Chapter 7 Skeletal System Anatomy PDF

Chapter 07 *Lecture Outline *See separate Image PowerPoint slides for all fi...

Chapter 07 *Lecture Outline *See separate Image PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes. PowerPoints prepared by Melanie Waite-Altringer Biology Faculty Member of Anoka-Ramsey Community College Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.  Chapter 7 Skeletal System 2 Introduction: A. Bones are very active, living tissues B. Each bone is made up of several types of tissues and so is an organ. C. Bone functions include: Muscle attachment Protection and support of soft materials Blood cell production Storage of minerals 3 Bone Structure A. Bones differ in size and shape, yet are similar in several ways. B. Classification of Bones Bones are classified according shape: Long Short Flat Irregular Sesamoid 4 C. Parts of a Long Bone 1. Expanded ends of bones that form joints with adjacent bones are called epiphyses. 2. Articular cartilages (hyaline cartilage) cover the epiphyses. 3. The shaft of the bone is the diaphysis. 4. A tough layer of vascular connective tissue, called the periosteum, covers the bone and is continuous with ligaments and tendons. 5 5. A bone's shape makes possible its function; bony processes or grooves indicate places of attachment for muscles. 6. Compact bone makes up the wall of the diaphysis; the epiphyses are filled with spongy bone to reduce the weight of the skeleton. 7. Spongy bone has many branching bony plates called trabeculae. 8. The diaphysis contains a hollow medullary cavity that is lined with endosteum and filled with marrow. 6 Fig07.01 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Epiphyseal plates Articular cartilage Proximal Spongy bone epiphysis Space containing red marrow Endosteum Compact bone Medullary cavity Yellow marrow Periosteum Diaphysis Distal epiphysis Femur 7 D. Microscopic Structure 1. Bone cells (osteocytes) are located within lacunae that lie in concentric circles around central (Haversian) canals. 2. Osteocytes pass nutrients and gasses in the matrix via canaliculi. 3. Extracellular matrix of bone consists mainly of collagen and inorganic salts. 8 Fig05.19 Copyright ©The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Osteon Lamella Central canal Lacuna Canaliculi ©The McGraw-Hill Companies, Inc./Dennis Strete, photographer (a) (b) ©Prof. P. Motta/Univ."La Sapienza"/Photo Researchers (c) 9 4. In compact bone, osteocytes and extracellular matrix layers are organized into osteons (Haversian systems) that are cemented together. 5. Central canals contain blood vessels and nerve fibers, and extend longitudinally through bone. 6. Central canals are interconnected by transverse perforating (Volkmann’s) canals. 7. Unlike compact bone, spongy bone is made of osteocytes and extracellular matrix that lie within trabeculae. 10 Fig07.03 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Osteon t c Central canal ne pa bo om containing blood C Endosteum vessels and nerves ne gy bo pon Periosteum S Nerve Blood Pores Central vessels canal Perforating canal Compact Nerve bone Blood vessels Nerve Trabeculae Bone matrix Canaliculus Osteocyte Lacuna (space) 11 Bone Development and Growth A. Bones form by replacing connective tissues in the fetus. B. Some form within sheetlike layers of connective tissue (intramembranous bones), while others replace masses of cartilage (endochondral bones). C. Intramembranous Bones 1. The broad, flat bones of the skull form as intramembranous bones 2. Osteoblasts deposit a bony matrix around themselves. 12  3. Once the deposited bony matrix completely surrounds the osteoblasts, they are then called osteocytes. 4. Cells of the membranous tissue that lie outside the developing bone give rise to the periosteum. 5. The formation of bone is referred to as ossification. 13 D. Endochondral Bones 1. Most of the bones of the skeleton fall into this category. 2. They first develop as hyaline cartilage models and are then replaced with bone. 3. Cartilage is broken down in the diaphysis and progressively replaced with bone while the periosteum develops on the outside. 4. Disintegrating cartilage is invaded by blood vessels and osteoblasts that first form spongy bone at the primary ossification center in the diaphysis. 14 5. Osteoblasts from the periosteum lay down compact bone around the primary ossification center. 