Chapter 7: Skeletal System (PDF) - Hole's Essentials of Human Anatomy & Physiology

Because learning changes everything.® Chapter 07 Skeletal System HOLE’S ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY Fifteenth Edition Charles J. Welsh and Cynthia Prentice-Craver © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent o...

Because learning changes everything.® Chapter 07 Skeletal System HOLE’S ESSENTIALS OF HUMAN ANATOMY & PHYSIOLOGY Fifteenth Edition Charles J. Welsh and Cynthia Prentice-Craver © McGraw Hill LLC. All rights reserved. No reproduction or distribution without the prior written consent of McGraw Hill LLC.  7.1: Introduction to the Skeletal System “Skeleton” is derived from Greek and Latin words, meaning “dried framework” The skeletal system is strong enough for weight-bearing yet light enough for movement Bones are very active, living tissues, containing nerves and blood The skeletal system consists of bones, tendons, ligaments and cartilage, which function together in the joints Bone functions: muscle attachment, protection and support of soft tissues, blood cell production, and storage of inorganic salts, bear weight and allow movement There are 2 divisions of the skeletal system: the axial and appendicular skeleton © McGraw Hill, LLC 2  7.2: Bone Structure Classification of bones according to shape: Long bones: long with expanded ends; examples: arm and leg bones Short bones: almost equal in length and width; examples: bones of the wrist and ankles Sesamoid (round) bones: small, nodular bones that develop within a tendon; special type of short bone; example: patella Flat bones: plate-like shape with broad surface; examples: ribs, scapula, flattened skull bones Irregular bones: varied shape; examples: vertebrae, some facial bones © McGraw Hill, LLC 3  Structure of a Long Bone 1 Expanded ends of bones that form joints with adjacent bones are called epiphyses Articular cartilage (hyaline cartilage) covers the epiphyses The shaft of the bone is called the diaphysis The epiphyseal (growth) plate is an area of cartilage in which a bone grows in length; it lies between the epiphyses and diaphysis A tough layer of dense connective tissue, called the periosteum, covers the bone, and is continuous with ligaments and tendons The diaphysis contains a hollow chamber called the medullary cavity The medullary cavity is lined with a thin layer of cells called the endosteum The medullary cavity is filled with a special type of connective tissue called bone marrow © McGraw Hill, LLC 4  Structure of a Long Bone 2 A bone's shape makes its function possible Bony processes (projections) provide attachment sites for tendons and ligaments, openings or grooves for blood vessels and nerves, and depressions for articulation (forming a joint with another bone) Compact bone is a very tightly packed tissue, which makes up the wall of the diaphysis The epiphyses are filled with spongy bone, which reduces the weight of the skeleton Spongy (cancellous) bone consists of many branching bony plates called trabeculae © McGraw Hill, LLC 5  Figure 7.1: Structure of a Long Bone Access the text alternative for these images © McGraw Hill, LLC 6  Figure 7.2: Cross Section of a Long Bone Ed Reschke Access the text alternative for these images © McGraw Hill, LLC 7  Microscopic Structure of Bone Tissue 1 Bone cells, called osteocytes, are located within chambers called lacunae In compact bone, lacunae lie in concentric circles of matrix called lamellae Lamellae are deposited around a cylindrical tube called a central (Haversian) canal; central canals contain blood vessels and nerves Osteocytes pass nutrients and gases through the matrix via tiny canals called canaliculi Extracellular matrix of bone consists mainly of collagen and inorganic salts: Collagen provides strength and resilience Inorganic salts (mostly calcium phosphate) provides hardness and resistance to crushing © McGraw Hill, LLC 8  Microscopic Structure of Bone Tissue 2 In compact bone, osteocytes and extracellular matrix layers are organized into osteons (Haversian systems) that are cemented together Central canals contain blood vessels and nerve fibers, and extend longitudinally through the bone tissue Central canals of adjacent osteons are interconnected by transverse perforating (Volkmann’s) canals; these help osteons share blood supply and nerves Unlike compact bone, spongy bone is made of osteocytes and extracellular matrix that lie within trabeculae © McGraw Hill, LLC 9  Figure 7.3: Compact and Spongy Bone Access the text alternative for these images © McGraw Hill, LLC 10  7.3: Bone Function Support and protection: Bones give shape to the head, face, thorax, and