Chapter 8 *Lecture Powerpoint the Skeletal System

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Chapter 8 *Lecture PowerPoint The Skeletal System

*See separate FlexArt PowerPoint slides for all figures and tables preinserted into PowerPoint without notes.

• 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

7-2 Overview of the Skeleton

Frontal bone Parietal bone • Axial skeleton is Occipital bone Skull Maxilla colored tan Mandible Mandible – Forms central Clavicle Clavicle Pectoral girdle Scapula Scapula supporting axis of the 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 Phalanges 8-3 Figure 8.1 (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 (patella) – Bones that form within some tendons in response to stress • Varies with presence of sutural (wormian) bones in skull – Extra bones that develop in skull suture lines – 270 bones at birth, decreases with fusion • Surface markings – Ridges, spines, bumps, depressions, canals, pores, slits, cavities, and articular surfaces

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, show spatial relationship to each other – Disarticulated bones: bones taken apart so their surface features can be studied in more detail

8-5 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

• 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. 8-7 The Skull

• Skull—the most complex part of the skeleton • 22 bones joined together by sutures (immovable joints) • 8 cranial bones surround cranial cavity which encloses the brain • Other cavities—orbits, nasal cavity, oral (buccal) cavity, middle- and inner-ear cavities, and paranasal sinuses

8-8 The Skull

• Paranasal sinuses—frontal, sphenoid, ethmoid, and maxillary – Lined by mucous membrane and air-filled – Lighten the anterior portion of the skull – Act as chambers that add resonance to the voice • Foramina—holes that allow passage for nerves and blood vessels • 14 facial bones support teeth, facial, and jaw muscles

8-9 The Skull

Cranial cavity

Ethmoid Frontal bone air cells

Ethmoid bone Orbit Superior Zygomatic Nasal Middle bone conchae Inferior Maxilla

Maxillary Vomer sinus

Anterior cranial Frontal lobe fossa

Temporal lobe

Middle cranial fossa Cerebellum

Posterior cranial Posterior cranial fossa fossa Middle cranial fossa

Figure 8.9 Anterior cranial fossa

(a) Superior view (b) Lateral view • Cranium (braincase)—protects the brain and associated sense organs – Meninges separates brain from direct contact with bones—that is, dura mater – Swelling of the brain inside the rigid cranium may force tissue through foramen magnum (large hole, exit for spinal cord) resulting in death – Consists of two parts: calvaria (skullcap) and cranial base 8-11 Cranial Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Figure 8.9

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 • 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 8-12 The Frontal Bone

• Forms forehead and part of the roof of the cranium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal bone Supraorbital • Coronal suture—posterior Glabella foramen

Parietal bone boundary of frontal bone Coronal suture Supraorbital margin Squamous suture • Supraorbital margin forms Temporal bone Sphenoid bone roof of the orbit Lacrimal bone Ethmoid bone Nasal bone Middle nasal • Supraorbital foramen concha Zygomatic bone Infraorbital foramen Inferior nasal concha provides passage for nerve, Maxilla artery, and vein Vomer Mandible • Glabella—smooth area Mental protuberance Mental foramen above root of the nose • Contains frontal sinus Figure 8.3

8-13 The Parietal Bones

Coronal suture

Frontal bone Parietal bone Temporal lines • Form most of cranial roof and

Lambdoid suture Ethmoid bone part of its lateral walls Sphenoid bone Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone • Bordered by four sutures Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla – Sagittal: between parietal Mastoid process Temporal process Styloid process Mandible bones Mandibular condyle Mental foramen (a) Right lateral view Figure 8.4a – Coronal: at anterior margin Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Lambdoid: at posterior Anterior margin Frontal bone – Squamous: at lateral border Coronal suture

Parietal bone • Two temporal lines serve as

Sagittal suture attachment of the temporalis

Sutural bone muscle

Parietal foramen

Lambdoid suture

Occipital bone Figure 8.6 8-14 Posterior The Temporal Bones

• Lateral wall and part of floor Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. of cranial cavity Coronal suture Frontal bone – Squamous part Parietal bone Temporal lines • Encircled by squamous Lambdoid suture Ethmoid bone Sphenoid bone Nasal bone suture Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone • Zygomatic process Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla • Mandibular fossa Mastoid process Temporal process Styloid process Mandible Mandibular condyle Mental foramen (a) Right lateral view – Tympanic part Figure 8.4a • External auditory meatus • Styloid process

8-15 The Temporal Bones

Coronal suture • Mastoid process Frontal bone Parietal bone Temporal lines – Mastoiditis from ear Lambdoid suture Ethmoid bone infection Sphenoid bone Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen • Mastoid notch Temporal bone Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla • Stylomastoid foramen Mastoid process Temporal process Styloid process Mandible Mandibular condyle Mental foramen • Mastoid foramen (a) Right lateral view Figure 8.4a

8-16 The Temporal Bones

Frontal bone Crista galli • Separates middle from Cribriform plate Cribriform foramina of ethmoid bone posterior cranial fossa

Sphenoid bone Optic foramen • Houses middle- and inner- Foramen rotundum Sella turcica Foramen ovale ear cavities Foramen spinosum Temporal bone Internal acoustic meatus Petrous part of temporal bone • Receptors for hearing and Jugular foramen Parietal bone

