Chapter 8 *Lecture PowerPoint The Skeletal System Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Introduction • 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Skull Pectoral girdle • Axial skeleton is colored tan Parietal bone Frontal bone Occipital bone Maxilla Mandible Mandible Clavicle Clavicle Scapula Scapula – Forms central supporting axis of the body – Skull, vertebrae, sternum, ribs, sacrum, and hyoid Sternum Humerus Thoracic Ribs cage Costal cartilages Vertebral column Pelvis Hip bone Sacrum Ulna Radius Coccyx • Appendicular skeleton is colored green Carpus Metacarpal bones Phalanges – – – – Femur Patella Fibula Tibia Pectoral girdle Upper extremity Pelvic girdle Lower extremity Metatarsal bones Tarsus Phalanges Figure 8.1 (a) Anterior view 8-3 (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 Copyright © The McGraw-Hill Companies, Inc. 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Lines Crest Sinuses Foramen Fovea Head Meatus Crest Trochanters Process Condyle Spine Head Tubercle Alveolus Foramen Tuberosity (a) Skull (lateral view) Line Process Fossae Spine Epicondyles Fossae Condyles (b) Scapula (posterior view) Figure 8.2 (c) Femur (posterior view) (d) Humerus (anterior view) 8-6 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. 8-7 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cranial cavity Ethmoid air cells Frontal bone Ethmoid bone Orbit Superior Nasal conchae Middle Zygomatic bone Inferior Maxilla Maxillary sinus Vomer Nasal cavity Oral cavity Mandible Figure 8.7 8-10 Cranial Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal lobe Anterior cranial fossa Temporal lobe Middle cranial fossa Cerebellum Posterior cranial fossa Posterior cranial 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 Frontal lobe Anterior cranial fossa Temporal lobe Middle cranial fossa Cerebellum Posterior cranial fossa Posterior cranial 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 • Coronal suture—posterior boundary of frontal bone • Supraorbital margin forms roof of the orbit • Supraorbital foramen provides passage for nerve, artery, and vein • Glabella—smooth area above root of the nose • Contains frontal sinus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal bone Supraorbital foramen Glabella Parietal bone Coronal suture Supraorbital margin Squamous suture Temporal bone Sphenoid bone Lacrimal bone Ethmoid bone Nasal bone Middle nasal concha Zygomatic bone Inferior nasal concha Infraorbital foramen Maxilla Vomer Mandible Mental foramen Mental protuberance Figure 8.3 8-13 The Parietal Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Parietal bone Temporal lines Lambdoid suture Ethmoid bone • Form most of cranial roof and part of its lateral walls Sphenoid bone Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla Mastoid process Temporal process Styloid process Mandible Mandibular condyle Mental foramen (a) Right lateral view Figure 8.4a Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior Frontal bone Coronal suture • Bordered by four sutures – Sagittal: between parietal bones – Coronal: at anterior margin – Lambdoid: at posterior margin – Squamous: at lateral border • Two temporal lines serve as attachment of the temporalis muscle Parietal bone Sagittal suture Sutural bone Parietal foramen Lambdoid suture Occipital bone Posterior Figure 8.6 8-14 The Temporal Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Parietal bone Temporal lines Lambdoid suture Ethmoid bone • Lateral wall and part of floor of cranial cavity – Squamous part Sphenoid bone Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla Mastoid process • Encircled by squamous suture • Zygomatic process • Mandibular fossa Temporal process Styloid process Mandible Mandibular condyle Mental foramen (a) Right lateral view Figure 8.4a – Tympanic part • External auditory meatus • Styloid process 8-15 The Temporal Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Parietal bone Temporal lines Lambdoid suture Ethmoid bone Sphenoid bone Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla Mastoid process Temporal process Styloid process Mandible Mandibular condyle Mental foramen – Mastoid part • Mastoid process – Mastoiditis from ear infection • Mastoid notch • Stylomastoid foramen • Mastoid foramen (a) Right lateral view Figure 8.4a 8-16 The Temporal Bones – Petrous part Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diploe (spongy bone) Frontal bone Crista galli Cribriform plate of ethmoid bone Cribriform foramina Sphenoid bone Optic foramen Sella turcica Foramen rotundum Foramen ovale Temporal bone Foramen spinosum Internal acoustic meatus Petrous part of temporal bone Jugular foramen Parietal bone Groove for venous sinus Foramen magnum Occipital bone Hypoglossal canal (b) Superior view of cranial floor Figure 8.5b • Part of cranial floor • Separates middle from posterior cranial fossa • Houses middle- and innerear cavities • Receptors for hearing and sense of balance • Internal auditory meatus—opening for CN VII (vestibulocochlear 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 Mastoid process Styloid process External acoustic meatus Tympanic part (a) Lateral surface Squamous suture Squamous part Petrous part Zygomatic process Internal acoustic meatus Mastoid process Styloid process (b) Medial surface Figure 8.10 8-18 The Occipital Bone • Rear and base of skull • Foramen magnum holds spinal cord • Basilar part, thick median plate • Skull rests on atlas at occipital condyles – Condylar canal, posterior to each occipital condyle • Hypoglossal canal transmits hypoglossal nerve (CN XII) supplying tongue muscles • External occipital protuberance for nuchal ligament • Superior