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Chapter 08 Lecture Outline

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• Many organs are named for their relationships to nearby bones • Understanding muscle movements also depends on knowledge of skeletal anatomy • Positions, shapes, and processes of bones can serve as landmarks for clinicians

8-2 Overview of the Skeleton

Frontal bone Parietal bone • Axial skeleton is Occipital bone Skull Maxilla colored beige Mandible Mandible – Forms central Clavicle Clavicle Pectoral girdle Scapula Scapula supporting axis of Sternum body Thoracic Ribs Humerus cage Costal cartilages – Skull, vertebrae, sternum, ribs, Vertebral column sacrum, and hyoid Hip bone Pelvis Sacrum Ulna Coccyx Radius Carpus • Appendicular Metacarpal bones Phalanges skeleton is colored green Femur – Pectoral girdle Patella – Upper extremity

Fibula – Pelvic girdle Tibia – Lower extremity

Metatarsal bones Tarsus Figure 8.1 Phalanges 8-3 (a) Anterior view (b) Posterior view Bones of the Skeletal System

• Number of bones – 206 in typical adult skeleton • Varies with development of sesamoid bones – Bones that form within tendons (e.g., patella) • Varies with presence of sutural (wormian) bones in skull – Extra bones that develop in skull suture lines – 270 bones at birth, but number decreases with fusion

8-4 Anatomical Features of Bones

• Bone markings—ridges, spines, bumps, depressions, canals, pores, slits, cavities, and articular surfaces

• Ways to study bones – Articulated skeleton: held together by wire and rods, shows spatial relationships between bones – Disarticulated bones: taken apart so their surface features can be studied in detail

8-5 Anatomical Features of Bones

8-6 Anatomical Features of Bones

Lines Crest

Sinuses Fovea Head Foramen Meatus Crest Head Trochanters Tubercle Process Condyle Alveolus Spine Foramen

Tuberosity (a) Skull (lateral view) Line

Process Spine Fossae

Epicondyles Fossae

Condyles

Figure 8.2 (c) Femur (d) Humerus 8-7 (b) Scapula (posterior view) (posterior view) (anterior view) The Skull

• Expected Learning Outcomes – Distinguish between cranial and facial bones. – Name the bones of the skull and the anatomical features. – Identify the cavities in the skull and in some of its individual bones. – Name the principal sutures that join the bones of the skull. – Describe some bones that are closely associated with the skull. – Describe the development of the skull from infancy through childhood.

8-8 The Skull

• Skull—most complex part of skeleton • 22 bones joined together by sutures (immovable joints) • Several cavities—cranial cavity (brain case), orbits (eye sockets), nasal cavity, oral (buccal) cavity, middle- and inner-ear cavities, and paranasal sinuses

8-9 The Skull

• Foramina—holes that allow passage for nerves and blood vessels • Paranasal sinuses—frontal, sphenoid, ethmoid, maxillary – Lined by mucous membrane and are air-filled – Act as chambers that add resonance to the voice; lighten the skull

8-10 The Skull

Cranial cavity

Ethmoid Frontal bone air cells

Ethmoid bone Orbit Superior Zygomatic Nasal Middle bone conchae Inferior Maxilla

Maxillary Vomer sinus

Nasal cavity Oral cavity Mandible Figure 8.7 8-11 Cranial Bones

Anterior cranial Frontal lobe fossa

Temporal lobe

Middle cranial fossa Cerebellum

Posterior cranial Posterior cranial fossa fossa Middle cranial fossa

Anterior cranial fossa

(a) Superior view (b) Lateral view Figure 8.9 • Cranium (braincase) – Meninges (membranes) separate brain from bones • Dura mater is thickest membrane – Consists of two parts: calvaria (skullcap) and cranial base

8-12 Cranial Bones

Anterior cranial Frontal lobe fossa

Temporal lobe

Middle cranial fossa Cerebellum

Posterior cranial Posterior cranial fossa fossa Middle cranial fossa

Anterior cranial fossa (a) Superior view Figure 8.9 (b) Lateral view • Base is divided into three basins that comprise the cranial floor – Anterior cranial fossa holds the frontal lobe of the brain – Middle cranial fossa holds the temporal lobes of the brain – Posterior cranial fossa contains the cerebellum • 8 cranial bones: 1 frontal, 2 parietal, 2 temporal, 1 occipital, 1 sphenoid, 1 ethmoid 8-13 The Frontal Bone

• Forms forehead and part of the roof of the cranium • Coronal suture—posterior boundary of frontal bone • Supraorbital margin—ridge of bone deep to eyebrow • Supraorbital foramen provides passage for nerve, artery, and vein

• Glabella—smooth area Figure 8.3 above root of the nose • Contains frontal sinus

8-14 The Parietal Bones

• Form most of cranial roof and part of its lateral walls

• Bordered by four sutures – Sagittal: between parietal bones – Coronal: at anterior margin Figure 8.4a – Lambdoid: at posterior margin Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Squamous: at lateral border Anterior Frontal bone • Two temporal lines for Coronal suture attachment of the temporalis Parietal bone muscle

Sagittal suture

Sutural bone

Parietal foramen

Lambdoid suture

Occipital bone Figure 8.6 8-15 Posterior The Temporal Bones

• Temporal bone: lateral wall and part of floor of cranial cavity • Four parts: squamous, tympanic, mastoid, and petrous • Squamous part – Encircled by squamous suture – Zygomatic process – Mandibular fossa • Tympanic part – External auditory meatus – Styloid process • Mastoid part Figure 8.4a – Mastoid process – Mastoid notch – Mastoid foramen – Stylomastoid foramen 8-16 The Temporal Bones