Groove for Foramen magnum sense of balance venous sinus Occipital bone Hypoglossal canal • Internal auditory meatus—opening for CN (b) Superior view of cranial floor VII (vestibulocochlear Figure 8.5b nerve) • Carotid canal • Jugular foramen 8-17 The Temporal Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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

cord Incisive foramen Palatine process of maxilla

Intermaxillary suture • Basilar part, thick median plate Zygomatic bone

Palatine bone Zygomatic arch • Skull rests on atlas at occipital Greater palatine foramen Posterior nasal Medial pterygoid plate aperture Lateral pterygoid plate condyles Vomer Sphenoid bone Foramen ovale – Condylar canal, posterior to Mandibular fossa Foramen spinosum Foramen lacerum Styloid process Basilar part of each occipital condyle External acoustic meatus occipital bone Occipital condyle Carotid canal Mastoid process Stylomastoid foramen • Hypoglossal canal transmits Mastoid notch Jugular foramen Temporal bone Foramen magnum hypoglossal nerve (CN XII) Condylar canal Mastoid foramen Parietal bone Lambdoid suture supplying tongue muscles Inferior nuchal line Superior nuchal line External occipital protuberance • External occipital Occipital bone protuberance for nuchal (a) Inferior view ligament Figure 8.5a • Superior and inferior nuchal lines mark neck muscles 8-19 The Sphenoid Bone

Lesser wing Dorsum sellae Greater wing Superior orbital Body fissure Foramen Foramen ovale rotundum Lateral pterygoid plate • Body Medial pterygoid plate Pterygoid processes

(b) Posterior view Figure 8.11b • Greater wing

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Lesser wing Diploe (spongy bone) Frontal bone Crista galli Cribriform plate Cribriform foramina of ethmoid bone • Optic foramen Sphenoid bone Optic foramen Foramen rotundum Sella turcica Foramen ovale • Anterior clinoid Foramen spinosum Temporal bone Internal acoustic Petrous part of meatus processes temporal bone Jugular foramen Parietal bone Groove for Foramen magnum venous sinus Occipital bone Hypoglossal canal • Superior orbital fissure

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

Optic foramen Hypophyseal fossa Lesser wing • Foramen Greater wing Foramen rotundum rotundum Sella turcica Anterior clinoid process Dorsum sellae Foramen ovale Foramen spinosum • Foramen ovale (a) Superior view Figure 8.11a • Foramen lacerum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Posterior nasal Diploe (spongy bone) apertures or Frontal bone Crista galli Cribriform plate Cribriform foramina choanae of ethmoid bone

Sphenoid bone Optic foramen • Medial pterygoid Foramen rotundum Sella turcica Foramen ovale plate Foramen spinosum Temporal bone Internal acoustic Petrous part of meatus temporal bone Jugular foramen Parietal bone • Lateral pterygoid Groove for Foramen magnum venous sinus Occipital bone plate Hypoglossal canal Figure 8.5b • Sphenoid sinus

(b) Superior view of cranial floor 8-21 The Sphenoid Bone

Frontal bone Incisive foramen Parietal bone Palatine process Sphenoid sinus of maxilla Squamous suture Intermaxillary suture Frontal sinus Zygomatic bone

Crista galli Palatine bone Occipital bone Zygomatic arch Cribriform plate of Greater palatine foramen Temporal bone ethmoid bone Posterior nasal Medial pterygoid plate Sella turcica aperture Perpendicular plate Lambdoid suture Lateral pterygoid plate Internal acoustic meatus of ethmoid bone Vomer Jugular foramen Nasal bone Sphenoid bone Foramen ovale Hypoglossal canal Vomer Mandibular fossa Foramen spinosum Foramen lacerum Palatine process Styloid process Styloid process of maxilla Basilar part of Mandibular foramen External acoustic meatus occipital bone Maxilla Occipital condyle Carotid canal Palatine bone Mastoid process Stylomastoid foramen Mandible Mastoid notch Jugular foramen Mental spines Temporal bone Foramen magnum Condylar canal Mastoid foramen

(b) Median section Parietal bone Lambdoid suture Inferior nuchal line

Superior nuchal line External occipital Figure 8.4b protuberance Occipital bone

(a) Inferior view Figure 8.5a Sphenoid sinus

Supraorbital foramen

Orbital plate of frontal bone Roof of orbit Lesser wing of sphenoid bone Zygomatic process of frontal bone

Greater wing of Optic foramen Lateral wall sphenoid bone of orbit

Orbital plate of ethmoid bone Orbital surface of zygomatic bone • Anterior cranial bones Medial Lacrimal bone wall Superior orbital fissure Frontal process of maxilla Inferior orbital located between the fissure

Orbital process of eyes palatine bone Infraorbital Floor of foramen orbit Orbital surface of maxilla • Contributes to medial Figure 8.14 wall of orbit Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Lateral walls and roof of Cribriform plate nasal cavity, and nasal Cribriform Crista galli septum foramina Orbital plate • Three major portions of Superior nasal concha this porous, delicate Ethmoidal cells bone Middle nasal concha Perpendicular • Perpendicular plate plate forms superior two-thirds of nasal septum Figure 8.12 8-23 The Ethmoid Bone

Coronal suture

Frontal bone Crista galli Frontal bone Parietal bone Cribriform plate Sphenoid sinus Frontal sinus Squamous suture Cribriform foramina Frontal sinus Nasal bone Sella turcica Crista galli Nasal conchae: Occipital bone Cribriform plate of Superior Temporal bone ethmoid bone Middle Sella turcica Sphenoid sinus Lambdoid suture Perpendicular plate Inferior Internal acoustic meatus of ethmoid bone Nasal cartilages Jugular foramen Nasal bone Occipital bone Hypoglossal canal Vomer Palatine process Styloid process Sphenoid bone of maxilla Mandibular foramen Anterior nasal spine Maxilla Palatine bone Incisive foramen Palatine bone Lacrimal bone Lip Mandible Figure 8.4b Maxilla Mental spines Incisor (b) Median section Figure 8.13 • Cribriform plate—forms roof of nasal cavity – Crista galli: attachment point for meninges – Cribriform (olfactory) foramina • Labyrinth—large mass on each side of perpendicular plate – Ethmoidal cells make up the ethmoid sinus – Orbital plate 8-24 The Ethmoid Bone