and inferior nuchal lines mark neck muscles Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Incisive foramen Palatine process of maxilla Intermaxillary suture Zygomatic bone Palatine bone Zygomatic arch Greater palatine foramen Posterior nasal aperture Medial pterygoid plate Lateral pterygoid plate Vomer Sphenoid bone Foramen ovale Mandibular fossa Foramen spinosum Foramen lacerum Basilar part of occipital bone Carotid canal Styloid process External acoustic meatus Occipital condyle Stylomastoid foramen Mastoid process Mastoid notch Temporal bone Jugular foramen Foramen magnum Condylar canal Mastoid foramen Parietal bone Lambdoid suture Inferior nuchal line External occipital protuberance Superior nuchal line Occipital bone (a) Inferior view Figure 8.5a 8-19 The Sphenoid Bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lesser wing Dorsum sellae Greater wing Superior orbital fissure Foramen rotundum Body Foramen ovale Lateral pterygoid plate Medial pterygoid plate Pterygoid processes (b) Posterior view Figure 8.11b Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diploe (spongy bone) Frontal bone Cribriform plate of ethmoid bone Crista galli Cribriform foramina • Body • Greater wing • Lesser wing • Optic foramen Sphenoid bone Optic foramen Foramen rotundum Foramen ovale Foramen spinosum Internal acoustic meatus Jugular foramen Sella turcica Temporal bone Petrous part of temporal bone Parietal bone Foramen magnum Groove for venous sinus Hypoglossal canal Occipital bone (b) Superior view of cranial floor Figure 8.5b • Anterior clinoid processes • Superior orbital fissure 8-20 The Sphenoid Bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Optic foramen Hypophyseal fossa Lesser wing Greater wing Foramen rotundum Sella turcica Anterior clinoid process Foramen ovale Foramen spinosum Dorsum sellae • Foramen rotundum • Foramen ovale (a) Superior view Figure 8.11a Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Diploe (spongy bone) Frontal bone Cribriform plate of ethmoid bone Crista galli Cribriform foramina Sphenoid bone Optic foramen Foramen rotundum Foramen ovale Foramen spinosum Internal acoustic meatus Jugular foramen Sella turcica Temporal bone Petrous part of temporal bone Parietal bone Foramen magnum Groove for venous sinus Hypoglossal canal Occipital bone Figure 8.5b • Foramen lacerum • Posterior nasal apertures or choanae • Medial pterygoid plate • Lateral pterygoid plate • Sphenoid sinus (b) Superior view of cranial floor 8-21 The Sphenoid Bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Incisive foramen Parietal bone Palatine process of maxilla Sphenoid sinus Squamous suture Frontal sinus Intermaxillary suture Zygomatic bone Crista galli Palatine bone Zygomatic arch Cribriform plate of ethmoid bone Posterior nasal aperture Perpendicular plate of ethmoid bone Vomer Occipital bone Temporal bone Sella turcica Lambdoid suture Internal acoustic meatus Jugular foramen Hypoglossal canal Styloid process Mandibular foramen Greater palatine foramen Medial pterygoid plate Lateral pterygoid plate Nasal bone Sphenoid bone Foramen ovale Vomer Mandibular fossa Palatine process of maxilla Styloid process Foramen spinosum Foramen lacerum Basilar part of occipital bone Carotid canal Maxilla External acoustic meatus Occipital condyle (b) Median section Stylomastoid foramen Palatine bone Mandible Mastoid process Mastoid notch Mental spines Temporal bone Jugular foramen Foramen magnum Condylar canal Mastoid foramen Parietal bone Lambdoid suture Inferior nuchal line Figure 8.4b External occipital protuberance Superior nuchal line Occipital bone (a) Inferior view Figure 8.5a Sphenoid sinus 8-22 The Ethmoid Bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supraorbital foramen Roof of orbit Medial wall Orbital plate of frontal bone Lesser wing of sphenoid bone Zygomatic process of frontal bone Optic foramen Greater wing of sphenoid bone Orbital plate of ethmoid bone Orbital surface of zygomatic bone Lacrimal bone Superior orbital fissure Frontal process of maxilla Inferior orbital fissure Orbital process of palatine bone Floor of orbit Lateral wall of orbit Infraorbital foramen Orbital surface of maxilla Figure 8.14 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cribriform plate Cribriform foramina Orbital plate Ethmoidal cells Perpendicular plate Crista galli Superior nasal concha Middle nasal concha • Anterior cranial bones located between the eyes • Contributes to medial wall of orbit • Lateral walls and roof of nasal cavity, and nasal septum • Three major portions of this porous, delicate bone • Perpendicular plate forms superior two-thirds of nasal septum Figure 8.12 8-23 The Ethmoid Bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Crista galli Parietal bone Frontal bone Cribriform plate Sphenoid sinus Frontal sinus Cribriform foramina Squamous suture Frontal sinus Nasal bone Sella turcica Crista galli Nasal conchae: Occipital bone Temporal bone Sella turcica Lambdoid suture Internal acoustic meatus Jugular foramen Hypoglossal canal Cribriform plate of ethmoid bone Superior Perpendicular plate Sphenoid sinus of ethmoid bone Inferior Nasal bone Middle Nasal cartilages Occipital bone Vomer Palatine process of maxilla Styloid process Mandibular foramen Maxilla Palatine bone Mandible Figure 8.4b Mental spines Sphenoid bone Anterior nasal spine Palatine bone Incisive foramen Lacrimal bone Lip Maxilla 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Crista galli Parietal bone Frontal bone Cribriform plate Sphenoid sinus Frontal sinus Squamous suture Cribriform foramina Frontal sinus Nasal bone Sella turcica Crista galli Nasal conchae: Occipital bone Temporal bone Sella