(Continued) • Petrous part – Part of cranial floor – Separates middle from posterior cranial fossa – Houses middle- and inner-ear cavities – Receptors for hearing and balance – Internal auditory meatus— opening for CN VIII (vestibulocochlear nerve) Figure 8.5b – Carotid canal – Jugular foramen

8-17 The Temporal Bones

Squamous suture

Squamous part

Mastoid part Zygomatic process Mandibular fossa Mastoid notch External acoustic Mastoid process meatus Styloid process Tympanic part

(a) Lateral surface

Squamous suture

Squamous part

Zygomatic Petrous part process Internal acoustic meatus

Mastoid process Styloid process 8-18 (b) Medial surface Figure 8.10 The Occipital Bone

• Rear and base of skull • Foramen magnum opening for spinal cord • Basilar part—thick median plate • Occipital condyles—knobs resting on spinal column – Condylar canal, posterior to occipital condyle (only present in some people) • Hypoglossal canal transmits hypoglossal nerve (CN XII) • External occipital protuberance for nuchal ligament • Superior and inferior nuchal lines for neck muscle attachment Figure 8.5a

8-19 The Sphenoid Bone

Lesser wing Dorsum sellae Greater wing Superior orbital Body fissure Foramen • Body Foramen ovale rotundum

Lateral pterygoid plate • Greater wing

Medial pterygoid plate Pterygoid processes (b) Posterior view • Lesser wing Figure 8.11b

Diploe (spongy bone) Frontal bone Crista galli Cribriform plate Cribriform foramina • Anterior of ethmoid bone

Sphenoid bone clinoid Optic foramen Foramen rotundum Sella turcica Foramen ovale processes Foramen spinosum Temporal bone Internal acoustic Petrous part of meatus temporal bone Jugular foramen Parietal bone • Superior Groove for Foramen magnum venous sinus Occipital bone Hypoglossal canal orbital fissure • Sella turcica

(b) Superior view of cranial floor 8-20 Figure 8.5b The Sphenoid Bone

• Foramen rotundum • Foramen ovale Figure 8.11a • Foramen lacerum • Posterior nasal apertures or choanae • Medial and lateral pterygoid plates • Sphenoid sinus

Figure 8.5b 8-21 The Sphenoid Bone

Figure 8.4b

8-22 The Sphenoid Bone

Figure 8.5a

8-23 The Ethmoid Bone

• Located between eyes • Contributes to medial Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. wall of orbit, walls and Cribriform plate roof of nasal cavity, and Cribriform Crista galli foramina nasal septum Orbital plate Superior • Perpendicular plate nasal concha Ethmoidal forms superior two-thirds cells Middle of nasal septum nasal concha Perpendicular • Cribriform plate forms plate roof of nasal cavity • Crista galli: blade, attachment for dura • Cribriform (olfactory) foramina Figure 8.12 • Labyrinth forms lateral masses - Ethmoidal cells - Orbital plate 8-24 The Ethmoid Bone

Figure 8.14

8-25 The Ethmoid Bone

Figure 8.4b • Superior and middle nasal conchae—scroll-like plates that project into the nasal fossa • Along with an inferior concha (a separate bone), these plates occupy most of the nasal cavity, create turbulence of airflow, and help humidify air 8-26 The Ethmoid Bone

Figure 8.13

8-27 Facial Bones

• Facial bones (14)—skull bones anterior to the cranial cavity (do not enclose brain) – Support teeth – Give shape to face – Form part of orbital and nasal cavities – Provide attachments for muscles of facial expression and mastication

2 maxillae 2 nasal bones 2 palatine bones 2 inferior nasal conchae 2 zygomatic bones 1 vomer 2 lacrimal bones 1 mandible

8-28 The Maxillae

• Largest facial bones • Forms upper jaw and meets at median intermaxillary suture – Alveolar processes: bony points between teeth – Alveolus: sockets that hold teeth – Cleft palate and cleft lip occur when the two maxillae fail to join at the suture

Figure 8.3

8-29 The Maxillae

Figure 8.5a 8-30 The Maxillae

(Continued) • Forms inferomedial wall of orbit – Infraorbital foramen – Inferior orbital fissure

• Forms most of the hard palate – Forms roof of mouth and floor of nasal cavity – Palate allows us to chew while breathing – Palatine process – Incisive foramen

8-31 The Maxillae

Sphenoid sinus Frontal sinus Ethmoid sinus Maxillary sinus

Figure 8.8 Figure 8.8

• Maxillary sinus fills maxillae bone • Larger in volume than frontal, sphenoid, and ethmoid sinuses 8-32 The Palatine Bones • L-shaped bones • Form posterior portion of the hard palate • Part of lateral nasal cavity wall • Part of the orbital floor Figure 8.13 • Greater palatine foramina

8-33 The Palatine Bones

Figure 8.5a 8-34 The Zygomatic Bones

• Form angles of cheekbones and part of each lateral orbital wall • Zygomaticofacial foramen • Zygomatic arch is formed from temporal process of zygomatic Figure 8.4a bone and zygomatic process of temporal bone

