Saladin Anatomy and Physiology The Unity of Form and Function Episode 5 ppt

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Saladin Anatomy and Physiology The Unity of Form and Function Episode 5 ppt

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Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Chapter 8 The Skeletal System 265 Excessive stress can crack the annulus and cause the nucleus to ooze out. This is called a herniated disc (“rup- tured” or “slipped” disc in lay terms) and may put painful pressure on the spinal cord or a spinal nerve. To relieve the pressure, a procedure called a laminectomy may be performed—each lamina is cut and the laminae and spin- ous processes are removed. This procedure is also used to expose the spinal cord for anatomical study or surgery. Regional Characteristics of Vertebrae We are now prepared to consider how vertebrae differ from one region of the vertebral column to another and from the generalized anatomy just described. Knowing these variations will enable you to identify the region of the spine from which an isolated vertebra was taken. More importantly, these modifications in form reflect functional differences among the vertebrae. Cervical Vertebrae The cervical vertebrae (C1–C7) are the smallest and lightest ones other than the coccygeals. The first two (C1 and C2) have unique structures that allow for head movements (fig. 8.24). Vertebra C1 is called the atlas because it supports the head in a manner reminiscent of the Titan of Greek mythology who was condemned by Zeus to carry the world on his shoulders. It scarcely resembles the typical vertebra; it is little more than a del- icate ring surrounding a large vertebral foramen. On each side is a lateral mass with a deeply concave supe- rior articular facet that articulates with the occipital condyle of the skull. A nodding motion of the skull, as in gesturing “yes,” causes the occipital condyles to rock back and forth on these facets. The inferior articular facets, which are comparatively flat or only slightly con- cave, articulate with C2. The lateral masses are con- nected by an anterior arch and a posterior arch, which bear slight protuberances called the anterior and poste- rior tubercle, respectively. Vertebra C2, the axis, allows rotation of the head as in gesturing “no.” Its most distinctive feature is a promi- nent knob called the dens (denz), or odontoid 36 process, on its anterosuperior side. No other vertebra has a dens. It begins to form as an independent ossification center dur- ing the first year of life and fuses with the axis by the age of 3 to 6 years. It projects into the vertebral foramen of the atlas, where it is nestled in a facet and held in place by a transverse ligament (fig. 8.24c). A heavy blow to the top of the head can cause a fatal injury in which the dens is driven through the foramen magnum into the brainstem. The articulation between the atlas and the cranium is called the atlanto-occipital joint; the one between the atlas and axis is called the atlantoaxial joint. The axis is the first vertebra that exhibits a spinous process. In vertebrae C2 to C6, the process is forked, or bifid, 37 at its tip (fig. 8.25a). This fork provides attachment for the nuchal ligament of the back of the neck. All seven cervical vertebrae have a prominent round transverse foramen in each transverse process. These foramina pro- vide passage and protection for the vertebral arteries, which supply blood to the brain. Transverse foramina occur in no other vertebrae and thus provide an easy means of recognizing a cervical vertebra. Transverse process L3 L4 Centrum (body) Intervertebral disc Inferior articular process of L3 Superior articular process of L4 Lamina Inferior vertebral notch of L1 Superior vertebral notch of L2 L1 L2 L3 Superior articular process of L1 Inferior articular process of L3 (a) Intervertebral disc Spinous process Intervertebral foramen (b) Figure 8.23 Articulated Vertebrae. (a) Dorsal view of vertebrae L3 to L4. (b) Left lateral view of vertebrae L1 to L3. 