Lab 3 Axial Skeleton F24 PDF

1 Lab 3: The Skeletal System (Part 1) Part A. Overview of the Skeleton Part B. Bones of the Human Skeleton: Axial Skeleton Pre-lab Checklist: (to be completed before Lab 3) o Complete t...

1 Lab 3: The Skeletal System (Part 1) Part A. Overview of the Skeleton Part B. Bones of the Human Skeleton: Axial Skeleton Pre-lab Checklist: (to be completed before Lab 3) o Complete the Review Sheets from Lab 2. o Be prepared for the lab quiz at the beginning of this lab. It will be based on last week’s lab. o Read the entire Lab 3 before coming to lab. o If you own A Brief Atlas of the Human Body, please bring it to lab for use in your study of the axial skeleton. Copies will also be available for you in the lab. o You may wish to visit the BIOL 1220/1221 Virtual Models website and review the skeletal system. Learning Objectives: The student should be able to: 1. Name the two tissue types that form the skeleton. 2. List the functions of the skeletal system. 3. Identify and locate the three major types of skeletal cartilages. 4. Describe the classification of bones. 5. Describe the gross anatomy of a typical long bone. 6. Explain the role of inorganic salts and organic matrix in providing flexibility and hardness to bone. 7. Locate and identify the major parts of an osteon microscopically, or on a histological model or appropriate image of compact bone. 8. Identify the bones of the axial skeleton and name the important landmarks. Please note the key terms for this objective will be contained in the Lab Manual and will not be listed with the rest of the key terms shown below. 9. Discuss the importance of intervertebral discs and spinal curvatures. 10. Identify three abnormal spinal curvatures. 11. Define fontanelle and discuss the function and fate of fontanelles.  2 Key Terms: cartilage, compact bone connective tissue, hyaline cartilage connective tissue, elastic cartilage connective tissue, fibrocartilage connective tissue, axial skeleton long bones, short bones, flat bones, irregular bones, sesamoid bones, sutural bones compact bone, spongy bone, trabeculae, diaphysis, medullary cavity (yellow bone marrow cavity), epiphyses, articular cartilage, epiphyseal line, epiphyseal plate, periosteum, endosteum, hematopoietic tissue (red bone marrow) inorganic calcium salts, collagen fibers osteon (Haversian system), lamellae, central (Haversian) canal, perforating (Volkmann's) canal, canaliculi, osteocytes, lacunae cervical curvature, thoracic curvature, lumbar curvature, intervertebral discs, scoliosis, kyphosis, lordosis fontanelle  3 Part A: Overview of the Skeleton Bone (osseous tissue) is a hard, dense connective tissue that forms most of the adult skeleton. Cartilage can be found in the areas of the skeleton where bones move (for example, the ribcage and joints). In Lab 3, you learned that cartilage is a semi-rigid form of connective tissue and, just as elastic cartilage provides flexibility to structures like your external ear and epiglottis. Cartilage associated with the skeleton provides flexibility and smooth surfaces for movement. The skeletal system is composed of bones and cartilage and performs several critical functions for the human body including: supporting the body, facilitating movement, protecting internal organs, producing blood cells, and storing and releasing minerals and fat (Figure 3.1). Figure 3.1 Axial and Appendicular Skeleton. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  4 Major Divisions of the Body The skeletal system includes all of the bones, cartilages, and ligaments of the body that support and give shape to the body and body structures. Children have a higher number of bones because some bones fuse together during childhood and adolescence to form an adult bone, but there are 206 bones in the adult skeleton. The primary functions of the skeleton are to provide a rigid, internal structure that can support the weight of the body against the force of gravity, and to provide a structure upon which muscles can act to produce movements of the body. The skeleton is subdivided into two major divisions—the axial and appendicular. The axial skeleton forms the vertical, central axis of the body and includes all bones of the head, neck, chest, and back (Figure 3.1). It serves to protect the brain, spinal cord, heart, and lungs, and serves as the attachment site for muscles that move the head, neck, and back, and for muscles that act across the shoulder and hip joints to move their corresponding limbs. The axial skeleton of the adult consists of 80 bones, including the skull (22), the vertebral column (7 cervical, 12 thoracic, 5 lumbar, 5 fused sacral, and 4 fused coccygeal vertebrae), and the thoracic cage (25). The appendicular skeleton includes all bones of the upper and lower limbs, plus the bones that attach each limb to the axial skeleton (Figure 3.1). Further information on the appendicular skeleton is found in Lab 4. Bone shapes The bones that compose the adult skeleton are divided into five categories based on their shapes (Figure 3.2). Each categorical shape of bone has a distinct function. Long Bones A long bone is one that is cylindrical and is longer than it is wide. A cavity (medullary cavity) extends the length of the shaft along its center. Long bones are found in the arms (humerus, ulna, radius) and legs (femur, tibia, fibula), as well as in the fingers (metacarpals, phalanges) and toes (metatarsals, phalanges). Long bones function as levers; they move when muscles contract. Short Bones A short bone is one that is cube-like in shape, being approximately equal in length, width, and thickness. Short bones in the human skeleton include the carpals of the wrists, tarsals of the ankles and sesamoid bones. Short bones provide stability and support as well as some limited motion. Flat Bones The term “flat bone” is somewhat of a misnomer because, although a flat bone is typically thin, it is also often curved. Examples include the cranial (skull) bones, the sternum (breastbone), and the ribs. Flat bones serve as points of attachment for muscles and often protect internal organs. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  5 Irregular Bones An irregular bone is one that does not have any easily characterized shape and therefore does not fit any other classification. These bones tend to have more complex shapes, like the vertebrae that support the spinal cord and protect it from compressive forces. Many facial bones, particularly the ones containing sinuses, are classified as irregular bones. Sesamoid Bones A sesamoid bone is a small, round bone that, as the name suggests, is shaped like a sesame seed. Sesamoid bones are specialized type of short bone that form in tendons (the sheaths of tissue that connect bones to muscles) where a great deal of pressure is generated in a joint. Sesamoid bones protect tendons by helping them overcome compressive forces. Sesamoid bones vary in number and placement from person to person but are typically found in tendons associated with the feet, hands, and knees. The patellae (singular = patella) are the only sesamoid bones found in common with every person. Figure 3.2 Classification of Bones based on their shape. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  6 Gross Anatomy The structure of a long bone allows for the best visualization of all the parts of a bone (Figure 3.3). A long bone has two major parts: the diaphysis and the epiphysis. The diaphysis is the tubular shaft that runs between the proximal and distal ends of the bone which are called epiphyses (pl). The epiphyses are made of spongy bone surrounded by a thin layer of compact bone. In children there is a line of hyaline cartilage at the junction between the diaphysis and epiphysis (sing). This line is called an epiphyseal plate, and allows for longitudinal bone growth. The plates are eventually replaced with bone when growth ceases and leaves a faint line called the epiphyseal line. The hollow region in the diaphysis is called the medullary cavity, which is initially filled with hematopoietic tissue (red bone marrow) in infants which is mostly replaced with yellow marrow in adults. Red marrow, in an adult, is only found within the epiphyseal spongy bone. The walls of the diaphysis are composed of dense and hard compact bone. The medullary cavity has a delicate Figure 3.3 Anatomy of a Long Bone. membranous lining called the endosteum (end- = “inside”), where bone growth, repair, and remodeling occur. The outer surface of the bone is covered with a fibrous membrane called the periosteum (peri- = “around” or “surrounding”). The periosteum contains blood vessels, nerves, and lymphatic vessels that nourish compact bone. Tendons and ligaments also attach to bones at the periosteum. The periosteum covers the entire outer surface except where the epiphyses meet other bones to form joints (Figure 3.3). In this region, the epiphyses are covered with articular cartilage, a thin layer of hyaline cartilage that reduces friction and acts as a shock absorber. Flat bones, like those of the cranium, consist of a layer of diploë (spongy bone), lined on either side by a layer of compact bone (Figure 3.4). The two layers of compact bone and the interior spongy bone work together to protect the internal organs. If the outer layer of a cranial bone fractures, the brain is still protected by the intact inner layer. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  7 Figure 3.4 Anatomy of a Flat Bone. This cross-section of a flat bone shows the spongy bone lined on either side by a layer of compact bone. Bone Features The surface features of bones vary considerably, depending on the function and location in the body. (Table 3.1) There are three general classes of bone markings: (1) articulations, (2) projections, and (3) holes. As the name implies, an articulation is where two bone surfaces come together. These surfaces tend to conform to one another, such as one being rounded and the other cupped, to facilitate the function of the articulation. A projection is an area of a bone that projects above the surface of the bone. These are the attachment points for tendons and ligaments. In general, their size and shape are an indication of the forces exerted through the attachment to the bone. A hole is an opening or groove in the bone that allows blood vessels and nerves to enter the bone. As with the other markings, their size and shape reflect the size of the vessels and nerves that penetrate the bone at these points. Table 3.1 Selected List of Bone Features. Marking Description Example Head Prominent rounded surface Head of femur Facet Flat surface Articular facets of vertebrae Condyle Rounded surface Occipital condyle Process Projection from the bone Spinous process of vertebrae Spine Short, sharp projection Ischial spine Tubercle Small, rounded process Lesser tubercle of humerus Tuberosity Large, rough surface of a bone Ischial tuberosity Crest Larger elevated ridge of bone Iliac crest Fossa Larger pit in a bone Subscapular fossa Sulcus Groove Sigmoid sulcus of temporal bone Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  8 Canal Small passage in bone Carotid canal Foramen Hole through bone Foramen magnum Meatus Opening into a canal External auditory meatus Sinus Open space in bone Nasal sinus Microscopic Anatomy Bone contains a relatively small number of cells entrenched in a crystallized matrix of collagen fibers and inorganic salt crystals. These salt crystals form when calcium phosphate and calcium carbonate combine to create hydroxyapatite, which incorporates other inorganic salts (hard inorganic components) like magnesium hydroxide, fluoride, and sulfate as it crystallizes, or calcifies, on the collagen fibers (soft organic components). The hydroxyapatite crystals give bones their hardness and strength, while the collagen fibers give them flexibility so that they are not brittle. Activity 1. Chemical Composition of Bone This demonstration has two sets of bones that were treated differently, altering their chemical composition. Follow the instructions below, and answer the questions. 