limbs Bones such as the pelvis and lower limbs provide support for the body’s weight Bones of the skull protect the eyes, ears, and brain Bones of the rib cage and shoulder girdle protect the heart and lungs Bones of the pelvic girdle protect lower abdominal and reproductive organs Movement: Bones act with muscles to cause movement of limbs and other body parts © McGraw Hill, LLC 11  Bone Function 1 Blood cell formation (hematopoiesis): Blood cell formation begins in the yolk sac during embryonic development They are later manufactured in the liver and spleen, and then finally in the bone marrow Two kinds of bone marrow occupy the medullary cavities and the larger central canals of bone: Red marrow occupies the spongy bone of the skull, ribs, sternum, clavicles, vertebrae, and pelvis in adults. Functions in formation of red blood cells, white blood cells, & platelets. Color comes from the O2 - carrying pigment hemoglobin. Yellow marrow stores fat and occupies most cavities of bone in adults © McGraw Hill, LLC 12  Bone Function 2 Storage of inorganic salts: Extracellular matrix of bone is rich in calcium salts, mainly calcium phosphate Calcium is important in many metabolic processes, such as muscle contraction, nerve impulse conduction, and blood clotting Calcium in bone is a reservoir for body calcium When blood levels of calcium are low, osteoclasts release calcium from bone under the influence of the parathyroid hormone When blood calcium is too high, osteoclasts are inhibited, and osteoblasts are stimulated to deposit bone matrix by the hormone calcitonin Bone also stores magnesium, sodium, potassium, & carbonate ions Bones can also accumulate harmful metallic elements, such as lead, radium, and strontium © McGraw Hill, LLC 13  Figure 7.4: Calcium Homeostasis: Hormonal Regulation Access the text alternative for these images © McGraw Hill, LLC 14  7.4: Bone Development, Growth, & Repair Bones form by replacing existing connective tissues in the fetus There are 2 methods of connective tissue replacement: Intramembranous bones originate within sheet-like layers of connective tissue Endochondral bones form from a hyaline cartilage model Formation of bone from connective tissue is called ossification © McGraw Hill, LLC 15  Figure 7.5: Ossification in a 14-Week Fetus Biophoto Associates/Science Source Access the text alternative for these images © McGraw Hill, LLC 16  Intramembranous Bones Intramembranous bones develop from sheet-like layers of undifferentiated connective tissue The broad, flat bones of the skull form as intramembranous bones Some progenitor cells differentiate into osteoblasts, bone-forming cells Osteoblasts deposit a bony matrix around themselves in all directions, forming spongy bone Once the osteoblasts have encased themselves with matrix, they are called osteocytes Cells of the membranous tissue that lie outside the developing bone give rise to the periosteum Osteoblasts on the inside of the periosteum form a layer of compact bone over the spongy bone © McGraw Hill, LLC 17  Endochondral Bones 1 Endochondral bones develop as hyaline cartilage models shaped like the future bones; the cartilage is then replaced with bone tissue Most of the bones of the skeleton fall into this category Cartilage is first broken down in the diaphysis, and progressively replaced with bone, while the periosteum develops on the outside Disintegrating cartilage is invaded by blood vessels and osteoblasts that first form spongy bone at the primary ossification center in the diaphysis Osteoblasts from the periosteum lay down compact bone around the primary ossification center Secondary ossification centers appear later in the epiphyses A band of hyaline cartilage, the epiphyseal plate, remains between the two ossification centers Layers of cartilage cells undergoing mitosis make up the epiphyseal plate; this will be a growth area for the bone to increase in length © McGraw Hill, LLC 18  Endochondral Bones 2 Bone-resorbing cells, called osteoclasts, break down the calcified matrix Bone-building cells, called osteoblasts, then deposit bone in place of calcified cartilage A long bone continues to lengthen while the cartilaginous cells of the epiphyseal plate are active; once the plate ossifies, the bone can no longer grow in length As compact bone is deposited on the outside of the developing bone, the medullary cavity forms in the diaphysis, as osteoclasts erode the bone on the inside Medullary cavity eventually fills with bone marrow, which produces blood cells © McGraw Hill, LLC 19  Figure 7.6: Development of an Endochondral Bone Access the text alternative for these images © McGraw Hill, LLC 20  Figure 7.7: Epiphyseal Plates