The Axial Skeleton Consists of 80 bones Three major regions Skull

The Axial Skeleton Consists of 80 bones Three major regions Skull
Vertebral column Thoracic cage

Cranium Skull Facial bones Clavicle Thoracic cage Scapula (ribs and
sternum) Scapula Sternum Rib Humerus Vertebra Vertebral column Radius Ulna Sacrum Carpals Phalanges Metacarpals Femur Patella Tibia Fibula Tarsals Metatarsals (a) Anterior view Phalanges Figure 7.1a

The Skull Two sets of bones Cranial bones
Enclose the brain in the cranial cavity Cranial vault (calvaria) Cranial base: anterior, middle, and posterior cranial fossae Provide sites of attachment for head and neck muscles

The Skull Facial bones Framework of face
Cavities for special sense organs for sight, taste, and smell Openings for air and food passage Sties of attachment for teeth and muscles of facial expression

Bones of cranium (cranial vault)
Coronal suture Squamous suture Lambdoid suture Facial bones (a) Cranial and facial divisions of the skull Figure 7.2a

(b) Superior view of the cranial fossae
Anterior cranial fossa Middle cranial fossa Posterior cranial fossa (b) Superior view of the cranial fossae Figure 7.2b

Cranial Bones Frontal bone Parietal bones (2) Occipital bone Temporal bones (2) Sphenoid bone Ethmoid bone

Frontal Bone Anterior portion of cranium Most of anterior cranial fossa Superior wall of orbits Contains air-filled frontal sinus

Frontal bone Glabella Parietal bone Frontonasal suture
Supraorbital foramen (notch) Squamous part of frontal bone Supraorbital margin Nasal bone Superior orbital fissure Sphenoid bone (greater wing) Optic canal Temporal bone Inferior orbital fissure Ethmoid bone Lacrimal bone Middle nasal concha Zygomatic bone Ethmoid bone Infraorbital foramen Perpendicular plate Maxilla Inferior nasal concha Mandible Vomer Mental foramen (a) Anterior view Mandibular symphysis Figure 7.4a

Parietal Bones and Major Associated Sutures
Superior and lateral aspects of cranial vault Four sutures mark the articulations of parietal bones with frontal, occipital, and temporal bones: Coronal suture—between parietal bones and frontal bone Sagittal suture—between right and left parietal bones Lambdoid suture—between parietal bones and occipital bone Squamous (squamosal) sutures—between parietal and temporal bones on each side of skull

(a) External anatomy of the right side of the skull
Coronal suture Frontal bone Sphenoid bone (greater wing) Parietal bone Ethmoid bone Temporal bone Lacrimal bone Lambdoid suture Lacrimal fossa Squamous suture Nasal bone Occipital bone Zygomatic bone Zygomatic process Maxilla Occipitomastoid suture External acoustic meatus Mastoid process Alveolar margins Styloid process Mandibular condyle Mandible Mandibular notch Mental foramen Mandibular ramus Mandibular angle Coronoid process (a) External anatomy of the right side of the skull Figure 7.5a

Occipital Bone Most of skull’s posterior wall and posterior cranial fossa Articulates with 1st vertebra Sites of attachment for the ligamentum nuchae and many neck and back muscles

Sagittal suture Parietal bone Sutural bone Lambdoid suture
Occipital bone Superior nuchal line External occipital protuberance Mastoid process Inferior nuchal line Occipitomastoid suture External occipital crest Occipital condyle (b) Posterior view Figure 7.4b

Intermaxillary suture Hard palate Palatine bone (horizontal plate)
(palatine process) Incisive fossa Intermaxillary suture Hard palate Palatine bone (horizontal plate) Median palatine suture Infraorbital foramen Maxilla Zygomatic bone Sphenoid bone (greater wing) Temporal bone (zygomatic process) Foramen ovale Vomer Foramen spinosum Foramen lacerum Mandibular fossa Carotid canal External acoustic meatus Styloid process Stylomastoid foramen Mastoid process Temporal bone (petrous part) Jugular foramen Occipital condyle Pharyngeal tubercle of basilar region of the occipital bone Inferior nuchal line Parietal bone Superior nuchal line External occipital crest External occipital protuberance Foramen magnum (a) Inferior view of the skull (mandible removed) Figure 7.6a