8-35 The Lacrimal Bones

• Form part of medial wall of each orbit • Smallest bone of skull • Lacrimal fossa houses lacrimal sac – Tears collect in sac and drain into nasal Figure 8.4a cavity

8-36 The Nasal Bones

• Form bridge of nose • Support cartilages that shape lower portion of the nose • Often fractured

Figure 8.3

8-37 The Inferior Nasal Conchae

• Inferior nasal concha is largest of three conchae in the nasal cavity – It is separate from the other conchae that are parts of the ethmoid bone Figure 8.13

8-38 The Vomer

• Inferior half of the nasal septum – Inferior to perpendicular plate of ethmoid • Supports cartilage that forms anterior part of nasal septum

Figure 8.4b

8-39 The Mandible • Strongest bone of skull – Only one to noticeably move • Supports lower teeth – Alveolar processes between teeth • Provides attachments for muscles of expression and mastication • Mental symphysis—joint at midline – Ossifies in early childhood – Mental protuberance—point of chin • Mental foramen on anterolateral surface Figure 8.15 – For nerves and vessels of chin • Mandibular foramen on medial surface

– For nerves and vessels of lower teeth 8-40 The Mandible

• Major parts – Body: supports teeth – Ramus: articulates with cranium – Angle—where body meets ramus • Features of ramus – Condylar process with mandibular condyle that articulates with temporal bone forming TMJ Figure 8.15 (temporomandibular joint) – Coronoid process for temporalis muscle – Mandibular notch between processes

8-41 Bones Associated with the Skull

• Auditory ossicles

– Three in each middle-ear cavity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Malleus, incus, and stapes • Hyoid bone – Slender U-shaped bone between chin and larynx Styloid process

– Does not articulate with any Stylohyoid muscle other bone Hyoid

– Suspended from styloid Larynx Lesser horn process of skull Greater horn – Body and greater and lesser

horns (cornua) Body – Fractured hyoid bone is Figure 8.16 evidence of strangulation

8-42 The Skull in Infancy and Childhood

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Fontanels—spaces between Coronal suture unfused cranial bones Frontal Parietal bone bone Sphenoid – Contain fibrous membrane Lambdoid fontanel suture Nasal – Allow shifting of bones during Squamous bone suture Maxilla birth and growth of brain Occipital bone Zygomatic bone Mastoid – Anterior, posterior, fontanel Mandible Sphenoid sphenoid (anterolateral), and Temporal bone bone (a) Lateral view mastoid (posterolateral) fontanels

Frontal bone Anterior fontanel • Two frontal bones fuse by age 6 (metopic suture) Sagittal suture

Parietal bone • Skull approaches adult size

Posterior fontanel by 8 or 9 years of age

(b) Superior view Figure 8.17 8-43 The Vertebral Column and Thoracic Cage

• Expected Learning Outcomes – Describe the general features of the vertebral column and those of a typical vertebra. – Describe the structure of the intervertebral discs and their relationship to the vertebrae. – Describe the special features of vertebrae in different regions of the vertebral column, and discuss the functional significance of the regional differences. – Describe the anatomy of the sternum and ribs and how the ribs articulate with the thoracic vertebrae.

• Functions of spine Atlas (C1) Axis (C2) – Supports skull and trunk and allows Cervical vertebrae

for their movement C7 – Protects spinal cord T1 – Absorbs stresses of movements

– Provides attachments for limbs, Thoracic vertebrae thoracic cage, and postural muscles

• 33 vertebrae with intervertebral T12 discs between most of them L1 – Discs account for about one-quarter Lumbar vertebrae of spine’s 71 cm length (on average) – Discs compress a bit during the day L5 due to pressure of body weight S1 Sacrum

S5 Coccyx Coccyx

Atlas (C1) Axis (C2) • Five vertebral groups Cervical vertebrae

– 7 cervical in the neck C7 – 12 thoracic in the chest T1 – 5 lumbar in lower back – 5 fused sacral at base Thoracic vertebrae of spine – 4 fused coccygeal T12 • Variations in number L1 of vertebrae occur in 1 Lumbar vertebrae

in 20 people L5

– Generally in the number S1 of fused vertebrae in Sacrum inferior part of spine S5 Coccyx Coccyx Figure 8.18 8-46 General Features of the Vertebral Column • Primary curvature: spine exhibits one continuous C- shaped curve at birth (convex) – This persists as the curvature of the thoracic and pelvic spine • With crawling and walking, secondary curvatures develop in cervical and lumbar areas (concave) – Vertebral column is S-shaped beyond the age of 3 years

C1 Cervical curvature • S-shaped vertebral column

C7 with four normal T1 curvatures – Cervical Thoracic curvature – Thoracic – Lumbar T12 L1 – Pelvic

Lumbar curvature

L5 S1

Pelvic curvature

Figure 8.19 8-48 Abnormal Spinal Curvatures • Abnormalities result from Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. disease, paralysis of trunk muscles, poor posture, pregnancy, or congenital defects

• Scoliosis—abnormal lateral curvature – Most common – Usually in thoracic region

(a) Scoliosis (b) Kyphosis (c) Lordosis (“hunchback”) (“swayback”) – Particularly of adolescent girls Key Normal Pathological – Developmental abnormality in Figure 8.21 which the body and arch fail to develop on one side of the vertebrae

8-49 Abnormal Spinal Curvatures

• Kyphosis (hunchback)—exaggerated thoracic curvature – Usually from osteoporosis, also osteomalacia or spinal tuberculosis, wrestling or weight lifting in young boys