36 dens ϭ odont ϭ tooth ϩ oid ϭ resembling 37 bifid ϭ cleft into two parts Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Think About It How would head movements be affected if vertebrae C1 and C2 had the same structure as C3? What is the functional advantage of the lack of a spinous process in C1? Cervical vertebrae C3 to C6 are similar to the typical vertebra described earlier, with the addition of the trans- verse foramina and bifid spinous processes. Vertebra C7 is a little different—its spinous process is not bifid, but it is especially long and forms a prominent bump on the lower back of the neck. This feature is a convenient landmark for counting vertebrae. Because it is so conspicuous, C7 is sometimes called the vertebra prominens. Thoracic Vertebrae There are 12 thoracic vertebrae (T1–T12), corresponding to the 12 pairs of ribs attached to them. They lack the transverse foramina and bifid processes that distinguish the cervicals, but possess the following distinctive fea- tures of their own (fig. 8.25b): • The spinous processes are relatively pointed and angle sharply downward. • The body is somewhat heart-shaped, more massive than in the cervical vertebrae but less than in the lumbar vertebrae. • The body has small, smooth, slightly concave spots called costal facets (to be described shortly) for attachment of the ribs. • Vertebrae T1 to T10 have a shallow, cuplike transverse costal 38 facet at the end of each transverse process. These provide a second point of articulation for ribs 1 to 10. There are no transverse costal facets on T11 and T12 because ribs 11 and 12 attach only to the bodies of the vertebrae. No other vertebrae have ribs articulating with them. Thoracic vertebrae vary among themselves mainly because of variations in the way the ribs articulate. In most cases, a rib inserts between two vertebrae, so each vertebra contributes one-half of the articular surface. A rib articu- lates with the inferior costal facet (FASS-et) of the upper vertebra and the superior costal facet of the vertebra below that. This terminology may be a little confusing, but note that the superior and inferior facets are named for 266 Part Two Support and Movement Anterior tubercle Anterior arch Superior articular facet Transverse foramen Transverse foramen Transverse process Inferior articular process Spinous process Lamina (b) Posterior arch Posterior tubercle Dens (odontoid process) Superior articular facet Body Atlas Axis Pedicle Lateral masses Dens Axis of rotation Transverse ligament Atlas Axis (a) (c) Figure 8.24 The Atlas and Axis, Cervical Vertebrae C1 and C2. (a) The atlas, superior view. (b) The axis, posterosuperior view. (c) Articulation of the atlas and axis and rotation of the atlas. This movement turns the head from side to side, as in gesturing “no.” Note the transverse ligament holding the dens of the axis in place. 38 costa ϭ rib ϩ al ϭ pertaining to Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Chapter 8 The Skeletal System 267 their position on the vertebral body, not for which part of the rib’s articulation they provide. Vertebrae T1 and T10 to T12, however, have complete costal facets on the bodies for ribs 1 and 10 to 12, which articulate on the vertebral body instead of between vertebrae. Vertebrae T11 and T12, as noted, have no transverse costal facets. These variations will be more functionally understandable after you have studied the anatomy of the ribs, so we will return then to the details of these articular surfaces. Lumbar Vertebrae There are five lumbar vertebrae (L1–L5). Their most dis- tinctive features are a thick, stout body and a blunt, squar- ish spinous process (fig. 8.25c). In addition, their articular processes are oriented differently than on other vertebrae. In thoracic vertebrae, the superior processes face forward and the inferior processes face to the rear. In lumbar ver- tebrae, the superior processes face medially (like the palms of your hands about to clap), and the inferior processes face laterally, toward the superior processes of the next vertebra. This arrangement makes the lumbar region of the spine especially resistant to twisting. These differences are best observed on an articulated skeleton. Vertebra L1 is an exception to this pattern, as it represents a transition between the thoracic and lumbar pattern. Its superior articular surfaces face dorsally to meet the infe- rior processes of T12, while its inferior articular surfaces face laterally like those of the rest of the lumbar vertebrae. Sacrum The sacrum is a bony plate that forms the dorsal wall of the pelvic cavity (fig. 8.26). It is