The bones of the axial skeleton
SKELETAL SYSTEM 206 Cranium 8 APPENDICULAR SKELETON (see Section 2) Skull 126 Face 14 Skull and associated bones 29 Auditory ossicles 6 Associated bones Hyoid 1 AXIAL SKELETON Costal cartilages (cartilages of ribs) 80 Sternum 1 Thoracic cage 25 Ribs 24 Intervertebral discs (cartilage) Vertebrae 24 Vertebral column 26 Sacrum 1 Coccyx 1 Figure 7 Section 1 The Axial Skeleton Figure 7 Section 1 1 Section 1: Axial Skeleton
Forms longitudinal axis of body Includes: Skull and associated bones Thoracic cage Vertebral column Various supplemental cartilages Typically 80 bones Module 7.9: Vertebral column
Consists of 26 bones (24 vertebrae, 1 sacrum, 1 coccyx) Functions Provides a column of support Transfers weight to lower limbs Protects spinal column Helps maintain upright position Module 7.9: Vertebral column
Spinal curves Primary (before birth) and secondary (after birth) Cervical curve (secondary) Develops as infant learns to balance head on vertebrae Thoracic curve (primary) Accommodation of thoracic organs Lumbar curve (secondary) Develops with ability to stand to balance trunk over limbs Sacral curve (primary) Accommodates abdominopelvic organs The spinal curves and vertebral regions in the adult vertebral column
Primary curves develop before birth, and secondary curves after birth. Regions are defined by anatomical characteristics of individual vertebrae. C1 C2 Cervical curve (a secondary curve) C3 C4 Cervical (7 vertebrae) C5 C6 C7 T1 T2 T3 T4 T5 Thoracic curve (a primary curve) T6 T7 Thoracic (12 vertebrae) T8 T9 T10 T11 T12 Figure The vertebral column has four spinal curves, and vertebrae have both anatomical similarities and regional differences L1 L2 Lumbar curve (a secondary curve) L3 Lumbar (5 vertebrae) L4 L5 Sacral Sacral curve (a primary curve) Coccygeal Figure 5 Figure The vertebral column has four spinal curves, and vertebrae have both anatomical similarities and regional differences Figure 6 Module 7.9: Vertebral column
Vertebral regions (defined by anatomical characteristics of individual vertebrae) Cervical (7 vertebrae) Thoracic (12 vertebrae) Lumbar (5 vertebrae) Sacral Coccygeal The parts of a typical vertebra Parts of a Vertebra
Articular processes Vertebral arch Vertebral body Figure The vertebral column has four spinal curves, and vertebrae have both anatomical similarities and regional differences Superior view Figure 8 Module 7.9: Vertebral column
Parts of typical vertebra Articular processes Extend superiorly and inferiorly to articulate with adjacent vertebrae Vertebral body Transfers weight along vertebral column axis Vertebral arch (next slide) Vertebral foramen Formed by vertebral body and arch The parts of the vertebral arch The Vertebral Arch
Spinous process Vertebral foramen Laminae Transverse process Figure The vertebral column has four spinal curves, and vertebrae have both anatomical similarities and regional differences Pedicles Inferior view Figure 10 Module 7.9: Vertebral column
Characteristics of articulated vertebrae Intervertebral discs Pads of fibrous cartilage found between bodies of adjacent vertebrae Intervertebral foramina Spaces between successive pedicles Passage of nerves and blood vessels Vertebral canal Encloses spinal cord A lateral view of three vertebrae
Pedicle Intervertebral disc Intervertebral foramina Figure The vertebral column has four spinal curves, and vertebrae have both anatomical similarities and regional differences Vertebral body Vertebral canal Figure 12 Superior articular process Inferior articular process
A posterior view of two vertebrae Articular facet Superior articular process Inferior articular process Figure The vertebral column has four spinal curves, and vertebrae have both anatomical similarities and regional differences Figure 13 Module 7.9 Review a. Name the major components of a typical vertebra.