Inferolateral aspects of skull and parts of cranial floor
Temporal Bones Inferolateral aspects of skull and parts of cranial floor Four major regions Squamous Tympanic Mastoid Petrous

Squamous region External acoustic meatus Mastoid region
Zygomatic process Mandibular fossa Mastoid process Tympanic region Styloid process Figure 7.8

Anterior cranial fossa Optic canal Lesser wing Sphenoid
Cribriform plate Frontal bone Ethmoid bone Crista galli Olfactory foramina Anterior cranial fossa Optic canal Lesser wing Sphenoid Foramen rotundum Greater wing Foramen ovale Hypophyseal fossa of sella turcica Foramen spinosum Foramen lacerum Middle cranial fossa Internal acoustic meatus Temporal bone (petrous part) Jugular foramen Hypoglossal canal Posterior cranial fossa Foramen magnum View Parietal bone Occipital bone (a) Superior view of the skull, calvaria removed Figure 7.7a

Complex, bat-shaped bone Keystone bone
Sphenoid Bone Complex, bat-shaped bone Keystone bone Articulates with all other cranial bones Three pairs of processes Greater wings Lesser wings Pterygoid processes

Lesser wing Optic canal Superior orbital fissure Foramen Greater
rotundum Greater wing Foramen ovale Hypophyseal fossa of sella turcica Foramen spinosum Body of sphenoid (a) Superior view Figure 7.9a

Body of sphenoid Lesser wing Superior orbital fissure Greater wing
Pterygoid process (b) Posterior view Figure 7.9b

Ethmoid Bone Deepest skull bone Superior part of nasal septum, roof of nasal cavities Contributes to medial wall of orbits

Crista galli Olfactory foramina Cribriform plate Orbital plate
Left lateral mass Ethmoidal air cells Perpendicular plate Middle nasal concha Figure 7.10

Anterior cranial fossa Optic canal Lesser wing Sphenoid
Cribriform plate Frontal bone Ethmoid bone Crista galli Olfactory foramina Anterior cranial fossa Optic canal Lesser wing Sphenoid Foramen rotundum Greater wing Foramen ovale Hypophyseal fossa of sella turcica Foramen spinosum Foramen lacerum Middle cranial fossa Internal acoustic meatus Temporal bone (petrous part) Jugular foramen Hypoglossal canal Posterior cranial fossa Foramen magnum View Parietal bone Occipital bone (a) Superior view of the skull, calvaria removed Figure 7.7a

Sutural Bones Tiny irregularly shaped bones that appear within sutures

Sagittal suture Parietal bone Sutural bone Lambdoid suture
Occipital bone Superior nuchal line External occipital protuberance Mastoid process Inferior nuchal line Occipitomastoid suture External occipital crest Occipital condyle (b) Posterior view Figure 7.4b

Facial Bones Mandible Maxillary bones (maxillae) (2)
Zygomatic bones (2) Nasal bones (2) Lacrimal bones (2) Palatine bones (2) Vomer Inferior nasal conchae (2)

Mandible Lower jaw Largest, strongest bone of face Temporomandibular joint: only freely movable joint in skull

(a) Mandible, right lateral view
Mandibular fossa of temporal bone Temporomandibular joint Mandibular notch Coronoid process Mandibular condyle Mandibular foramen Alveolar margin Ramus of mandible Mental foramen Mandibular angle Body of mandible (a) Mandible, right lateral view Figure 7.11a

Maxillary Bones Medially fused to form upper jaw and central portion of facial skeleton Keystone bones Articulate with all other facial bones except mandible