named for the fact that it Transverse foramen Transverse process Transverse process Superior costal facet Inferior costal facet Transverse process Pedicle Body Body Transverse costal facet Spinous process Lamina Spinous process Spinous process Spinous process Inferior articular process Inferior articular facet Inferior articular facet Transverse costal facet Spinous process Spinous process Lamina Superior articular facet Superior articular process Superior articular facet Superior articular facet Body (a) Cervical vertebrae (b) Thoracic vertebrae (c) Lumbar vertebrae Figure 8.25 Typical Cervical, Thoracic, and Lumbar Vertebrae. The left-hand figures are superior views, and the right-hand figures are left lateral views. List all the features that distinguish vertebra L1 from T12. Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 was once considered the seat of the soul. 39 In children, there are five separate sacral vertebrae (S1–S5). They begin to fuse around age 16 and are fully fused by age 26. The anterior surface of the sacrum is relatively smooth and concave and has four transverse lines that indicate where the five vertebrae have fused. This surface exhibits four pairs of large anterior sacral (pelvic) foram- ina, which allow for passage of nerves and arteries to the pelvic organs. The dorsal surface of the sacrum is very rough. The spinous processes of the vertebrae fuse into a dorsal ridge called the median sacral crest. The transverse processes fuse into a less prominent lateral sacral crest on each side of the median crest. Again on the dorsal side of the sacrum, there are four pairs of openings for spinal nerves, the posterior sacral foramina. The nerves that emerge here supply the gluteal region and lower limb. A sacral canal runs through the sacrum and ends in an inferior opening called the sacral hiatus (hy-AY-tus). This canal contains spinal nerve roots in life. On each side of the sacrum is an ear-shaped region called the auricular 40 (aw-RIC-you-lur) surface. This articulates with a similarly shaped surface on the os coxae and forms the strong, nearly immovable sacroiliac (SAY-cro-ILL-ee-ac) joint. At the superior end of the sacrum, lateral to the median crest, are a pair of superior articular processes that articulate with vertebra L5. Lateral to these are a pair of large, rough, wing- like extensions called the alae 41 (AIL-ee). Coccyx The coccyx 42 (fig. 8.26) usually consists of four (some- times five) small vertebrae, Co1 to Co4, which fuse by the age of 20 to 30 into a single triangular bone. Vertebra Co1 has a pair of hornlike projections, the cornua, which serve as attachment points for ligaments that bind the coccyx to the sacrum. The coccyx can be frac- tured by a difficult childbirth or a hard fall to the but- tocks. Although it is the vestige of a tail, it is not entirely useless; it provides attachment for muscles of the pelvic floor. The Thoracic Cage The thoracic cage (fig. 8.27) consists of the thoracic verte- brae, sternum, and ribs. It forms a more or less conical enclosure for the lungs and heart and provides attachment for the pectoral girdle and upper limb. It has a broad base and a somewhat narrower superior apex; it is rhythmically expanded by the respiratory muscles to create a vacuum that draws air into the lungs. The inferior border of the thoracic cage is formed by a downward arc of the ribs called the costal margin. The ribs protect not only the tho- racic organs but also the spleen, most of the liver, and to some extent the kidneys. 268 Part Two Support and Movement Anterior sacral foramina Superior articular process Transverse process Transverse lines Coccyx Cornu of coccyx Sacral hiatus Median sacral crest Coccyx Posterior sacral foramina Ala Sacral canal Lateral sacral crest Auricular surface S1 S2 S3 S4 S5 Co1 Co2 Co3 Co4 (a) (b) Figure 8.26 The Sacrum and Coccyx. (a) Anterior surface, which faces the viscera of the pelvic cavity. (b) Posterior surface. The processes of this surface can be palpated in the sacral region. 