b.What is the importance of the secondary curves of the spine? c.To which part of the vertebra do the intervertebral discs attach? Module 7.10: Cervical and thoracic vertebrae
Cervical vertebrae Characteristics Smallest of vertebral column Extend from occipital bone to thorax Large vertebral foramen Spinal cord here has many axons connecting to brain Vertebral body is small and light Only supports weight of head A typical cervical vertebra
Bifid spinous process Vertebral foramen Transverse foramen Transverse process Figure There are seven cervical vertebrae and twelve thoracic vertebrae Vertebral body Costal process Figure 16 Module 7.10: Cervical and thoracic vertebrae
First two cervical vertebrae Specialized to stabilize cranium while permitting head movement Atlas (C1) (named after Greek god who holds world) No spinous process No vertebral body Large round vertebral foramen Axis (C2) Prominent dens or odontoid (odontos, tooth) process of body The first two cervical vertebrae: the atlas and the axis Anterior
arch of atlas Atlas Dens (odontoid process) Ligament that enables rotation (as in shaking the head to indicate no) Joint that permits nodding (as in indicating yes) Figure There are seven cervical vertebrae and twelve thoracic vertebrae Axis Posterior arch of atlas Figure 18 A lateral view of the seven cervical vertebrae
prominens Figure There are seven cervical vertebrae and twelve thoracic vertebrae Figure 20 Module 7.10: thoracic vertebrae
Twelve thoracic vertebrae Body of each (moving inferior) is more robust than the one superior due to bearing of increasing weight Each has costal facets that articulate with ribs Characteristics Distinctive heart-shaped body Smaller vertebral foramen Long, slender, inferiorly pointing spinous process Figure 7.10.4 There are seven cervical vertebrae and twelve thoracic vertebrae
22 A typical thoracic vertebra in superior view
Transverse process Spinous process Superior articular facet Vertebral foramen Superior costal facet Figure There are seven cervical vertebrae and twelve thoracic vertebrae Vertebral body Figure 23 A typical thoracic vertebra in lateral view
Superior costal facet Transverse costal facet Vertebral body Spinous process Inferior costal facet Figure There are seven cervical vertebrae and twelve thoracic vertebrae Transverse process Figure 24 Lumbar vertebrae Five lumbar vertebrae
Largest and transmit most weight Characteristics Do not have costal facets Have slender transverse processes Triangular vertebral foramen Module 7.11: Lumbar vertebrae, sacrum, and coccyx
Five fused vertebrae Completely fused by ~2530 years old Module 7.11: Lumbar vertebrae, sacrum, and coccyx
Three to five fused vertebrae Begin fusing about age 2 Module 7.11 Review a.How many vertebrae are present in the lumbar region? In the sacrum? b.What structure forms the posterior wall of the pelvic girdle?We have not gone over this yet but what do you think it would be? c.Why are the bodies of the lumbar vertebrae so large? Module 7.12: Thoracic cage Thoracic cage
Provides bony support to thoracic cavity walls Protects heart, lungs, thymus, and other thoracic cavity organs Attachment for muscles involved in Respiration Maintenance of vertebral column position Movements of pectoral girdle and upper limbs An anterior view of the thoracic cage
Jugular notch T1 1 2 3 Sternum Manubrium 4 5 Ribs Figure The thoracic cage protects organs in the chest and provides sites for muscle attachment Vertebrosternal ribs (ribs 17) 6 Body 11 T11 Vertebrosternal ribs (ribs 810) 7 T12 12 8 9 Floating ribs (ribs 11 and 12) Xiphoid process 10 Costal cartilages Figure 30 Module 7.12: Thoracic cage Thoracic cage components Ribs
Very mobile and flexible bones Types Vertebrocostal ribs (ribs 17) Connect to sternum via individual costal cartilages Vertebrochondral ribs (ribs 810) Connect to sternum via shared costal cartilages Floating ribs (ribs 11 and 12) No connection to sternum Also known as vertebral ribs Module 7.12: Thoracic cage Thoracic cage components (continued)