in a Child’s Hand Ed Reschke/Getty Images Access the text alternative for these images © McGraw Hill, LLC 21  Homeostasis of Bone Tissue Osteoclasts resorb and osteoblasts deposit bone throughout life, in a process called bone remodeling An average of 3% to 5% of bone calcium is exchanged each year The remodeling process is controlled by hormones that regulate blood calcium levels © McGraw Hill, LLC 22  Factors Affecting Bone Development, Growth, & Repair Nutrition: vitamin D is needed for calcium absorption Hormonal secretions: Growth hormone: stimulates division of cartilage cells of the epiphyseal plate Sex hormones: stimulate ossification of the epiphyseal plates to end growth in height Physical exercise: when muscles pull on bones at their attachment sites, it stresses the bone, which will cause it to increase in thickness and strength © McGraw Hill, LLC 23  7.5: Skeletal Organization The skeleton can be organized into 2 major portions: the axial skeleton and the appendicular skeleton The axial skeleton consists of the bony and cartilaginous parts that support the and protect the head, neck and trunk: Skull: cranium and facial bones Hyoid bone: supports the tongue and aids in swallowing Vertebral column Thoracic cage: ribs and sternum © McGraw Hill, LLC 24  Skeletal Organization 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: clavicle and scapula Upper limbs: humerus, ulna, radius, carpals, metacarpals, and phalanges Pelvic girdle: 2 hip bones Lower limbs: femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges © McGraw Hill, LLC 25  Figure 7.8: Major Bones of the Skeleton Access the text alternative for these images © McGraw Hill, LLC 26  Bones of the Adult Skeleton TABLE 7.1 Bones of the Adult Skeleton 1. Axial Skeleton 2. Appendicular Skeleton a. Skull temporal 2 a. Pectoral girdle 8 cranial bones sphenoid 1 scapula 2 frontal 1 ethmoid 1 clavicle 2 4 bones parietal 2 occipital 1 lacrimal 2 b. Upper limbs 14 facial bones nasal 2 humerus 2 maxilla 2 vomer 1 radius 2 zygomatic 2 ulna 2 palatine 2 22 bones carpal 16 inferior nasal concha 2 metacarpal 10 mandible 1 phalanx 28 b. Middle ear bones malleus 2 c. Pelvic girdle incus 2 coxal (hip) bone 2 2 bones stapes 2 6 bones d. Lower limbs c. Hyoid femur 2 hyoid bone 1 1 bone tibia 2 fibula 2 d. Vertebral column patella 2 cervical vertebra 7 tarsal 14 thoracic vertebra 12 metatarsal 10 lumbar vertebra 5 phalanx 28 sacrum 1 coccyx 1 60 bones 26 bones Total 206 bones e. Thoracic cage rib 24 sternum 1 25 bones © McGraw Hill, LLC 27  Terms Used to Describe Skeletal Structures 1 TABLE 7.2 Terms Used to Describe Skeletal Structures Term Definition Examples Condyle (kon'dīI) Rounded process that usually Occipital condyle of the occipital bone (fig. articulates with another bone 7.12) Crest (krest) Narrow, ridgelike projection Iliac crest of the ilium (fig. 7.27) Epicondyle (ep"ĭ- Projection situated above a Medial epicondyle of the humerus (fig. kon'dīI) condyle 7.23) Facet (fas'et) Small, nearly flat surface Costal facet of the thoracic vertebra (fig. 7.16) Fontanel (fon"tah-nel') Soft spot in the skull where Anterior fontanel between the frontal and membranes cover the space parietal bones (fig. 7.15) between bones Foramen (fo-ra'men) Opening through a bone that Foramen magnum of the occipital bone usually is a passageway for blood (fig. 7.12) vessels, nerves, or ligaments Fossa (fos'ah) Relatively deep pit or depression Olecranon fossa of the humerus (fig. 7.23) Fovea (fo've-ah) Tiny pit or depression Fovea capitis of the femur (fig. 7.29) Head (hed) Enlargement on the end of a bone Head of the humerus (fig. 7.23) © McGraw Hill, LLC 28  Terms Used to Describe Skeletal Structures 2 TABLE 7.2 Terms Used to Describe Skeletal Structures Term Definition Examples Meatus (me-a'tus) Tubelike passageway within a External acoustic meatus of the temporal bone bone (fig. 7.11) Process (pros'es) Prominent projection on a Mastoid process of the temporal bone (fig. bone 7.11) Sinus (si'nus) Cavity within a bone Frontal sinus of the frontal bone (fig. 7.14) Spine (spīn) Thornlike projection Spine of the scapula (fig. 7.22) Sulcus (sul'kus) Furrow or groove Intertubercular sulcus of the humerus (fig. 7.23) Suture (soo'cher) Interlocking line of union Lambdoid suture between the occipital and between bones parietal bones (fig. 7.11) Trochanter (tro-kan'ter) Relatively large process Greater trochanter of the femur (fig. 7.29) Tubercle (tu'ber-kl) Small, knoblike process Greater tubercle of the humerus (fig. 7.23) Tuberosity (tu"bĕ-ros'ǐ-te) Knoblike process usually Radial tuberosity of the radius (fig. 7.24) larger than a tubercle © McGraw Hill, LLC 29  7.6: Skull The skull: Made