39 sacr ϭ sacred 40 auri ϭ ear ϩ cul ϭ little ϩ ar ϭ pertaining to 41 alae ϭ wings 42 coccyx ϭ cuckoo (named for resemblance to a cuckoo’s beak) Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Chapter 8 The Skeletal System 269 Sternum The sternum (breastbone) is a bony plate anterior to the heart. It is subdivided into three regions: the manubrium, body, and xiphoid process. The manubrium 43 (ma-NOO- bree-um) is the broad superior portion. It has a superome- dial suprasternal notch (jugular notch), which you can easily palpate between your clavicles (collarbones), and right and left clavicular notches, where it articulates with the clavicles. The body, or gladiolus, 44 is the longest part of the sternum. It joins the manubrium at the sternal angle, which can be palpated as a transverse ridge at the point where the sternum projects farthest forward. In some people, however, it is rounded or concave. The second rib attaches here, making the sternal angle a useful landmark for counting ribs in a physical examination. The manubrium and body have scalloped lateral margins where cartilages of the ribs are attached. At the inferior end of the sternum is a small, pointed xiphoid 45 (ZIF-oyd) process that provides attachment for some of the abdomi- nal muscles. Ribs There are 12 pairs of ribs, with no difference between the sexes. Each is attached at its posterior (proximal) end to the vertebral column. A strip of hyaline cartilage called the costal cartilage extends from the anterior (distal) ends of ribs 1 to 7 to the sternum. Ribs 1 to 7 are thus called true ribs. Ribs 8 to 10 attach to the costal cartilage of rib 7, and ribs 11 and 12 do not attach to anything at the distal end but are embedded in thoracic muscle. Ribs 8 to 12 are therefore called false ribs, and ribs 11 and 12 are also called floating ribs for lack of any connection to the sternum. Ribs 1 to 10 each have a proximal head and tubercle, connected by a narrow neck; ribs 11 and 12 have a head only (fig. 8.28). Ribs 2 to 9 have beveled heads that come to a point between a superior articular facet above and an inferior articular facet below. Rib 1, unlike the others, is a flat horizontal plate. Ribs 2 to 10 have a sharp turn called the angle, distal to the tubercle, and the remainder con- sists of a flat blade called the shaft. Along the inferior mar- gin of the shaft is a costal groove that marks the path of the intercostal blood vessels and nerve. Variations in rib anatomy relate to the way different ribs articulate with the vertebrae. Once you observe these articulations on an intact skeleton, you will be better able to understand the anatomy of isolated ribs and vertebrae. Sternoclavicular joint Acromioclavicular joint Clavicle Scapula Suprasternal notch Clavicular notch Manubrium Angle Body Xiphoid process Costal cartilages Costal margin True ribs (1–7) 1 2 3 4 5 6 7 8 9 10 11 12 T12 L1 False ribs (8–12) Floating ribs (11–12) Sternum Pectoral girdle Figure 8.27 The Thoracic Cage and Pectoral Girdle, Anterior View. 43 manubrium ϭ handle 44 gladiolus ϭ sword 45 xipho ϭ sword ϩ oid ϭ resembling Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Vertebra T1 has a complete superior costal facet on the body that articulates with rib 1, as well as a small inferior costal facet that provides half of the articulation with rib 2. Ribs 2 through 9 all articulate between two vertebrae, so these ver- tebrae have both superior and inferior costal facets on the respective margins of the body. The inferior costal facet of each vertebra articulates with the superior articular facet of the rib, and the superior costal facet of the next vertebra articulates with the inferior articular facet of the same rib (fig. 8.29a). Ribs 10 through 12 each articulate with a single costal facet on the bodies of the respective vertebrae. Ribs 1 to 10 each have a second point of attachment to the vertebrae: the tubercle of the rib articulates with the costal facet of the same-numbered vertebra (fig. 8.29b). Ribs 11 and 12 articulate only with the vertebral bodies; they do not have tubercles and vertebrae T11 and T12 do not have costal facets. Table 8.5 summarizes these variations. Table 8.6 pro- vides a checklist that you can use to review your knowl- edge of the vertebral column and thoracic cage. 270 Part Two Support and Movement Head Neck Neck Tubercle Shaft Head Superior Articular facets for vertebral bodies Articular facet for transverse process Costal groove Inferior Tubercle Angle (a) (b) (c) Figure 8.28 Anatomy of the Ribs. (a) Rib 1 is an atypical flat plate. (b) Typical features of ribs 2 to 10. (c) Appearance of the floating ribs, 