Coronal suture

Frontal bone Crista galli Frontal bone Parietal bone Cribriform plate Sphenoid sinus Frontal sinus Squamous suture Cribriform foramina Frontal sinus Nasal bone Sella turcica Crista galli Occipital bone Nasal conchae: Superior Temporal bone Cribriform plate of ethmoid bone Sella turcica Middle Lambdoid suture Perpendicular plate Sphenoid sinus Inferior Internal acoustic meatus of ethmoid bone Jugular foramen Nasal cartilages Nasal bone Occipital bone Hypoglossal canal Vomer Palatine process Styloid process Sphenoid bone of maxilla Mandibular foramen Anterior nasal spine Maxilla Palatine bone Incisive foramen Palatine bone Lacrimal bone Lip Mandible Maxilla Mental spines Incisor (b) Median section Figure 8.4b Figure 8.13

• Superior and middle nasal conchae—scroll-like plates project into the nasal fossa • Inferior nasal concha—separate bone • Three chonchae occupy most of the nasal cavity, create turbulence of airflow, humidify air before it reaches the lungs 8-25 Facial Bones

• Facial bones (14)—those that have no direct contact with the brain or meninges – Support the teeth – Give shape and individuality to the face – Form part of the 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

8-26 The Maxillae

Frontal bone Supraorbital Glabella foramen

Parietal bone Coronal suture Supraorbital margin Squamous suture Temporal bone Sphenoid bone • Largest facial bones Lacrimal bone Ethmoid bone Nasal bone Middle nasal • Forms upper jaw and meets at concha Zygomatic bone Infraorbital foramen Inferior nasal concha median intermaxillary suture Maxilla Vomer – Alveolar processes: bony points Mandible Figure 8.3 between teeth Mental protuberance Mental foramen – Alveolus: sockets that hold teeth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Incisive foramen Palatine process of maxilla Zygomatic bone Intermaxillary suture

Zygomatic arch Palatine bone Greater palatine foramen Posterior nasal Medial pterygoid plate aperture Vomer Lateral pterygoid plate Sphenoid bone Foramen ovale Mandibular fossa Foramen spinosum Foramen lacerum Styloid process Basilar part of External acoustic meatus occipital bone Occipital condyle Carotid canal Mastoid process Stylomastoid foramen Mastoid notch Jugular foramen Temporal bone Foramen magnum Condylar canal Mastoid foramen Parietal bone Lambdoid suture Inferior nuchal line Superior nuchal line External occipital protuberance Occipital bone Figure 8.5a (a) Inferior view 8-27 The Maxillae

Cont. • Forms inferomedial wall of orbit – Infraorbital foramen – Inferior orbital fissure

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

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 8-29 The Palatine Bones

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • L-shaped bone Crista galli Frontal bone Cribriform plate Frontal sinus Cribriform foramina Nasal bone • Form the posterior Sella turcica Nasal conchae: Superior portion of the hard Middle Sphenoid sinus Inferior

Nasal cartilages palate Occipital bone

Sphenoid bone Anterior nasal spine • Part of lateral nasal Palatine bone Incisive foramen Lacrimal bone Lip cavity wall Maxilla Incisor Figure 8.13

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Part of the orbital Supraorbital foramen Orbital plate of frontal bone Roof of orbit Lesser wing of sphenoid bone Zygomatic process floor of frontal bone Greater wing of Optic foramen Lateral wall sphenoid bone of orbit

Orbital plate of ethmoid bone Orbital surface of zygomatic bone • Greater palatine Medial Lacrimal bone wall Superior orbital fissure Frontal process of maxilla Inferior orbital foramina fissure Orbital process of palatine bone Infraorbital Floor of foramen orbit Orbital surface of maxilla

Figure 8.14 8-30 The Zygomatic Bones

Frontal bone Parietal bone Temporal lines • Zygomaticofacial

Lambdoid suture Ethmoid bone Sphenoid bone foramen Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen Zygomatic process • Zygomatic arch is External acoustic meatus Zygomatic bone Maxilla Mastoid process Temporal process formed from temporal Styloid process Mandible Mandibular condyle Mental foramen process of zygomatic (a) Right lateral view bone and zygomatic Figure 8.4a process of temporal bone

8-31 The Lacrimal Bones

Coronal suture

Frontal bone Parietal bone Temporal lines • Smallest bone of skull

Lambdoid suture Ethmoid bone Sphenoid bone Nasal bone Occipital bone • Lacrimal fossa Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen houses lacrimal sac Zygomatic process External acoustic meatus Zygomatic bone Maxilla Mastoid process Temporal process in life Styloid process Mandible Mandibular condyle Mental foramen – Tears collect in (a) Right lateral view lacrimal sac and drain Figure 8.4a into nasal cavity

8-32 The Nasal Bones

Parietal bone • Supports cartilages Coronal suture Supraorbital margin that shape lower Squamous suture Temporal bone Sphenoid bone portion of the nose Lacrimal bone Ethmoid bone Nasal bone Middle nasal concha Zygomatic bone Infraorbital foramen Inferior nasal • Often fractured by concha Maxilla blow to the nose Vomer Mandible

Mental protuberance Mental foramen

Figure 8.3

8-33 The Inferior Nasal Conchae

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Three conchae in the Crista galli Frontal bone Cribriform plate Frontal sinus nasal cavity Cribriform foramina Nasal bone Sella turcica Nasal conchae: – Superior and middle are Superior Middle part of the ethmoid Sphenoid sinus Inferior Nasal cartilages Occipital bone bone Sphenoid bone Anterior nasal spine

Palatine bone Incisive foramen

Lacrimal bone Lip

Maxilla Incisor • Inferior nasal concha is a separate bone Figure 8.13 – Largest of the three