1. Using forceps, obtain a bone sample that was soaked in acid (vinegar or HCl), and another sample that was baked at high temperatures. 2. Again, with forceps, gently put pressure on both samples. a. Do the two bones react the same? Describe what happens to the baked bone and compare to the soaked bone. b. What did baking the bone remove? c. What did leaving the bone in acid remove? d. What does that tell you about the normal structure of bone? Compact vs. Spongy Bone The differences between compact and spongy bone are best explored via their histology. Most bones contain compact and spongy bone, but their distribution and concentration vary based on the bone’s overall function. Compact bone is dense so that it can withstand compressive forces, while spongy bone has open spaces and supports shifts in weight distribution. Compact bone is the denser, stronger of the two types of bone tissue (Figure 3.5). It can be found under the periosteum and in the diaphysis of long bones, where it provides support and protection. The microscopic structural unit of compact bone is called an osteon (Haversian Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  9 system). Each osteon is composed of concentric rings of calcified matrix called lamellae (singular = lamella). Running down the center of each osteon is the central canal (Haversian canal) which contains blood vessels, nerves, and lymphatic vessels. These vessels and nerves branch off at right angles through a perforating canal (Volkmann’s canal) to extend to the periosteum and endosteum. Osteocytes are located inside spaces called lacunae (singular = lacuna), found at the borders of adjacent lamellae. They can communicate with each other and receive nutrients via long cytoplasmic processes that extend through canaliculi (singular = canaliculus), channels within the bone matrix. Canaliculi connect with the canaliculi of other lacunae and eventually with the central canal. This system allows nutrients to be transported to osteocytes and wastes to be removed from them. Like compact bone, spongy bone (trabecular bone), contains osteocytes housed in lacunae, but they are not usually arranged in concentric circles. Instead, the lacunae and osteocytes are found in a latticelike network of matrix spikes called trabeculae (singular = trabecula) (Figure 3.5). The trabeculae may appear to be a random network, but each trabecula forms along lines of stress to provide strength to the bone. Figure 3.5 Diagram of Compact Bone (a) This cross-sectional view of compact bone shows the osteon. (b) This micrograph of the osteon, you can clearly see the concentric lamellae and central canals. LM × 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012) Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  10 Activity 2. Three-Dimensional Model of Compact Bone The model (see the following illustration) represents an osteon of compact bone with a cross section the size of this dot (.) magnified about 500 times. An osteon is an elongated cylinder oriented parallel to the long axis of the bone. Perforating canals are not represented on the 3- dimensional model. Using the BIOL 1220 Virtual Lab Models website and other materials available to you, label the following model with the features given below: Figure 3.6 Model of compact bone. Use the following words to label the above figure. Artery, vein, lymphatic vessel, nerve, concentric lamella, interstitial lamella, osteocyte, lacuna, canaliculus Activity 3. Histology of Compact Bone Plate # in Name of Tissue Microscope Slide A Brief Atlas of the Human Body Compact bone (osseous tissue) #16 20 1. Go to the prepared microscope station and observe the specimen listed above. 2. Identify the osteons, lamellae, osteocytes, lacunae, and canaliculi.  11 Part B: Bones of the Human Skeleton: Axial Skeleton The skull is formed by 22 bones (and 6 ear ossicles) and the vertebral column consists of 24 bones, each called a vertebra, plus the sacrum and coccyx. The thoracic cage includes 12 pairs of ribs in addition to the sternum, the flattened bone of the anterior chest. The Skull The cranium (skull) is the skeletal structure of the head that protects the brain and supports the face (Figure 3.7). It is subdivided into the brain case and facial bones. The rounded brain case surrounds and protects the brain and houses the middle and inner ear structures. The facial bones underlie the facial structures, form the nasal cavity, enclose the eyeballs, and support the teeth of the upper and lower jaws. Figure 3.7 Lateral View of Skull. Cranial Bones The brain case contains and protects the brain. The interior space that is almost completely occupied by the brain is called the cranial cavity. The bones that form the top and sides of the brain case are usually referred to as the “calvaria”. The floor of the brain case is referred to as the base of the skull. This is a complex area that varies in depth and has numerous openings for the passage of cranial nerves, blood vessels, and the spinal cord. The brain case consists of eight bones including the paired parietal and temporal bones, plus the unpaired frontal, occipital, sphenoid, and ethmoid bones (Figures 3.7-3.9). The frontal bone is the single bone that forms the forehead and contains the supraorbital margin of the orbit, forming rounded ridges under the eyebrows. The parietal bone forms most of the upper lateral side of the skull. These are paired bones, with the right and left parietal bones joining together at the top of the skull. The occipital bone is the single bone that forms the posterior skull and posterior base of the cranial cavity. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  12 Figure 3.8 Anterior and Posterior View of Skull. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  13 Figure 3.9 External and Internal Views of the Base of the Skull. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  14 On the base of the skull, the occipital bone contains the large opening of the foramen magnum, which allows for passage of the spinal cord as it exits the skull. On either side of the foramen magnum is an oval shaped occipital condyle, which form joints with the first cervical vertebra and thus support the skull on top of the vertebral column. The temporal bone forms the lower lateral side of the skull. Figure 3.10 Sphenoid (yellow) and Ethmoid (purple) Bones. The sphenoid bone is a single, complex bone of the central skull (Figure 3.10). It serves as a “keystone” bone, because it joins with almost every other bone of the skull. The sphenoid forms much of the base of the central skull (Figure 3.9) and also extends laterally to contribute to the sides of the skull (Figure 3.7). The sella turcica is found internally, and is so named for its resemblance to the horse saddles used by the Ottoman Turks. The rounded depression in the floor of the sella turcica houses the pea-sized pituitary gland. The sphenoid bone also forms a portion of the orbit (Figure 3.12). At the posterior apex of the orbit is the opening of the optic canal, which allows for passage of the optic nerve from the eyeball to the brain. The ethmoid bone (Figure 3.10) is a single, midline bone that forms the roof and lateral walls of the upper nasal cavity, the upper portion of the nasal septum, and contributes to the medial wall of the orbit (Figures 3.7 and 3.11). Facial Bones The anterior skull consists of the facial bones and provides the bony support for the eyes and structures of the face. The facial bones of the skull form the upper and lower jaws, the nose, nasal cavity and nasal septum, and the orbit. The facial bones include 14 bones (six paired bones and two unpaired bones). Although classified with the cranial bones, the ethmoid bone also contributes to the nasal cavity and orbit and the sphenoid and frontal bones make up part of the orbit. The maxillary bone (Figure 3.8), often referred to simply as the maxilla (plural = maxillae), is one of a pair that together form the upper jaw, much of the hard palate, the medial floor of the orbit, and the lateral base of the nose. On the inferior skull, the maxillary bone can be seen joining together at the midline to form the anterior three-quarters of the hard palate that forms the roof of the mouth and floor of the nasal cavity, separating the oral and nasal cavities (Figure 3.9). Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  15 Figure 3.11 Bones of the Orbit. The palatine bone is one of a pair of irregularly shaped bones that contribute small areas to the lateral walls of the nasal cavity and the medial wall of each orbit (Figure 3.8). The plates from the right and left palatine bones join together at the midline to form the posterior quarter of the hard palate (Figure 3.9). The zygomatic bone is also known as the cheekbone. The zygomatic arch is the bony arch on the side of the skull that spans from the area of the cheek to just above the ear canal. It is formed by the junction of two bony processes, the temporal process of the zygomatic and the zygomatic process of the temporal bone. The nasal bone (Figure 3.8) is one of two small bones that articulate with each other to form the bony bridge of the nose. They also support the cartilages that form the lateral walls of the nose. These are the bones that are damaged when the nose is broken. Each lacrimal bone is a small, rectangular bone that forms the anterior, medial wall of the orbit (Figures 3.8 and 3.11). The lacrimal fluid (tears of the eye) drains at the medial corner of the eye, which extends downward to open into the nasal cavity. The unpaired vomer is triangular-shaped bone that forms the posterior-inferior part of the nasal septum (Figures 3.8 and 3.9). Extending horizontally on the lateral wall of the nasal cavity are the paired inferior nasal conchae (sing = concha). The mandible forms the lower jaw and is the only moveable bone of the skull. Each side of the mandible consists of a horizontal body and posteriorly, a vertically oriented ramus of the mandible. The ramus on each side of the mandible has two upward-going bony projections. The more anterior projection is the flattened coronoid process of the mandible. The posterior projection is the condylar process. The condylar process articulates (joins) with the temporal bone to form the temporomandibular joint, which allows for opening and closing of the mouth. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  16 Additionally, the outside margin of the mandible, where the body and ramus come together is called the angle of the mandible. Sutures of the Skull A suture is an immobile fibrous joint between adjacent bones of the skull. The narrow gap between the bones is filled with dense, fibrous connective tissue that unites the bones. The long sutures located between the bones of the cranium are not straight, but instead follow irregular, tightly twisting paths. These twisting lines serve to tightly interlock the adjacent bones, thus adding strength to the skull for brain protection (Figures 3.7 and 3.8). The coronal suture runs from side to side across the skull, within the coronal plane of section. It joins the frontal bone to the right and left parietal bones. The sagittal suture extends posteriorly from the coronal suture, running along the midline at the top of the skull in the sagittal plane of section to unite the right and left parietal bones. On the posterior skull, the sagittal suture terminates by joining the lambdoid suture. The lambdoid suture extends downward and laterally to either side away from its junction with the