Download Laboratory 5 The Skeleton

Laboratory 5 The Skeleton Goals: •
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Identify the internal structural components compact and spongy bone. Identify bone markings (spines, processes, foramina, etc.) and describe their function (e.g., point of articulation, muscle tendon attachment, ligament attachment, passageway for nerves and vessels. Define the two major divisions of the skeletal system (axial and appendicular) and list the general bone structures contained within each. Identify the individual bones and their location within the axial skeleton. 1. Compact and Spongy Bone Osseous tissue is a type of connective tissue with an extensive extracellular matrix composed of calcium phosphate and collagen fibers. Based on the structure, osseous tissue can be divided into two types: compact bone and spongy (or cancellous) bone. Compact bone appears smooth to the naked eye. It forms the hard, outer layer of all bones and a significant portion of the shaft of long bones. Overall, greater than 75% of the mass of the skeleton is compact bone. Histologically, compact bone appears of multiple round units called osteons, which give the appearance of tree rings under the microscope. Each osteon has a central canal, running parallel to the long axis of the bone, that protects blood vessels and nerves supplying the bone. Mature osteoctytes, housed in open spaces called lacuna, form concentric circles around the central. Each circle is called a lamella. Lamellae are connected to each other through small canals called caniculi. Additionally, larger canals, perforating canals, allow blood vessels and nerves to pass through the osteon structure. Figure 1. Structure of compact and spongy bone (A) and microscopic structure of compact bone (B). Spongy bone, in contrast, is highly porous composed of small bars of bones called trabeculae with significant amounts of open space between the trabeculae. The open spaces allow storage of bone marrow, particularly red bone marrow. Spongy bone is the site of hematopoiesis. 51 •
Observe and draw compact bone under the microscope. Label the osteon, central canal, osteocyte, lacunae and lamellae. 2. Major Subdivision of the Skeleton The skeleton is subdivided into two major portions: the axial and the appendicular skeletons. The axial skeleton consists of 80 bones, not including Wormian bones of the skull, that form the head and trunk. This includes 8 crainial bones, 14 facial bones, the hyoid bone found in the cervical region, 6 bones of the inner ear, 25 bones forming the bony thorax and 26 bones forming the vertebral column. These bones are shown in green in Figure 2. The appendicular skeleton consists of 126 bones forming the pectoral girdle, the pelvic girdle and the appendages. The bones are shown in purple. • Find the bones of the axial and appendicular skeleton on a model of the entire skeleton. Figure 2. The axial (white) and appendicular (pink) skeleton. 3. Axial Skeleton – Bones of the Skull The skull is composed of eight bones bone of the cranium which houses and protects the brain, fourteen bones of the face, and the hyoid bone that anchors the tongue. The eight bones of the cranium are (with mneumonic): Figure 3. The bones of the cranium. P Parietal (2) O Occipital E Ethmoid F Frontal S Spenoid T Temporal (2) 8. 52 The frontal bone forms the superior orbit of the eye and the forehead. Features of note include the supraorbital margin forming the superior orbit of the eye, the supraorbital notch that allows the passage of blood vessels, and the frontal sinus, an air-­‐filled opening above the nose. Figure 4. Features of the frontal bone. Figure 5. Features of the occipital bone. Two parietal bones are directly posterior to the frontal bone and meet at the midsagittal plane in the sagittal suture. Forming the posterior of the cranium is the occipital bone. The foramen magnum (meaning large hole) is the large opening that allows the spinal cord to pass through. On either side of the foramen magnum, the occipital condyles form a surface for articulation of the skull with the vertebral column. Two temporal bones form the lateral portions of the cranium. The zygomatic process extends anterior and forms the posterior portion of the cheek bone by connecting to the temporal process of the zygomatic bone. The styloid process projects inferiorly and serves as an attachment point for the tongue and muscles joining the hyloid bone. The large prominence posterior to the zygomatic process is