turcica Lambdoid suture Internal acoustic meatus Jugular foramen Hypoglossal canal Cribriform plate of ethmoid bone Superior Perpendicular plate Sphenoid sinus of ethmoid bone Inferior Styloid process Palatine process of maxilla Nasal bone Middle Nasal cartilages Occipital bone Vomer Mandibular foramen Maxilla Palatine bone Mandible Mental spines (b) Median section Figure 8.4b Sphenoid bone Anterior nasal spine Palatine bone Incisive foramen Lacrimal bone Lip Maxilla Incisor 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 palatine bones 2 zygomatic bones 2 lacrimal bones 2 nasal bones 2 inferior nasal conchae 1 vomer 1 mandible 8-26 The Maxillae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal bone Supraorbital foramen Glabella Parietal bone Coronal suture Supraorbital margin Squamous suture • Largest facial bones • Forms upper jaw and meets at median intermaxillary suture – Alveolar processes: bony points between teeth – Alveolus: sockets that hold teeth Temporal bone Sphenoid bone Lacrimal bone Ethmoid bone Nasal bone Middle nasal concha Zygomatic bone Inferior nasal concha Infraorbital foramen Maxilla Vomer Figure 8.3 Mandible Mental foramen Mental protuberance 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 Medial pterygoid plate Lateral pterygoid plate Posterior nasal aperture Vomer Sphenoid bone Mandibular fossa Foramen ovale Foramen spinosum Foramen lacerum Basilar part of occipital bone Carotid canal Stylomastoid foramen Jugular foramen Foramen magnum Mastoid foramen Styloid process External acoustic meatus Occipital condyle Mastoid process Mastoid notch Temporal bone Condylar canal Parietal bone Lambdoid suture Inferior nuchal line External occipital protuberance Superior nuchal line 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 8-28 The Maxillae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 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 • Form the posterior portion of the hard palate Frontal sinus Cribriform foramina Nasal bone Sella turcica Nasal conchae: Superior Middle Sphenoid sinus Inferior Nasal cartilages Occipital bone Sphenoid bone • Part of lateral nasal cavity wall • Part of the orbital floor Frontal bone Cribriform plate Anterior nasal spine Palatine bone Incisive foramen Lacrimal bone Lip Maxilla Incisor Figure 8.13 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Supraorbital foramen Roof of orbit Orbital plate of frontal bone Lesser wing of sphenoid bone Zygomatic process of frontal bone Greater wing of sphenoid bone Optic foramen • Greater palatine foramina Orbital surface of zygomatic bone Orbital plate of ethmoid bone Medial wall Lacrimal bone Superior orbital fissure Frontal process of maxilla Inferior orbital fissure Orbital process of palatine bone Floor of orbit Lateral wall of orbit Infraorbital foramen Orbital surface of maxilla Figure 8.14 8-30 The Zygomatic Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture • Forms angles of the cheekbones and part of lateral orbital wall Frontal bone Parietal bone Temporal lines Lambdoid suture Ethmoid bone Sphenoid bone Nasal bone Occipital bone • Zygomaticofacial foramen Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla Mastoid process Temporal process Styloid process Mandible Mandibular condyle Mental foramen (a) Right lateral view Figure 8.4a • Zygomatic arch is formed from temporal process of zygomatic bone and zygomatic process of temporal bone 8-31 The Lacrimal Bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Form part of medial wall of each orbit Coronal suture Frontal bone Parietal bone Temporal lines Lambdoid suture Ethmoid bone Sphenoid bone Nasal bone Occipital bone Lacrimal bone Squamous suture Zygomaticofacial foramen Temporal bone Infraorbital foramen Zygomatic process External acoustic meatus Zygomatic bone Maxilla Mastoid process Temporal process Styloid process Mandible Mandibular condyle Mental foramen (a) Right lateral view Figure 8.4a • Smallest bone of skull • Lacrimal fossa houses lacrimal sac in life – Tears collect in lacrimal sac and drain into nasal cavity 8-32 The Nasal Bones • Forms bridge of nose Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Frontal bone • Supports cartilages that shape lower portion of the nose • Often fractured by blow to the nose Supraorbital foramen Glabella Parietal bone Coronal suture Supraorbital margin Squamous suture Temporal bone Sphenoid bone Lacrimal bone Ethmoid bone Nasal bone Middle nasal concha Zygomatic bone Inferior nasal concha Infraorbital foramen Maxilla Vomer Mandible Mental foramen Mental protuberance 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 nasal cavity – Superior and middle are part of the ethmoid bone Crista galli Frontal bone Cribriform plate Frontal sinus Cribriform foramina Nasal bone Sella turcica Nasal conchae: Superior Middle Sphenoid sinus Inferior Nasal cartilages Occipital bone Sphenoid bone Anterior nasal spine • Inferior nasal concha is a separate bone Palatine bone Incisive foramen Lacrimal bone Lip Maxilla Incisor Figure 8.13 – Largest of the three 8-34 The Vomer Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Parietal bone Sphenoid sinus Squamous suture Frontal sinus Crista galli Occipital bone Cribriform plate of ethmoid bone Temporal bone Sella turcica Lambdoid suture Internal acoustic meatus Jugular foramen Hypoglossal canal Perpendicular plate of ethmoid bone Nasal bone Vomer Palatine process of maxilla Styloid process Mandibular foramen Maxilla Palatine bone Mandible Mental spines (b) Median section Figure 8.4b • Inferior half of the nasal septum – Superior half formed by perpendicular plate of ethmoid • Supports cartilage that forms the anterior part of