• Lordosis (swayback)—exaggerated lumbar curvature – From pregnancy or obesity

8-50 General Structure of Vertebra • Body (centrum) – Spongy bone (with red Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. marrow) covered with a shell Posterior of compact bone Spinous process Superior articular Lamina – Weight-bearing portion facet Vertebral – Rough surfaces enhance Transverse arch process attachment of intervertebral Pedicle discs Vertebral foramen • Vertebral foramina Body – Collectively form vertebral

canal for spinal cord Anterior • Vertebral arch Figure 8.22a – Pedicle: pillar-like – Lamina: plate-like • Spinous process – Projects from arch – Bump that is visible under skin 8-51 General Structure of Vertebra

• Transverse process – Extends laterally from point where pedicel and lamina meet • Superior articular processes – Project upward from one vertebra and meets inferior articular processes from the vertebra above • Facets – Flat articular surfaces Figure 8.23a covered with hyaline cartilage

8-52 General Structure of Vertebra

Superior articular process of L1 • Intervertebral foramen

Inferior vertebral – Opening between pedicles notch of L1 L1 of two adjoining vertebrae Intervertebral foramen – Passageway for spinal Superior vertebral notch of L2 nerves L2 – Inferior vertebral notch in Spinous process the pedicle of the upper Intervertebral disc vertebra L3 – Superior vertebral notch Inferior articular process of L3 in the pedicle of the lower (b) Left lateral view vertebra Figure 8.23b

8-53 Intervertebral Discs

• Intervertebral discs (23) – Pad consisting of: • Nucleus pulposus—inner gelatinous mass • Anulus fibrosus—outer ring of fibrocartilage – Bind vertebrae together – Support weight of the body – Absorb shock – Herniated disc (“ruptured” or “slipped” disc) puts painful pressure on spinal nerve or Figure 8.22b,c spinal cord

8-54 Regional Characteristics of Vertebrae

Spinous process

Lamina Superior articular facet

Transverse foramen Body Transverse process Spinous process (a) Cervical vertebrae Figure 8.25a Inferior articular process

• Cervical vertebrae (C1-C7) are small and light • Bifid or forked spinous processes in C2 to C6 • Small body and large vertebral foramen • Transverse foramen in each short transverse process – Provides passage for vertebral artery and vertebral vein • C1 = atlas; C2 = axis • C7 = vertebra prominens—prominent spinous process 8-55 Cervical Vertebrae

• Atlas (C1) – Supports the head – Has no body; consists of delicate ring around large vertebral foramen – Lateral masses • Superior articular facets articulate with occipital condyles forming atlanto– occipital joint; allows nodding “yes” Figure 8.24a • Inferior articular facets articulate with C2 – Anterior and posterior arches • Anterior and posterior tubercles

8-56 Cervical Vertebrae

• Axis (C2) – Allows head rotation gesturing “no” – Dens or odontoid process— prominent knob on its anterosuperior side • Fuses with axis by age 3 to 6 years • Projects into vertebral foramen of the atlas • Held in place by a transverse ligament – Atlantoaxial joint: between atlas and axis Figure 8.24b

8-57 Atlas and Axis Articulation

Dens Atlas

Transverse ligament Axis

Figure 8.24c 8-58 (c) Atlantoaxial joint The Thoracic Vertebrae

Transverse costal facet Superior costal facet Transverse costal facet Inferior costal facet Body Inferior articular facet (b) Thoracic vertebrae Spinous process Figure 8.25b

• 12 thoracic vertebrae (T1–T12) – Correspond to the 12 pairs of ribs attached to them • Spinous processes pointed and angled sharply downward • Have larger body than cervical, but smaller than lumbar • Superior and inferior costal facets for attachment of ribs – On body as small, smooth, slightly concave spots • Transverse costal facets at end of each transverse process T1–T10 – Provide second point of articulation for ribs 1–10

8-59 The Lumbar Vertebrae

Spinous process

Superior articular facet Superior articular process

Transverse process Pedicle

Body Spinous process

• Five lumbar vertebrae (L1–L5) • Thick, stout body • Blunt, squarish spinous process • Superior articular processes face medially – Lumbar region resistant to twisting movements 8-60 The Sacrum • Sacrum—bony plate that forms posterior wall of pelvic cavity Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Five separate sacral vertebrae Superior articular process (S1–S5) begin fusing around age 16 and complete fusion by Sacral promontory age 26 Ala S1 • Anterior surface

S2 – Smooth and concave Transverse lines – Four transverse lines indicate S3 regions of fusion Anterior sacral foramina S4 – Four pairs of large anterior S5 sacral (pelvic) foramina Co1 Coccyx Co2 Co3 • Allow passage of nerves and Co4 arteries to pelvic organs (a) Anterior view – Sacral promontory—ridge Figure 8.26a jutting from front of S1

8-61 The Sacrum (Continued) • Posterior surface very rough – Median sacral crest—fusion of spinous processes – Lateral sacral crests—fusion of transverse processes – Posterior sacral foramina—four pairs of openings for nerves to gluteal region and lower limbs • Sacral canal runs vertically through sacrum and ends as sacral hiatus – Contains spinal nerve roots • Auricular surface is part of sacroiliac (SI) joint formed with hip bone • Superior articular processes on S1; Figure 8.26b articulates with L5 • Alae—pair of large, wing-like extensions lateral to the superior articular processes