Sternum Forms anterior midline of thoracic wall Three regions Manubrium (superior portion that articulates with clavicles and first pair of ribs) Body (attaches inferiorly to manubrium and to ribs 7) Xiphoid process (smallest, most inferior region) Ribs: Head or capitulum (attachment to vertebra)
Angle (bend connecting head to shaft) Shaft (tubular body) Posterior view of a representative rib (ribs 29) Articular facets on head Capitulum Tubercle Angle of the rib Shaft Figure The thoracic cage protects organs in the chest and provides sites for muscle attachment Superficial surface Costal groove Figure 33 The action of a typical rib, which can be likened to the movement
of a buckets handle Sternum Ribs Figure The thoracic cage protects organs in the chest and provides sites for muscle attachment Figure 34 Superior view of a representative rib
Transverse process Tubercular facet Superior articular facet Transverse costal facet Figure The thoracic cage protects organs in the chest and provides sites for muscle attachment Inferior articular facet Figure 35 Section 2: Appendicular Skeleton
Consists of bones of the limbs and supporting elements (or girdles) that connect them to trunk 126 bones Pectoral girdle (4) Upper limbs (60) Pelvic girdle (2) Lower limbs (60) The bones of the appendicular skeleton
SKELETAL SYSTEM 206 AXIAL SKELETON 80 Clavicle 2 Pectoral girdle 4 Scapula 2 Humerus 2 Radius 2 Ulna 2 Upper limbs 60 Carpal bones 16 Metacarpal bones 10 APPENDICULAR SKELETON 126 Phalanges (proximal, middle, distal) 28 Hip bone (coxal bone) 2 Pelvic girdle 2 Figure 7 Section 2 The Appendicular Skeleton Femur 2 Patella 2 Tibia 2 Fibula 2 Lower limbs 60 Tarsal bones 14 Metatarsal bones 10 Phalanges 28 Figure 7 Section 2 37 Pectoral (shoulder) girdle Joins arm to trunk
Consists of clavicle and scapula The relationship of the clavicle to adjacent bones Clavicle Jugular notch Scapula Humerus Figure The pectoral girdlesthe clavicles and scapulaeconnect the upper limbs to the axial skeleton Anterior view Figure 38 Module 7.13: Pectoral girdle
Clavicle Originate or Attaches at superior, lateral border of manubrium Characteristics Sternal end Pyramid-shaped Articulates with acromion of scapula Acromial end Flatter, broader than sternal end Rough interior surface bearing lines and tubercles Two views of the right clavicle
Superior view LATERAL MEDIAL Acromial end Sternal end Figure The pectoral girdlesthe clavicles and scapulaeconnect the upper limbs to the axial skeleton LATERAL Inferior view MEDIAL Figure 40 Module 7.13: Pectoral girdle
Scapula Body Broad, smooth triangle Subscapular fossa Anterior surface depression Glenoid cavity Cup-shaped Articulates with humerus Scapular spine Ridge on posterior surface Supraspinous fossa (supra, above) Infraspinous fossa (infra, below) Acromion process End of spine Coracoid process Anterior, superior to glenoid cavity Two views of the right scapula
Scapular spine Acromion Coracoid process Superior border Superior angle Acromion Supraspinous fossa Subscapular fossa Process that supports the cup-shaped glenoid cavity Figure The pectoral girdlesthe clavicles and scapulaeconnect the upper limbs to the axial skeleton Medial border Infraspinous fossa Lateral border Anterior view Posterior view Inferior angle Figure 4 42 Two views of the right scapula
Scapular spine Acromion Coracoid process Superior border Superior angle Acromion Supraspinous fossa Subscapular fossa Process that supports the cup-shaped glenoid cavity Figure The pectoral girdlesthe clavicles and scapulaeconnect the upper limbs to the axial skeleton Medial border Infraspinous fossa Lateral border Anterior view Posterior view Inferior angle Figure 4 43 A lateral view of the right scapula
Coracoid process Glenoid cavity Acromion Figure The pectoral girdlesthe clavicles and scapulaeconnect the upper limbs to the axial skeleton Figure 44 Module 7.13 Review a. Name the bones of the pectoral girdle.