sagittal suture. The lambdoid suture joins the occipital bone to the right and left parietal bones. This suture is named for its upside-down "V" shape, which resembles the capital letter version of the Greek letter lambda (λ). On occasion extra pieces of bone called sutural bones can be found within the cranial sutures. The squamous suture is located on the lateral skull. It unites the temporal bone with the parietal bone. Activity 4. Labelling the Skull The following guide has been designed to enable you to use figures in A Brief Atlas of the Human Body for the study of the bones of the skeleton. This section of the study guide contains the lists of bones and landmarks for the axial skeleton that you will be required to know. The insertion of an arrow bulleted point ( ) in this study guide indicates a clinical significance of the bony landmark. You will not be tested on the clinical significances. They are included for your interest only. Using the BIOL 1220 Virtual Lab Models website and other materials available to you, label the following model with the features given below. IMPORTANT: When naming a feature on a bone, ALWAYS name the feature and the bone. If you fail to do this on a quiz or lab test, you will lose marks. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  17 Figure 3.12 Skull: anterior view. (Atlas: p. 27) frontal bone maxillae (maxillary bones) supraorbital margin of frontal bone sphenoid bone ⮚ palpated to assess sinus infections optic canal of sphenoid bone coronal suture lacrimal bone parietal bone ethmoid bone temporal bone vomer mastoid process of temporal bone inferior nasal concha nasal bone mandible zygomatic bone ⮚ palpated to assess sinus infections Which of the bones in the above list form parts of the bony orbits (the depressions in which the eyeballs are located)? What is the only movable bone of the skull?  18 Figure 3.13 Skull, right external view of lateral surface. (Atlas: p. 28) frontal bone sphenoid bone parietal bone ethmoid bone temporal bone lacrimal bone external auditory meatus of temporal lacrimal fossa of lacrimal bone bone nasal bone mastoid process of temporal bone zygomatic bone zygomatic process of temporal bone maxilla (The zygomatic process joins with a alveolar processes of maxilla process of the zygomatic bone to form the mandible _____________ arch.) ramus of mandible coronal suture angle of mandible squamous suture condylar process of mandible lambdoid suture coronoid process of mandible occipital bone alveolar processes of mandible ⮚ common site for pressure sore The bones joined by the coronal suture are the and. The bones joined by the squamous suture are the and. The bones joined by the lambdoid suture are the and. The above list contains three of the four sutures of the skull that you are required to learn. On the superior surface of the skull, locate the sagittal suture, which joins the two bones.  19 Once again, locate all four sutures. Which bones of the skull participate in forming all four sutures? Label the sutures on the following left figure. Figure 3.14 Skull: superior external view (anterior is bottom), inferior external view (anterior is top). (Atlas: p. 30) Right image is derived from: "Sobotta 1909 fig.41 - The skull, inferior view - No labels" by Johannes Sobotta and is in the Public Domain The hard palate consists of two bones: carotid canal of temporal bone 1. maxilla jugular foramen of temporal bone 2. palatine bone occipital bone vomer occipital condyles of occipital bone sphenoid bone foramen magnum of occipital bone temporal bone What is the function of the occipital condyles? What is the function of the carotid canals?  20 Figure 3.15 Skull, internal view of base (anterior is top). This work is a derivative of “Cranial fossae” by OpenStax CNX used under CC BY 4.0. This work is licenced under CC BY-SA 4.0 by Mount Royal University. (Atlas: p. 31) frontal bone frontal sinus of frontal bone temporal bone ethmoid bone jugular foramen of temporal bone sphenoid bone zygomatic arch sella turcica of sphenoid bone parietal bone optic canal of sphenoid bone occipital bone foramen magnum of occipital bone What is the function of the optic canal? What is the function of the jugular foramen? What is the function of the foramen magnum? What is the function of the sella turcica?  21 Figure 3.16 Mandible. (Atlas: p. 38) mandible condylar process of mandible angle of mandible ramus of mandible body of mandible coronoid process of mandible alveolar process of mandible Figure 3.17 Bony Orbit. (Atlas: p. 41) frontal bone lacrimal fossa of lacrimal bone zygomatic bone ethmoid bone maxilla (maxillary bone) sphenoid bone nasal bone (not part of the orbit) optic canal of sphenoid bone lacrimal bone  22 Bones of the skull are classified as either cranial bones or facial bones. Put the names of the bones of the skull into the correct category: Facial bones: Cranial bones: Fetal Skull As the cranial vault bones grow in the fetal skull, they remain separated from each other by large areas of dense connective tissue, each of which is called a fontanelle (Figure 3.18). The fontanelles are the soft spots on an infant’s head, and they are important during birth because these areas allow the skull to change shape as it squeezes through the birth canal. After birth, the fontanelles allow for continued growth and expansion of the skull as the brain enlarges. However, the skull bones remain separated from each other at the sutures, which contain dense fibrous connective tissue that unites the adjacent bones. The connective tissue of the sutures allows for continued growth of the skull bones as the brain enlarges during childhood growth. The second mechanism for bone development in the skull produces the facial bones and floor of the brain case. A hyaline cartilage model of the future bone is produced and as this cartilage model grows, it is gradually converted into bone. This is a slow process and the cartilage is not completely converted to bone until the skull achieves its full adult size. Figure 3.18 Bones and Fontanelles of the Fetal Skull. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  23 Activity 5. Fetal Skull Using the BIOL 1220 Virtual Lab Models website and other materials available to you, label the following model with the features given below: Figure 3.19 Model of a Fetal Skull (upper left: anterior, upper right: lateral, bottom: superior) frontal bone maxilla (maxillary bone) temporal bone mandible occipital bone frontal suture parietal bone fontanelles Using your own words, what is a fontanelle? What is the importance of fontanelles in the fetal skull, and during early childhood? (See p. 246 in your textbook.)  24 The Vertebral Column Regions of the Vertebral Column The vertebral column is subdivided into five regions (Figure 3.20), with the vertebrae in each area named for that region and numbered in descending order. In the neck, there are usually seven cervical vertebrae, each designated with the letter “C” followed by its number. Superiorly, the C1 vertebra articulates with the occipital condyles of the skull. Inferiorly, C1 articulates with the C2 vertebra, and so on. Below these are the 12 thoracic vertebrae, designated T1–T12. The lower back contains 5 lumbar vertebrae, the L1–L5 lumbar vertebrae. The single sacrum, which is also part of the pelvis, is formed by the fusion of five sacral vertebrae. Similarly, the coccyx, or tailbone, results from the fusion of four small coccygeal vertebrae. Figure 3.20 Regions of the Vertebral Column. General Structure of a Vertebra Within the different regions of the vertebral column, vertebrae vary in size and shape, but they all follow a similar structural pattern. A typical vertebra will consist of a body, a vertebral arch, and seven processes (Figure 3.21). The body is the anterior portion of each vertebra and is the part that supports the body weight. Because of this, the vertebral bodies progressively increase in size and thickness going down the vertebral column. The bodies of adjacent vertebrae are separate but strongly united by an intervertebral disc. The vertebral arch forms the posterior portion of each vertebra. It consists of four parts, the right and left pedicles and the right and left laminae. The pedicles are anchored to the posterior side of the vertebral body. Each lamina forms part of the posterior roof of the vertebral arch. The large opening between the vertebral arch and body is the vertebral foramen, which contains the spinal cord. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  25 Seven processes arise from the vertebral arch. Each paired transverse process projects laterally and arises from the junction point between the pedicle and lamina. The single spinous process projects posteriorly at the midline of the back. The spinous processes can easily be felt as a series of bumps just under the skin down the middle of the back. Additionally, a superior articular process extends upward, and an inferior articular process projects downward on each side of a vertebra. Each process has a smooth articular surface called a facet. The paired superior articular processes of one vertebra join with the corresponding paired inferior articular processes from the next higher vertebra. These junctions form slightly moveable joints between the adjacent vertebrae. Figure 3.21 Parts of a Typical Vertebra. Cervical Vertebrae Typical cervical vertebrae have a small body, reflecting the fact that they carry the least amount of body weight (Figure 3.22). Cervical vertebrae usually have a bifid (Y-shaped) spinous process. Each transverse process of the cervical vertebrae has an opening called the transverse foramen to allow for passage of the cervical spinal nerves and an important artery that supplies the brain. You will learn these later in 1220 and 1221. The first and second cervical vertebrae are further modified, giving each a distinctive appearance. The first cervical vertebra (C1) is also called the atlas. The atlas is ring-shaped and does not have a body or spinous process. The second cervical vertebra (C2) is called the axis. The axis resembles typical cervical vertebrae in most respects but is easily distinguished by the bony projection (the Figure 3.22 dens) that extends upward from the vertebral body and fits inside the atlas Cervical Vertebrae. above. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  26 Thoracic Vertebrae The bodies of the thoracic vertebrae are larger than those of cervical vertebrae (Figure 3.23). The characteristic feature for a typical midthoracic vertebra is the spinous process, which is long and has a pronounced downward angle that causes it to overlap the next inferior vertebra. Unique to thoracic vertebrae, several additional articulation sites where ribs attach, called facets, are located on the lateral sides of the body and the transverse process. Lumbar Vertebrae Lumbar vertebrae carry the greatest amount of body weight and are thus characterized by the large size and thickness of the vertebral body (Figure 3.24). They have short transverse processes and a short, blunt spinous process that projects posteriorly. The Figure 3.23 articular processes are large, with the superior process facing Thoracic posteriorly and the inferior facing anteriorly. Vertebrae. Sacrum and Coccyx The sacrum is a triangular-shaped bone that is thick and wide across its superior base where it is weight bearing and then tapers down to an inferior, non-weight bearing apex (Figure 3.25). It is formed by the fusion of five sacral vertebrae. On the anterior surface of the older adult sacrum, the lines of vertebral fusion can be seen as four transverse ridges. On the posterior surface, the remnant of the fused Figure 3.24 spinous processes and transverse processes of the sacral vertebrae can be seen Lumbar Vertebrae. as vertical bumpy ridges. The coccyx (the tailbone) is derived from the fusion of four very small coccygeal vertebrae. It articulates with the inferior tip of the sacrum. It is not weight bearing in the standing position but may receive some body weight when sitting. Figure 3.25 Sacrum and Coccyx. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  27 Disease States of the Vertebral Column Developmental anomalies, pathological changes, or obesity can enhance the normal vertebral column curves, resulting in the development of abnormal or excessive curvatures (Figure 3.26). Kyphosis (humpback or hunchback) is an excessive posterior curvature of the thoracic region. This can develop when osteoporosis causes weakening and erosion of the anterior portions of the upper thoracic vertebrae, resulting in their gradual collapse. Lordosis (swayback) is an excessive anterior curvature of the lumbar region and is most commonly associated with obesity or late pregnancy. Scoliosis is an abnormal, lateral curvature, accompanied by twisting of the vertebral column. Compensatory curves may also develop in other areas of the vertebral column to help maintain the head positioned over the feet. The cause of scoliosis is usually unknown, but it may result from weakness of the back muscles, defects such as differential growth rates in the right and left sides of the vertebral column, or differences in the length of the lower limbs. When present, scoliosis tends to get worse during adolescent growth spurts. Although most individuals do not require treatment, a back brace may be recommended for growing children. In extreme cases, surgery may be required. Figure 3.26 Abnormal Curvature of the Vertebral Column. Activity 6. Labelling the Vertebral Column The following guide has been designed to enable you to use figures in A Brief Atlas of the Human Body for the study of the bones of the skeleton. This section of the study guide contains the lists of bones and landmarks for the axial skeleton that you will be required to know. The insertion of an arrow bulleted point ( ) in this study guide indicates a clinical significance of the bony landmark. You will not be tested on the clinical significances. They are included for your interest only. Using the BIOL 1220 Virtual Lab Models website and other materials available to you, label the following model with the features given below. IMPORTANT: When naming a feature on a bone, ALWAYS name the feature and the bone. If you fail to do this on a quiz or lab test, you will lose marks. Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  28 Figure 3.27 Articulated Vertebral Column (Atlas: pp. 44-45) Note: The vertebrae articulate (form joints) with one another, however, they are separated by pads of fibrocartilage called intervertebral discs. These discs absorb shocks and prevent compression. spinous processes ⮚ used to locate points for lumbar punctures and epidurals transverse processes intervertebral disc intervertebral foramen sacrum coccyx cervical curvature thoracic curvature lumbar curvature Cervical – anteriorly curves convex/concave (circle the appropriate curvature) Thoracic – anteriorly curves convex/concave (circle the appropriate curvature) Lumbar – anteriorly curves convex/concave (circle the appropriate curvature)  29 Figure 3.28 Cervical Vertebrae. (Atlas: pp. 46-49) atlas (C1) vertebral foramen of cervical vertebra axis (C2) lamina of cervical vertebra dens of axis pedicle of cervical vertebra body of axis body of cervical vertebra Cervical Vertebrae superior articular facet of cervical transverse process of cervical vertebra vertebra transverse foramen of cervical vertebra inferior articular facet of cervical bifid spinous process of cervical vertebra vertebra Name all the surfaces of vertebrae that form joints with adjacent vertebrae. How many cervical vertebrae are there in the vertebral column? How many thoracic vertebrae are there in the vertebral column? The thoracic vertebrae are the only vertebrae that articulate (form joints) with the.  30 Figure 3.29 Thoracic Vertebrae. (Atlas: pp. 50-51) Thoracic vertebrae transverse process of thoracic vertebra body of thoracic vertebra spinous process of thoracic vertebra transverse costal facets vertebral foramen of thoracic vertebra superior articular process of thoracic lamina of thoracic vertebra vertebra pedicle of thoracic vertebra inferior articular process of thoracic vertebral arch of thoracic vertebra vertebra Figure 3.30 Lumbar Vertebrae. (Atlas : pp. 52-53) Lumbar vertebrae transverse process of lumbar vertebra body of lumbar vertebra spinous process of lumbar vertebra superior articular process of lumbar vertebral foramen of lumbar vertebra vertebra lamina of lumbar vertebra inferior articular process of lumbar pedicle of lumbar vertebra vertebra vertebral arch of lumbar vertebra How many lumbar vertebrae are there in the vertebral column?  31 Figure 3.31 Sacrum and Coccyx. (Atlas: pp. 54-55) Sacrum body of sacrum auricular surface of sacrum (sacroiliac median sacral crest of sacrum joint) posterior sacral foramina of sacrum ⮚ the sacrum and coccyx are both anterior sacral foramina of sacrum common sites for pressure sores sacral canal of sacrum  32 The Thoracic Cage The thoracic cage (rib cage) protects the heart and lungs. The thoracic cage consists of the sternum and 12 pairs of ribs with their costal cartilages (Figure 3.32). The ribs are anchored posteriorly to the 12 thoracic vertebrae (T1–T12). Figure 3.32 Thoracic Cage. Sternum The sternum (Figure 3.32) is the elongated bony structure that anchors the anterior thoracic cage. It consists of three parts: the manubrium, body, and xiphoid process. The manubrium is the wider, superior portion of the sternum. The top of the manubrium has a shallow, U-shaped border called the jugular (suprasternal) notch. The clavicular notch is the shallow depression located on either side of the jugular notch. The elongated, central