up of 22 bones: 8 cranial bones and 14 facial bones; there are also 3 bones in each middle ear Except for lower jaw, skull bones are connected by immovable joints called sutures Bones of 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. Frontal bone forms anterior part of skull, above eyes; features include the supraorbital foramen and the frontal sinuses Parietal bones form the roof and sides of the skull, just behind the frontal bone; they join along the midline at the sagittal suture, and meet the frontal bone along the coronal suture © McGraw Hill, LLC 30  The Cranium The occipital bone forms the back of the skull and the base of the cranium; features include foramen magnum, and occipital condyles; joins parietal bones at lambdoid suture The temporal bones form parts of the sides and base of the cranium; features include the external acoustic meatus, mandibular fossae, mastoid process, styloid process, and zygomatic process; connects to parietal bones at squamous suture 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 The ethmoid bone is located in front of the sphenoid bone; features include the cribriform plates, crista galli, a perpendicular plate, superior and middle nasal conchae, and ethmoidal sinus © McGraw Hill, LLC 31  Figure 7.9: Anterior View of the Skull Access the text alternative for these images © McGraw Hill, LLC 32  Figure 7.10: The Paranasal Sinuses Access the text alternative for these images © McGraw Hill, LLC 33  Facial Skeleton 1 Contains 13 immovable bones and a movable lower jawbone These bones form the basic shape of the face, and provide attachments for muscles that move the jaw and control facial expressions Bones of the Facial Skeleton: The maxillae form the upper jaw, hard palate, floor of the eye orbits, sides of the nasal cavity, house the upper teeth, and contain large maxillary sinuses; features include the maxillary sinuses, palatine and alveolar processes, and alveolar arch 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 © McGraw Hill, LLC 34  Facial Skeleton 2 Zygomatic bones form the cheekbones and lateral walls of the orbits; features include the temporal process, which joins the zygomatic process to form the zygomatic arch Lacrimal bones form part of the medial walls of the orbits Nasal bones form the bridge of the nose Vomer bone makes up a portion of the nasal septum Inferior nasal conchae are fragile, scroll-shaped bones that support mucous membranes in the nasal cavity Mandible, or lower jawbone, supports the lower teeth and includes the body, mandibular condyle, coronoid process, and alveolar arch; only movable bone in skull © McGraw Hill, LLC 35  Figure 7.11: Lateral View of the Skull Access the text alternative for these images © McGraw Hill, LLC 36  Figure 7.12: Inferior View of the Skull Access the text alternative for these images © McGraw Hill, LLC 37  Figure 7.13: Floor of the Cranial Cavity, Viewed from Above Access the text alternative for these images © McGraw Hill, LLC 38  Figure 7.14: Sagittal Section of the Skull Access the text alternative for these images © McGraw Hill, LLC 39  Infantile Skull Not completely developed at the time of birth Fibrous membranes connect cranial bones Fontanels (soft spots) are membranous areas of incomplete intramembranous ossification; allow bone movement during childbirth and brain growth As cranial bones grow together, fontanels will eventually close Infantile skull has small face, prominent forehead, large orbits Nasal cavity and jaw are small, and sinuses are not completely formed yet © McGraw Hill, LLC 40  Figure 7.15: Fontanels of the Infantile Skull Access the text alternative for these images © McGraw Hill, LLC 41  7.7: Vertebral Column Vertebral Column: Forms vertical axis of skeleton Runs from skull to pelvis It supports the head and trunk and protects the spinal cord Composed of bony vertebrae, separated by fibrocartilaginous intervertebral discs Vertebrae are connected by ligaments Structure of a Typical Vertebra: A typical vertebrae consists of a body, pedicles, laminae, spinous process, vertebral foramen, transverse processes, superior and inferior articular processes and intervertebral foramina © McGraw Hill, LLC 42  Figure 7.16: The Vertebral Column: Lateral & Posterior Views Access the text alternative for these images © McGraw Hill, LLC 43  Cervical Vertebrae 7 cervical vertebrae in the neck Support the head Unique in that they have distinctive transverse foramina in their transverse processes; they serve as passageways for blood vessels of the brain Vertebrae 2 to 6 have bifid spinous processes, which no other vertebrae have The first vertebra, atlas, supports the head; has two facets that