(b) Maxilla, right lateral view
Articulates with frontal bone Frontal process Orbital surface Infraorbital foramen Zygomatic process (cut) Anterior nasal spine Alveolar margin (b) Maxilla, right lateral view Figure 7.11b

Zygomatic Bones Cheekbones Inferolateral margins of orbits

Nasal Bones and Lacrimal Bones
Form bridge of nose Lacrimal bones In medial walls of orbits Lacrimal fossa houses lacrimal sac

(a) External anatomy of the right side of the skull
Coronal suture Frontal bone Sphenoid bone (greater wing) Parietal bone Ethmoid bone Temporal bone Lacrimal bone Lambdoid suture Lacrimal fossa Squamous suture Nasal bone Occipital bone Zygomatic bone Zygomatic process Maxilla Occipitomastoid suture External acoustic meatus Mastoid process Alveolar margins Styloid process Mandibular condyle Mandible Mandibular notch Mental foramen Mandibular ramus Mandibular angle Coronoid process (a) External anatomy of the right side of the skull Figure 7.5a

Palatine Bones and Vomer
Posterior one-third of hard palate Posterolateral walls of the nasal cavity Small part of the orbits Vomer Plow shaped Lower part of nasal septum

Inferior Nasal Conchae
Form part of lateral walls of nasal cavity

(perpendicular plate) Palatine bone (horizontal plate)
Frontal sinus Superior, middle, and inferior meatus Superior nasal concha Ethmoid bone Middle nasal concha Inferior nasal concha Nasal bone Anterior nasal spine Sphenoid sinus Maxillary bone (palatine process) Sphenoid bone Pterygoid process Palatine bone (perpendicular plate) Palatine bone (horizontal plate) (a) Bones forming the left lateral wall of the nasal cavity (nasal septum removed) Figure 7.14a

Orbits Encase eyes and lacrimal glands Sites of attachment for eye muscles Formed by parts of seven bones (next slide)

• Lesser wing of sphenoid bone
Superior orbital fissure Roof of orbit Supraorbital notch Optic canal • Lesser wing of sphenoid bone • Orbital plate of frontal bone Medial wall • Sphenoid body Lateral wall of orbit • Orbital plate of ethmoid bone • Zygomatic process of frontal bone • Frontal process of maxilla • Greater wing of sphenoid bone • Lacrimal bone • Orbital surface of zygomatic bone Nasal bone Floor of orbit Inferior orbital fissure Infraorbital groove • Orbital process of palatine bone Zygomatic bone • Orbital surface of maxillary bone Infraorbital foramen • Zygomatic bone (b) Contribution of each of the seven bones forming the right orbit Figure 7.13a

Nasal Cavity Roof, lateral walls, and floor formed by parts of four bones Ethmoid Palatine bones Maxillary bones Inferior nasal conchae Nasal septum of bone and hyaline cartilage Vomer Anterior septal cartilage

(perpendicular plate) Palatine bone (horizontal plate)
Frontal sinus Superior, middle, and inferior meatus Superior nasal concha Ethmoid bone Middle nasal concha Inferior nasal concha Nasal bone Anterior nasal spine Sphenoid sinus Maxillary bone (palatine process) Sphenoid bone Pterygoid process Palatine bone (perpendicular plate) Palatine bone (horizontal plate) (a) Bones forming the left lateral wall of the nasal cavity (nasal septum removed) Figure 7.14a

Crista galli Ethmoid bone Cribriform plate Frontal sinus Sella turcica
Nasal bone Perpendicular plate of ethmoid bone Sphenoid sinus Septal cartilage Palatine bone Vomer Alveolar margin of maxilla Hard palate Palatine process of maxilla (b) Nasal cavity with septum in place showing the contributions of the ethmoid bone, the vomer, and septal cartilage Figure 7.14b

Paranasal Sinuses Mucosa-lined, air-filled spaces Lighten the skull Enhance resonance of voice Found in frontal, sphenoid, ethmoid, and maxillary bones