called the mastoid process. This is the attachment for one of the major neck muscles, the sternocleidomastiod. The ear canal, or auditory meatus, has openings on both the external and internal sides of the temporal bone. Figure 6. External and internal views of the temporal bone. 53 The sphenoid bone, a bat-­‐shaped bone with three paired processes—greater wings, lesser wings, and ptergoid processes—forms the base of the cranium and a small portion of its sides. The sella turcica on the superior aspect houses the pituitary gland. The optic nerve passes through the sphenoid at optic foramen located near the junction of the lesser wings and the body of the sphenoid. Here is a rotating 3D view of the sphenoid relative the rest of the cranium. The ethmoid bone forms the anterior base of the cranium between the eye orbits. It is a sponge-­‐like bone with much open space. (ethmoid sinuses). The cribiform plate of the ethmoid forms the base of the cranium with the cristi galli projecting upward from the medial portion of the plate. The perpendicular plate forms the nasal septum. Two of the three nasal conchae, the superior and middle, are formed by the lateral portions of the ethmoid. Figure 7. Superior and anterior views of the sphenoid bone. Figure 8. Ethmoid bone, posterior view and from a sagittal cut of the skull. The bones of the skull are connected by fibrose, synarthrose (immovable) joints called sutures. The sagittal suture joins the right and left parietal bones. The coronal suture is found in the 54 Figure 9. Bones of the face. coronal plane and joins the frontal bone to the two parietal bones. The lamboidal suture connects the occipital bone to the two parietal bones. In the transverse plane, the two squamousal sutures are found between the parietal and temporal bones. See Figure 3. Several small wormian bones commonly form in the sutures. Fourteen bones form the structure of the face. All of these bones are paired Vomer with the exception of the vomer and mandible. One mneumonic for Concha, inferior (2) remembering the bones of the face is: Nasal (2) Virgil Can Not Make My Pet Zebra Laugh. Of these, seven are involved in the Mandible forming the structure of the orbit for the eyes: frontal, zygomatic, sphenoid, Maxilla (2) palantine, ethmoid, lacrimal, and maxilla. A handy pneumonic is Friendly Palantine (2) Zebras Speed Past Elderly Lions Mating. Zygomatic (2) Lacrimal. The vomer forms the central floor of the nasal cavity. It is found inferior to the ethmoid and superior to the maxilla and palatine. The platine bone is located located in the back part of the nasal cavity and forms the dorsal aspect of the roof of the mouth. 55 Figure 10. The paranasal sinuses. The nasal bones form the bridge of the nose. The ethmoid bone and the inferior nasal conchae bone form the three paired conchae or bumps in the nasal cavity. The zygomatic bone has a temporal process that joins with the zygomatic process of the temporal bone to form what we think of as the cheek bones. Make sure to delineate between the processes and the bones. To lighten the weight of the skull and provide resonating chambers for the voice, four of the bones of the skull have empty air pockets, collectively called the paranasal sinuses, enclosed within them. The final bone we will include with the skull bones is the hyoid bone. It is the only bone in the human body that does not articulate with another bone. It serves as an anchor for the muscles of the tongue. • Using the models, identify each of the bones and features listed on our bone list. 4. Axial Skeleton – Bones of the Vertebral Column The vertebral column surrounds and protects the spinal Figure 11. The hyoid bone cord while also providing support for the head and trunk. It consists of 24 single vertebrae and nine vertebrae that fuse into the sacrum and coccyx. The unfused vertebrae are grouped in regions with the upper seven vertebra forming the cervical region, the next twelve forming the thoracic region, and the final five forming the lumbar region. Four distint curve are seen in the spinal column: cervical, thoracic, lumbar and pelvic. Vertebrae are separated by vertebral discs composed of fibrocartilage. Most of the mass of the vertebra is in the body, the disc-­‐shaped anterior portion of the bone. The spinous process protrudes on the dorsal surface. Laterally, are two transverse processes. Between 56 the spinous and transverse processes are the lamina while between the transverse process and bony is the peduncle. The openings on the transverse process, transverse formina, allows spinal nerves to exit the spinal cord, located in the v ertebral forminen. The top two cervical vertebrae, C1 or atlas and C2 or axis, are specialized to form the joint with the occipital bone, connecting the head to the body. The atlas lacks a body, has two lateral facets that articulate with the occipital bone, and includes a concave facet that articulates with the dens, a projection found on the axis. Figure 12. The vertebral column. •