11 and 12. Superior costal facet for rib 6 Superior articular facet Transverse costal facet for rib 6 Head Neck Tubercle Rib 6 T6 ( b ) Figure 8.29 Articulation of Rib 6 with Vertebrae T5 and T6. (a) Anterior view. Note the relationships of the articular facets of the rib with the costal facets of the two vertebrae. (b) Superior view. Note that the rib articulates with a vertebra at two points: the costal facet on the vertebral body and the transverse costal facet on the transverse process. Inferior costal facet of T5 Superior articular facet of rib 6 Inferior articular facet of rib 6 Superior costal facet of T6 (a) Vertebral body T6 Vertebral body T5 Rib 6 Before You Go On Answer the following questions to test your understanding of the preceding section: 10. Make a table with three columns headed “cervical,” “thoracic,” and “lumbar.” In each column, list the identifying characteristics of each type of vertebra. 11. Describe how rib 5 articulates with the spine. How do ribs 1 and 12 differ from this and from each other in their modes of articulation? 12. Distinguish between true, false, and floating ribs. State which ribs fall into each category. 13. Name the three divisions of the sternum and list the sternal features that can be palpated on a living person. The Pectoral Girdle and Upper Limb Objective When you have completed this section, you should be able to • identify and describe the features of the clavicle, scapula, humerus, radius, ulna, and bones of the wrist and hand. Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Chapter 8 The Skeletal System 271 Table 8.5 Articulations of the Ribs Articulating Articulating with a Rib Type Costal Cartilage Vertebral Bodies Transverse Costal Facet? Rib Tubercle 1 True Individual T1 Yes Present 2 True Individual T1 and T2 Yes Present 3 True Individual T2 and T3 Yes Present 4 True Individual T3 and T4 Yes Present 5 True Individual T4 and T5 Yes Present 6 True Individual T5 and T6 Yes Present 7 True Individual T6 and T7 Yes Present 8 False Shared with rib 7 T7 and T8 Yes Present 9 False Shared with rib 7 T8 and T9 Yes Present 10 False Shared with rib 7 T10 Yes Present 11 False, floating None T11 No Absent 12 False, floating None T12 No Absent Pectoral Girdle The pectoral girdle (shoulder girdle) supports the arm. It consists of two bones on each side of the body: the clavicle (collarbone) and the scapula (shoulder blade). The medial end of the clavicle articulates with the ster- num at the sternoclavicular joint, and its lateral end articulates with the scapula at the acromioclavicular joint (see fig. 8.27). The scapula also articulates with the humerus at the humeroscapular joint. These are loose attachments that result in a shoulder far more flexible than that of most other mammals, but they also make the shoulder joint easy to dislocate. Think About It How is the unusual flexibility of the human shoulder joint related to the habitat of our primate ancestors? Clavicle The clavicle 46 (fig. 8.30) is a slightly S-shaped bone, some- what flattened dorsoventrally and easily seen and pal- pated on the upper thorax (see fig. B.1b in atlas B). The superior surface is relatively smooth, whereas the inferior surface is marked by grooves and ridges for muscle attach- ment. The medial sternal end has a rounded, hammerlike head, and the lateral acromial end is markedly flattened. Near the acromial end is a rough tuberosity called the conoid tubercle—a ligament attachment that faces toward the rear and slightly downward. The clavicle braces the shoulder and is thickened in people who do heavy man- ual labor. Without it, the pectoralis major muscles would pull the shoulders forward and medially, as occurs when a clavicle is fractured. Indeed, the clavicle is the most commonly fractured bone in the body because it is so close to the surface and because people often reach out with their arms to break a fall. Scapula The scapula (fig. 8.31) is a triangular plate that dorsally overlies ribs 2 to 7. The three sides of the triangle are called the superior, medial (vertebral), and lateral (axil- lary) borders, and its three angles are the superior, infe- rior, and lateral angles. A conspicuous suprascapular notch in the superior border provides passage for a nerve. The broad anterior surface of the scapula, called the subscapular fossa, is slightly concave and relatively featureless. The posterior surface has a transverse ridge called the spine, a deep indentation superior to the spine called the supraspinous fossa, and a broad surface infe- rior to it called the infraspinous fossa. 