Frontal sinus Frontal sinus Ethmoidal air cells (sinus) Ethmoidal
Sphenoid sinus Sphenoid sinus Maxillary sinus Maxillary sinus (a) Anterior aspect (b) Medial aspect Figure 7.15

Hyoid Bone Not a bone of the skull Does not articulate directly with another bone Site of attachment for muscles of swallowing and speech

Greater horn Lesser horn Body Figure 7.12

Vertebral Column Transmits weight of trunk to lower limbs
Surrounds and protects spinal cord Flexible curved structure containing 26 irregular bones (vertebrae) Cervical vertebrae (7)—vertebrae of the neck Thoracic vertebrae (12)—vertebrae of the thoracic cage Lumbar vertebrae (5)—vertebra of the lower back Sacrum—bone inferior to the lumbar vertebrae Coccyx—terminus of vertebral column

Vertebral Column: Curvatures
Increase the resilience and flexibility of the spine Two posteriorly concave curvatures Cervical and lumbar Two posteriorly convex curvatures Thoracic and sacral Abnormal spine curvatures Scoliosis (abnormal lateral curve) Kyphosis (hunchback) Lordosis (swayback)

Figure 7.16 C1 Cervical curvature (concave) 7 vertebrae, C1–C7 Spinous
process Transverse processes Thoracic curvature (convex) 12 vertebrae, T1–T12 Intervertebral discs Intervertebral foramen Lumbar curvature (concave) 5 vertebrae, L1–L5 Sacral curvature (convex) 5 fused vertebrae sacrum Coccyx 4 fused vertebrae Anterior view Right lateral view Figure 7.16

Anterior and posterior longitudinal ligaments
From neck to sacrum Ligamentum flavum Connects adjacent vertebrae Short ligaments Connect each vertebra to those above and below

Cushionlike pad composed of two parts
Intervertebral Discs Cushionlike pad composed of two parts Nucleus pulposus Inner gelatinous nucleus that gives the disc its elasticity and compressibility Anulus fibrosus Outer collar composed of collagen and fibrocartilage

Supraspinous ligament
Intervertebral disc Supraspinous ligament Transverse process Anterior longitudinal ligament Sectioned spinous process Intervertebral foramen Ligamentum flavum Posterior longitudinal ligament Interspinous ligament Anulus fibrosus Nucleus pulposus Inferior articular process Sectioned body of vertebra Median section of three vertebrae, illustrating the composition of the discs and the ligaments Figure 7.17a

Vertebral spinous process (posterior aspect of vertebra)
Spinal cord Spinal nerve root Transverse process Herniated portion of disc Anulus fibrosus of disc Nucleus pulposus of disc (c) Superior view of a herniated intervertebral disc Figure 7.17c

General Structure of Vertebrae
Body or centrum Anterior weight-bearing region Vertebral arch Composed of pedicles and laminae that, along with centrum, enclose vertebral foramen Vertebral foramina Together make up vertebral canal for spinal cord Intervertebral foramina Lateral openings between adjacent vertebrae for spinal nerves

General Structure of Vertebrae
Seven processes per vertebra: Spinous process—projects posteriorly Transverse processes (2)—project laterally Superior articular processes (2)—protrude superiorly inferiorly Inferior articular processes (2)—protrude inferiorly PLAY Animation: Rotatable Spine (horizontal) PLAY Animation: Rotatable Spine (vertical)

Posterior Vertebral Lamina arch Spinous Transverse process process
Superior articular process and facet Vertebral foramen Pedicle Body (centrum) Anterior Figure 7.18

C1 to C7: smallest, lightest vertebrae
Cervical Vertebrae C1 to C7: smallest, lightest vertebrae C3 to C7 share the following features Oval body Spinous processes are bifid (except C7) Large, triangular vertebral foramen Transverse foramen in each transverse process

Table 7.2

(a) Cervical vertebrae
Dens of axis Transverse ligament of atlas C1 (atlas) C2 (axis) C3 Inferior articular process Bifid spinous process Transverse processes C7 (vertebra prominens) (a) Cervical vertebrae Figure 7.20a