8-62 The Coccyx • Coccyx—usually consists of four small vertebrae

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (Co1–Co4); sometimes five Superior articular Sacral canal process • Fuse into single, triangular bone by age 20 Median sacral crest to 30

Auricular surface • Horns (cornua) on Co1

Lateral sacral – Serve as attachment points crest for ligaments that bind Posterior sacral foramina coccyx to sacrum

Sacral hiatus • Fractured during difficult Horn childbirth or by hard fall Transverse process Coccyx • Provides attachment for muscles of the pelvic (b) Posterior view floor Figure 8.26b 8-63 The Thoracic Cage • Thoracic cage consists of thoracic vertebrae, sternum, and ribs • Encloses lungs and heart

Sternum: Acromioclavicular joint protection of spleen, liver T1 Suprasternal notch

1 Clavicular notch kidneys Pectoral girdle: Clavicle Manubrium Scapula 2 Angle • Provides attachment for

3 pectoral girdle and upper Body 4 True ribs (1–7) limbs

5 Xiphoid process • Broad base, narrower

6 Costal cartilages apex 7 11 • Rhythmically expanded 8

Floating ribs 12 T12 False ribs (8–12) 9 (11–12) by respiratory muscles 10 L1 Costal margin to draw air into lungs Figure 8.27 • Costal margin—inferior border of thoracic cage formed by arc of lower ribs 8-64 The Sternum • Sternum (breastbone)—bony plate anterior to the heart • Divided into three regions – Manubrium • Broad superior portion • Suprasternal (jugular) notch • Clavicular notches—articulate with clavicle – Body (gladiolus) • Longest part of sternum • Sternal angle—point where body joins manubrium • Ribs attach along scalloped lateral margins – Xiphoid • Inferior point of sternum • Attachment for some abdominal muscles • CPR (cardiopulmonary resuscitation) should avoid pressure against the xiphoid to avoid internal bleeding

8-65 The Ribs

Sternoclavicular joint • 12 pairs of ribs

Sternum: Acromioclavicular joint T1 Suprasternal notch - Posterior (proximal)

1 Clavicular notch Pectoral girdle: ends attached to Clavicle Manubrium Scapula 2 Angle vertebral column 3 Body - Most ribs’ anterior 4 True ribs (1–7) (distal) ends attached 5 Xiphoid process to sternum 6 Costal cartilages • Costal cartilages 7 11 8 (made of hyaline Floating ribs 12 T12 False ribs (8–12) 9 (11–12) cartilage) attach rib 10 L1 Costal margin to sternum Figure 8.27

8-66 The Ribs

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tubercle Neck Head • Head—portion of rib that articulates with bodies of Superior Inferior Articular facet thoracic vertebrae Angle for transverse Articular facets process for vertebral bodies – Superior and inferior articular facets Costal groove • Neck—narrow portion distal Shaft

(b) Ribs 2–10 Figure 8.28b to the head • Tubercle—wider, rough Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. area distal to the neck Superior Transverse articular costal facet facet for rib 6 – Articulates with transverse costal facet of vertebra

Tubercle Superior Neck Rib 6 costal facet Head T6 for rib 6 8-67 (b) Superior view Figure 8.29b The Ribs

Superior Inferior • Shaft—long, gentle Articular facet Angle for transverse Articular facets sloping, blade-like portion process for vertebral bodies of rib Costal groove – Costal groove on inferior Shaft margin of shaft (b) Ribs 2–10 Figure 8.28b

8-68 The Ribs

Inferior costal facet of T5 Vertebral Superior articular body T5 facet of rib 6 Rib 6

Inferior articular Vertebral facet of rib 6 body T6 Superior costal facet of T6 (a) Anterior view

Superior Transverse articular costal facet facet for rib 6

Tubercle

Superior Neck Rib 6 costal Head facet T6 for rib 6 Figure 8.29 8-69 (b) Superior view The Ribs

• True ribs (ribs 1–7) – Each is directly connected to sternum • False ribs (ribs 8–12) – Lack independent connections to sternum – Floating ribs (ribs 11–12) • Do not have cartilaginous connection to sternum or higher costal cartilages Figure 8.27 • Do not have tubercles or attachments to transverse processes of vertebra

8-70 The Pectoral Girdle and Upper Limb

• Expected Learning Outcome – Identify and describe the features of the clavicle, scapula, humerus, radius, ulna, and bones of the wrist and hand.

8-71 The Pectoral Girdle

• Pectoral girdle (shoulder girdle) supports the arm

• Consists of two bones on each side of the body – Clavicle (collarbone) and scapula (shoulder blade)

• Clavicle articulates medially to the sternum and laterally to the scapula – Sternoclavicular joint – Acromioclavicular joint

• Scapula articulates with the clavicle and the humerus – Glenohumeral joint: shoulder joint – Easily dislocated due to loose attachment

8-72 The Clavicle

Sternal Acromial end end Conoid tubercle

(a) Superior view

Conoid tubercle Sternal end Acromial end (b) Inferior view Figure 8.30 • Clavicle—S-shaped, somewhat flattened bone • Sternal end—hammer-like head • Acromial end—flattened • Conoid tubercle—rough bump near acromial end • Braces shoulder, keeps arm away from midline • Frequently fractured 8-73 The Scapula • Scapula—named for resemblance to a shovel • Triangular plate that posteriorly overlies ribs 2 to 7 – Three sides: superior, medial, and lateral borders – Three angles: superior, inferior, and lateral angles • Suprascapular notch—conspicuous notch on superior border – Provides passage for a nerve • Spine—transverse ridge on posterior surface – Supraspinous fossa: indentation superior to the spine – Infraspinous fossa: broad surface inferior to the spine