8-34 The Vomer

Frontal bone Parietal bone nasal septum Sphenoid sinus Squamous suture Frontal sinus

Crista galli – Superior half formed Occipital bone Cribriform plate of Temporal bone ethmoid bone Sella turcica by perpendicular Lambdoid suture Perpendicular plate Internal acoustic meatus of ethmoid bone Jugular foramen Nasal bone plate of ethmoid Hypoglossal canal Vomer Palatine process Styloid process of maxilla Mandibular foramen Maxilla • Supports cartilage Palatine bone Mandible Mental spines that forms the (b) Median section anterior part of the Figure 8.4b nasal septum

8-35 The Mandible

Intermaxillary suture – Only bone of skull that moves Zygomatic bone

Palatine bone Zygomatic arch noticeably Greater palatine foramen Posterior nasal Medial pterygoid plate aperture Lateral pterygoid plate – Supports lower teeth Vomer Sphenoid bone Foramen ovale Mandibular fossa Foramen spinosum Foramen lacerum • Provides attachments for Styloid process Basilar part of External acoustic meatus occipital bone Occipital condyle Carotid canal muscles of facial expression Stylomastoid foramen Mastoid process Mastoid notch Jugular foramen Temporal bone Foramen magnum and mastication Condylar canal Mastoid foramen

Parietal bone Lambdoid suture Inferior nuchal line

Superior nuchal line External occipital protuberance Occipital bone • Mental symphysis— (a) Inferior view Mandibular condyles median cartilaginous joint in Condylar process Coronoid process fetus Mandibular notch

– Develops as two separate Mandibular foramen bones in fetus Alveolar process Ramus – Ossifies in early childhood Mental foramen

Mental protuberance 8-36 Figure 8.15 Angle Body The Mandible

Intermaxillary suture point of chin Zygomatic bone

Palatine bone Zygomatic arch Greater palatine foramen • Two major parts on each Posterior nasal Medial pterygoid plate aperture Lateral pterygoid plate Vomer side Foramen ovale Sphenoid bone Mandibular fossa Foramen spinosum Foramen lacerum – Body: supports teeth Styloid process Basilar part of External acoustic meatus occipital bone Occipital condyle Carotid canal Mastoid process Stylomastoid foramen – Ramus: articulates with Mastoid notch Jugular foramen Temporal bone Foramen magnum cranium Condylar canal Mastoid foramen Parietal bone Lambdoid suture • Angle—where body and Inferior nuchal line Superior nuchal line External occipital protuberance ramus meet Occipital bone (a) Inferior view

Mandibular condyles • Alveolar processes Condylar process Coronoid process

between teeth Mandibular notch

• Mental foramen—permits Mandibular foramen passage of nerves and BVs Alveolar process Ramus

• Mental spines Mental foramen

Mental protuberance 8-37 Figure 8.15 Angle Body The Mandible

• Condylar process bears the mandibular condyle—oval Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. knob that articulates with the Mandibular condyles Condylar process mandibular fossa of the Coronoid process

Mandibular notch temporal bone forming the hinge temporomandibular Mandibular foramen joint (TMJ) Alveolar process Ramus • Coronoid process—point of Mental foramen insertion of temporalis muscle Mental protuberance Angle • Mandibular notch Body Figure 8.15 • Mandibular foramen—BVs, nerves supply lower teeth

8-38 Bones Associated with the Skull

• Auditory ossicles

• Hyoid bone – Slender U-shaped bone Styloid process between the chin and larynx Stylohyoid muscle

– Does not articulate with any Hyoid

other bone Larynx Lesser horn Greater horn – Suspended from styloid process of skull by muscle and

ligament Body – Body and greater and lesser horns (cornua) Figure 8.16 – Fractured hyoid bone is evidence of strangulation 8-39 The Skull in Infancy and Childhood

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Fontanels—spaces between Coronal suture unfused bones Frontal Parietal bone bone Sphenoid – Filled with 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 reaches adult size by 8

Posterior fontanel or 9 years of age

(b) Superior view Figure 8.17 8-40 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.

Atlas (C1) • Functions Axis (C2) Cervical vertebrae – Supports the skull and trunk C7

– Allows for their movement T1 – Protects the spinal cord – Absorbs stress of walking, running, and lifting Thoracic vertebrae – Provides attachments for limbs, thoracic cage, and postural muscles T12 L1 • 33 vertebrae with Lumbar vertebrae

intervertebral discs of L5

fibrocartilage between S1 most of them Sacrum

Atlas (C1) Axis (C2) • Adult vertebral column Cervical vertebrae

averages 71 cm (28 in.) C7 long T1 – Intervertebral discs

account for about one- Thoracic vertebrae quarter of its length – Person is 1% shorter when in bed T12 – Compression squeezes L1 water out during the day Lumbar vertebrae and absorbs water when compression is removed L5 during sleep S1 Sacrum

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 of L1 lumbar and sacral Lumbar vertebrae

vertebrae occur in 1 in L5

20 people S1 Sacrum

• Spine exhibits one continuous C-shaped curve at birth

• Known as primary curvature

Figure 8.20 © The McGraw-Hill Companies, Inc./Bob Coyle, photographer 8-45 General Features of the Vertebral Column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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

8-46 Figure 8.19 General Features of the Vertebral Column

• Primary curvatures—present at birth – Thoracic and pelvic

• Secondary curvatures—develop later – Cervical and lumbar – Lifting head as it begins to crawl develops cervical curvature – Walking upright develops lumbar curvature

8-47 Abnormal Spinal Curvatures

• From disease, paralysis of trunk muscles, poor posture, pregnancy, or congenital defect