C1 (atlas) and C2 (axis) have unique features Atlas (C1)
Cervical Vertebrae C1 (atlas) and C2 (axis) have unique features Atlas (C1) No body or spinous process Consists of anterior and posterior arches, and two lateral masses Superior surfaces of lateral masses articulate with the occipital condyles

(a) Superior view of atlas (C1) (b) Inferior view of atlas (C1)
Posterior Posterior Posterior tubercle Posterior tubercle Posterior arch Posterior arch Inferior articular facet Lateral masses Transverse process Lateral masses Transverse foramen Superior articular facet Transverse foramen Anterior arch Anterior tubercle Anterior arch Facet for dens Anterior tubercle (a) Superior view of atlas (C1) (b) Inferior view of atlas (C1) Figure 7.19a-b

Cervical Vertebrae Axis (C2)
Dens projects superiorly into the anterior arch of the atlas Dens is a pivot for the rotation of the atlas

(c) Superior view of axis (C2)
Posterior C2 Spinous process Lamina Inferior articular process Pedicle Superior articular facet Transverse process Dens Body (c) Superior view of axis (C2) Figure 7.19c

Thoracic Vertebrae T1 to T12 All articulate with ribs at facets and demifacets Long spinous process Location of articular facets allows rotation of this area of spine

Table 7.2

(b) Thoracic vertebrae
Superior articular process Transverse process Transverse costal facet (for tubercle of rib) Intervertebral disc Body Inferior costal facet (for head of rib) Spinous process Inferior articular process (b) Thoracic vertebrae Figure 7.20b

Lumbar Vertebrae L1 to L5 Short, thick pedicles and laminae Flat hatchet-shaped spinous processes Orientation of articular facets locks lumbar vertebrae together so as to prevent rotation

Table 7.2

Superior articular process Transverse Body process Intervertebral disc
Inferior articular process Spinous process (c) Lumbar vertebrae Figure 7.20c

Sacrum and Coccyx Sacrum Coccyx 5 fused vertebrae (S1–S5)
Forms posterior wall of pelvis Articulates with L5 superiorly, and with auricular surfaces of the hip bones laterally Coccyx Tailbone 3–5 fused vertebrae Articulates superiorly with sacrum

Sacral promontory Ala Body of first sacral vertebra Transverse
ridges (sites of vertebral fusion) Anterior sacral foramina Apex Coccyx (a) Anterior view Figure 7.21a

Sacral Facet of Body canal superior Ala articular process Auricular
surface Median sacral crest Lateral sacral crest Posterior sacral foramina Sacral hiatus Coccyx (b) Posterior view Figure 7.21b

Thoracic Cage Composed of Functions Thoracic vertebrae Sternum
Ribs and their costal cartilages Functions Protects vital organs of thoracic cavity Supports shoulder girdle and upper limbs Provides attachment sites for many muscles, including intercostal muscles used during breathing

Sternum (Breastbone) Three fused bones Manubrium
Articulates with clavicles and ribs 1 and 2 Body Articulates with costal cartilages of ribs 2 through 7 Xiphoid process Site of muscle attachment Not ossified until ~ age 40

Ribs and Their Attachments
12 pairs All attach posteriorly to thoracic vertebrae Pairs 1 through 7 True (vertebrosternal) ribs Attach directly to the sternum by individual costal cartilages

Ribs and Their Attachments
Pairs 8 through12 False ribs Pairs 8–10 also called vertebrochondral ribs Attach indirectly to sternum by joining costal cartilage of rib above Pairs 11–12 also called vertebral (floating) ribs No attachment to sternum

(a) Skeleton of the thoracic cage, anterior view
Jugular notch Clavicular notch Manubrium Sternal angle Body Sternum True ribs (1–7) Xiphisternal joint Xiphoid process False ribs (8–12) Intercostal spaces Costal cartilage Costal margin L1 Vertebra Floating ribs (11, 12) (a) Skeleton of the thoracic cage, anterior view Figure 7.22a