the nasal septum 8-35 The Mandible Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Strongest bone of the skull – Only bone of skull that moves noticeably – Supports lower teeth • Provides attachments for muscles of facial expression and mastication Figure 8.5a Incisive foramen Palatine process of maxilla Intermaxillary suture Zygomatic bone Palatine bone Zygomatic arch Greater palatine foramen Posterior nasal aperture Medial pterygoid plate Lateral pterygoid plate Vomer Sphenoid bone Foramen ovale Mandibular fossa Foramen spinosum Foramen lacerum Basilar part of occipital bone Carotid canal Styloid process External acoustic meatus Occipital condyle Stylomastoid foramen Mastoid process Mastoid notch Temporal bone Jugular foramen Foramen magnum Condylar canal Mastoid foramen Parietal bone Lambdoid suture Inferior nuchal line External occipital protuberance Superior nuchal line • Mental symphysis— median cartilaginous joint in fetus – Develops as two separate bones in fetus – Ossifies in early childhood Occipital bone (a) Inferior view Mandibular condyles Condylar process Coronoid process Mandibular notch Mandibular foramen Ramus Alveolar process Mental foramen Mental protuberance Figure 8.15 Angle Body 8-36 The Mandible Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Mental protuberance— point of chin • Two major parts on each side – Body: supports teeth – Ramus: articulates with cranium • Angle—where body and ramus meet • Alveolar processes between teeth • Mental foramen—permits passage of nerves and BVs • Mental spines Figure 8.5a Incisive foramen Palatine process of maxilla Intermaxillary suture Zygomatic bone Palatine bone Zygomatic arch Greater palatine foramen Posterior nasal aperture Medial pterygoid plate Lateral pterygoid plate Vomer Sphenoid bone Foramen ovale Mandibular fossa Foramen spinosum Foramen lacerum Basilar part of occipital bone Carotid canal Styloid process External acoustic meatus Occipital condyle Stylomastoid foramen Mastoid process Mastoid notch Temporal bone Jugular foramen Foramen magnum Condylar canal Mastoid foramen Parietal bone Lambdoid suture Inferior nuchal line External occipital protuberance Superior nuchal line Occipital bone (a) Inferior view Mandibular condyles Condylar process Coronoid process Mandibular notch Mandibular foramen Ramus Alveolar process Mental foramen Mental protuberance Figure 8.15 Angle Body 8-37 The Mandible Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mandibular condyles Condylar process Coronoid process Mandibular notch Mandibular foramen Ramus Alveolar process Mental foramen • Condylar process bears the mandibular condyle—oval knob that articulates with the mandibular fossa of the temporal bone forming the hinge temporomandibular joint (TMJ) • Coronoid process—point of insertion of temporalis muscle Mental protuberance Angle Body Figure 8.15 • Mandibular notch • Mandibular foramen—BVs, nerves supply lower teeth 8-38 Bones Associated with the Skull • Auditory ossicles – Three in each middle-ear cavity – Malleus, incus, and stapes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Hyoid bone – Slender U-shaped bone between the chin and larynx – Does not articulate with any other bone – Suspended from styloid process of skull by muscle and ligament – Body and greater and lesser horns (cornua) – Fractured hyoid bone is evidence of strangulation Styloid process Stylohyoid muscle Hyoid Larynx Lesser horn Greater horn Body Figure 8.16 8-39 The Skull in Infancy and Childhood Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Coronal suture Frontal bone Parietal bone • Fontanels—spaces between unfused bones – Filled with fibrous membrane – Allow shifting of bones during birth and growth of brain – Anterior, posterior, sphenoid (anterolateral), and mastoid (posterolateral) fontanels Sphenoid fontanel Lambdoid suture Nasal bone Squamous suture Maxilla Occipital bone Zygomatic bone Mastoid fontanel Temporal bone Mandible Sphenoid bone (a) Lateral view Frontal bone • Two frontal bones fuse by age 6 (metopic suture) Anterior fontanel Sagittal suture Parietal bone • Skull reaches adult size by 8 or 9 years of age Posterior fontanel (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. 8-41 General Features of the Vertebral Column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior view • Functions – – – – Supports the skull and trunk Allows for their movement Protects the spinal cord Absorbs stress of walking, running, and lifting – Provides attachments for limbs, thoracic cage, and postural muscles Posterior view Atlas (C1) Axis (C2) Cervical vertebrae C7 T1 Thoracic vertebrae T12 L1 • 33 vertebrae with intervertebral discs of fibrocartilage between most of them Lumbar vertebrae L5 S1 Sacrum S5 Coccyx Figure 8.18 Coccyx 8-42 General Features of the Vertebral Column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior view • Adult vertebral column averages 71 cm (28 in.) long – Intervertebral discs account for about onequarter of its length – Person is 1% shorter when in bed – Compression squeezes water out during the day and absorbs water when compression is removed during sleep Posterior view Atlas (C1) Axis (C2) Cervical vertebrae C7 T1 Thoracic vertebrae T12 L1 Lumbar vertebrae L5 S1 Sacrum S5 Coccyx Figure 8.18 Coccyx 8-43 General Features of the Vertebral Column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Anterior view • Five vertebral groups – – – – 7 cervical in the neck 12 thoracic in the chest 5 lumbar in lower back 5 fused sacral at base of spine – 4 fused coccygeal • Variations in number of lumbar and sacral vertebrae occur in 1 in 20 people Posterior view Atlas (C1) Axis (C2) Cervical vertebrae C7 T1 Thoracic