8-74 The Scapula

• Subscapular fossa—concave, anterior surface of scapula • Lateral angle of scapula has three main features – Acromion: plate-like extension of the spine • Forms apex of the shoulder • Articulates with clavicle—sole point of attachment of scapula and upper limb to the rest of the skeleton – Coracoid process: shaped like a bent finger • Provides attachment for tendons of biceps brachii and other arm muscles – Glenoid cavity: shallow socket that articulates with the head of the humerus • Helps form glenohumeral joint

8-75 The Scapula

Acromion Supraspinous Coracoid fossa process Lateral angle Glenoid Spine cavity

Subscapular Infraspinous fossa fossa

Lateral Medial border border

Inferior angle

(a) Anterior view (b) Posterior view Figure 8.31 8-76 The Upper Limb • Upper limb is divided into four regions containing a total of 30 bones per limb – Brachium (arm proper): extends from shoulder to elbow • Contains only 1 bone—humerus – Antebrachium (forearm): extends from elbow to wrist • Contains 2 bones—radius and ulna – Carpus (wrist) • Contains 8 small bones arranged in two rows – Manus (hand) • 19 bones in two groups – 5 metacarpals in palm – 14 phalanges in fingers

8-77 The Humerus

• Proximal end – Hemispherical head that articulates with the glenoid cavity of scapula – Anatomical neck – Greater and lesser tubercles and deltoid tuberosity – Intertubercular sulcus holds biceps tendon – Surgical neck

8-78 Figure 8.32 The Humerus

• Distal end – Rounded capitulum articulates with head of radius – Trochlea articulates with ulna – Lateral and medial epicondyles – Lateral and medial supracondylar ridges – Olecranon fossa holds olecranon process of ulna – Coronoid fossa – Radial fossa

8-79 Figure 8.32 The Radius

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olecranon Olecranon Trochlear notch Radial notch • Radius of ulna Head of radius – Head: disc-shaped, allows Head of Coronoid process radius Neck of for rotation during pronation Neck of radius radius Ulnar tuberosity and supination Radial • Superior surface tuberosity articulates with

Ulna capitulum on humerus • Side of disc spins on Radius radial notch on ulna Interosseous – Neck borders – Radial tuberosity for

Interosseous biceps muscle membrane – Styloid process can be palpated near thumb Ulnar notch of radius – Ulnar notch Head of ulna accommodates head of Styloid process ulna Styloid Articular facets Styloid process process (a) Anterior view (b) Posterior view Figure 8.33 8-80 The Ulna

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olecranon Olecranon Trochlear notch Radial notch • Ulna of ulna Head of radius – Trochlear notch articulates Head of Coronoid process radius Neck of with trochlea of humerus Neck of radius radius Ulnar tuberosity – Olecranon: bony point at Radial tuberosity back of elbow

Ulna – Coronoid process – Radial notch holds head of Radius radius Interosseous – Styloid process borders

Interosseous membrane • Interosseous membrane – Ligament attaches radius to Ulnar notch ulna along interosseous of radius Head of ulna margin of each bone Styloid process Styloid Articular facets Styloid process process (a) Anterior view (b) Posterior view Figure 8.33 8-81 The Carpal Bones

• Eight bones form wrist – Allow movements of flexion, extension, abduction, and adduction • Two rows (four bones each) – Proximal row: scaphoid, lunate, triquetrum, and pisiform • Pisiform is a sesamoid developed by age 9 to12 in tendon of flexor carpi ulnaris muscle – Distal row: trapezium, trapezoid, capitate, and hamate

8-82 The Right Wrist and Hand

Distal phalanx II

Key to carpal bones Middle phalanx II Distal row Proximal row Proximal phalanx II

III II Distal Head IV phalanx I

Phalanges Body V Proximal Base phalanx I I Head

Metacarpal Body First bones metacarpal Base Hamulus of hamate Trapezoid Hamate Trapezium Carpal Carpal Pisiform Capitate bones Triquetrum bones Scaphoid Lunate (a) Anterior view Figure 8.34a

8-83 The Metacarpal Bones and the Phalanges • Metacarpals—bones of the palm – Metacarpal I proximal to base of thumb – Metacarpal V proximal to base of little finger – Proximal base, body, and distal head • Phalanges—bones of the fingers – Thumb or pollex has two phalanges • Proximal, distal phalanx – Fingers have three phalanges • Proximal, middle, distal phalanx

8-84 The Right Wrist and Hand

Distal phalanx II

Key to carpal bones Middle phalanx II Distal row Proximal row Proximal phalanx II

III II Distal Head IV phalanx I

Phalanges Body V Proximal Base phalanx I I Head

Metacarpal Body First bones metacarpal Base Hamulus of hamate Trapezoid Hamate Trapezium Carpal Carpal Pisiform Capitate bones Triquetrum bones Scaphoid Lunate (a) Anterior view Figure 8.34a

8-85 The Pelvic Girdle and Lower Limb

• Expected Learning Outcomes – Identify and describe the features of the pelvic girdle, femur, patella, tibia, fibula, and bones of the foot. – Compare the anatomy of the male and female pelvic girdles and explain the functional significance of the differences.