b. How would a broken clavicle affect the mobility and stability of the scapula? c.Which bone articulates with the scapula at the glenoid cavity? Module 7.14: Humerus, radius, ulna
Skeleton of upper limbs includes those of arms, forearms, wrists, and hands Arm = shoulder to elbow Forearm = elbow to wrist Module 7.14: Humerus, radius, ulna
Head Proximal end that articulates with glenoid cavity (scapula) Lesser tubercle Smaller projection on anterior, medial epiphyseal surface Greater tubercle Rounded projection on lateral epiphyseal surface Establishes lateral contour of shoulder Intertubercular groove Between tubercles Important for muscle attachment Surface features of the right humerus
Anterior view Posterior view Head Greater tubercle Greater tubercle Lesser tubercle Intertubercular groove Anatomical neck Surgical neck Radial groove Shaft Deltoid tuberosity Figure The humerus of the arm articulates with the radius and ulna of the forearm Radial fossa Coronoid fossa Olecranon fossa Lateral epicondyle Medial epicondyle Trochlea Capitulum Trochlea Figure 48 Module 7.14: Humerus, radius, ulna
Humerus (continued) Anatomical neck Marks extent of joint capsule Surgical neck Fractures typically occur here Deltoid tuberosity Large, rough elevation on lateral surface Attachment of deltoid muscle Radial groove Crosses inferior end of deltoid tuberosity Depression marking path of radial nerve Surface features of the right humerus
Anterior view Posterior view Head Greater tubercle Greater tubercle Lesser tubercle Intertubercular groove Anatomical neck Surgical neck Radial groove Shaft Deltoid tuberosity Figure The humerus of the arm articulates with the radius and ulna of the forearm Radial fossa Coronoid fossa Olecranon fossa Lateral epicondyle Medial epicondyle Trochlea Capitulum Trochlea Figure 50 Module 7.14: Humerus, radius, ulna
Humerus (continued) Radial fossa Accommodates portion of radial head Condyle (attachment point for radius and ulna) Capitulum Lateral surface of condyle Trochlea (trochlea, pulley) Medial surface of condyle Extends from olecranon fossa (posterior) to coronoid fossa (anterior) These depressions accept projections of ulna Module 7.14: Humerus, radius, ulna
Ulna and radius Parallel bones that support forearm In anatomical position, ulna is medial to radius Shafts connected via interosseus membrane Proximal radio-ulnar joint Distal radio-ulnar joint Surface features of the right ulna and radius
Posterior view Anterior view Radial head Trochlear notch Olecranon Neck of the radius Coronoid process Proximal radio-ulnar joint Radial notch at proximal radio-ulnar joint Radial tuberosity Ulna Radius Radius Ulna Figure The humerus of the arm articulates with the radius and ulna of the forearm Interosseous membrane Ulnar notch Distal radio-ulnar joint Ulnar head Styloid process of the radius Ulnar head Styloid process of the ulna Figure 53 Module 7.14: Humerus, radius, ulna
Ulna (In anatomical Position Ulna is Medial to the Radius!!!) Olecranon Superior end of ulna Point of elbow Ulnar head Distal, slender, rounded end Styloid process (styloid, long and pointed) Posterior, lateral surface of head Module 7.14: Humerus, radius, ulna
Radial head Articulates with capitulum of humerus During flexion, swings into radial fossa of humerus Neck From radial head to tuberosity Styloid process Distal radius that articulates with bones of wrist Module 7.15: Carpal bones, metacarpals, and phalanges
Carpus Eight carpal bones arranged in two rows of four bones Proximal carpal bones Scaphoid (skaphe, boat) Lateral border of wrist Closest to styloid process of radius Lunate (luna, moon) Medial to scaphoid Articulates with radius Pisiform (pisum, pea) Anterior to triquetrum Triquetrum (triquetrus, three-cornered) Articulates with disc separating ulna from wrist Module 7.15: Carpal bones, metacarpals, and phalanges