articulate with the occipital condyles of the skull, and has no body or spinous process The second vertebra, axis, contains the tooth-like dens that pivots within the atlas © McGraw Hill, LLC 44  Figure 7.17a: Structure of a Cervical Vertebra Access the text alternative for these images © McGraw Hill, LLC 45  Figure 7.18: Atlas and Axis Access the text alternative for these images © McGraw Hill, LLC 46  Thoracic Vertebrae 12 thoracic vertebrae in the thoracic region Articulate with the ribs, and are larger and stronger than the cervical vertebrae Features include a long, pointed spinous process and facets on the side of the body to articular with the ribs Proceeding inferiorly, the bodies become larger, and are able to bear more weight © McGraw Hill, LLC 47  Figure 7.17b: Structure of a Thoracic Vertebra Access the text alternative for these images © McGraw Hill, LLC 48  Lumbar Vertebrae There are 5 lumbar vertebrae in the small of the back (loin) They support the weight of the body They are much larger and stronger than the cervical and thoracic vertebrae They are adapted for weight-bearing © McGraw Hill, LLC 49  Figure 7.17c: Structure of a Lumbar Vertebra Access the text alternative for these images © McGraw Hill, LLC 50  The Sacrum and Coccyx Sacrum: A triangular structure at the base of the vertebral column Consists of 5 fused vertebrae Features include a ridge of tubercles, posterior sacral foramina, sacral canal, sacral hiatus and 4 pairs of anterior sacral foramina Coccyx: Also called the tailbone Forms the lowest part of the vertebral column Typically composed of 4 fused vertebrae © McGraw Hill, LLC 51  Figure 7.19: The Sacrum and Coccyx Access the text alternative for these images © McGraw Hill, LLC 52  7.8: Thoracic Cage The thoracic cage consists of the ribs, thoracic vertebrae, sternum, and costal cartilages Supports the pectoral girdle and upper limbs Protects the viscera in the thoracic and upper abdominal cavities Plays a role in breathing © McGraw Hill, LLC 53  The Ribs Normally humans have 12 pairs of ribs Ribs attach to the thoracic vertebrae The superior 7 pairs of ribs are true (or vertebrosternal) ribs; these connect to the sternum directly by their costal cartilages The inferior 5 pairs are false ribs, because they do not reach the sternum directly: The upper 3 pairs (vertebrochondral ribs) join the cartilages of the 7th rib The lower 2 pairs are floating (vertebral) ribs, because they have no cartilaginous attachments to the sternum Features of a typical rib include a curved shaft, head, & tubercle The head articulates with the facet of the thoracic vertebra The tubercle articulates with the transverse process of the vertebra © McGraw Hill, LLC 54  The Sternum The sternum is also called the breastbone Located along the anterior midline of the thoracic cage Its 3 portions are an upper manubrium, middle body, and lower xiphoid process Sternum articulates with clavicles © McGraw Hill, LLC 55  Figure 7.20: The Thoracic Cage Access the text alternative for these images © McGraw Hill, LLC 56  7.9: Pectoral Girdle Pectoral girdle (shoulder girdle): Makes an incomplete ring Supports the upper limbs, and is an attachment site for muscles that move them Composed of 2 scapulae (shoulder blades) and 2 clavicles (collarbones) Clavicles (collarbones): Elongated, S-shaped bones located at the base of the neck, that function to brace the scapulae Provide attachment sites for muscles that move upper limbs, chest and back © McGraw Hill, LLC 57  Figure 7.21: The Pectoral Girdle (b): Dale Butler Access the text alternative for these images © McGraw Hill, LLC 58  Pectoral Girdle: Scapulae Scapulae (shoulder blades): Broad, triangular bones on either side of the upper back A spine divides the posterior scapula into unequal portions The spine ends with the acromion process, which articulates with clavicle; the acromion process forms the tip of the shoulder The coracoid process provides attachment sites for limb and chest muscles The glenoid cavity (fossa) articulates with the head of the humerus © McGraw Hill, LLC 59  Figure 7.22: Posterior, Lateral, and Anterior Views of the Scapula Access the text alternative for these images © McGraw Hill, LLC 60  7.10: Upper Limb Bones of the upper limb form the framework for the arm, forearm, and hand Provide for muscle attachments Function with muscles to move limb parts Bones of the upper limb: Humerus Radius Ulna Carpals Metacarpals Phalanges © McGraw Hill, LLC 61  The Humerus Humerus: A long bone extending from the scapula to the elbow Only bone of the upper arm It articulates with the scapulae at its head, with the radius at the capitulum, and with the ulna at the trochlea