Using the models, identify each of the bones and features listed on our bone list. Make sure to pay attention to how to identify the vertebrae (atlas, axis, or which region) as individual bones as well as part of the vertebral column. 5. Axial Skeleton – Bones of the Bony Thorax The bony thorax, or rib cage, includes the thoracic vertebrae,12 pair of ribs, the sternum, and the coastal cartilages. The sternum, or breastbone has three parts: manbrium, the upper region, the body, and the inferior xiphoid process. Facets exist for articulation with the clavicle and the coastal cartilages. 57 Figure 13. Bones of the thoracic cage. The first seven pairs of ribs (true ribs) articulate via coastal cartilages directly with the sternum, Ribs 8-­‐10 (false ribs) articulate with the sternum via the 7th coastal cartilage. Ribs 11 and 12 (floating ribs) do not articulate with the sternum. All ribs articulate with the body of the corresponding vertebrae. • Using the models, identify each of the bones and features listed on our bone list.. 6. Appendicular Skeleton – Bones of the Pectoral Girdle The pectoral, or shoulder, girdle consists of the clavicle, or collarbone, and the scapula, or shoulder blade. The clavicale articulates to the mandrium at the sternal end and the acromonion process of the scapula at the acromonional end. The scapula consists of a flattened bone with two major processes. The acromonion process is the large, flattened end of the spine, which connects with the clavicle. The coracoid process is the bent anterior process that helps anchor the muscles of the arm. The glenoid fossa is the socket that accommodates the humerus forming the shoulder joint. The supraspinous and infraspinous fossas are located above and below the spine, respectively. 58 Figure 14. The pelvic girdle. 7. Appendicular Skeleton – Bones of the Arms The upper arm consists of a single bone, the humerous. The smooth, rounded head forms the shoulder joint by articulating with the gelnoid fossa of the scapula. Two tuberosities are lateral to the head, the greater and lesser tubercles. Figure 15. The humerus. The distal portion of the humerus has numerous features contributing the acrticulation with the ulna and radius, forming the elbow. The trochlea and capitulum are rounded processes at the most distal edge of the humerus which join with the ulna and radius, respectively. The lateral and medial epicondyles are lateral to the trochlea. Two fossas, coronoid and olecranon fossas, on the anterior 59 and posterior, respectively, of the trochlea articulate with the coronoid and olecranon processes of the ulna. The forearm contains two bones, the lateral radius and medial ulna. The proximal portion of the ulna contain three features involved in articulation with the humerus: the coronoid process, trochlea notch, and olecranon process. Lateral to the coronoid process is the radial notch. The proximal radius contains a head with an ulna notch that articulates with the ulna. The distal end of both the radius and ulna features lateral styloid processes. The hand has three sets of bones: the carpals of the wrist, the metacarpals of the palm, and the phalanges, or fingers. The carpals are eight bones in two rows of four. The proximal row, medial to lateral is: scaphoid, lunate, triquetral and piiform. The distal row, medial to distal, is: trapezium, trapezoid, capitate and hamate. (Mnemonic – Some Lovers Try Postitions That They Can’t Handle). Figure 16. Ulna and radius. Figure 17. Bones of the hands. 60 8. Appendicular Skeleton – Bones of the Pelvic Girdle The pelvic girdle consists of paired coxal bones joined together at the pubic symphis anteriorly and articulated with the sacrum posteriorly. Each coxal bone is fused from the pubis, illium and ishium. The ishium and pubis jointly surround the large opening, the obturator foramen, through which blood vessels and nerves pass. The acetabellum, or vinegar cup, is the articular suface for the femur. Figure 18. Pelvic girdle: 1. Sacrum, 2. Ilium, 3. Ischium, 4. Pubic bone, 5. Pubic symphysis, 6. Acetabulum, 7. Obturator foramen, 8. Coccyx The pelvic girdle shows the most sexual dimorphism of the human bones. The female pelvis is larger and broader than the male pelvis. The male pelvis is taller and more compact. The changes in the female pelvis are optimized for childbirth having a larger opening to allow passage of a child. Figure 18. Comparison of the male and female pelvis. 