Structure of a Typical Rib
Main parts: Head Articulates posteriorly with facets (demifacets) on bodies of two adjacent vertebrae Neck Tubercle Articulates posteriorly with transverse costal facet of same-numbered thoracic vertebra Shaft

Transverse costal facet (for tubercle of rib) Superior costal facet
(for head of rib) Angle of rib Body of vertebra Head of rib Intervertebral disc Neck of rib Tubercle of rib Shaft Sternum Cross- section of rib Costal groove Costal cartilage (a) Vertebral and sternal articulations of a typical true rib Figure 7.23a

Articular facet on tubercle of rib Spinous process Shaft Transverse
costal facet (for tubercle of rib) Ligaments Neck of rib Body of thoracic vertebra Head of rib Superior costal facet (for head of rib) (b) Superior view of the articulation between a rib and a thoracic vertebra Figure 7.23b

Appendicular Skeleton
Bones of the limbs and their girdles Pectoral girdle attaches the upper limbs to the body trunk Pelvic girdle secures the lower limbs

Pectoral Girdle (Shoulder Girdle)
Clavicles and the scapulae Attach the upper limbs to the axial skeleton Provide attachment sites for muscles that move the upper limbs

Articulated pectoral girdle
Acromio- clavicular joint Clavicle Scapula (a) Articulated pectoral girdle Figure 7.24a

Clavicles (Collarbones)
Flattened acromial (lateral) end articulates with the scapula Cone-shaped sternal (medial) end articulates with the sternum Act as braces to hold the scapulae and arms out laterally

Right clavicle, superior view
Sternal (medial) end Posterior Anterior Acromial (lateral) end (b) Right clavicle, superior view Figure 7.24b

Scapulae (Shoulder Blades)
Situated on the dorsal surface of rib cage, between ribs 2 and 7 Flat and triangular, with three borders and three angles Seven large fossae, named according to location

(a) Right scapula, anterior aspect
Acromion Suprascapular notch Superior border Coracoid process Superior angle Glenoid cavity Subscapular fossa Lateral border Medial border Inferior angle (a) Right scapula, anterior aspect Figure 7.25a

(b) Right scapula, posterior aspect
Coracoid process Suprascapular notch Superior angle Acromion Supraspinous fossa Glenoid cavity at lateral angle Spine Infraspinous fossa Medial border Lateral border (b) Right scapula, posterior aspect Figure 7.25b

(c) Right scapula, lateral aspect Inferior angle
Supraspinous fossa Supraglenoid tubercle Acromion Coracoid process Glenoid cavity Spine Supraspinous fossa Infraspinous fossa Infraglenoid tubercle Infraspinous fossa Subscapular fossa Subscapular fossa Posterior Anterior (c) Right scapula, lateral aspect Inferior angle Figure 7.25c

The Upper Limb 30 bones form the skeletal framework of each upper limb
Arm Humerus Forearm Radius and ulna Hand 8 carpal bones in the wrist 5 metacarpal bones in the palm 14 phalanges in the fingers

Humerus Largest, longest bone of upper limb Articulates superiorly with glenoid cavity of scapula Articulates inferiorly with radius and ulna

Greater Head of tubercle humerus Lesser Anatomical tubercle neck
Inter- tubercular sulcus Deltoid tuberosity Lateral supracondylar ridge Coronoid fossa Radial fossa Medial epicondyle Capitulum Trochlea (a) Anterior view Figure 7.26a

Bones of the Forearm Ulna Radius Medial bone in forearm
Forms the major portion of the elbow joint with the humerus Radius Lateral bone in forearm Head articulates with capitulum of humerus and with radial notch of ulna Interosseous membrane connects the radius and ulna along their entire length