Carpus (continued) Distal carpal bones Trapezium (trapezion, four sided with no parallel sides) Lateral bone that articulates with scaphoid Trapezoid Medial to trapezium Proximal articulation with scaphoid Capitate (caput, head) Largest carpal bone Between trapezoid and hamate Hamate Medial carpal bone The bones of the carpus (wrist)
Proximal Carpal Bones Scaphoid Lunate Pisiform Triquetrum Right wrist and hand, anterior (palmar) view Radius Ulna I II III IV V Metacarpal bones Figure The wrist is composed of carpal bones, and the hand consists of metacarpal bones and phalanges Proximal phalanx Distal Carpal Bones Trapezium Trapezoid Capitate Hamate Middle phalanx Distal phalanx Figure 58 Module 7.15: Carpal bones, metacarpals, and phalanges
Metacarpals (metacarpus, hand) Articulate with distal carpal bones and support hand Identified by Roman numerals IV, from lateral to medial Distally articulate with proximal finger bones Phalanges 14 phalanges per hand Pollex (thumb) has 2 phalanges (proximal and distal) All other fingers have 3 phalanges (proximal, middle, and distal) The metacarpal bones (designated IV) and the phalanges of the hand Radius Ulna Proximal Carpal Bones Scaphoid Lunate Triquetrum Distal Carpal Bones Pisiform Trapezium Trapezoid Capitate Hamate I V III II IV Proximal phalanx of pollex Metacarpal bones Proximal phalanx Distal phalanx of pollex Figure The wrist is composed of carpal bones, and the hand consists of metacarpal bones and phalanges Middle phalanx Right wrist and hand, posterior (dorsal) view Distal phalanx Figure 60 Module 7.16: Pelvic girdle Pelvic girdle
Consists of paired hip bones (coxal bones) Hip bone formed by fusion of three bones Ilium Ischium Pubis Acetabulum (acetabulum, vinegar cup) Concave socket formed by all three fused bones Articulates with head of femur Module 7.16: Pelvic girdle Ilium
Iliac spines Attachment of important muscles and ligaments Iliac crest Important ridge for muscle attachment Ischium Ischial spine Projects superior to sciatic notch Passage of blood vessels, nerves, and small muscle Ischial tuberosity Roughened projection Supports body weight when seated Pubis Pubic symphysis Connects pubic bones via fibrous cartilage pad A hip bone, which consists of an
ilium, an ischium, and a pubis Ilium A lateral view of the right hip bone POSTERIOR ANTERIOR Pubis Ischium Iliac crest Gluteal Lines Medial Anterior Anterior superior iliac spine Posterior Posterior superior iliac spine Lunate surface Posterior inferior iliac spine Figure The hip bone forms by the fusion of the ilium, ischium, and pubis Greater sciatic notch Acetabulum Ischial spine Ischial ramus Ischial tuberosity Acetabular notch Figure 2 63 A hip bone, which consists of an
ilium, an ischium, and a pubis Ilium A lateral view of the right hip bone POSTERIOR ANTERIOR Pubis Ischium Iliac crest Gluteal Lines Medial Anterior Anterior superior iliac spine Posterior Posterior superior iliac spine Lunate surface Posterior inferior iliac spine Figure The hip bone forms by the fusion of the ilium, ischium, and pubis Greater sciatic notch Acetabulum Ischial spine Ischial ramus Ischial tuberosity Acetabular notch Figure 2 64 A medial view of the right hip bone
Ilium ANTERIOR POSTERIOR Pubis Ischium Iliac crest Iliac tuberosity Iliac fossa Auricular surface of the ilium Arcuate line of the ilium Figure The hip bone forms by the fusion of the ilium, ischium, and pubis Greater sciatic notch Pectineal line Obturator foramen Superior pubic ramus Pubic symphysis Ischial ramus Inferior pubic ramus Figure 65 Module 7.16 Review a. Describe the acetabulum.