vertebrae T12 L1 Lumbar vertebrae L5 S1 Sacrum S5 Coccyx Figure 8.18 Coccyx 8-44 General Features of the Vertebral Column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • 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 C7 T1 Thoracic curvature T12 L1 • S-shaped vertebral column with four normal curvatures – Cervical – Thoracic – Lumbar – Pelvic Lumbar curvature L5 S1 Pelvic curvature Figure 8.19 8-46 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • From disease, paralysis of trunk muscles, poor posture, pregnancy, or congenital defect • Scoliosis—abnormal lateral curvature (a) Scoliosis Key (b) Kyphosis (“hunchback”) Normal Pathological Figure 8.21 (c) Lordosis (“hunchback”) – – – – Most common Usually in thoracic region Particularly of adolescent girls Developmental abnormality in which the body and arch fail to 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Posterior • Body (centrum) – Mass of spongy bone that contains red bone marrow – Covered with thin shell of compact bone – Weight-bearing portion – Rough superior and inferior surfaces provide firm attachment for intervertebral discs • Vertebral foramina – Collectively form vertebral canal for spinal cord Spinous process Lamina Superior articular facet Vertebral arch Transverse process Pedicle Vertebral foramen Body Anterior (a) 2nd lumbar vertebra (L2) Nucleus pulposus 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Intervertebral foramen Superior articular process of L1 Inferior vertebral notch of L1 L1 Intervertebral foramen Superior vertebral notch of L2 L2 Spinous process Intervertebral disc L3 Inferior articular process of L3 (b) Left lateral view Figure 8.23b – When two vertebrae are joined they exhibit an opening between their pedicles – Passageway for spinal nerves – Inferior vertebral notch in the pedicle of the upper vertebra – Superior vertebral notch in the pedicle of 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) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Transverse process L2 Body (centrum) Intervertebral disc Inferior articular process of L2 Superior articular process of L3 L3 Lamina (a) Posterior (dorsal) view Figure 8.23a – Supports the head – Has no body – Delicate ring surrounding a large vertebral foramen – Lateral masses with superior articular facets • Articulates with occipital condyles • Allows nodding motion of skull gesturing “yes” – Inferior articular facets articulate with C2 – Anterior and posterior arches – Anterior and posterior tubercles 8-54 The Cervical Vertebrae • Cervical vertebrae—axis (C2) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Dens (odontoid process) Superior articular facet Transverse foramen Transverse process Inferior articular process Lamina Spinous process (b) Axis Figure 8.24b – Allows rotation of the head gesturing “no” – Dens or odontoid process— prominent knob on its anterosuperior side Body • Forms as an independent ossification center during first year of life • Fuses with axis by age 3 to 6 Pedicle years • Projects into vertebral foramen of the atlas • Held in place by a transverse ligament – 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 (c) Atlantoaxial joint 8-56 The Cervical Vertebrae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior views Lateral views Spinous process Lamina Superior articular facet Transverse foramen Transverse process Body Figure 8.25a 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinous process Lamina Transverse costal facet Superior articular facet Transverse process Superior costal facet Figure 8.25b 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Spinous process Superior articular facet Superior articular process Figure 8.25c Transverse process Pedicle Body Spinous process (c) Lumbar vertebrae Inferior articular facet • 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 The Sacrum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior articular process Sacral promontory Ala S1 S2 Transverse lines S3 Anterior sacral foramina S4 S5 Coccyx Co2 Co1 Co3 Co4 (a) Anterior view Figure 8.26a • Sacrum—bony plate that forms posterior wall of pelvic cavity • Once considered seat of the soul • In children, five separate sacral vertebrae (S1–S5) • Begin fusion around age 16 and complete fusion by age 26 • Anterior surface – Smooth and concave – Four transverse lines indicate line of fusion of vertebrae – Four pairs of large anterior sacral (pelvic) foramina • Allow for passage of nerves and arteries into pelvic organs • Sacral promontory on S1 supports L5 8-60 • • The Sacrum Posterior surface very rough Median sacral crest – • Lateral sacral crest – Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior articular process – Sacral canal • Auricular surface • Lateral sacral crest Posterior sacral foramina Sacral hiatus Horn Transverse process Coccyx (b) Posterior view Figure 8.26b • • Four pairs of openings for spinal nerves that supply gluteal region and lower limbs Sacral canal runs through sacrum and ends as sacral hiatus – • Less prominent, and on either side of median sacral crest Formed from the fusion of the transverse processes Posterior sacral foramina – Median sacral crest Formed from fusion of spinous processes Contains spinal nerve roots Auricular surface is part of sacroiliac (SI) joint formed with hip bone Superior articular processes on S1; articulates with L5 Alae—pair of large, rough, winglike extensions lateral to the superior articular processes 8-61 The Coccyx Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior articular process Sacral canal Median sacral crest Auricular surface Lateral sacral crest Posterior sacral foramina Sacral hiatus Horn Transverse process Coccyx (b) Posterior view Figure 8.26b • Coccyx—usually consists of four small vertebrae (Co1–Co4); sometimes five • Fuse into a single, triangular bone by age 20 to 30 • Horns (cornua) on Co1 – Serve as attachment points for ligaments that bind the coccyx to the sacrum • Fractured during difficult childbirth or by hard fall on buttocks • Provide attachment for muscles of the pelvic floor 8-62 The Thoracic Cage Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sternoclavicular joint Sternum: Acromioclavicular joint T1 1 Pectoral girdle: Clavicle Scapula Suprasternal notch Clavicular notch Manubrium 2 Angle 3 Body 4 True ribs (1–7) 5 Xiphoid process 6 7 Costal cartilages 11 8 False ribs (8–12) Floating ribs (11–12) 12 9 10 T12 L1 Costal margin Figure 8.27 • Consists of thoracic vertebrae, sternum, ribs • Forms conical enclosure for lungs and heart • Provides attachment for pectoral girdle and upper limbs • Broad base and narrower apex • Rhythmically expanded by respiratory muscles to draw air into lungs • Costal margin—inferior border of thoracic cage formed by downward arc of ribs • Protect thoracic organs, but also spleen, most of liver, and to some extent the 8-63 kidneys 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 8-64 fatal hemorrhage The Ribs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tubercle Neck Head Superior Inferior Angle Articular facet for transverse process Articular facets for vertebral bodies Costal groove Shaft Figure 8.28b (b) Ribs 2–10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior articular facet Transverse costal facet for rib 6 Tubercle Superior costal facet for rib 6 Neck T6 (b) Superior view Rib 6 Head Figure 8.29b • 12 pairs of ribs – No difference between sexes – Posterior (proximal) end attached to vertebral column – Anterior (distal) ends mostly attached to the sternum – Costal cartilages composed of hyaline cartilage attach anterior ends to sternum • Head—portion of rib that articulates with thoracic vertebrae – Superior articular facet – Inferior articular facet 8-65 The Ribs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Tubercle Neck Head Superior Inferior Angle Articular facet for transverse process Articular facets for vertebral bodies Costal groove Shaft Figure 8.28b (b) Ribs 2–10 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior articular facet Transverse costal facet for rib 6 Tubercle Superior costal facet for rib 6 Neck T6 (b) Superior view Rib 6 Head Figure 8.29b • Neck—narrow portion distal to the head • Tubercle—wider rough area distal to the neck – Articulates with transverse costal facet of vertebra • Angle—lateral curve of rib • Shaft—long, gentle sloping, bladelike portion of rib – Costal groove on inferior margin of shaft 8-66 The Ribs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Inferior costal facet of T5 Vertebral body T5 Superior articular facet of rib 6 Vertebral body T6 Inferior articular facet of rib 6 Superior costal facet of T6 Rib 6 (a) Anterior view Superior articular facet Transverse costal facet for rib 6 Tubercle Figure 8.29 Superior costal facet for rib 6 T6 Neck Head Rib 6 8-67 (b) Superior view The Ribs Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sternoclavicular joint Sternum: Acromioclavicular joint T1 1 Pectoral girdle: Clavicle Scapula Suprasternal notch Clavicular notch Manubrium 2 Angle 3 Body 4 True ribs (1–7) 5 Xiphoid process 6 7 Costal cartilages 11 8 False ribs (8–12) Floating ribs (11–12) 12 9 10 T12 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Sternal end Acromial 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Superior border Suprascapular notch Superior angle Acromion Acromion Supraspinous fossa Coracoid process Glenoid cavity Lateral angle Spine Subscapular fossa Infraspinous fossa Lateral border Medial 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 tubercle Head Lesser tubercle Greater tubercle Anatomical neck Surgical neck Intertubercular sulcus Nutrient foramen Deltoid tuberosity Deltoid tuberosity Coronoid fossa Radial fossa Lateral epicondyle Capitulum Medial supracondylar ridge Medial epicondyle Trochlea (a) Anterior view Lateral supracondylar ridge Lateral epicondyle Olecranon fossa (b) Posterior view • 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 Figure 8.32 8-80 The Humerus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Greater tubercle Head Lesser tubercle Greater tubercle Anatomical neck • Distal end Surgical neck Intertubercular sulcus Nutrient foramen Deltoid tuberosity Deltoid tuberosity Coronoid fossa Radial fossa Lateral epicondyle Capitulum Medial supracondylar ridge Medial epicondyle Trochlea Figure 8.32 (a) Anterior view Lateral supracondylar ridge Lateral epicondyle Olecranon fossa (b) Posterior view – 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 8-81 The Radius Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olecranon Olecranon Trochlear notch Radial notch of ulna Head of radius Neck of radius Head of radius Coronoid process Neck of radius Ulnar tuberosity Radial tuberosity Ulna Radius Interosseous borders • Radius – Head: disc-shaped, allows for rotation around the longitudinal axis of the bone during pronation and supination of hand • Superior surface articulates with capitulum on humerus • Side of disc spins on radial notch on ulna Interosseous membrane Ulnar notch of radius Head of ulna Styloid process Styloid process Styloid process Articular facets (a) Anterior view (b) Posterior view Figure 8.33 – Neck – Radial tuberosity for biceps muscle – Styloid process can be palpated near thumb 8-82 – Ulnar notch The Ulna Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Olecranon Olecranon Trochlear