Other features include the greater and lesser tubercles, intertubercular sulcus, anatomical and surgical necks, deltoid tuberosity, 2 condyles (capitulum & trochlea), 2 epicondyles, coronoid fossa, and olecranon fossa © McGraw Hill, LLC 62  Figure 7.23: The Humerus: Anterior & Posterior Views Access the text alternative for these images © McGraw Hill, LLC 63  The Radius and Ulna Radius: Located on the thumb (lateral) side of the forearm, extending from the elbow to the wrist The disc-like head of the radius articulates with the capitulum of the humerus and radial notch of ulna; allows rotation of radius Other features of the radius include the radial tuberosity and styloid process Ulna: The longer of the 2 bones of the forearm, lateral to the radius Trochlear notch that articulates with the trochlea of the humerus Other features include the olecranon process, coronoid process, head, and styloid process The distal end (head) articulates with the ulnar notch of radius The ulna is on the medial side in anatomical position © McGraw Hill, LLC 64  Figure 7.24: The Radius and Ulna Access the text alternative for these images © McGraw Hill, LLC 65  The Hand Consists of the wrist, palm, and fingers The wrist is made up of 8 carpal bones, arranged into 2 rows of 4; the entire group is called the carpus The framework of the hand is made up of 5 metacarpal bones The fingers are each composed of 3 phalanges, except the thumb, which has only 2 © McGraw Hill, LLC 66  Figure 7.25: The Hand: Anterior and Posterior Views Access the text alternative for these images © McGraw Hill, LLC 67  7.11: Pelvic Girdle Consists of the 2 hip (coxal, pelvic, or innominate) bones The hip bones articulate with each other anteriorly, and with sacrum posteriorly The pelvis consists of the sacrum, coccyx and pelvic girdle Supports the trunk of the body on the lower limbs, provides attachments for the lower limbs and protects the organs within it, such as the urinary bladder, and end of large intestine © McGraw Hill, LLC 68  Figure 7.26: The Pelvic Girdle (b): Dale Butler Access the text alternative for these images © McGraw Hill, LLC 69  The Coxal Bone Each coxal bone is made up of 3 bones: ilium, ischium, and pubis Ilium: largest and upper-most portion of the hip bone; features include the iliac crest, sacroiliac joint, and the anterior superior iliac spine Ischium: forms the L-shaped, posterior portion, that supports weight during sitting; features include the ischial tuberosity and ischial spine Pubis: constitutes the anterior portion of each hip bone; the 2 pubic bones join at the pubic symphysis; other features include the pubic arch, obturator foramen, and pelvic brim These 3 bones are fused in the region of the acetabulum, the cuplike depression that articulates with the head of the femur © McGraw Hill, LLC 70  Figure 7.27: The Coxal (Hip) Bone: Medial & Lateral Views Access the text alternative for these images © McGraw Hill, LLC 71  Figure 7.28: Female and Male Pelvis Access the text alternative for these images © McGraw Hill, LLC 72  Differences Between Male & Female Pelvic Regions TABLE 7.3 Differences Between the Female and Male Pelvic Regions Part Differences Pelvic Female hip bones are lighter, thinner, and have less evidence of girdle muscular attachments. The female obturator foramina are triangular, whereas the male's are oval. The female acetabula are smaller and the pubic arch is wider than corresponding structures of a male. Pelvic Female pelvic cavity is wider in all diameters and is shorter, cavity roomier, and less funnel-shaped. The distances between the female ischial spines and ischial tuberosities are greater than in a male. Sacrum Female sacrum is wider, and the sacral curvature is bent more sharply posteriorly than in a male. Coccyx Female coccyx is more movable than that of a male. © McGraw Hill, LLC 73  7.12: Lower Limb The bones of the lower limb provide the framework for the thigh, lower leg, and foot Bones of the lower limb: Femur Tibia Fibula Patella Tarsals Metatarsals Phalanges © McGraw Hill, LLC 74  Femur The femur: Also called the thighbone Extends from the hip to the knee Longest bone in the body Head fits into the acetabulum of the hip bone Also articulates with the tibia at the medial and lateral condyles Other features include the fovea capitis, neck, and greater and lesser trochanters Patella (kneecap) articulates with the femur at distal anterior surface, and is situated in the tendon that passes anteriorly over the knee © McGraw Hill, LLC 75  Figure 7.29: Femur Access the text alternative for these images © McGraw Hill, LLC 76  The Tibia and Fibula Tibia: Also called the shinbone; weight-bearing Larger of 2 lower