6. Secondary ossification centers appear later in the epiphyses. 7. A band of hyaline cartilage, the epiphyseal plate, forms between the two ossification centers. 8. Layers of cartilage cells undergoing mitosis make up the epiphyseal plate. 9. Osteoclasts break down the calcified matrix and are replaced with bone- building osteoblasts that deposit bone in place of calcified cartilage. 15 10. Increases in thickness are due to intramembranous ossification underneath the periosteum, while epiphyseal plates are responsible for lengthening bones. 11. The medullary cavity forms in the diaphysis due to the activity of osteoclasts. 16 Fig07.05 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Articular Remnants of cartilage Secondary Epiphyseal ossification plates Cartilaginous Developing Compact bone center model periosteum developing Spongy bone Epiphyseal plates Blood Medullary Medullary Medullary vessel cavity cavity cavity Compact bone Remnant of Epiphyseal Epiphyseal Calcified Primary plate plate cartilage Ossification Secondary Spongy center Ossification bone center Articular cartilage (a) (b) (c) (d) (e) (f) Major stages (a-d fetal, e child, f adult) in the development of an endochondral bone 18 E. Homeostasis of Bone Tissue 1. Osteoclasts tear down and osteoblasts build bone throughout the lifespan with the processes of resorption and deposition, with an average of 3% to 5% of bone calcium exchanged each year. 19 Bone Function A. Support and Protection 1. Bones give shape to the head, face, thorax, and limbs. 2. Bones such as the pelvis and lower limbs provide support for the body’s weight. 3. Bones of the skull protect the eyes, ears, and brain. 20 B. Body Movement 1. Bones can act as levers. a. A lever has four components: a rigid bar or rod, a pivot or fulcrum, an object that is moved against resistance, and a force that supplies energy. 21 Fig07.07 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Forearm Mo vem movement en t Biceps brachii contracting muscle Force Radius Relaxed (a) muscle Fulcrum Resistance Relaxed muscle Triceps brachii Ulna contracting muscle nt eme Force Fulcrum Mov Resistance (b) 22 C. Blood Cell Formation 1. Blood cells begin to form through hematopoieses in the yolk sac; they are later manufactured in the liver and spleen and then finally formed in the bone marrow. 23 2. Two kinds of marrow occupy the medullary cavities and the larger central canals of bone. a. Red marrow occupies the spongy bone of the skull, ribs, sternum, clavicles, vertebrae, and pelvis in adults. It function in the formation of red blood cells, white blood cells, and platelets. Its color comes from the O2 carrying pigment hemoglobin. b. Yellow marrow stores fat and occupies most cavities of bone in adults. 24 D. Storage of Inorganic Salts 1. The extracellular matrix of bone is rich in calcium salts mainly in the form of calcium phosphate that is important in many metabolic processes. 2. Calcium in bone is a reservoir for body calcium; when blood levels are low, osteoclasts release calcium from bone under the influence of the parathyroid hormone. 25  3. Calcium is stored in bone under the influence of calcitonin when blood levels of calcium are high. 4. Bone also stores magnesium, sodium, potassium, and carbonate ions. 5. Bones can also accumulate harmful metallic elements, such as lead, radium, and strontium. 26 Fig07.08 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Control center Thyroid gland releases calcitonin. Receptors Effectors Cells in the thyroid Osteoblasts deposit gland sense the calcium in bones. increase in blood calcium. Stimulus Response Blood calcium Blood calcium level increases. level is returned toward normal. too high Normal blood calcium level too low Stimulus Response Blood calcium Blood calcium level decreases. level is returned to normal. Receptors Effectors Cells in the parathyroid Osteoclasts break gland sense the down bone to release decrease in blood calcium. calcium. Control center Parathyroid glands release parathyroid hormone. 