notch Radial notch of ulna Head of radius Neck of radius Head of radius Coronoid process Neck of radius Ulnar tuberosity Radial tuberosity Ulna Radius Interosseous borders Ulnar notch of radius Head of ulna Styloid process Styloid process Articular facets (a) Anterior view – Trochlear notch articulates with trochlea of humerus – Olecranon: bony point at back of elbow – Coronoid process – Radial notch holds head of radius – Styloid process • Interosseous membrane Interosseous membrane Styloid process • Ulna – Ligament attaches radius to ulna along interosseous margin of each bone – Enables the two elbow joints to share the load (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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Distal phalanx II Middle phalanx II Key to carpal bones Distal row Proximal row Proximal phalanx II IV Head Phalanges Body III Distal phalanx I II V Base I Proximal phalanx I Head Metacarpal Body bones Base Carpal bones First metacarpal Hamulus of hamate Hamate Pisiform Triquetrum Lunate (a) Anterior view Trapezoid Trapezium Carpal Capitate bones Scaphoid 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 • Pelvic girdle— consists of a complete ring composed of three bones – Two hip (coxal) bones, also called ossa coxae or innominate bones – Sacrum is also part of the vertebral column Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Iliac crest Iliac fossa Base of sacrum Ilium Sacroiliac joint Anterior superior iliac spine Pelvic surface of sacrum Anterior inferior iliac spine Pelvic inlet Spine Coccyx Acetabulum Ischium Body Interpubic disc Ramus Pubis Obturator foramen Superior ramus Inferior ramus Body Pubic symphysis (a) Anterosuperior view Figure 8.35a 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 • Anteriorly, interpubic disc—pad of fibrocartilage joins pubic bones Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Iliac crest Iliac fossa Base of sacrum Ilium Sacroiliac joint Anterior superior iliac spine Pelvic surface of sacrum Anterior inferior iliac spine Pelvic inlet Spine Coccyx Acetabulum Ischium Body • Pubic symphysis— the interpubic disc and adjacent regions of the pubic bone on each side Interpubic disc Ramus Pubis Obturator foramen Superior ramus Inferior ramus Body Pubic symphysis (a) Anterosuperior view Figure 8.35a 8-90 The Pelvic Girdle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Iliac crest Iliac fossa Ilium Anterior superior iliac spine Anterior inferior iliac spine Spine Sacroiliac joint Pelvic surface of sacrum Pelvic brim Pelvic inlet Coccyx Pelvic inlet Acetabulum Ischium Body Ramus Pubis Greater pelvis Base of sacrum Superior ramus Inferior ramus Body Lesser pelvis Interpubic disc Obturator foramen Pubic symphysis (a) Anterosuperior view Figure 8.35a Pelvic outlet (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 • Three distinct features of hip bone – Iliac crest: superior crest of hip – Acetabulum: hip socket – Obturator foramen: large hole below acetabulum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ilium Ischium Pubis Iliac crest Anterior gluteal line Inferior gluteal line Anterior superior iliac spine Posterior gluteal line Posterior superior Iliac spine Posterior inferior Iliac spine Anterior r inferior iliac spine Greater sciatic notch Body of ilium Acetabulum Superior ramus of pubis Ischial spine Body of pubis Lesser sciatic notch Body of ischium Inferior ramus 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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Triangular pubic body Rectangular pubic body Large, oval obturator foramen Narrow subpubic angle (a) Male, anterior view Wide subpubic angle Triangular obturator foramen (c) Female, anterior view Preauricular sulcus Wide greater sciatic notch (b) Male, medial view Narrow greater sciatic notch (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 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fovea capitis Greater trochanter Greater trochanter Head Neck Intertrochanteric crest Intertrochanteric line Lesser trochanter Spiral line Gluteal tuberosity Linea aspera Shaft Medial supracondylar line Lateral supracondylar line Popliteal surface Lateral epicondyle Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle Intercondylar fossa Medial condyle Base of patella Articular facets Apex of patella (a) Anterior view Figure 8.38 (b) Posterior view • Longest and strongest bone of the body • Hemispherical head that articulates with the acetabulum of the pelvis – Forms ball-and-socket joint – Fovea capitis: pit in head of femur for attachment of a ligament • Greater and lesser trochanters for muscle attachment • Intertrochanteric crest— thick oblique ridge on the posterior surface that connects the trochanters 8-97 The Femur Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fovea capitis Greater trochanter Greater trochanter Head Neck Intertrochanteric crest Intertrochanteric line Lesser trochanter Spiral line Gluteal tuberosity Linea aspera • Linea aspera—ridge on posterior of the shaft • Spiral (pectineal) line and gluteal tuberosity Shaft Medial supracondylar line Lateral supracondylar line Popliteal surface Lateral epicondyle • Intertrochanteric line—more delicate ridge on the anterior surface that connects trochanters Medial epicondyle Lateral epicondyle Patellar surface • Medial and lateral condyles and epicondyles found distally Lateral condyle Intercondylar fossa Medial condyle Base of patella • Intercondylar fossa Articular facets Apex of patella (a) Anterior view Figure 8.38 (b) Posterior view • Patellar and popliteal surface 8-98 The Patella Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fovea capitis Greater trochanter Greater