Radial notch of the ulna Olecranon process Trochlear notch Head
Head of radius Neck Coronoid process Radial tuberosity Neck of radius Proximal radioulnar joint Interosseous membrane Ulna Radius Ulnar notch of the radius Radius Head of ulna Styloid process of ulna Styloid process of radius Distal radioulnar joint Styloid process of radius (a) Anterior view (b) Posterior view Figure 7.27a-b

(c) Proximal portion of ulna, lateral view
Olecranon process View Trochlear notch Coronoid process Radial notch (c) Proximal portion of ulna, lateral view Ulnar notch of radius Articulation for lunate Articulation for scaphoid Styloid process Head of ulna Styloid process View (d) Distal ends of the radius and ulna at the wrist Figure 7.27c-d

(c) Anterior view at the elbow region
Humerus Coronoid fossa Capitulum Medial epicondyle Head of radius Trochlea Coronoid process of ulna Radial tuberosity Radius Radial notch Ulna (c) Anterior view at the elbow region Humerus Olecranon fossa Olecranon process Lateral epicondyle Medial epicondyle Head Ulna Neck Radius (d) Posterior view of extended elbow Figure 7.26c-d

Only scaphoid and lunate articulate with radius to form wrist joint
Hand: Carpus Eight bones in two rows Proximal row Scaphoid, lunate, triquetrum, and pisiform proximally Distal row Trapezium, trapezoid, capitate, and hamate distally Only scaphoid and lunate articulate with radius to form wrist joint

Hand: Metacarpus and Phalanges
Five metacarpal bones (#1 to #5) form the palm Phalanges Each finger (digit), except the thumb, has three phalanges—distal, middle, and proximal Fingers are numbered 1–5, beginning with the thumb (pollex) Thumb has no middle phalanx

(a) Anterior view of left hand (b) Posterior view of left hand
Phalanges • Distal • Middle • Proximal Metacarpals • Head • Shaft Sesamoid bones • Base Carpals Carpals Carpals • Trapezium • Hamate • Trapezium • Trapezoid • Capitate • Trapezoid • Scaphoid • Pisiform • Scaphoid • Triquetrum Radius • Lunate Ulna Radius (a) Anterior view of left hand (b) Posterior view of left hand Figure 7.28a-b

Pelvic (Hip) Girdle Two hip bones (each also called coxal bone or os coxae) Attach the lower limbs to the axial skeleton with strong ligaments Transmit weight of upper body to lower limbs Support pelvic organs Each hip bone consists of three fused bones: ilium, ischium, and pubis Together with the sacrum and the coccyx, these bones form the bony pelvis

Animation: Rotatable pelvis
Base of sacrum Iliac crest Sacroiliac joint Iliac fossa Anterior superior iliac spine Sacral promontory Coxal bone (os coxae or hip bone) Anterior inferior iliac spine llium Sacrum Pubic bone Pelvic brim Coccyx Acetabulum Pubic tubercle Ischium Pubic crest Pubic symphysis Pubic arch PLAY Animation: Rotatable pelvis Figure 7.29

Hip Bone Three regions Ilium Superior region of the coxal bone
Auricular surface articulates with the sacrum (sacroiliac joint) Ischium Posteroinferior part of hip bone Pubis Anterior portion of hip bone Midline pubic symphysis joint

(a) Lateral view, right hip bone
Anterior gluteal line Ilium Ala Posterior gluteal line Iliac crest Posterior superior iIiac spine Anterior superior iliac spine Posterior inferior iliac spine Inferior gluteal line Greater sciatic notch Anterior inferior iliac spine Ischial body Acetabulum Ischial spine Lesser sciatic notch Pubic body Pubis Ischium Inferior ramus of pubis Ischial tuberosity Obturator foramen Ischial ramus (a) Lateral view, right hip bone Figure 7.30a

(b) Medial view, right hip bone
Ilium Iliac fossa Iliac crest Posterior superior iliac spine Anterior superior iliac spine Posterior inferior iliac spine Anterior inferior iliac spine Auricular surface Body of the ilium Arcuate line Greater sciatic notch Superior ramus of pubis Ischial spine Lesser sciatic notch Pubic tubercle Obturator foramen Articular surface of pubis (at pubic symphysis) Ischium Inferior ramus of pubis Ischial ramus (b) Medial view, right hip bone Figure 7.30b