8-86 The Pelvic Girdle • Pelvic girdle—a ring composed of three

Iliac – Two hip (coxal) bones, crest Iliac fossa also called ossa coxae or Base of Ilium sacrum

Anterior Sacroiliac joint innominate bones superior Pelvic surface iliac spine of sacrum

Anterior inferior Pelvic inlet – One sacrum (also part of iliac spine Spine Coccyx

vertebral column) Ischium Acetabulum Body Interpubic disc Ramus

Superior ramus Obturator • Pelvis—the pelvic girdle Pubis Inferior ramus foramen Body Pubic symphysis

plus ligaments and (a) Anterosuperior view muscles that line the Figure 8.35a pelvic cavity and form its floor

8-87 The Pelvic Girdle

• Sacroiliac joint—joins

Iliac column crest Iliac fossa Base of – Auricular surface of Ilium sacrum Anterior Sacroiliac joint superior Pelvic surface ileum to auricular iliac spine of sacrum

Anterior inferior Pelvic inlet surface of sacrum iliac spine Spine Coccyx

Ischium Acetabulum Body Interpubic disc Ramus

Superior ramus Obturator • Pubic symphysis—the Pubis Inferior ramus foramen Body interpubic disc (of Pubic symphysis (a) Anterosuperior view fibrocartilage) joins Figure 8.35a pubic bones anteriorly

8-88 The Pelvic Girdle

Iliac fossa Base of Ilium sacrum

Anterior Sacroiliac joint superior Pelvic surface iliac spine of sacrum

Anterior inferior Pelvic inlet iliac spine Spine Coccyx

Ischium Acetabulum Body Interpubic disc Ramus

Superior ramus Obturator Pubis Inferior ramus foramen Body Pubic symphysis (a) Anterosuperior view Figure 8.35a Figure 8.35b

• Greater (false) pelvis—between flare of the hips • Lesser (true) pelvis—narrower and below • Pelvic brim—round margin that separates the two • Pelvic inlet—opening circumscribed by brim that infant’s head must pass during birth • Pelvic outlet—lower margin of the lesser pelvis 8-89 The Pelvic Girdle • Three distinct features of hip bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Iliac crest: superior crest of hip Ilium Ischium Pubis Iliac crest

Anterior gluteal – Acetabulum: hip socket line Inferior gluteal line – Obturator foramen: Anterior superior Posterior gluteal iliac spine line

large hole below Posterior superior Iliac spine acetabulum Posterior inferior Anteriorr inferior Iliac spine iliac spine Greater sciatic notch Body of ilium

Acetabulum Superior ramus • Each adult hip bone is of pubis Ischial spine Body of pubis Lesser sciatic notch formed by the fusion Inferior ramus Body of ischium of pubis of three childhood Ischial tuberosity Obturator foramen bones: ilium, Ramus of ischium (a) Lateral view

ishchium, pubis Figure 8.36a 8-90 The Pelvic Girdle • Ilium – Largest bone in hip – Extends from iliac crest to center of the acetabulum – Anterior and posterior superior spine – Anterior and posterior inferior spines – Greater sciatic notch and iliac fossa • Ischium – Inferioposterior portion of hip – Heavy body with prominent spine – Lesser sciatic notch – Ischial tuberosity – Ramus • Pubis (pubic bone) – Most anterior portion of the hip bone – Body, superior, and inferior ramus 8-91 The Pelvic Girdle

Figure 8.37 • Male—heavier and thicker • Female—wider and shallower, and adapted to the needs of pregnancy and childbirth, larger pelvic inlet and outlet for passage of infant’s head

8-92 The Pelvic Girdle

8-93 The Lower Limb

• Lower limb divided into four regions containing 30 bones per limb – Femoral region (thigh): extends from hip to knee region • Contains femur and patella – Crural region (leg proper): extends from knee to ankle • Contains medial tibia and lateral fibula – Tarsal region (tarsus): ankle—the union of the crural region with the foot • Tarsal bones are considered part of the foot – Pedal region (pes): foot • Composed of 7 tarsal bones, 5 metatarsals, and 14 phalanges in the toes

8-94 The Femur

Fovea capitis Greater trochanter Greater trochanter of the body Head

Neck • Hemispherical head articulates Intertrochanteric crest Intertrochanteric line Lesser trochanter with acetabulum of pelvis Spiral line Gluteal tuberosity – Fovea capitis: pit in head of femur for attachment of a Linea aspera ligament

Shaft • Greater and lesser trochanters for muscle attachment • Intertrochanteric crest—thick

Medial supracondylar line Lateral supracondylar line ridge on posterior surface that Popliteal surface Lateral epicondyle Medial epicondyle Lateral epicondyle connects the trochanters Patellar surface Lateral condyle Medial condyle Intercondylar fossa • Intertrochanteric line—more Base of patella Articular facets delicate ridge on anterior Apex of patella surface that connects (a) Anterior view (b) Posterior view Figure 8.38 trochanters 8-95 The Femur

Fovea capitis Greater trochanter Greater trochanter Head

Neck Intertrochanteric crest Intertrochanteric line Lesser trochanter • Linea aspera—ridge on Spiral line Gluteal tuberosity posterior of the shaft

Linea aspera • Spiral (pectineal) line and gluteal tuberosity Shaft • Medial and lateral condyles and epicondyles found distally