27 Skeletal Organization A. The axial skeleton consists of the bony and cartilaginous parts that support the and protect the head, neck and trunk. (Skull, hyoid bone, vertebral column, & thoracic cage) B. The appendicular skeleton consists of the bones of the upper and lower limbs and the bones that anchor the limbs to the axial skeleton. (pectoral girdle, upper limbs, pelvic girdle, & lower limbs) 29 Fig07.09 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cranium Skull Face Hyoid Clavicle Scapula Sternum Humerus Ribs Vertebral Vertebral column column Hip bone Carpals Radius Sacrum Ulna Coccyx Femur Metacarpals Phalanges Patella Tibia Fibula Tarsals Metatarsals Phalanges (a) (b) 30 Skull A. The skull is made up of 22 bones: 8 cranial bones, 13 facial bones, and the mandible. B. The Cranium encloses and protects the brain, provides attachments for muscles, and contains air-filled paranasal sinuses that reduce its weight and increase vocal resonance. 1. The frontal bone features include the supraorbital foramen and the frontal sinuses. 31 Fig07.10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Parietal bone Frontal bone Coronal suture Lacrimal bone Ethmoid bone Squamous suture Supraorbital foramen Sphenoid bone Temporal bone Nasal bone Sphenoid bone Perpendicular plate of the ethmoid bone Middle nasal concha of the ethmoid bone Infraorbital foramen Zygomatic bone Inferior nasal concha Vomer bone Maxilla Mandible Mental foramen 32 Fig07.11 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal sinus Ethmoidal sinuses Sphenoidal sinus Maxillary sinus 33 2. Parietal bones lie at the sides of the skull, just behind the frontal bone. They join along the midline sagittal suture and meet the frontal bone along the coronal suture. 3. The occipital bone forms the back of the skull and the base of the cranium. Features include the lambdoid suture, foramen magnum, and occipital condyles. 34 4. The temporal bones form parts of the sides and base of the cranium. Features include the squamous suture, external auditory meatus, mandibular fossae, mastoid process, styloid process, and zygomatic process. 5. The sphenoid bone helps form the base of the cranium, sides of the skull and portions of the orbits. Features include the sella turcica and sphenoidal sinuses. 35  6. The ethmoid bone is located in front of the spenoid bone. Features include the cribriform plates, crista galli, a perpendicular plate, superior and middle nasal conchae, and ethmoidal sinuses. 36 C. Facial Skeleton has 13 immovable bones and a movable lower jawbone which forms the basic shape of the face and provide attachments for muscles that move the jaw and control facial expressions. 1. The maxillae form the upper jaw, hard palate, floor of the orbits, sides of the nasal cavity, house the upper teeth, and contain large maxillary sinuses. Features include the hard palate, maxillary sinuses, palatine and alveolar processes, and alveolar arch. 37 2. Palatine bones are L-shaped bones located behind the maxillae that form the floor & lateral walls of the nasal cavity and the posterior portion of the hard palate. 3. Zygomatic bones form the cheekbones and lateral walls of the orbits. Features include the temporal and zygomatic processes, which form the zygomatic arch. 4. The lacrimal bones form part of the medial walls of the orbits. 5. Nasal bones form the bridge of the nose. 38  6. The vomer bone makes up a portion of the nasal septum. 7. Inferior nasal conchae are fragile, scroll-shaped bones that support mucous membranes in the nasal cavity. 8. The mandible, or lower jawbone, supports the lower teeth and includes the mandibular condyle, coronoid process, and alveolar arch. 39 Fig07.12 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Parietal bone Frontal bone Squamous suture Sphenoid bone Lambdoid suture Ethmoid bone Occipital bone Lacrimal bone Nasal bone Temporal bone Zygomatic bone External acoustic meatus Temporal process of zygomatic bone Mastoid process Maxilla Mandibular condyle Styloid process Mental foramen Zygomatic process of temporal bone Mandible Coronoid process 40 Fig07.13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Palatine process of maxilla Zygomatic bone Frontal bone Palatine bone Sphenoid bone Zygomatic arch Vomer bone Mandibular fossa Styloid process External acoustic meatus Occipital condyle Foramen magnum Lambdoid suture Temporal bone Occipital bone 41 Fig07.14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Crista galli Ethmoid Cribriform plate bone Frontal bone Sphenoid bone Sella turcica Temporal bone Parietal bone Foramen magnum Occipital bone 42 Fig07.15 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Temporal bone Parietal bone Frontal bone Squamous suture Sphenoid bone Frontal sinus Lambdoid suture Nasal bone Occipital bone Crista galli Internal acoustic meatus Cribriform plate Ethmoid bone Perpendicular plate (nasal septum) Sella turcica Inferior nasal concha Palatine process of maxilla Styloid process Foramen magnum Maxilla Sphenoidal sinus Mastoid process Palatine bone Vomer bone Mandible Alveolar processes 43 D. Infantile Skulls are not completely developed and have fontanels (soft spots) that are membranous areas of incomplete intramembranous ossification. 