47 The scapula is held in place by numerous muscles attached to these three fossae. The most complex region of the scapula is its lateral angle, which has three main features: 1. The acromion 48 (ah-CRO-me-on) is a platelike extension of the scapular spine that forms the apex 46 clav ϭ hammer, club, key ϩ icle ϭ little 47 supra ϭ above; infra ϭ below 48 acr ϭ extremity, point ϩ omi ϭ shoulder Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 272 Part Two Support and Movement Table 8.6 Anatomical Checklist for the Vertebral Column and Thoracic Cage Vertebral Column Spinal Curvatures (fig. 8.19) Cervical curvature Thoracic curvature Lumbar curvature Pelvic curvature General Vertebral Structure (figs. 8.22 and 8.23) Body (centrum) Vertebral foramen Vertebral canal Vertebral arch Pedicle Lamina Spinous process Transverse process Superior articular process Inferior articular process Intervertebral foramen Inferior vertebral notch Superior vertebral notch Intervertebral Discs (fig. 8.22) Annulus fibrosus Nucleus pulposus Cervical Vertebrae (figs. 8.24 and 8.25a) Transverse foramina Bifid spinous process Atlas Anterior arch Anterior tubercle Posterior arch Thoracic Cage Sternum (fig. 8.27) Manubrium Suprasternal notch Clavicular notch Sternal angle Body (gladiolus) Xiphoid process Rib Types (fig. 8.27) True ribs (ribs 1–7) False ribs (ribs 8–12) Floating ribs (ribs 11 and 12) Cervical Vertebrae (figs. 8.24 and 8.25a)—(Cont.) Posterior tubercle Lateral mass Superior articular facet Inferior articular facet Transverse ligament Axis Dens (odontoid process) Thoracic Vertebrae (fig. 8.25b) Superior costal facet Inferior costal facet Transverse costal facet Lumbar Vertebrae (fig. 8.25c) Sacral Vertebrae (fig. 8.26) Sacrum Anterior sacral foramina Posterior sacral foramina Median sacral crest Lateral sacral crest Sacral canal Sacral hiatus Auricular surface Superior articular process Alae Coccygeal Vertebrae (fig. 8.26) Coccyx Cornu Rib Features (fig. 8.28) Head Superior articular facet Inferior articular facet Neck Tubercle Angle Shaft Costal groove Costal cartilage Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies, 2003 Chapter 8 Chapter 8 The Skeletal System 273 of the shoulder. It articulates with the clavicle—the sole point of attachment of the arm and scapula to the rest of the skeleton. 2. The coracoid 49 (COR-uh-coyd) process is shaped like a finger but named for a vague resemblance to a crow’s beak; it provides attachment for the biceps brachii and other muscles of the arm. 3. The glenoid 50 (GLEN-oyd) cavity is a shallow socket that articulates with the head of the humerus. Upper Limb The upper limb is divided into four regions containing a total of 30 bones per limb: 1. The brachium 51 (BRAY-kee-um), or arm proper, extends from shoulder to elbow. It contains only one bone, the humerus. 2. The antebrachium, 52 or forearm, extends from elbow to wrist and contains two bones—the radius and ulna. In anatomical position, these bones are parallel and the radius is lateral to the ulna. 3. The carpus, 53 or wrist, contains eight small bones arranged in two rows. 4. The manus, 54 or hand, contains 19 bones in two groups—5 metacarpals in the palm and 14 phalanges in the fingers. Conoid tubercle Acromial end Sternal end Conoid tubercle (a) (b) Figure 8.30 The Right Clavicle (collarbone). (a) Superior view; (b) inferior view. Superior angle Acromion Suprascapular notch Coracoid process Glenoid cavity Subscapular fossa Lateral border Spine Medial border Supraspinous fossa Infraspinous fossa Superior border Acromion Lateral angle Inferior angle (a) (b) Figure 8.31 The Right Scapula. (a) Anterior view; (b) posterior view. 50 glen ϭ pit, socket 51 brachi ϭ arm 52 ante ϭ before 53 carp ϭ wrist 54 man ϭ hand 49 corac ϭ crow ϩ oid ϭ resembling [...]