leg bones; found on medial side Articulates with the femur at the medial and lateral condyles, and with the talus of the ankle Its anterior tibial tuberosity is the point of attachment for the patellar ligament, the continuation of the patellar tendon Other features include the medial malleolus (inner ankle) Fibula: A slender bone lying lateral to the tibia Does not bear body weight, and is not part of the knee joint Features include the head and a distal lateral malleolus (outer ankle) © McGraw Hill, LLC 77  Figure 7.30: The Tibia and Fibula Access the text alternative for these images © McGraw Hill, LLC 78  The Foot The foot consists of the ankle, the instep and toes: Ankle (tarsus): Composed of 7 tarsal bones The talus articulates with the tibia and fibula The calcaneus (heel bone) supports the body weight Instep (metatarsus): Consists of 5 long metatarsal bones Distal heads form ball of foot Forms arches of foot, along with the tarsals Toes: Each consists of 3 phalanges: proximal, middle, distal phalanx Exception is great toe, which lacks a middle phalanx © McGraw Hill, LLC 79  Figure 7.31: Medial View of the Right Foot Access the text alternative for these images © McGraw Hill, LLC 80  Figure 7.32: Superior View of the Right Foot Access the text alternative for these images © McGraw Hill, LLC 81  7.13: Joints Joints (articulations): Functional junctions between bones Enable a wide variety of body movements, bind parts of the body together, make bone growth possible, and permit shape changes during childbirth Can be classified according to the degree of movement they allow: Immovable, or synarthrotic Slightly movable, or amphiarthrotic Freely movable, or diarthrotic Can also be classified according to the type of tissue that binds them together: Fibrous: composed of dense connective tissue Cartilaginous: composed of cartilage Synovial: having a complex structure © McGraw Hill, LLC 82  Fibrous Joints Found between bones that lie in close contact Held close together by layer of dense connective tissue Most are immovable, such as the sutures of the skull A few are slightly movable, such as the joint between the distal tibia and fibula © McGraw Hill, LLC 83  Figure 7.33: Fibrous Joints Access the text alternative for these images © McGraw Hill, LLC 84  Cartilaginous Joints Connected by either hyaline or fibrocartilage Intervertebral discs between vertebrae help absorb shock and are slightly movable Other examples include the pubic symphysis and the first rib with the sternum © McGraw Hill, LLC 85  Synovial Joints 1 Are diarthrotic (allow free movement) Have a more complex structure than fibrous or cartilaginous joints Most joints of the skeleton are synovial joints Articular ends of bones in a synovial joint are covered with hyaline (articular) cartilage Joint capsule consists of an outer layer of dense connective tissue, and an inner layer, called the synovial membrane Synovial membrane secretes synovial fluid, which lubricates the joints © McGraw Hill, LLC 86  Synovial Joints 2 Some synovial joints contain shock absorbing pads of fibrocartilage called menisci (singular is meniscus) Some have fluid-filled sacs called bursae that aid in movement of tendons as they slide over bone Synovial joints are classified by shape of their parts and the movements they allow © McGraw Hill, LLC 87  Figure 7.34: The General Structure of a Synovial Joint Access the text alternative for these images © McGraw Hill, LLC 88  Figure 7.35: The Menisci and Bursae of the Knee Joint Access the text alternative for these images © McGraw Hill, LLC 89  Classification of Synovial Joints 1 Ball-and-socket (spheroidal) joint: Consists of a bone with a globular or egg-shaped head articulating with the cup-shaped cavity of another bone Allows widest range of motion, including movement in all planes (multiaxial) Examples: the shoulder and hip joints Condylar (ellipsoidal) joint: Consists of an ovoid condyle fitting into an elliptical cavity Permits back and forth and side to side movements within 2 planes (biaxial), but not rotation Examples: joints between metacarpals and phalanges © McGraw Hill, LLC 90  Classification of Synovial Joints 2 Plane (gliding) joint: Articulating surfaces are nearly flat or slightly curved Allows a sliding or twisting movement (nonaxial) Examples: joints of the wrist and ankle, as well as those between vertebrae, sacroiliac joints Hinge joint: A convex surface of a bone fits into a concave surface of another Allows movement in 1 plane (uniaxial), like hinge of a door Examples: the elbow and joints between phalanges © McGraw Hill, LLC 91  Classification of Synovial Joints 3 Pivot (trochoid) joint: A cylindrical surface