44 Fig07.16 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior fontanel Coronal suture Frontal bone Parietal bone Nasal bone Posterior fontanel Occipital bone Zygomatic bone Maxilla Mastoid fontanel (posterolateral Sphenoid bone fontanel) Mandible Temporal bone Sphenoid fontanel (a) (anterolateral fontanel) Frontal suture (metopic suture) Frontal bone Anterior fontanel Sagittal suture Posterior fontanel (b) 45 Vertebral Column A. The vertebral column is composed of bony vertebrae separated by fibrocartilagenous intervertebral discs, connected together by ligaments and extends from the skull to the pelvis. It supports the head and trunk and protects the spinal cord that passes through its vertebral canal. B. A typical vertebrae consists of a body, pedicles, laminae, spinous process, vertebral foramen, transverse process, superior and inferior processes and a intervertebral foramina. 47 Fig07.17 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cervical Cervical curvature vertebrae Spinous process Rib facet Thoracic Thoracic vertebrae curvature Intervertebral discs Intervertebral foramina Lumbar Lumbar vertebrae curvature Sacrum Sacral curvature Coccyx 48 C. Cervical Vertebrae 1. These seven bones are the smallest of the vertebrae that comprise the neck and support the head and have distinctive transverse foramina. 2. The first vertebra is the atlas, supports the head. It has two facets that articulate with the occipital condyles. 3. The second vertebra is the axis, with its, tooth-like dens that pivots within the atlas. 4. Features that separate cervical 49 D.Thoracic Vertebrae 1. Twelve thoracic vertebrae articulate with the ribs and are larger and stronger than the cervical vertebrae. E. Lumbar Vertebrae 1. The five massive lumbar vertebrae support the weight of the body and are located in the small of the back. 50 Fig07.18 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Bifid spinous process Vertebral foramen Lamina Superior articular facet Transverse foramen Body Transverse process (a) Cervical vertebra Spinous process Lamina Transverse process Facet that articulates with rib tubercule Superior articular facet Pedicle Vertebral foramen Facet that articulates Body with rib head (b) Thoracic vertebra Spinous process Lamina Superior articular process Transverse process Pedicle Vertebral foramen Body (c) Lumbar vertebra 51 Fig07.19 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Posterior Facet that articulates with occipital condyle Vertebral foramen Transverse process Facet that articulates Transverse Anterior with dens (odontoid process) foramen of axis Atlas (a) Anterior articular facet for atlas Dens Spinous process Spinous process Superior articular facet Transverse foramen Body Inferior articular process Transverse process Dens (odontoid Axis (b) (c) process) 52 F. Sacrum 1. The sacrum is a triangular structure at the base of the vertebral column made up of five vertebrae fused together into one bone. 2. Features include a ridge of tubercles, posterior sacral foramina, sacral canal, sacral hiatus and four pairs of anterior sacral foramina. E. Coccyx 1. The coccyx is the lowest part of the vertebral column and is typically composed of four 53 fused vertebrae Fig07.20 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sacral promontory Superior articular process Sacral canal Auricular surface Sacrum Tubercle of median sacral crest Posterior sacral foramen Sacral hiatus Anterior sacral foramen Coccyx (a) (b) 54 Thoracic Cage A. The thoracic cage includes the ribs, thoracic vertebrae, sternum, and costal cartilages. B. It supports the pectoral girdle and upper limbs, protects the viscera in the thoracic and abdominal cavities and plays a role in breathing. 55 C. Ribs normally humans have 12 pairs that attach to the thoracic vertebrae. 1. The first seven pairs of ribs are true (or vertebrosternal) ribs that join the sternum directly by their costal cartilages. 