The Appendicular Skeleton
• Composed of 126 bones
– Limbs (appendages)
– Pectoral girdle
– Pelvic girdle
Cranium
Skull
Facial bones
Clavicle
Thoracic cage
(ribs and
sternum)
Scapula
Sternum
Rib
Humerus
Vertebral
column
Vertebra
Radius
Ulna
Sacrum
Carpals
Phalanges
Metacarpals
Femur
Patella
Tibia
Fibula
Tarsals
Metatarsals
Phalanges
(a) Anterior view
Figure 5.8a
Cranium
Bones of
pectoral
girdle
Clavicle
Scapula
Upper
limb
Rib
Humerus
Vertebra
Radius
Ulna
Carpals
Bones
of
pelvic
girdle
Phalanges
Metacarpals
Femur
Lower
limb
Tibia
Fibula
(b) Posterior view
Figure 5.8b
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
Acromioclavicular Clavicle
joint
Scapula
(a) Articulated right shoulder (pectoral) girdle
showing the relationship to bones of the
thorax and sternum
Figure 5.23a
Posterior
Sternal (medial)
end
Acromial (lateral)
end
Anterior
Superior view
Acromial end
Sternal end
Anterior
Posterior
Inferior view
(b) Right clavicle, superior and inferior views
Figure 5.23b
Suprascapular notch
Coracoid process
Superior
angle
Acromion
Glenoid cavity
at lateral angle
Spine
Medial
border
Lateral border
(c) Right scapula, posterior aspect
Figure 5.23c
Acromion
Coracoid
process
Suprascapular notch
Superior border
Superior
angle
Glenoid
cavity
Lateral
(axillary)
border
Medial
(vertebral)
border
Inferior angle
(d) Right scapula, anterior aspect
Figure 5.23d
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
Greater
tubercle
Lesser
tubercle
Head of
humerus
Anatomical neck
Intertubercular
sulcus
Deltoid
tuberosity
Radial
fossa
Coronoid
fossa
Capitulum
(a)
Medial
epicondyle
Trochlea
Figure 5.24a
Head of
humerus
Anatomical
neck
Surgical
neck
Radial
groove
Deltoid
tuberosity
Medial
epicondyle
Olecranon
fossa
Trochlea
Lateral
epicondyle
(b)
Figure 5.24b
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
Trochlear notch
Olecranon
Head
Neck
Radial
tuberosity
Coronoid
process
Proximal
radioulnar
joint
Radius
Ulna
Interosseous
membrane
Ulnar styloid
process
Radial
styloid
process
(c)
Distal
radioulnar
joint
Figure 5.24c
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
Distal
Phalanges
(fingers)
Middle
Proximal
Metacarpals
(palm)
4
3
2
5
1
Trapezium
Hamate
Trapezoid
Carpals Pisiform
(wrist) Triquetrum
Scaphoid
Capitate
Lunate
Ulna
Radius
Figure 5.25
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
lliac crest
Sacroiliac
joint
llium
Coxal bone
(or hip bone)
Sacrum
Pubis
Pelvic brim
Coccyx
Ischial spine
Acetabulum
Pubic symphysis
Ischium
Pubic arch
(a)
Figure 5.26a
IIium
Ala
IIiac crest
Posterior
superior
iliac
spine
Anterior superior
iliac spine
Posterior
inferior
iliac spine
Anterior inferior
iliac spine
Greater sciatic
notch
Acetabulum
Ischial body
Body of pubis
Ischial spine
Pubis
Ischial
tuberosity
Ischium
Ischial ramus
(b)
Inferior pubic
ramus
Obturator
foramen
Figure 5.26b
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
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)
Figure 5.26c
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
Neck
Head
Intertrochanteric
line
Lesser trochanter
Lateral
condyle
Patellar
surface
(a)
Figure 5.27a
Head
Lesser trochanter
Gluteal tuberosity
Intercondylar
fossa
Medial
condyle
(b)
Greater
trochanter
Intertrochanteric
crest
Lateral
condyle
Figure 5.27b
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
Intercondylar
eminence
Medial
condyle
Tibial
tuberosity
Lateral
condyle
Head
Proximal
tibiofibular
joint
Interosseous
membrane
Anterior
border
Fibula
Tibia
Distal
tibiofibular
joint
Medial
malleolus
Lateral
malleolus
(c)
Figure 5.27c
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
Phalanges:
Distal
Middle
Proximal
Tarsals:
Medial
cuneiform
Intermediate
cuneiform
Navicular
Metatarsals
Tarsals:
Lateral
cuneiform
Cuboid
Talus
Calcaneus
Figure 5.28
Arches of the Foot
• Bones of the foot are arranged to form three
strong arches
– Two longitudinal
– One transverse
Medial longitudinal arch
Transverse arch
Lateral longitudinal
arch
Figure 5.29