically cube-shaped Contain more spongy bone than compact bone Flat bones Bones of the skull Generally thin with two wafer like layers of compact bone sandwiching a layer of spongy bone between them Many are curved Irregular bones vertebrae Bones that do not fall into one of the preceding categories.


Slide 5:Two other subcategories of bones (these two types do NOT count in the total 206 adult skeletal bones): Sesamoid bones Kneecap Are small bones formed in tendons Wormian bones Tiny bones between cranial bones


Overview of Skeletal System :Overview of Skeletal System


THE AXIAL SKELETON :THE AXIAL SKELETON


The Axial Skeleton :The Axial Skeleton Divided into three parts: Skull; Vertebral column; and Bony thorax.


SKULL :SKULL The skull is composed of two sets of bones: Cranium Encloses and protects the fragile brain Facial bones Present the eyes in an anterior position; and Form the base for the facial muscles, which makes it possible for us to present our feelings to the world.


Slide 11:All but one of the bones of the skull are joined by interlocking joints termed sutures The mandible (lower jawbone) is attached to the rest of the skull by a freely movable joint


THE CRANIUMPORTION OF THE SKULL :THE CRANIUMPORTION OF THE SKULL Frontal bone: Forms the forehead Joins with the parietal; zygomatic bone; ethmoid bone; maxilla; and nasal bone. Parietal bone: Forms the sides and the major top portion of the cranium, (basically the top of your head) Joins with the occipital bone; frontal bone; temporal bone; and sphenoid bone. Temporal bone: Located above you ears Joins with the parietal bone; occipital bone; sphenoid bone; and maxilla Occipital bone: Located at the back of the cranium (the back of you head) Joins with the parietal bone; and temporal bone Houses the foramen magnum (your spinal cord starts here) Ethmoid bone: Located just inside the eye socket at the top portion of the nasal bone. Joins with the frontal bone; sphenoid bone; and maxilla bone.


Vertebral Column :Vertebral Column


Vertebral Column :Vertebral Column Consists of 24 single bones called vertebrae. And two composite (fused) bones the sacrum and coccyx that are connected to provide a flexible curved structure Extending from the skull to the pelvis Forms the body’s major axial support Surrounds and protects the spinal cord while allowing the spinal nerves to issue from the cord via openings between adjacent vertebrae


Number of Vertebrae :Number of Vertebrae The 24 single vertebrae are groups as follows: Cervical Vertebrae 7 bones Forms a concave shape Commonly termed “NECK” Thoracic Vertebrae 12 bones Forms a convex shape Connected to the ribs Lumbar Vertebrae 5 bones Forms a concave shape Supports the lower back


LETS NOT FORGET THE SACRUM AND COCCYX :LETS NOT FORGET THE SACRUM AND COCCYX The sacrum 5 FUSED bones Forms a convex shape Coccyx 3-5 FUSED bones Termed the tailbone. Other vertebrates still have actual tails It is attached to the sacrum by ligaments


HINT!!!! IN REMEMBERING THE VERTEBRAL COLUMN :HINT!!!! IN REMEMBERING THE VERTEBRAL COLUMN ALWAYS REMEMBER BREAKFEST AT 7 AM 7 CERVICAL LUNCH AT 12 PM 12 THORACIC DINNER AT 5 PM 5 LUMBAR


Cervical Vertebrae :Cervical Vertebrae Seven bones Referred to as C1-C7 The first two cervical vertebrae termed Atlas (C1) Lacks a body Receives the occipital condyles of the skull Allows you to nod ‘YES’ Axis (C2) Acts as a pivot for the rotation of the atlas and skull Along with the atlas it allows you to rotate your head from side to side to indicate “NO”


C3-C7 Cervical :C3-C7 Cervical Distinguished from the thoracic and lumbar vertebrae by several features: They are the smallest; Lightest; and Triangular The C7 is visible through the skin it is sometimes termed the “VERTEBRA PROMINENS” They have foramina (holes) to allow blood vessels. So anytime you see vertebrae with holes on the side you are looking at cervical vertebrae.


Thoracic Vertebrae :Thoracic Vertebrae 12 bones Referred to as T1-T12 Have larger body (somewhat heart shaped) Spinous process are long with a sharp downward hook The closer the thoracic vertebra is to the lumbar region the less sharp and shorter the spinous process.


Lumbar Vertebrae :Lumbar Vertebrae Five bones Termed L1-L5 Have massive block like bodies and short thick hatchet-shaped spinous processes extending directly backward The following chart has the regional characteristics and diagrams


Intervertebral Disk :Intervertebral Disk Vertebrae are separated by pads termed “fibrocartilage’ They cushion the vertebrae and absorb shocks There is two regions of these disks: Nucleus pulposus Central gelatinous that acts like fluid Annulus fibrosus The outer ring of encircling collagen fibers that stabilizes the disc and contains pulposus


Ruptured Disk :Ruptured Disk As a person ages the water content of the discs decreases and the discs become thinner and less compressible Also other degenerative changes such as weakening of ligaments and tendons predisposes people to “Ruptured Discs” This causes the nucleus pulposus herniation Corrected by surgery


Vertebral Column Abnormalities :Vertebral Column Abnormalities


Thoracic Cage :Thoracic Cage


Thoracic Cage :Thoracic Cage Also referred to as the “RIBCAGE” or “BONY THORAX” Forms a protective cone-shaped enclosure around the organs of the thoracic cavity Heart; lungs; and major arteries/veins. The thoracic is composed of the following: The sternum Ribs Thoracic vertebrae


Sternum :Sternum Also termed “BREASTBONE” Flat bone The sternum is a favored site to obtaining samples of blood-forming tissue for diagnosis of suspected blood diseases (termed sternal puncture) Is a fusion of three bones: Manubrium Top part Looks like a knot of a tie Connects to the clavicle (collarbone) Body Middle Forms the bulk of the sternum Xiphoid process Pointed tip Lies at the level of the fifth intercostal space (the spaces between your ribs) Is made of cartilage in children turning to bone at adulthood Can easily break with a strike or during CPR and can penetrate the heart or liver Is attached to the first seven pairs of ribs


Slide 32:The sternum has three important bony landmarks Jugular notch Located on the manubrium Is concave, you can feel it TRY TO FIND YOURS! Sternal angle Is where the manubrium and body join You can also feel this too!! It starts at the second rib so doctors use this to count ribs before placing needles into the body or to listen to heart valves Xiphisternal joint The point where the body and xiphoid process fuses Is the level of the ninth thoracic vertebrae (T9)


Rib Cage :Rib Cage


Individual Rib :Individual Rib 12 pair of ribs Forms the thoracic cage All the ribs connect to the thoracic vertebrae (T1-T12) TRUE RIBS First 7 ribs Attached directly to the sternum FALSE RIBS Next five ribs Attach indirectly to the sternum or entirely lack a sternal attachment via cartilage) Ribs 8-10 connect via cartilage attachment to sternum FLOATING RIBS Last two pair of ribs Have no sternal attachment Commonly are the one that can rupture the spleen or liver during trauma.