2. The remaining five pairs are false ribs because that do not reach the sternum directly. The first three pairs join the cartilages of the seventh rib, and the last two pairs are floating ribs, because they have no cartilaginous rib attachments. 56  3. Features of a typical rib include a shaft, head, and tubercle. a. The head articulates with the vertebra facet and the tubercle articulates with the transverse process of the vertebrae. D. Sternum (breastbone) is located along the anterior midline of the thoracic cage. 1. Its features include an upper manubrium, middle body, and lower xiphoid process. 57 Fig07.21 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1 Thoracic vertebra 2 Clavicular notch Manubrium 3 Trueribs 4 (vertebrosternal ribs) 5 Sternum Body 6 7 Xiphoid process 8 Ribs Vertebrochondral 9 False ribs Costal ribs cartilage 10 11 12 Floating ribs (vertebralribs) 58 Pectoral Girdle A. The pectoral girdle makes an incomplete ring that supports the upper limbs and is composed of two scapulae and two clavicles. B. The clavicles are elongated S-shaped bones located at the base of the neck that function to brace the scapulae. 59 Fig07.22 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Acromion Acromial end Clavicle process Sternal end Head of humerus Acromion process Head of Coracoid humerus rocess Coracoid process Sternum Humerus Rib Costal Scapula Rib cartilage Humerus Courtesy Eastman Kodak Ulna Radius 60 C. The scapulae (shoulder blades) are broad, triangular bones on either side of the upper back. 1. A spine divides the posterior scapula into unequal portions. 2. The spine has two processes, an acromion process (articulates with clavicle) and a coracoid process (provides attachments for limb and chest muscles). 3. The glenoid cavity articulates with the head of the humerus. 61 Fig07.23 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior border Coracoid process Suprascapular Acromion notch process Acromion Coracoid process process Spine Glenoid Glenoid cavity cavity Supraspinous Latera fossa (axillaryl border) Infraspinous fossa Medial (vertebral border) (a) (b) (c) 62 Upper Limb A. Bones of the upper limb form the framework for the arm, forearm, and hand. They also provide for muscle attachments and they function in levers to move limb parts. 63  B. The humerus is a long bone extending from the scapula to the elbow. 1. It articulates with the scapulae at its head, with the radius at the capitulum, and with the ulna at the trochlea. 2. Other features include the greater and lesser tubercles, intertubercular groove, anatomical and surgical necks, deltoid tuberosity, two condyles (capitulum & trochanter) epicondyles, coronoid fossa, and olecranon fossa. 64 Fig07.24 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Greater tubercle Head Greater tubercle Anatomical Intertubercular neck groove Surgical Lesser tubercle neck Deltoid tuberosity Coronoid Olecranon fossa fossa Lateral Lateral epicondyle Medial epicondyle epicondyle Capitulum Trochlea (a) (b) 65 C. The radius is located on the thumb side of the forearm, extending from the elbow to the wrist. 1. The flattened head of the radius pivots with the humerus. 2. Other features of the radius include the radial tuberosity and styloid process. 66 D. The ulna is the longer of the two bones making up the forearm and has a trochlear notch that articulates with the humerus. 1. Other features include the olecranon process, coronoid process, head, and styloid process. 67 Fig07.25 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Trochlear notch Olecranon process Coronoid process Head of radius Olecranon process Radial tuberosity Trochlear notch Coronoid process Radial notch Radius (b) Ulna Head of ulna Styloid process Styloid process Ulnar notch of radius (a) 68 E. The hand is made up of the wrist, palm, and fingers. 1. The wrist of the hand is made up of eight carpal bones bound into a carpus. 2. The framework of the hand is made up of five metacarpal bones. 3. The fingers are composed of three phalanges in each finger except the thumb, which lacks the middle phalanx. 69 Fig07.26 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Radius Scaphoid Ulna Scaphoid Lunate Capitate Capitate Hamate Trapezoid Trapezoid Triquetrum Trapezium Trapezium Pisiform Carpals (carpus) 1 1 Metacarpals 5 5 2 4 2 (metacarpus) 3 4 3 Proximal phalanx Middle Phalanges phalanx Distal phalanx 70 (a) (b) Pelvic Girdle A. The pelvic girdle consists of the two hip (innominate) bones; it supports the trunk of the body on the lower limbs, provides attachments for the lower limbs and protect the organs within it. B. The pelvis is the sacrum, coccyx and pelvic girdle al together. 