b.Which three bones fuse to make up a hip bone? c.When you are seated, which part of the hip bone bears your bodys weight? Pelvis: two hip bones, sacrum, and coccyx
The structures of the pelvis Pelvis: two hip bones, sacrum, and coccyx Sacrum Hip Bone Ilium Coccyx Pubis Ischium L5 Iliac crest Iliac fossa Ilium Sacrum Figure The pelvis consists of the two hip bones plus the sacrum and the coccyx Sacro-iliac joint Acetabulum Pubic tubercle Obturator foramen Ischium Pubic symphysis Figure 67 Module 7.18: Femur, tibia, and fibula
Skeleton of lower limb consists of: Femur (thigh) Patella (kneecap) Tibia and fibula (leg) Connected with interosseus membrane Metatarsal bones and phalanges (foot) Same number of bones as upper limb Functional anatomy is different due to weight-bearing properties Module 7.18: Femur, tibia, and fibula
Longest and heaviest bone in body Articulates with hip at hip joint Articulates with tibia at knee joint Characteristics Femoral head Articulates with pelvis at acetabulum Fovea capitis Small pit containing ligament attaching head to acetabulum Neck Joins shaft at about 125 Figure 7.18.1-2 The femur articulates with the patella and tibia
Landmarks of the right femur Neck Fovea capitis Greater trochanter Greater trochanter Femoral head Intertrochanteric crest Gluteal tuberosity Intertrochanteric line Linea aspera Lesser trochanter Anterior view Posterior view Figure The femur articulates with the patella and tibia Shaft Lateral supracondylar ridge Popliteal surface Adductor tubercle Patellar surface Lateral epicondyle Medial epicondyle Intercondylar fossa Lateral condyle Medial condyle Lateral epicondyle Lateral condyle Figure 70 Module 7.18: Femur, tibia, and fibula
Femur (continued) Characteristics Greater trochanter Large, rough projection that extends laterally Attachment site for large tendons Lesser trochanter Smaller process that projects posteriorly and mediall Linea aspera (aspera, rough) Attachment of powerful hip muscles Popliteal surface (poples, hollow of knee) Flattened triangular area on posterior Medial and lateral condyles Participate in knee joint at distal end Separated by: Patellar surface (anterior) Intercondylar fossa (posterior) Figure 7.18.1-2 The femur articulates with the patella and tibia
Landmarks of the right femur Neck Fovea capitis Greater trochanter Greater trochanter Femoral head Intertrochanteric crest Gluteal tuberosity Intertrochanteric line Linea aspera Lesser trochanter Anterior view Posterior view Figure The femur articulates with the patella and tibia Shaft Lateral supracondylar ridge Popliteal surface Adductor tubercle Patellar surface Lateral epicondyle Medial epicondyle Intercondylar fossa Lateral condyle Medial condyle Lateral epicondyle Lateral condyle Figure 72 Module 7.18: Femur, tibia, and fibula
Patella Large sesamoid bone that forms in quadriceps tendon Characteristics Base Attachment of quadriceps tendon Apex Attachment of patellar ligament (patella to tibia) Lateral facet For lateral condyle of femur Medial facet For medial condyle of femur Anterior view Posterior view
The surface features of the patella Base of patella Lateral facet, for lateral condyle of femur Attachment area for quadriceps tendon Medial facet, for medial condyle of femur Attachment area for the patellar ligament, which attaches the patella to the tibia Articular surface of patella Apex of patella Figure The femur articulates with the patella and tibia Anterior view Posterior view Figure 74 Module 7.18: Femur, tibia, and fibula
Tibia (shinbone) Large medial bone of leg Characteristics Intercondylar eminence Ridge separating lateral and medial tibial condyles Tibial tuberosity Attachment of patellar ligament Medial malleolus (malleolus, hammer) Medial projection of ankle that supports joint Module 7.18: Femur, tibia, and fibula
Attachment of muscles that move foot and toes Provides lateral stability to ankle joint Characteristics Head Articulates with tibia proximally Lateral malleolus Anterior view Posterior view
The features of the right tibia and fibula Superior tibiofibular joint Articular surface of medial tibial condyle Intercondylar eminence Lateral tibial condyle Articular surface of lateral tibial condyle Medial tibial condyle Head of the fibula Lateral tibial condyle Tibial tuberosity Head of fibula Interosseous membrane Anterior view Posterior view Anterior margin of the tibia Figure The femur articulates with the patella and tibia Tibia Fibula Fibula Medial malleolus of the tibia Inferior tibiofibular joint Lateral malleolus of the fibula Lateral malleolus (fibula) Inferior articular surface Figure 77 Module 7.18 Review a. Identify the bones of the lower limb.