61 9. Appendicular Skeleton – Bones of the Legs The upper leg bone, or femur, is both the longest and the strongest bone in the skeleton. The proximal end has a head that forms the hip joint and is connected to the body of the bone by the neck. The greater and lesser trochanters are on the lateral and medial surfaces near the neck. On the distal end, the medial and lateral condyles are on either side of the intercondylar fossa with the medial and epicondyles above each condyle. Figure 21. The lower leg. Figure 20. The femur. The lower leg has a large medial bone, the tibia, and a smaller lateral bone, the fibula. At the proximal end, medial and lateral condyles help form the knee joint. The distal end has a medial process, the medial malleolus. The lateral malleolus is on the lateral surface of the fibula. The foot has seven tarsal bones, five metatarsals, and fourteen phalanges. Most of the body weight is supported on the two largest tarsal’s – the talus and the calcaneous. The calcaneous is the heel bone. The talus is in the ankle between the tibia and the calcaneous. The metatarsals and phalanges are numbered 1 through 5, medial to lateral. Figure 22. The bones of the foot. 62 Attribution of images used in this document: Figure 1A. U.S. National Cancer Institute. (2000). [Structure of bone tissue]. Surveillance, Epidemiology and End Results (SEER) Program retrieved May 15, 2012 from: http://training.seer.cancer.gov/anatomy/skeletal/tissue.html Figure 1B. Gray, H. (1918). [Microscopic structure of compact bone.] from Gray's Anatomy, 20th Figure 2. Villarreal, Maria Ruiz (LadyofHats). (2007). [Appendicular Skeleton]. WikimediaCommons, retrieved August 17, 2012 from http://commons.wikimedia.org/wiki/File:Appendicular_skeleton_diagram.svg. Figure 4. Life Science Database Archive (2009). [Frontal Bone]. Life Science Database Achive, retrieved May 17, 2012 from http://lifesciencedb.jp/bp3d/?lng=en. Figure 5. Boch, CE (1841). [Features of the occipital bone]. Handbuch der Anatomie des Menschen. Figure 6. Gray, H. (1918). [Superior and anterior views of the sphenoid bone]. From Gray's Anatomy, 20th ed. Figure 7. Gray, H. (1918). [External and internal views of the temporal bone]. From Gray's Anatomy, 20th ed. Figure 8. Gray, H. (1918). [Ethmoid bone, posterior view and from a sagittal cut of the skull]. From Gray's Anatomy, 20th ed. Figure 9. Green, P.S. (2012) adapted from http://commons.wikimedia.org/wiki/File:Human_skull_side_simplified.PNG and http://en.wikipedia.org/wiki/File:Gray190.png. Figure 10.Komorniczak, M. (2009) [Paranasal sinuses]. Retrieved August 22, 2012 from http://commons.wikimedia.org/wiki/File:Paranasal_sinuses_numbers.svg. Figure 11. Boch, CE (1841). [The hyoid bone]. Handbuch der Anatomie des Menschen. Figure 12. Gray, H. (1918). [Vertebral Column, Cervical, Thoracic, Lumbar and Sacral Vertebrae]. From Gray's Anatomy, 20th ed. Figure 13. Gray, H. (1918). [Bones of the thoracic cage]. From Gray's Anatomy, 20th ed. Figure 14. zygotebody.com. (2012). [The pelvic girdle]. Zygotebody.com, retrieved May 7, 2012 from http://zygotebody.com/#nav=1.37,81.5,250. Figure 15. BDB. (2007). [Humerus front and back]. Wikimedia Commons retrieved July 12, 2012 from http://commons.wikimedia.org/wiki/File:HumerusFront.png. Figure 16. Darling, D. (n.d.) [Ulna and radius]. Encyclopedia of Science retrieved July 12, 2012 from http://www.daviddarling.info/encyclopedia/R/radius_arm.html. Figure 17. Villarreal, Maria Ruiz (LadyofHats). (2007). [Bones of the hands]. WikimediaCommons, retrieved May 17, 2012 from http://commons.wikimedia.org/wiki/File:Scheme_human_hand_bones-en.svg. Figure 18. Wiechers. (2006). [Bones of the pelvic girdle]. Wikimedia Commons, retrieved July 12, 2012 from http://commons.wikimedia.org/wiki/File:Skeletpelvis-pubis.jpg. Figure 19. Gray, H. (1918). [Comparison of the male and female pelvis]. From Gray's Anatomy, 20th ed. 63 Figure 20. Gaillard, F. (2009). [Femur posterior annotated]. Wikimedia Commons retrieved July 12, 2012 from http://commons.wikimedia.org/wiki/File:Fumur_Posterior_annoted.png. Figure 21. zygotebody.com. (2012). [The