trochanter Head Neck Intertrochanteric crest Intertrochanteric line Lesser trochanter Spiral line Gluteal tuberosity Linea aspera Shaft Medial supracondylar line Lateral supracondylar line Popliteal surface Lateral epicondyle Medial epicondyle Lateral epicondyle Patellar surface Lateral condyle Intercondylar fossa Medial condyle Base of patella Articular facets Apex of patella (a) Anterior view (b) Posterior view Figure 8.38 • Patella—triangular sesamoid bone embedded in tendon of knee • Cartilaginous at birth – Ossifies at age 3 to 6 years • Base—broad, superior portion • Apex—pointed, inferior portion • Articular facets—shallow, posterior portion • Quadriceps femoris tendon extends from anterior muscle of thigh to patella – Continues as the patellar ligament from patella to tibia 8-99 Tibia Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Intercondylar eminence Medial condyle Lateral condyle Apex Head of fibula Tibial tuberosity Proximal tibiofibular joint • Tibia—thick, medial, weightbearing bone • Fairly flat articular surfaces • Articulate with condyle of femur Interosseous membrane Lateral surface Anterior crest Tibia Fibula Distal tibiofibular joint Medial malleolus Lateral malleolus (a) Anterior view – Only weight-bearing bone of the crural region – Broad superior head – Medial and lateral condyles Lateral malleolus (b) Posterior view Figure 8.39 – Intercondylar eminence— ridge separating condyles – Tibial tuberosity— attachment of quadricep muscles – Anterior crest—sharp, angular – Medial malleolus—bony knob on inside of ankle 8100 The Fibula Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Intercondylar eminence Medial condyle Lateral condyle Apex Head of fibula Tibial tuberosity Proximal tibiofibular joint • Does not bear any body weight – Spare bone tissue for grafts Interosseous membrane Lateral surface • Fibula—slender, lateral strut that helps stabilizes ankle • Head—proximal end Anterior crest • Apex—point of the head Tibia Fibula • Lateral malleolus—distal expansion, bony knob on lateral side of ankle Distal tibiofibular joint Medial malleolus Lateral malleolus (a) Anterior view Lateral malleolus (b) Posterior view Figure 8.39 • Joined to tibia by interosseous membrane 8101 The Ankle and Foot • Tarsal bones—arranged in proximal and distal groups – Tarsal bones are shaped and arranged differently from carpal bones due to loadbearing role of the ankle • Calcaneus—largest tarsal bone Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Distal phalanx I – Forms heel – Distal portion is point of attachment for calcaneal (Achilles) tendon Distal phalanx V Proximal phalanx I Middle phalanx V Proximal phalanx V Metatarsal I II III IV • Talus is most superior tarsal bone V Medial cuneiform Intermediate cuneiform Lateral cuneiform Navicular Cuboid Talus Calcaneus Trochlear surface of talus Key to tarsal bones Distal group Tuberosity of calcaneus (a) Superior (dorsal) view Figure 8.40a Proximal group – Forms ankle joint with tibia and fibula – Sits upon calcaneus and articulates with navicular • Proximal row of tarsal bones – Talus, calcaneus, navicular • Distal row of tarsal bones – Medial, intermediate, lateral cuneiforms and cuboid 8- The Ankle and Foot • Remaining bones of foot are similar in name and arrangement to the hand Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Metatarsals Distal phalanx I Distal phalanx V Proximal phalanx I – Metatarsal I is proximal to the great toe (hallux) – Metatarsal V is proximal to the little toe – Proximal base, intermediate shaft, and distal head Middle phalanx V Proximal phalanx V Metatarsal I II III IV V Medial cuneiform Intermediate cuneiform Lateral cuneiform Navicular Cuboid Talus • Phalanges Calcaneus Trochlear surface of talus Key to tarsal bones Distal group Tuberosity of calcaneus (a) Superior (dorsal) view Figure 8.40a Proximal group – Two in great toe • Proximal and distal phalanx – Three in all other toes • Proximal, middle, distal phalanx 8103 The Ankle and Foot Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Thumb Future thumb Elbow Knee Future great toe (a) Seven weeks Great toe (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 8anteriorly 104 The Ankle and Foot Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Medial longitudinal arch Transverse arch Lateral longitudinal arch Figure 8.42a (a) Inferior (plantar) view • Sole of foot is not flat on ground • Three springy arches absorb stress – Medial longitudinal arch • From heel to hallux • Formed from the calcaneus, talus, navicular, cuneiforms, and metatarsals I and III • Lateral longitudinal arch – From heel to little toe – Includes calcaneus, cuboid, and metatarsals IV and V 8105 The Ankle and Foot Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. • Transverse arch Medial longitudinal arch Transverse arch Lateral longitudinal arch Figure 8.42a (a) Inferior (plantar) view – Across middle of foot – Includes the cuboid, cuneiforms, and proximal heads of metatarsals – Arches held together by short, strong ligaments • Pes planus (flat feet)— excessive weight, repetitious stress, or congenital weakness 8106 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 8107 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 Figure 8.43a,b Chimpanzee Human 8108 Skeletal Adaptations for Bipedalism Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (c) Gluteal muscles Chimpanzee (d) Pelvis (e) Vertebral column Chimpanzee Chimpanzee Human Human Figure 8.43c,d,e Human 8109 Skeletal Adaptations for Bipedalism Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. (f) Skull Supraorbital ridge Pivot Foramen magnum Chimpanzee Pivot Figure 8.43f Foramen magnum Human 8110 8111