• Scoliosis—abnormal lateral curvature – Most common – Usually in thoracic region (a) Scoliosis (b) Kyphosis (“hunchback”) (c) Lordosis – Particularly of adolescent girls Key (“hunchback”) Normal Pathological – Developmental abnormality in which the body and arch fail to Figure 8.21 develop on one side of the vertebrae

8-48 Abnormal Spinal Curvatures

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

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

8-49 General Structure of Vertebra

Spinous process

• Body (centrum) Superior articular Lamina facet

– Mass of spongy bone that Vertebral Transverse arch contains red bone marrow process – Covered with thin shell of Vertebral foramen Pedicle compact bone – Weight-bearing portion Body – Rough superior and inferior surfaces provide firm Anterior attachment for (a) 2nd lumbar vertebra (L2) intervertebral discs

• Vertebral foramina Nucleus pulposus – Collectively form vertebral canal for spinal cord Anulus fibrosus

(b) Intervertebral disc

Figure 8.22a,b 8-50 General Structure of Vertebra

• Vertebral arch – Composed of two parts on each side – Pedicle: pillarlike and lamina: platelike • Spinous process – Projection extending from the apex of arch – Extends posteriorly and downward • 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 covered with hyaline cartilage

8-51 General Structure of Vertebra

Superior articular process of L1 • Intervertebral foramen

Inferior vertebral – When two vertebrae are notch of L1 L1 joined they exhibit an Intervertebral foramen opening between their Superior vertebral pedicles notch of L2 L2 – Passageway for spinal Spinous process nerves

Intervertebral disc – Inferior vertebral notch L3 in the pedicle of the Inferior articular process of L3 upper vertebra

(b) Left lateral view – Superior vertebral notch in the pedicle of Figure 8.23b the lower vertebra

8-52 General Structure of Vertebra

• Intervertebral discs (23) – First one between C2 and C3 – Last one between L5 and sacrum – 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 spinal cord

8-53 The Cervical Vertebrae

• Cervical vertebrae—atlas (C1) – Supports the head Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Has no body – Delicate ring surrounding a Transverse process large vertebral foramen L2 – Lateral masses with superior Body (centrum) articular facets Intervertebral disc Inferior articular • Articulates with occipital process of L2 condyles Superior articular process of L3 • Allows nodding motion of L3 Lamina skull gesturing “yes” – Inferior articular facets articulate with C2 (a) Posterior (dorsal) view – Anterior and posterior arches Figure 8.23a – Anterior and posterior tubercles 8-54 The Cervical Vertebrae

• Cervical vertebrae—axis (C2) – Allows rotation of the head gesturing “no” – Dens or odontoid process— Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. prominent knob on its Dens (odontoid process) anterosuperior side Superior articular facet Body • Forms as an independent ossification center during Transverse foramen first year of life Transverse process Pedicle • Fuses with axis by age 3 to 6 Inferior articular process years Lamina • Projects into vertebral foramen of the atlas Spinous process • Held in place by a (b) Axis transverse ligament Figure 8.24b – Atlanto–occipital joint: between atlas and cranium – Atlantoaxial joint: between atlas and axis 8-55 Atlas and Axis Articulation Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Axis of rotation

Dens Atlas

Transverse ligament Axis

Figure 8.24c

8-56 (c) Atlantoaxial joint The Cervical Vertebrae

Spinous process

Lamina Superior articular facet Figure 8.25a

Transverse foramen Body Transverse process Spinous process (a) Cervical vertebrae Inferior articular process • C1 to C7 are smallest and lightest vertebrae, other than the coccygeals • Bifid or forked spinous processes in C2 to C6 • Small body and larger vertebral foramen • Transverse foramen in each short transverse process – Provides passage and protection for vertebral arteries (supply blood to brain) and vertebral veins (drain blood from various neck structures) – Transverse foramen only found in cervical vertebrae • C7 vertebra prominens—spinous process not bifid and especially long – Prominent bump on lower back of neck; convenient landmark for counting vertebrae 8-57 The Thoracic Vertebrae

Spinous process Superior articular facet Lamina Transverse process Figure 8.25b

Transverse costal facet Superior costal facet Transverse costal facet Inferior costal facet Body Inferior articular facet (b) Thoracic vertebrae Spinous process • 12 thoracic vertebrae (T1–T12) – Corresponds to the 12 pairs of ribs attached to them • Spinous processes pointed and angled sharply downward • Larger body than cervical, but smaller than lumbar • 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 • Inferior and superior costal facets on vertebral body – In most cases, ribs insert between the two vertebra 8-58 The Lumbar Vertebrae

Spinous process Figure 8.25c 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 8-59 • Sacrum—bony plate that forms The Sacrum posterior wall of pelvic cavity • Once considered seat of the soul Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior articular • In children, five separate sacral process vertebrae (S1–S5) Sacral promontory • Begin fusion around age 16 Ala S1 and complete fusion by age 26 • Anterior surface S2 Transverse lines – Smooth and concave S3 – Four transverse lines indicate Anterior sacral foramina S4 line of fusion of vertebrae S5 – Four pairs of large anterior Co1 Coccyx Co2 Co3 sacral (pelvic) foramina Co4 • Allow for passage of nerves (a) Anterior view and arteries into pelvic organs Figure 8.26a • Sacral promontory on S1 supports L5 8-60 • Posterior surface very rough The Sacrum • Median sacral crest – Formed from fusion of spinous processes • Lateral sacral crest – Less prominent, and on either side of median sacral crest Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. – Formed from the fusion of the Superior articular Sacral canal process transverse processes • Posterior sacral foramina – Four pairs of openings for spinal Median nerves that supply gluteal region and sacral crest lower limbs Auricular • Sacral canal runs through surface sacrum and ends as sacral Lateral sacral hiatus crest – Contains spinal nerve roots

Posterior sacral • Auricular surface is part of foramina sacroiliac (SI) joint formed with hip bone Sacral hiatus Horn • Superior articular processes on