Medial supracondylar line Lateral supracondylar line Popliteal surface Lateral epicondyle • Intercondylar fossa Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle Medial condyle Intercondylar fossa • Patellar and popliteal Base of patella Articular facets surface Apex of patella

(a) Anterior view (b) Posterior view Figure 8.38 8-96 The Patella • Patella—triangular sesamoid bone embedded

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. in tendon of knee Fovea capitis Greater trochanter Greater trochanter Head • Cartilaginous at birth Neck Intertrochanteric crest Intertrochanteric line Lesser trochanter – Ossifies at age 3 to 6 years Spiral line Gluteal tuberosity • Base—broad, superior portion Linea aspera • Apex—pointed, inferior Shaft portion • Articular facets—shallow, posterior portion Medial supracondylar line Lateral supracondylar line Popliteal surface Lateral epicondyle • Quadriceps tendon Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle Medial condyle Intercondylar fossa extends from front of thigh Base of patella Articular facets to patella Apex of patella

(a) Anterior view (b) Posterior view – Continues as the patellar Figure 8.38 ligament from patella to tibia 8-97 Tibia

• Tibia—thick, medial, leg bone – Only weight-bearing bone of the crural region – Medial and lateral condyles • Flat surfaces that articulate with condyles of femur – Intercondylar eminence— ridge separating condyles – Tibial tuberosity— attachment of patellar ligament, a continuation of quadriceps tendon – Anterior border—sharp, angular – Medial malleolus—bony knob on inside of ankle

Figure 8.39 8-98 The Fibula

• Fibula—slender, lateral strut that helps stabilize ankle • Does not bear any body weight • Head—proximal end – Apex—point of the head • Lateral malleolus—distal expansion, bony knob on lateral side of ankle • Joined to tibia by interosseous membrane

Figure 8.39 8-99 The Ankle and Foot • Tarsal bones—in ankle – Differ from carpal bones due to load-bearing role of the ankle • Calcaneus—largest tarsal bone – Forms heel Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Distal portion is point of Distal phalanx I attachment for calcaneal Distal Proximal phalanx I phalanx V (Achilles) tendon Middle phalanx V • Talus is most superior tarsal bone Proximal Metatarsal phalanx V I II III – Forms ankle joint with tibia and IV V fibula Medial cuneiform Intermediate cuneiform Lateral cuneiform – Sits upon calcaneus and Navicular Cuboid articulates with navicular Talus Calcaneus • Proximal row of tarsal bones Trochlear surface Key to tarsal bones of talus Distal – Talus, calcaneus, navicular group Tuberosity of calcaneus Proximal group • Distal row of tarsal bones (a) Superior (dorsal) view – Medial, intermediate, lateral Figure 8.40a cuneiforms and cuboid

8-100 The Ankle and Foot

• The rest of the foot bones resemble the hand bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. in name and arrangement Distal phalanx I • Metatarsals Distal Proximal phalanx I phalanx V

Middle – Metatarsal I is proximal to the phalanx V great toe (hallux) Proximal Metatarsal phalanx V I II III – Metatarsal V is proximal to the IV V little toe Medial cuneiform Intermediate cuneiform – Proximal base, intermediate Lateral cuneiform Navicular Cuboid shaft, and distal head

Talus Calcaneus • Phalanges Trochlear surface Key to tarsal bones of talus Distal – Two in great toe group Tuberosity of calcaneus Proximal group • Proximal and distal phalanx (a) Superior (dorsal) view – Three in all other toes Figure 8.40a • Proximal, middle, distal phalanx 8-101 The Ankle and Foot

Thumb Future thumb Elbow

Future Knee great toe Great toe

(a) Seven weeks (b) Eight weeks Figure 8.41 • Rotation of upper and lower limbs in opposite directions – Starts seventh week of embryonic development – Largest digit medial in foot and lateral in hand – Each limb rotates about 90° in opposite directions – Rotation also explains why elbow flexes posteriorly and knee flexes anteriorly 8-102 The Ankle and Foot

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Sole of foot is not flat on ground • Three springy arches absorb stress – Medial longitudinal arch • From heel to hallux • Formed from the Medial longitudinal arch calcaneus, talus, navicular, Transverse cuneiforms, and arch metatarsals I and III

Lateral • Lateral longitudinal arch longitudinal – From heel to little toe arch – Includes calcaneus, cuboid, and metatarsals IV and V Figure 8.42a

(a) Inferior (plantar) view 8-103 The Ankle and Foot

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Transverse arch – Across middle of foot – Includes the cuboid, cuneiforms, and proximal heads of metatarsals – Arches held together by Medial short, strong ligaments longitudinal arch Transverse arch • Pes planus (flat feet)— Lateral longitudinal excessive weight, arch repetitious stress, or congenital weakness Figure 8.42a

(a) Inferior (plantar) view 8-104 Skeletal Adaptations for Bipedalism

• Humans are only animals habitually bipedal – 3.6-million-year-old human footprints indicate upright walking • Adaptations – Strong, springy foot arches – Great toe not opposable – Femurs angle inward so knees are closer together— erect posture requires less muscular effort – Viscera supported in bowl-shaped pelvis – Insertions of gluteal muscles differ from other primates

8-105 Skeletal Adaptations for Bipedalism

8-106 Figure 8.43a,b Skeletal Adaptations for Bipedalism

Figure 8.43c,d,e 8-107 Skeletal Adaptations for Bipedalism

Figure 8.43f 8-108