b.Which structure articulates with the acetabulum? c.The fibula neither participates in the knee joint nor bears weight. Yet, when it is fractured, walking becomes difficult. Why? Module 7.19: Tarsals, metatarsals, and phalanges
Tarsals (7 bones) Calcaneus (heel bone) Largest of tarsal bones Most weight transmitted from tibia to ground through it Posterior portion is attachment site for calcaneal tendon (Achilles tendon) Talus Transmits weight from tibia toward toes Trochlea of talus bone forms articulation between tibia and talus Module 7.19: Tarsals, metatarsals, and phalanges
Tarsals (continued) Navicular Articulates with talus and three cuneiform bones Cuboid Articulates with anterior surface of calcaneus 57. Cuneiform bones Medial, intermediate, lateral Module 7.19: Tarsals, metatarsals, and phalanges
Articulate with distal surfaces of cuboid and cuneiforms and phalanges Form distal portion of foot Identified by Roman numerals IV from medial to lateral IIII articulate with cuneiform bones IV & V articulate with cuboid Phalanges (toe bones) Same anatomical organization as fingers (14 bones) Hallux (great toe) has two bones (proximal and distal) All other toes have three bones (proximal, middle, distal) The Ankle (Tarsus) The bones of the ankle and foot The ankle consists of seven tarsal bones. Calcaneus Talus Navicular Trochlea Cuboid Cuneiform bones Metatarsals Articulations of the cuboid and the cuneiform bones with the metatarsal bones V IV III II I Figure 7.19 The ankle and foot contain tarsal bones, metatarsal bones, and phalanges Metatarsal bones (designated IV) Proximal phalanx Phalanges Distal phalanx Proximal, middle, and distal phalanges Hallux Figure 82 Module 7.19: Tarsals, metatarsals, and phalanges
Arches of the foot Longitudinal arch Transfers weight between toes and calcaneus Present because of ligaments and tendons connecting calcaneus to distal portions of metatarsals Lateral (calcaneal) portion has much less curvature than medial (talar) portion Therefore, medial plantar surface elevated to allow passage of inferior surface muscles, blood vessels, and nerves Creates transverse arch A lateral view of the right ankle and foot
Cuboid bone Navicular bone Cuneiform bones Metatarsal bones (IV) Lateral surface of the trochlea Phalanges Lateral view I II Attachment site for the calcaneal tendon (Achilles tendon) III IV V Figure The ankle and foot contain tarsal bones, metatarsal bones, and phalanges Figure 84 A medial view of the right ankle and foot
Phalanges Metatarsal bones Medial cuneiform bone Navicular bone Talus Medial view I Calcaneus Figure The ankle and foot contain tarsal bones, metatarsal bones, and phalanges Longitudinal arch Transverse arch Figure 85 Module 7.19 Review a. Identify the tarsal bones.
b.Which foot bone transmits the weight of the body from the tibia toward the toes? c.While jumping off the back steps at his house, 10-year-old Joey lands on his right heel and breaks his foot. Which foot bone is most likely broken?