... joint and state to which bone each of these features belongs 17 Name the four bones of the proximal row of the carpus from lateral to medial, and then the four bones of the distal row in the same order 18 Name the four bones from the tip of the little finger to the base of the hand on that side matches the one on the sacrum On the anterior side of the pelvis is the pubic symphysis,63 the point where the. .. The sacroiliac joint is formed where the surface of the sacrum articulates with that of the ilium 18 The processes of the radius and ulna form bony protuberances on each side of the wrist 19 The thumb is also known as the and the great toe is also known as the 20 The arch of the foot extends from the heel to the great toe 10 Which of these is the bone of the heel? a cuboid b calcaneus... palpated in the shin At the ankle, just above the rim of a standard dress shoe, you can palpate a prominent bony knob on each side These are the medial and lateral malleoli70 (MAL-ee-OH-lie) The medial malleolus is part of the tibia, and the lateral malleolus is the part of the fibula Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8 The Skeletal System © The McGraw−Hill... general are the foramen magnum where the spinal cord joins the brainstem; the calvaria, which forms a roof over the cranial cavity; the orbits, which house the eyes; the three cranial fossae that form the floor of the cranial cavity; the hard palate, forming the roof of the mouth; and the zygomatic arches, or “cheekbones.” 5 The cranial bones are the frontal, parietal, temporal, occipital, sphenoid, and ethmoid... Bones of the palm are called metacarpals.60 Metacarpal I is located at the base of the thumb and metacarpal V at the base of the little finger On a skeleton, the metacarpals look like extensions of the fingers, so that the fingers seem much longer than they really are The proximal end of a metacarpal bone is called the base, the shaft is called the body, and the distal end is called the head The heads of. .. bones The parietal and temporal bones are paired, and the others single 6 The facial bones are the maxillae; the palatine, zygomatic, lacrimal, and nasal bones; the inferior nasal conchae; and the vomer and mandible All but the last two are paired The mandible is the only movable bone of the skull 7 Features of the individual bones are summarized in table 8.4 8 Associated with the skull are the hyoid... pelvis and an inferior, narrower true (lesser) pelvis The passage from the false to the true pelvis is called the pelvic inlet and its margin is the pelvic brim; the exit from the true pelvis is called the pelvic outlet 3 Two other major features of the os coxa are the iliac crest, which forms the flare of the hip, and the acetabulum, the cuplike socket for the femur 4 The lower limb bones are the femur... Charlie home.” The first letters of these words correspond to the first letters of the carpal bones, from lateral to medial, proximal row first (b) X ray of an adult hand Identify the unlabeled bones in the X ray by comparing it to the drawing How does figure b differ from the X ray of a child’s hand, figure 7.11? Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8 The Skeletal... of one pubis meets the body of the other at the pubic symphysis The pubis and ischium encircle the obturator foramen The female pelvis is adapted to the needs of pregnancy and childbirth Some of the differences between the male and female pelves are described in table 8.8 and illustrated in figure 8.37 Table 8.8 Lower Limb The number and arrangement of bones in the lower limb are similar to those of. .. each side of your wrist are the styloid processes of the radius and ulna The radius and ulna are attached along their shafts by a ligament called the interosseous (IN-tur-OSS-ee-us) membrane, which is attached to an angular ridge called the interosseous margin on the medial side of each bone Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8 The Skeletal System © The McGraw−Hill . scapula, humerus, radius, ulna, and bones of the wrist and hand. Saladin: Anatomy & Physiology: The Unity of Form and Function, Third Edition 8. The Skeletal System Text © The McGraw−Hill Companies,. medial, and then the four bones of the distal row in the same order. 18. Name the four bones from the tip of the little finger to the base of the hand on that side. The Pelvic Girdle and Lower. identify and describe the features of the pelvic girdle, femur, patella, tibia, fibula, and bones of the foot; and • compare the anatomy of the male and female pelvis and explain the functional

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