Transverse S1; articulates with L5 process Coccyx • Alae—pair of large, rough, winglike extensions lateral to the superior articular processes (b) Posterior view Figure 8.26b 8-61 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 a single, triangular bone by age 20 to Median sacral crest 30

Auricular surface • Horns (cornua) on Co1

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

Sacral hiatus • Fractured during difficult Horn childbirth or by hard fall on Transverse process Coccyx buttocks • Provide attachment for (b) Posterior view muscles of the pelvic floor Figure 8.26b 8-62 The Thoracic Cage • Consists of thoracic vertebrae, sternum, ribs • Forms conical enclosure for lungs and heart • Provides attachment for Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sternoclavicular joint pectoral girdle and upper Sternum: Acromioclavicular joint T1 Suprasternal notch limbs 1 Clavicular notch Pectoral girdle: Clavicle Manubrium • Broad base and narrower Scapula 2 Angle apex 3 Body 4 • Rhythmically expanded by True ribs (1–7) respiratory muscles to draw 5 Xiphoid process air into lungs 6 Costal cartilages

7 11 • Costal margin—inferior 8 border of thoracic cage Floating ribs 12 T12 False ribs (8–12) 9 (11–12) 10 L1 formed by downward arc of Costal margin ribs Figure 8.27 • Protect thoracic organs, but also spleen, most of liver, and to some extent the kidneys 8-63 The Sternum • Sternum (breastbone)—bony plate anterior to the heart • Divided into three regions – Manubrium • Broad superior portion • Suprasternal (jugular) notch medially • Clavicular notches—articulate with clavicle • Ribs attach along scalloped lateral margins – Body (gladiolus) • Longest part of sternum • Sternal angle—point where body joins manubrium • Ribs attach along scalloped lateral margins – Xiphoid • Inferior end of sternum • Attachment for some abdominal muscles • In cardiopulmonary resuscitation, improperly performed chest compressions can drive xiphoid process into the liver and cause a fatal hemorrhage 8-64 The Ribs

Tubercle Neck Head • 12 pairs of ribs – No difference between sexes – Posterior (proximal) end Superior Inferior Articular facet attached to vertebral column Angle for transverse Articular facets process for vertebral bodies – Anterior (distal) ends mostly attached to the Costal groove sternum Shaft – Costal cartilages composed (b) Ribs 2–10 Figure 8.28b of hyaline cartilage attach

Superior Transverse • Head—portion of rib that articular costal facet facet for rib 6 articulates with thoracic

Tubercle vertebrae Superior Neck Rib 6 costal – Superior articular facet facet Head T6 for rib 6 – Inferior articular facet 8-65 (b) Superior view Figure 8.29b The Ribs

Superior Inferior • Tubercle—wider rough Articular facet Angle for transverse Articular facets area distal to the neck process for vertebral bodies – Articulates with Costal groove transverse costal facet Shaft of vertebra (b) Ribs 2–10 Figure 8.28b • Angle—lateral curve of

Superior Transverse • Shaft—long, gentle articular costal facet facet for rib 6 sloping, bladelike portion

Tubercle of rib Superior Neck Rib 6 costal – Costal groove on inferior facet Head T6 for rib 6 margin of shaft 8-66 (b) Superior view Figure 8.29b 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 Figure 8.29 facet T6 for rib 6 8-67 (b) Superior view The Ribs

Sternoclavicular joint

Sternum: Acromioclavicular joint T1 Suprasternal notch

1 Clavicular notch Pectoral girdle: Clavicle Manubrium Scapula 2 Angle

3 Body 4 True ribs (1–7)

5 Xiphoid process

6 Costal cartilages

7 11 8

Floating ribs 12 T12 False ribs (8–12) 9 (11–12) 10 L1 Costal margin

Figure 8.27

8-68 The Ribs

• True ribs (ribs 1–7) – Each has own costal cartilage connecting to sternum

• False ribs (ribs 8–12) – Lack independent cartilaginous connection to sternum

– Floating ribs (ribs 11–12) • Articulate with bodies of vertebrae T11 and T12 • Do not have tubercles • Do not attach to transverse processes of the vertebra • No cartilaginous connection to the sternum or any of the higher costal cartilages

8-69 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.

8-70 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 humerus – Glenohumeral joint: shoulder joint – Easily dislocated due to loose attachment 8-71 The Clavicle

Sternal Acromial end end Conoid tubercle

(a) Superior view Figure 8.30

Conoid tubercle Sternal end Acromial end (b) Inferior view

• Clavicle—S-shaped, somewhat flattened bone • Inferior—grooves and ridges for muscle attachment • Sternal end—rounded head

8-72 The Clavicle

• Acromial end—flattened – Conoid tubercle: roughened tuberosity near acromial end; ligament attachment • Braces shoulder, keeping upper limb away from midline of body • Most frequently fractured bone in the body

8-73 The Scapula

• Scapula—named for its resemblance to a spade or shovel • Triangular plate that posteriorly overlies ribs 2 to 7 – Three sides: superior, medial (vertebral), and lateral (axillary) borders – Three angles: superior, inferior, and lateral angles

8-74 The Scapula

• 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

8-75 The Scapula

• Subscapular fossa—concave, anterior surface of scapula • Complex lateral angle of scapula has three main features – Acromion: platelike extension of the spine • Forms apex of the shoulder • Articulates with the clavicle—the sole point of attachment of the scapula and the upper limb to the rest of the skeleton

8-76 The Scapula

Cont. – Coracoid process: shaped like a bent finger • Provides attachment for tendons of the biceps brachii and other arm muscles

– Glenoid cavity: shallow socket that articulates with the head of the humerus • Forming glenohumeral joint

8-77 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 8-78 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

