The Appendicular Skeleton

• Composed of 126 bones– Limbs (appendages)– Pectoral girdle– Pelvic girdle

Figure 5.8a(a) Anterior view

Phalanges

Metatarsals

Tarsals

Fibula

Tibia

Patella

Femur

Metacarpals

Phalanges

Carpals

UlnaRadius

Vertebra

Humerus

Rib

Sternum

Scapula

Clavicle

Facial bones

Cranium

Skull

Thoracic cage(ribs andsternum)

Vertebralcolumn

Sacrum

Figure 5.8b(b) Posterior view

Fibula

Tibia

Femur

Metacarpals

Phalanges

Carpals

RadiusUlna

Vertebra

Humerus

Rib

Scapula

Clavicle

Cranium

Bones ofpectoralgirdle

Upperlimb

Bones ofpelvicgirdle

Lowerlimb

The Pectoral (Shoulder) Girdle

• Composed of two bones– Clavicle—collarbone• Articulates with the sternum medially and with the

scapula laterally– Scapula—shoulder blade• Articulates with the clavicle at the acromioclavicular

joint• Articulates with the arm bone at the glenoid cavity

• These bones allow the upper limb to have exceptionally free movement

Figure 5.23a

Acromio- clavicularjoint

Scapula

(a) Articulated right shoulder (pectoral) girdle showing the relationship to bones of the thorax and sternum

Clavicle

Figure 5.23b

PosteriorSternal (medial) end

Acromial (lateral) end

Superior view

Acromial end

Anterior

Anterior

Sternal end

Posterior

Inferior view

(b) Right clavicle, superior and inferior views

Figure 5.23c

Suprascapular notch

Superior angle

Spine

Medial border

Lateral border

Glenoid cavity at lateral angle

(c) Right scapula, posterior aspect

Coracoid process

Acromion

Figure 5.23d

Acromion

Coracoidprocess

Glenoidcavity

Lateral(axillary)border

(d) Right scapula, anterior aspect

Medial(vertebral)border

Inferior angle

Suprascapular notch

Superior border

Superior angle

Bones of the Upper Limbs

• Humerus– Forms the arm– Single bone– Proximal end articulation• Head articulates with the glenoid cavity of the scapula

– Distal end articulation• Trochlea and capitulum articulate with the bones of the

forearm

Figure 5.24a

Greater tubercle

Lesser tubercle

Head of humerus

Anatomical neck

Intertubercular sulcus

Medial epicondyle

Trochlea(a)

Capitulum

Coronoid fossa

Radial fossa

Deltoid tuberosity

Figure 5.24b

Head of humerus

Anatomical neck

Radial groove

Deltoid tuberosity

Medial epicondyle

Trochlea(b)

Olecranon fossa

Lateral epicondyle

Surgical neck

Bones of the Upper Limbs

• The forearm has two bones– Ulna—medial bone in anatomical position• Proximal end articulation

– Coronoid process and olecranon articulate with the humerus

– Radius—lateral bone in anatomical position• Proximal end articulation

– Head articulates with the capitulum of the humerus

Figure 5.24c

Head

Neck

Radial tuberosity

Radius

Radial styloid process

Distal radioulnar joint

Ulnar styloid process

(c)

Inter- osseous membrane

Ulna

Proximal radioulnar joint

Coronoid process

Olecranon

Trochlear notch

Bones of the Upper Limbs

• Hand– Carpals—wrist • Eight bones arranged in two rows of four bones in each

hand– Metacarpals—palm• Five per hand

– Phalanges—fingers and thumb• Fourteen phalanges in each hand• In each finger, there are three bones• In the thumb, there are only two bones

Figure 5.25

Phalanges (fingers)

Distal

Middle

Proximal

Metacarpals (palm)

Carpals (wrist)

Hamate

Pisiform

Triquetrum

Lunate

UlnaRadius

Capitate

Scaphoid

Trapezoid

Trapezium

1

2345

Bones of the Pelvic Girdle

• Formed by two coxal (ossa coxae) bones• Composed of three pairs of fused bones– Ilium– Ischium– Pubis

• Pelvic girdle = 2 coxal bones, sacrum• Bony pelvis = 2 coxal bones, sacrum, coccyx

Bones of the Pelvic Girdle

• The total weight of the upper body rests on the pelvis

• It protects several organs– Reproductive organs– Urinary bladder– Part of the large intestine

Figure 5.26a

Coxal bone (or hip bone)

llium

Pubis

Ischium

(a)

Pubic arch

Coccyx

Sacrum

lliac crest

Sacroiliac joint

Pelvic brim

Ischial spine

Acetabulum

Pubic symphysis

Figure 5.26b

Posterior superior iliac spine

Posterior inferior iliac spine

Greater sciatic notch

Ischial body

Ischial spine

Ischial tuberosity

Ischium

Ischial ramus

(b)

AlaIIium

IIiac crest

Anterior superior iliac spine

Anterior inferior iliac spine

Acetabulum

Body of pubis

Pubis

Inferior pubic ramus

Obturator foramen

Gender Differences of the Pelvis

• The female inlet is larger and more circular• The female pelvis as a whole is shallower, and

the bones are lighter and thinner• The female ilia flare more laterally• The female sacrum is shorter and less curved• The female ischial spines are shorter and

farther apart; thus the outlet is larger• The female pubic arch is more rounded

because the angle of the pubic arch is greater

Figure 5.26c

False pelvis

Inlet of true pelvis

Pelvic brim

Pubic arch (less than 90°)

False pelvis

Inlet of true pelvis

Pelvic brim

Pubic arch (more than 90°)

(c)

Bones of the Lower Limbs

• Femur—thigh bone– The heaviest, strongest bone in the body– Proximal end articulation• Head articulates with the acetabulum of the coxal (hip)

bone

– Distal end articulation• Lateral and medial condyles articulate with the tibia in

the lower leg

Figure 5.27a

Neck

Inter- trochanteric line

Lateral condyle

Patellar surface

(a)

Lesser trochanter

Head

Figure 5.27b

Head

Lesser trochanter

Gluteal tuberosity

Greater trochanterInter- trochanteric crest

Intercondylar fossa

Medial condyle

Lateral condyle

(b)

Bones of the Lower Limbs

• The lower leg has two bones– Tibia—Shinbone; larger and medially oriented• Proximal end articulation

– Medial and lateral condyles articulate with the femur to form the knee joint

– Fibula—Thin and sticklike; lateral to the tibia• Has no role in forming the knee joint

Figure 5.27c

Intercondylar eminence

Lateral condyleHead

Proximal tibiofibular joint

Fibula

Distal tibiofibular joint

Lateral malleolus

(c)

Medial malleolus

Tibia

Anterior border

Interosseous membrane

Tibial tuberosity

Medial condyle

Bones of the Lower Limbs

• The foot– Tarsals—seven bones• Two largest tarsals

– Calcaneus (heel bone)– Talus

– Metatarsals—five bones form the sole of the foot

– Phalanges—fourteen bones form the toes

Figure 5.28

Tarsals:

Medial cuneiform

Intermediatecuneiform

Navicular

Talus

Calcaneus

Cuboid

Lateral cuneiform

Tarsals:

Metatarsals

Proximal

MiddleDistal

Phalanges:

Arches of the Foot

• Bones of the foot are arranged to form three strong arches– Two longitudinal– One transverse

Figure 5.29

Medial longitudinal arch

Transverse arch

Lateral longitudinal arch