71 Fig07.27 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hip bones Sacrum Pubic symphysis Obturator foramen Femur ©Martin Rotker (b) (a) 72 C. Each hip bone is made up of three bones: ilium, ischium, and pubis. These bones are fused in the region of the acetabulum, the cuplike depression that articulates with the head of the femur. D. The ilium is the largest and upper-most portion of the hip bone. Features include the iliac crest, sacroiliac joint, and the anterior superior iliac spine 73 E. The ischium forms the L-shaped portion that supports weight during sitting. Features include the ischial tuberosity and ischial spine. F. The pubis constitutes the anterior portion of the hip bones and join at the pubic symphysis. Additional features include the pubic arch, obturator foramen, and pubic brim. G. Refer to Table 7.3 for differences between the female and male skeletons 74 Fig07.28 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Iliac crest Iliac fossa Iliac crest Anterior superior iliac spine Posterior Ilium Ilium superior Anterior iliac spine inferior iliac spine Posterior Inferior iliac spine Obturator foramen Acetabulum Greater sciatic notch Obturator Ischium Ischial spine foramen Pubis Ischium Lesser sciatic notch Pubis Ischial tuberosity (a) (b) 75 Fig07.29 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Flared ilium Sacral promontory Pelvic brim Pubic symphysis (a) Pubic arch Sacral promontory Sacral curvature (b) Pubic arch 76 Lower Limb A. The bones of the lower limb provide the framework for the thigh, lower leg, and foot. B. The femur, or thighbone, extends from the hip to the knee and is the longest bone in the body. 1. Its head joins with the acetabulum; it also joins with the tibia at the medial and lateral condyles. 77  3. Other features of the femur include the fovea capitis, neck, and greater and lesser trochanters. C. The patella (kneecap) is located in the tendon that passes over the knee. 78 Fig07.30 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fovea capitis Neck Head Greater trochanter Gluteal tuberosity Lesser trochanter Linea aspera Lateral Medial epicondyle epicondyle Medial Lateral condyle condyle Intercondylar fossa Patellar (a) surface (b) 79  D. The tibia (shinbone) supports the weight of the body and articulates with the femur (medial and lateral condyles) and with the tarsal bones of the foot. 1. Its anterior tibial tuberosity is the point of attachment for the patellar ligament. 2. Other features include the medial malleolus (inner ankle). 80  E. The fibula is a slender bone lying lateral to the tibia; it does not bear body weight. 1. Features include the head and a distal lateral malleolus (outer ankle). 81 Fig07.31 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Intercondylar eminence Lateral Medial condyle condyle Tibial Head of tuberosity fibula Anterior crest Fibula Tibia Medial malleolus Lateral malleolus 82 F. The foot is made up of the ankle, the instep and the toes. 1. The ankle (tarsus) is composed of seven tarsal bones. a. The talus articulates with the tibia and fibula. b. The calcaneus (heel bone) supports the body weight. 83  2. The instep (metatarsus) of the foot consists of five metatarsal bones and provides an arch. 3. Each toe is made up of three phalanges, with the exception of the great toe, which lacks a middle phalanx. 84 Fig07.32 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fibula Tibia Talus Medial Navicular Metatarsals cuneiform (metatarsus) Calcaneus Phalanges Tarsals (tarsus) 85 Fig07.33 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Calcaneus Talus Tarsals (tarsus) Navicular Cuboid Lateral cuneiform Intermediate cuneiform Medial cuneiform 5 4 3 Metatarsals 2 1 (metatarsus) Proximal phalanx Middle phalanx Distal phalanx Phalanges 86 Joints A. Joints (articulations) are the functional junctions between bones. B. Joints enable a wide variety of body movements. C. Joints can be classified according to the degree of movement possible and can be immovable, slightly movable, or freely movable. D. Joints can also classified according to the type of tissue that binds them together. (more commonly used today) 87 E. Fibrous joints are held close together by dense connective tissue and are immovable (sutures of skull) or only slightly movable (joint between the distal tibia and fibula). 