8-79 The Humerus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Greater Greater Head tubercle tubercle Lesser Anatomical tubercle neck • Proximal end Surgical neck – Hemispherical head Intertubercular Nutrient that articulates with sulcus foramen the glenoid cavity of Deltoid scapula tuberosity Deltoid tuberosity – Anatomical neck – Greater and lesser tubercles and deltoid tuberosity – Intertubercular Coronoid fossa sulcus holds biceps Radial Medial Lateral tendon fossa supracondylar supracondylar Lateral ridge ridge – Surgical neck epicondyle Medial Lateral Capitulum epicondyle epicondyle Olecranon Trochlea fossa 8-80 (a) Anterior view (b) Posterior view Figure 8.32 The Humerus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Greater Greater Head tubercle tubercle Lesser Anatomical • Distal end tubercle neck Surgical – Rounded capitulum neck articulates with head of Intertubercular Nutrient sulcus foramen radius – Trochlea articulates Deltoid tuberosity Deltoid with ulna tuberosity – Lateral and medial epicondyles – Lateral and medial supracondylar ridges – Olecranon fossa holds Coronoid fossa olecranon process of Radial Medial Lateral ulna fossa supracondylar supracondylar Lateral ridge ridge – Coronoid fossa epicondyle Medial Lateral Capitulum epicondyle epicondyle – Radial fossa Olecranon Trochlea fossa 8-81 Figure 8.32 (a) Anterior view (b) Posterior view The Radius

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olecranon Olecranon Trochlear notch • Radius Radial notch of ulna Head of – Head: disc-shaped, allows radius Head of Coronoid process radius for rotation around the Neck of Neck of radius radius Ulnar tuberosity longitudinal axis of the bone Radial during pronation and tuberosity supination of hand Ulna • Superior surface Radius articulates with capitulum on humerus Interosseous borders • Side of disc spins on radial notch on ulna Interosseous membrane – Neck Ulnar notch of radius – Radial tuberosity for Head of ulna biceps muscle Styloid process Styloid Articular facets Styloid – Styloid process can be process process (a) Anterior view (b) Posterior view palpated near thumb Figure 8.33 – Ulnar notch 8-82 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 – Enables the two elbow joints Styloid Articular facets Styloid process process to share the load (a) Anterior view (b) Posterior view Figure 8.33 8-83 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

8-84 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 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

8-86 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.

8-87 The Pelvic Girdle

Iliac consists of a complete fossa Base of Ilium sacrum ring composed of Anterior Sacroiliac joint superior Pelvic surface iliac spine of sacrum

Anterior inferior Pelvic inlet three bones iliac spine Spine Coccyx

– Two hip (coxal) Ischium Acetabulum Body Interpubic disc bones, also called Ramus Superior ramus Obturator Pubis Inferior ramus foramen ossa coxae or Body Pubic symphysis

innominate bones (a) Anterosuperior view – Sacrum is also part of Figure 8.35a the vertebral column

8-88 The Pelvic Girdle • Pelvis—bowl-shaped structure composed of the two coxal bones and sacrum as well as their ligaments and muscles that line the pelvic cavity and form its floor – Supports trunk on the lower limbs and protects viscera, lower colon, urinary bladder, and internal reproductive organs • Sacroiliac joint—joins hipbone to the vertebral column – Auricular surface of ileum to auricular surface of sacrum

8-89 The Pelvic Girdle

Iliac • Anteriorly, interpubic crest

Iliac disc—pad of fossa Base of Ilium sacrum

Anterior Sacroiliac joint fibrocartilage joins superior Pelvic surface iliac spine of sacrum

Anterior inferior Pelvic inlet pubic bones iliac spine Spine Coccyx

Ischium Acetabulum Body Interpubic disc Ramus

Superior ramus Obturator • Pubic symphysis— Pubis Inferior ramus foramen Body the interpubic disc and Pubic symphysis (a) Anterosuperior view adjacent regions of the Figure 8.35a pubic bone on each side

8-90 The Pelvic Girdle

Iliac crest

Iliac Greater pelvis fossa Base of Ilium sacrum

Anterior Sacroiliac joint superior Pelvic surface iliac spine of sacrum Pelvic brim Anterior inferior Pelvic inlet iliac spine Spine Pelvic inlet Coccyx

Ischium Acetabulum Body Interpubic Lesser disc Ramus pelvis

Superior ramus Obturator Pubis Inferior ramus foramen Body Pubic symphysis

(a) Anterosuperior view Pelvic outlet Figure 8.35a (b) Median section 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 8-91 The Pelvic Girdle

Anterior gluteal crest of hip line Inferior gluteal line Anterior superior – Acetabulum: hip socket Posterior gluteal iliac spine line

Posterior superior – Obturator foramen: Iliac spine

Posterior inferior Anteriorr inferior large hole below Iliac spine iliac spine Greater sciatic notch acetabulum Body of ilium Acetabulum Superior ramus of pubis Ischial spine Body of pubis Lesser sciatic notch Inferior ramus Body of ischium of pubis

Ischial tuberosity Obturator foramen

Ramus of ischium

(a) Lateral view Figure 8.36a 8-92 The Pelvic Girdle

• Each adult hip bone is formed by the fusion of three childhood bones: illeum, ishchium, pubis

• Ileum – Largest – Extends from the iliac crest to the center of the acetabulum – Anterior and posterior superior spine – Anterior and posterior inferior spines – Greater sciatic notch and iliac fossa

8-93 The Pelvic Girdle • 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

8-94 The Pelvic Girdle

Triangular pubic body Rectangular pubic body Large, oval obturator Triangular foramen obturator foramen Narrow subpubic angle Wide subpubic angle (a) Male, anterior view (c) Female, anterior view