lower leg]. Zygotebody.com, retrieved May 7, 2012 from http://zygotebody.com/#nav=1.37,81.5,250. Figure 22. VonTasha. (2006). [The bones of the feet]. Wikimedia Commons retrieved July 12, 2012 from http://commons.wikimedia.org/wiki/File:Ospied.svg. 64 Laboratory 4 The Skeleton Name ________________________ Section __________ 1. Classify the following bones as long, short, flat or irregular. Scapula ____________________________________________________________________________________________ Humerus ____________________________________________________________________________________________ Cuboid ____________________________________________________________________________________________ Maxilla ____________________________________________________________________________________________ Metacarpal ___________________________________________________________________________________________ Parietal ____________________________________________________________________________________________ Vertebra ____________________________________________________________________________________________ Triquetral ____________________________________________________________________________________________ 2. Define the following general bone structures. Process ____________________________________________________________________________________________ Crest ____________________________________________________________________________________________ Foramen ____________________________________________________________________________________________ Facet ____________________________________________________________________________________________ Ramus ____________________________________________________________________________________________ Tuberosity ____________________________________________________________________________________________ Meatus ____________________________________________________________________________________________ Condyle ____________________________________________________________________________________________ 65 3. For the following skull foramina, list what pass through them. Foramen Magnum __________________________________________________________________________ External Acoustic Meatus __________________________________________________________________________ Jugular Foramen __________________________________________________________________________ Carotid Canal __________________________________________________________________________ Internal Acoustic Meatus __________________________________________________________________________ Foramen Rotundum __________________________________________________________________________ Foramen Ovale __________________________________________________________________________ Foramen Spinosum __________________________________________________________________________ Mandibular Foramen __________________________________________________________________________ Optic Canal __________________________________________________________________________ Inferior Orbital Fissure __________________________________________________________________________ Superior Orbital Fissure __________________________________________________________________________ 4. List all the skull bones that contribute to the orbits. ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ 5. List 3 functions of the paranasal sinuses. ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ ______________________________________________________________________________________________________________ 66 6. For the following vertebral structures, indicate which type(s) of vertebrae possess them and summarize the function. Vertebral Foramen __________________________________________________________________________ Body __________________________________________________________________________ Spinous Process __________________________________________________________________________ Articular Processes __________________________________________________________________________ Transverse Foramina __________________________________________________________________________ Rib Facets __________________________________________________________________________ 7. Which bones comprise the: Pectoral Girdle __________________________________________________________________________ Pelvic Girdle __________________________________________________________________________ 8. Label the bones from your bone list on the following images: 67 68 69 70 71 72 73 74