portion of the sternum is the body. The manubrium and body join together at the sternal angle, so called because the junction between these two components is not flat, but forms a slight bend. The inferior tip of the sternum, known as the xiphoid process, serves as an attachment site for several muscles. Ribs Each rib is a curved, flattened bone that contributes to the wall of the thorax. The ribs articulate posteriorly with the T1–T12 thoracic vertebrae, and most attach anteriorly via their costal cartilages to the sternum. There are 12 pairs of ribs, numbered 1–12 in accordance with the thoracic vertebrae to which each articulates (Figure 3.32). The bony ribs do not extend anteriorly completely around to the sternum. Instead, the ends of each rib are attached to hyaline cartilage (the costal cartilage), which can extend for several inches. Most ribs are then attached, either directly or indirectly, to the sternum via this cartilage. The ribs are classified into three groups based on their relationship to the sternum. Ribs 1–7 are classified as true ribs because the cartilage from each of these ribs attaches directly to the sternum. Ribs 8–12 are Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  33 called false ribs because the cartilages from these ribs do not attach directly to the sternum. For ribs 8–10, the cartilages are attached to the cartilage of the next higher rib. The last two ribs (11–12) are called floating ribs because they are short ribs that do not attach to the sternum at all. Activity 7. Labelling the Thoracic Cage The following guide has been designed to enable you to use figures in A Brief Atlas of the Human Body for the study of the bones of the skeleton. This section of the study guide contains the lists of bones and landmarks for the axial skeleton that you will be required to know. The insertion of an arrow bulleted point ( ) in this study guide indicates a clinical significance of the bony landmark. You will not be tested on the clinical significances. They are included for your interest only. Using the BIOL 1220 Virtual Lab Models website and other materials available to you, label the following model with the features given below. IMPORTANT: When naming a feature on a bone, ALWAYS name the feature and the bone. If you fail to do this on a quiz or lab test, you will lose marks. Figure 3.33 Thoracic Cage. (Atlas: pp. 56-58) sternum jugular (suprasternal) notch of sternum manubrium of sternum clavicular notch of sternum body of sternum rib xiphoid process of sternum head of rib sternal angle of sternum neck of rib ⮚ used to locate proper position for tubercle of rib CPR true ribs ⮚ used to count ribs (2nd rib joins false ribs sternum at the sternal angle) floating ribs costal cartilage Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  34 What is the difference between true ribs and false ribs? Examine the articulated skeleton, and note the anterior rib joints with the skeleton and the posterior rib joints with the vertebrae. Post-Lab Assignment Post-Lab Assignments are due 24 hours after you leave the lab. These are found on your D2L site. You are free to work together with your peers; however, you must complete and submit the assignment individually. You have unlimited attempts within the 24 hours. Submissions after this 24-hour period will not be accepted.  35 Review Sheets 1. Identify whether the following bones are a part of the axial or appendicular skeleton by writing the correct region on the provided blank. a. Sternum b. Humerus c. Skull d. Ribs e. Femur f. Carpals g. Clavicle 2. Provide one general function of the axial skeleton that is not a function of the appendicular skeleton. 3. For a long bone, draw and label the diaphysis and an epiphysis. 4. Name one notable structural feature found in compact bone but not in spongy bone. 5. Name one notable structural feature found in spongy bone but not in compact bone. 6. Name the bone feature that best matches each provided description. a. Large rough surface of a bone b. Short sharp projection c. Hole through a bone d. Flat surface on a bone e. Prominent rounded projection 7. What does costal cartilage articulate with? Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  36 8. Complete the table below on bone shapes. Bone Shape Description Examples *Some authorities have described as irregular bone and others a flat bone 9. The sternal angle is found where? Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  37 10. Label the following figures: Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  38 11. What does suprasternal notch articulate to? 12. Order the following features of the sternum from most superior to most inferior: Body of sternum Most superior: _____________________ Suprasternal (jugular) notch _____________________ Manubrium _____________________ Xiphoid process _____________________ Sternal angle Most inferior: _____________________ 13. Label the following figure: 14. Identify the following vertebrae as cervical, thoracic, or lumbar: Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction  39 15. Define each of the following compact bone structures in one sentence each: a. Canaliculi b. Lacuna c. Osteon d. Central canal 16. What is the scientific term for the “soft spots” on an infant’s head? Why are they important? 17. What is the scientific term for an abnormal curvature of the spine known as “humpback or hunchback”? What region of the spine is it typically observed in? Sources used in the writing of this review include Hesse, et al. (2017). UGA Anatomy and Physiology 1 Lab Manual (3rd ed.). Biology Sciences Open Textbooks. 13. https://oer.galileo.usg.edu/biology-textbooks/13/ Most images and text found in this section are a derivative of "Anatomy and Physiology" by OpenStax CNX used under CC BY 4.0. Aug 2, 2019. Download the original text for free at https://openstax.org/books/anatomy-and-physiology/pages/1- introduction