Preauricular sulcus

Wide greater Narrow greater sciatic notch sciatic notch

(b) Male, medial view (d) Female, medial view (a): © David Hunt/specimens from the National Museum of Natural History, Smithsonian Institution; (b-c): © L. Bassett/Visuals Unlimited; (d): © David Hunt/specimens from the National Museum of Natural History, Smithsonian Institution Figure 8.37 • Male—heavier and thicker due to forces exerted by stronger muscles

• Female—wider and shallower, and adapted to the needs of pregnancy and childbirth, larger pelvic inlet and outlet for passage of infant’s head 8-95 The Lower Limb

• Lower limb divided into four regions containing 30 bones per limb – Femoral region (thigh): extends from hip to knee region • Contains the 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

8-96 The Femur

Neck Intertrochanteric crest • Hemispherical head that Intertrochanteric line Lesser trochanter

Spiral line Gluteal tuberosity articulates with the acetabulum of the pelvis

Linea aspera – Forms ball-and-socket joint – Fovea capitis: pit in head of Shaft femur for attachment of a ligament • Greater and lesser trochanters for muscle Medial supracondylar line Lateral supracondylar line Popliteal surface attachment Lateral epicondyle Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle • Intertrochanteric crest— Medial condyle Intercondylar fossa

Base of patella thick oblique ridge on the Articular facets Apex of patella posterior surface that

(a) Anterior view (b) Posterior view connects the trochanters

Figure 8.38 8-97 The Femur

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fovea capitis • Intertrochanteric line—more Greater trochanter Greater trochanter Head delicate ridge on the anterior Neck Intertrochanteric crest surface that connects Intertrochanteric line Lesser trochanter trochanters Spiral line Gluteal tuberosity • Linea aspera—ridge on Linea aspera posterior of the shaft

Shaft • Spiral (pectineal) line and gluteal tuberosity • Medial and lateral condyles

Medial supracondylar line Lateral supracondylar and epicondyles found line Popliteal surface distally Lateral epicondyle Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle Medial condyle Intercondylar fossa • Intercondylar fossa Base of patella Articular facets Apex of patella • Patellar and popliteal (a) Anterior view (b) Posterior view surface Figure 8.38 8-98 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 femoris tendon Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle Medial condyle Intercondylar fossa extends from anterior Base of patella Articular facets muscle of thigh to patella Apex of patella

(a) Anterior view (b) Posterior view – Continues as the patellar Figure 8.38 ligament from patella to tibia 8-99 Tibia • Tibia—thick, medial, weight-

Intercondylar eminence Medial Lateral condyle condyle – Only weight-bearing bone of Apex Head of fibula Proximal tibiofibular Tibial the crural region joint tuberosity – Broad superior head – Medial and lateral condyles

Lateral surface Interosseous membrane • Fairly flat articular surfaces • Articulate with condyle of Anterior crest femur Tibia – Intercondylar eminence— ridge separating condyles Fibula – Tibial tuberosity— attachment of quadricep muscles Distal tibiofibular joint – Anterior crest—sharp, Medial Lateral malleolus Lateral malleolus malleolus angular (a) Anterior view (b) Posterior view – Medial malleolus—bony Figure 8.39 knob on inside of ankle 8- 100 The Fibula

Intercondylar eminence Medial Lateral condyle condyle that helps stabilizes ankle Apex Head of fibula Proximal tibiofibular Tibial joint tuberosity • Does not bear any body weight

Lateral surface Interosseous – Spare bone tissue for grafts membrane

Anterior crest • Head—proximal end Tibia • Apex—point of the head

Fibula • Lateral malleolus—distal expansion, bony knob on lateral side of ankle Distal tibiofibular joint Medial Lateral malleolus Lateral malleolus malleolus • Joined to tibia by (a) Anterior view (b) Posterior view interosseous membrane Figure 8.39 8- 101 • Tarsal bones—arranged in The Ankle and Foot proximal and distal groups – Tarsal bones are shaped and arranged differently from carpal bones due to load- bearing role of the ankle

Distal phalanx I bone

Distal – Forms heel Proximal phalanx I phalanx V

Middle – Distal portion is point of phalanx V attachment for calcaneal Proximal Metatarsal phalanx V I II III (Achilles) tendon IV V • Talus is most superior tarsal Medial cuneiform Intermediate cuneiform bone Lateral cuneiform Navicular Cuboid – Forms ankle joint with tibia Talus Calcaneus and fibula

Trochlear surface Key to tarsal bones of talus – Sits upon calcaneus and Distal group articulates with navicular Tuberosity of calcaneus Proximal group (a) Superior (dorsal) view • Proximal row of tarsal bones – Talus, calcaneus, navicular Figure 8.40a • Distal row of tarsal bones – Medial, intermediate, lateral cuneiforms and cuboid 8- 102 The Ankle and Foot

• Remaining bones of foot are similar in name and Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. arrangement to the hand 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- 103 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- 104 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 calcaneus, talus, navicular, longitudinal arch cuneiforms, and Transverse arch metatarsals I and III

Lateral longitudinal • Lateral longitudinal arch arch – From heel to little toe – Includes calcaneus, cuboid, Figure 8.42a and metatarsals IV and V (a) Inferior (plantar) view 8- 105 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- 106 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- 107 Skeletal Adaptations for Bipedalism Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

(a) Foot (b) Knee

Chimpanzee

Human

8- Figure 8.43a,b Chimpanzee Human 108 Skeletal Adaptations for Bipedalism Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (c) Gluteal muscles (d) Pelvis (e) Vertebral column

Chimpanzee Chimpanzee

Chimpanzee

Human Human Human 8- Figure 8.43c,d,e 109 Skeletal Adaptations for Bipedalism

(f) Skull

Supraorbital ridge

Pivot

Foramen magnum

Chimpanzee

Pivot Figure 8.43f Foramen magnum 8- Human 110