rotates within a ring of bone and ligament Allows only rotation around central axis (uniaxial) Examples: joint between the dens of the axis and the atlas Saddle (sellar) joint: Found between bones that have both concave and convex areas in their articulating surfaces; bones have complementary surfaces Permits a variety of movements, mostly in 2 planes (biaxial) Example: the joint between the trapezium (carpal) and the metacarpal of the thumb © McGraw Hill, LLC 92  Figure 7.36: Types and Examples of Synovial Joints Access the text alternative for these images © McGraw Hill, LLC 93  Summary: Types of Joints 1 TABLE 7.4 Types of Joints Type of Joint Description Possible Movements Examples Fibrous Articulating bones are fastened None or slight twisting Suture between bones of skull, together by a thin layer of dense joint between the distal ends connective tissue. of tibia and fibula Cartilaginous Articulating bones are connected by Limited movement, as when Joints between the bodies of hyaline cartilage or fibrocartilage. back is bent or twisted vertebrae, pubic symphysis Synovial Articulating ends of bones are Allow free movement (see surrounded by a joint capsule of the following list, "Types of ligaments and synovial membranes; Joint Movements") ends of articulating bones are covered by hyaline cartilage and separated by synovial fluid. 1. Ball-and-socket Ball-shaped head of one bone Movements in all planes, Shoulder, hip articulates with cup-shaped cavity of including rotation another. 2. Condylar Oval-shaped condyle of one bone Variety of movements in Joints between the articulates with elliptical cavity of two planes, but no rotation metacarpals and phalanges another. © McGraw Hill, LLC 94  Summary: Types of Joints 2 TABLE 7.4 Types of Joints Type of Joint Description Possible Movements Examples 3. Plane Articulating surfaces are Sliding or twisting Joints between various nearly flat or slightly curved. bones of wrist and ankle, sacroiliac joints, joints between ribs 2 to 7 and sternum 4. Hinge Convex surface of one bone Flexion and extension Elbow, joints of phalanges articulates with concave surface of another. 5. Pivot Cylindrical surface of one Rotation around a Joint between the atlas bone articulates with ring of central axis and dens of the axis bone and ligament. 6. Saddle Articulating surfaces have Variety of movements, Joint between the carpal both concave and convex mainly in two planes and metacarpal of thumb regions; the surface of one bone fits the complementary surface of another. © McGraw Hill, LLC 95  Types of Joint Movements 1 When skeletal muscles move, they produce movement at synovial joints When a muscle contracts, its fibers pull its more movable end, the insertion, toward its more fixed end, the origin, causing a specific movement at a joint Terms that describe joint movements: Flexion: bending parts at a joint, so that the angle between them decreases Extension: straightening parts at a joint, so that the angle between them increases Lateral flexion: bending the head, neck, or trunk to the side Hyperextension: straightening beyond normal anatomical position Abduction: moving a body part away from the midline Adduction: moving a body part toward the midline © McGraw Hill, LLC 96  Figure 7.37: Types of Joint Movements ©J & J Photography Access the text alternative for these images © McGraw Hill, LLC 97  Types of Joint Movements 2 Terms to describe joint movements, continued: Dorsiflexion: ankle movement that brings the foot closer to the shin Plantar flexion: ankle movement that moves the foot farther from the shin; points the toes Rotation: movement of a part around an axis Circumduction: movement of a part so its end follows a circular path Pronation: rotation of forearm so that the palm is facing downward or posteriorly Supination: rotation of forearm so that the palm is facing upward or anteriorly © McGraw Hill, LLC 98  Figure 7.38: Types of Joint Movements ©J & J Photography Access the text alternative for these images © McGraw Hill, LLC 99  Types of Joint Movements 3 Terms to describe joint movements, continued: Inversion: turning the sole (plantar surface) of the foot medially Eversion: turning the sole (plantar surface) of the foot laterally Protraction: moving a part of the body forward Retraction: moving a part of the body backward Elevation: raising a part of the body Depression: lowering a part of the body © McGraw Hill, LLC 100  Figure 7.39: Types of Joint Movements ©J & J Photography Access the text alternative for these images © McGraw Hill, LLC 101  Because learning changes everything. ® www.mheducation.com © McGraw Hill LLC. 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