Comparison of Male and Female Pelves
Female pelvis Adapted for childbearing True pelvis (inferior to pelvic brim) defines birth canal Cavity of the true pelvis is broad, shallow, and has greater capacity

Male pelvis Tilted less forward Adapted for support of male’s heavier build and stronger muscles Cavity of true pelvis is narrow and deep

Characteristic Female Male Bone thickness Lighter, thinner, and smoother Heavier, thicker, and more prominent markings Pubic arch/angle 80˚– 90˚ 50˚– 60˚ Acetabula Small; farther apart Large; closer together Sacrum Wider, shorter; sacral curvature is accentuated Narrow, longer; sacral promontory more ventral Coccyx More movable; straighter Less movable; curves ventrally

Table 7.4

Carries the weight of the body Subjected to exceptional forces
The Lower Limb Carries the weight of the body Subjected to exceptional forces Three segments of the lower limb Thigh: femur Leg: tibia and fibula Foot: 7 tarsal bones in the ankle, 5 metatarsal bones in the metatarsus, and 14 phalanges in the toes

Femur Largest and strongest bone in the body Articulates proximally with the acetabulum of the hip and distally with the tibia and patella

Neck Fovea capitis Greater trochanter Head Inter- trochanteric crest
Lesser trochanter Intertrochanteric line Gluteal tuberosity Apex Linea aspera Anterior Facet for lateral condyle of femur Facet for medial condyle of femur Lateral condyle Medial and lateral supracondylar lines Lateral epicondyle Surface for patellar ligament Intercondylar fossa Posterior Medial condyle (a) Patella (kneecap) Adductor tubercle Lateral epicondyle Medial epicondyle Patellar surface Anterior view Posterior view (b) Femur (thigh bone) Figure 7.31

Bones of the Leg Tibia Fibula Medial leg bone
Receives the weight of the body from the femur and transmits it to the foot Fibula Not weight bearing; no articulation with femur Site of muscle attachment Connected to tibia by interosseous membrane Articulates with tibia via proximal and distal tibiofibular joints

Intercondylar eminence Head Medial condyle Proximal tibiofibular joint
Lateral condyle Intercondylar eminence Head Medial condyle Proximal tibiofibular joint Tibial tuberosity Interosseous membrane Anterior border Fibula Tibia Distal tibiofibular joint Articular surface Lateral malleolus Medial malleolus (a) Anterior view Figure 7.32a

Articular surface Articular surface of of medial condyle
lateral condyle Medial condyle Head of fibula Interosseous membrane Tibia Fibula Articular surface Medial malleolus Lateral malleolus (b) Posterior view Figure 7.32b

The Lower Limbs The Ankle Also called the tarsus
Consists of seven tarsal bones Bones of the ankle Talus: carries weight from tibia across trochlea Calcaneus (heel bone): transfers weight from talus to ground attaches calcaneal (Achilles) tendon Cuboid: articulates with calcaneus

The Lower Limbs The Ankle Bones of the ankle Navicular:
articulates with talus and three cuneiform bones Medial cuneiform Intermediate cuneiform Lateral cuneiform

The Lower Limbs Figure 8–14a Bones of the Ankle and Foot.

Metatarsal Bones of the Foot
The Lower Limbs Metatarsal Bones of the Foot Five long bones of foot Numbered I–V, medial to lateral Articulate with toes

The Lower Limbs Phalanges of the foot Phalanges 14 bones of the toes
Hallux Big toe or great toe, two phalanges (distal, proximal) Other four toes Three phalanges (distal, medial, proximal)

The Lower Limbs Figure 8–14a Bones of the Ankle and Foot.

The Axial Skeleton Consists of 80 bones Three major regions Skull

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