88 Fig07.34 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (a) Connective tissue (b) 89 F. Cartilaginous Joints are connected by either hyaline or fibrocartilage. 1. Intervertebral disks between vertebrae help absorb shock and are slightly movable. 2. Other examples of cartilaginous joints include the pubic symphysis and the first rib with the sternum. 90 G. Synovial Joints 1. Most joints of the skeleton are synovial joints, which are more complex than fibrous or cartilaginous joints. 2. The articular ends of bone in a synovial joint are covered with hyaline cartilage. 91 Fig07.35 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spongy bone Joint capsule Joint cavity Articular filled with cartilage synovial fluid Synovial membrane 92 3. A joint capsule consists of an outer layer of dense connective tissue that joins the periosteum, and an inner layer made up of synovial membrane. a. Synovial fluid has the consistency of egg whites enabling it to lubricate joints. 4. Some synovial joints contain shock absorbing pads of fibrocartilage called menisci. 5. Some synovial joints have fluid- filled sacs called bursae. 93 Fig07.36 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Femur Synovial membrane Suprapatellar bursa Patella Prepatellar bursa Subpatellar fat Articular cartilage Menisci Infrapatellar bursa Tibia 94 6. Based on the shapes of their parts and the movements they permit, synovial joints can be classified as follows: a. A ball-and-socket joint consists of a bone with a globular or egg- shaped head articulating with the cup-shaped cavity of another bone; a very wide range of motion is possible; examples include the shoulder and hip joints. 95 b. A condylar joint consists of an ovoid condyle fitting into an elliptical cavity, permitting a variety of motions; an example is the joint between a metacarpal and a phalange. c. Plane joints or Gliding joints occur where articulating surfaces are nearly flat or slightly curved, allowing a back- and-forth motion; the joints of the wrist and ankle, as well as those between vertebrae, are gliding joints. 96  d. In a hinge joint, a convex surface fits into a concave surface, as is found in the elbow and phalange joints; movement is in one plane only. e. In a pivot joint, a cylindrical surface rotates within a ring of bone and fibrous tissue; examples include the joint between the proximal ends of the radius and ulna. 97  f. A saddle joint forms where articulating surfaces have both concave and convex areas, permitting a wide range of movements; the joint between the trapezium and the metacarpal of the thumb is of this type. 98 Fig07.37 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Hip bone Head of femur Metacarpal in acetabulum Femur Phalanx (a) Ball-and-socket joint (b) Condylar joint Humerus Radius Carpals Ulna (c) Plane joint (d) Hinge joint Dens Transverse ligament First metacarpal Atlas Axis Trapezium (e) Pivot joint (f) Saddle joint 99 H. Types of Joint Movements 1. When a muscle contracts, its fibers pull its movable end (insertion) toward its stationary end (origin), causing movement at a joint. 2. These terms describe movements that occur at joints: flexion, extension, dorsiflexion, plantar flexion, hyperextension, abduction, adduction, rotation, circumduction, pronation, supination, eversion, inversion, retraction, protraction, elevation, and depression. 100 Fig07.38 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Hyperextension Hyperextension Extension E n Flexionn Flexion Abduction Extension Adduction Dorsiflexion Plantar flexion ©The McGraw-Hill Companies, Inc./Womack Photography, Ltd.; Plates 8-11: ©McGraw-Hill Higher Education, Inc./Jim Womack 101 Fig07.39 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Circumduction Supination Medial Pronation Lateral rotation rotation 102 ©The McGraw-Hill Companies, Inc./Womack Photography, Ltd.; Plates 8-11: ©McGraw-Hill Higher Education, Inc./Jim Womack Fig07.40 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Inversion Eversion Protraction Retraction Elevation Depression 103 ©The McGraw-Hill Companies, Inc./Womack Photography, Ltd.; Plates 8-11: ©McGraw-Hill Higher Education, Inc./Jim Womack