Chapter 8

The Appendicular
Skeleton
 An Introduction to the Appendicular
Skeleton

 The Appendicular Skeleton

 126 bones

 Allows us to move and manipulate objects

 Includes all bones besides axial skeleton

 The supportive girdles – pectoral and

pelvic
 The limbs – arms and legs
 8-1 The Pectoral Girdle

 Also called the shoulder girdle

 Connects the arms to the body
 Positions the shoulders
 Provides a base for arm movement
 Consists of
 Two clavicles
 Two scapulae
 Connects with the axial skeleton only at the
manubrium
 The Pectoral Girdle

 The Clavicles
 Also called collarbones

 Long, S-shaped bones

 Originate at the manubrium (sternal end)

 Articulate with the scapulae (acromial end)

The Pectoral Girdle
 The Pectoral Girdle

 The Scapulae
 Also called shoulder blades

 Broad, flat triangles

 Articulate with arm and collarbone

 Anterior surface: the subscapular fossa

 The Pectoral Girdle
 The Scapula
 Structures of the scapula
 Body has three sides:
–superior border
–medial border (vertebral border)
–lateral border (axillary border)
 Body has three corners:
–superior angle
–inferior angle
–lateral angle
 The Pectoral Girdle

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

 The Pectoral Girdle
 The Scapula
 The scapular head
 Holds glenoid cavity -Which articulates
with humerus - forms shoulder joint
 Processes of the glenoid cavity
 Coracoid process:
–anterior, smaller
 Acromion:
–posterior, larger
–articulates with clavicle
–at the acromioclavicular joint
 The Pectoral Girdle

 The Scapulae
 Posterior features of the scapula
 Scapular spine:
–ridge across posterior surface of body
 Separates two regions:
–supraspinous fossa
–infraspinous fossa
 8-2 The Upper Limbs

 The upper limbs consist of the arms,

forearms, wrists, and hands

Note: arm (brachium) = 1 bone, the humerus

 The Upper Limbs

 The Humerus

 Also called the arm

 The long, upper arm bone

 Articulates with the pectoral girdle

 The Upper Limbs

 The Humerus
 Tubercles of the proximal epiphysis
 Separated by the intertubercular groove:

–greater tubercle:
»lateral
»forms tip of shoulder
–lesser tubercle:
»anterior, medial
 The Upper Limbs

 The Humerus
 Head:
 Rounded, articulating surface

 Contained within joint capsule

 Anatomical neck:
 Margin of joint capsule

 Surgical neck:
 The narrow metaphysis
 The Upper Limbs

 The Humerus
 The Shaft
 Deltoid tuberosity:
– a bulge in the shaft
– attaches deltoid muscle

 Radial groove:
– for radial nerve
– posterior to deltoid tuberosity
The Upper Limbs
 The Upper Limbs
 The Humerus
 The distal epiphysis
 Medial and lateral epicondyles:
– for muscle attachment
 Condyle of the humerus:
– articulates with ulna and radius
 Articular regions of the condyle
 Trochlea:
– coronoid fossa and olecranon fossa
– articulates with ulna
 Capitulum:
– radial fossa
– articulates with radius
 The Upper Limbs

 The Forearm (also called the antebrachium)

 Consists of two long bones

Ulna (medial)

Radius (lateral)
 The Upper Limbs
 The Ulna
 The olecranon

 Superior end of ulna

 Point of elbow

 Superior lip of trochlear notch

 Articulates with trochlea of humerus

 The coronoid process

 Inferior lip of trochlear notch

 The Upper Limbs
 The Ulna
 Articulations with the humerus
 Forearm extended:
– olecranon enters olecranon fossa
 Forearm flexed:
– coronoid process enters coronoid fossa
 Other articulations
 Radial notch:
– articulates with head of radius
– forms proximal radio-ulnar joint
 Ulnar head:
– prominent styloid process
– attaches to articular disc between forearm and wrist
The Upper Limbs
 The Upper Limbs

 The Ulna
 Interosseous membrane - ligament
 A fibrous sheet
 Connects lateral margin of ulnar shaft
to radius
 The Upper Limbs
 The Radius
 Lateral bone of forearm
 Disk-shaped radial head above the neck
 Radial tuberosity below the neck, attaches biceps
 Articulations of the radius
 Ulnar notch:
– distal end
– articulates with wrist and radius
 Styloid process:
– stabilizes wrist joint
 The Upper Limbs

 Eight carpal bones

 Four proximal carpal bones

 Four distal carpal bones

 Allow wrist to bend and twist

 The Upper Limbs

Figure 8–6 Bones of the Wrist and Hand.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

 The Upper Limbs

 Metacarpal Bones
 The five long bones of the hand
 Numbered I–V from lateral (thumb) to medial
 Articulate with proximal phalanges
 Phalanges of the Hands (14 total finger
bones)
 Pollex (thumb)
 Two phalanges (proximal, distal)
 Fingers
 Three phalanges (proximal, middle, distal)
 8-3 The Pelvic Girdle & Pelvis

 Made up of two hip bones os coxae (coxal

bones)
 Strong to bear body weight, stress of
movement
 Part of the pelvis
 Coxal bones
 Made up of three fused bones
 Ilium (articulates with sacrum)
 Ischium
 Pubis
 The Pelvic Girdle

Figure 8–7a The Right Coxal Bone.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Sciatic Nerve
 The Pelvic Girdle
 Coxal Bones
 ) The acetabulum
 Also called the hip socket
 Is the meeting point of the ilium, ischium,
and pubis
 Is on the lateral surface of the hip bone
(coxal bone)
 Articulates with head of the femur (lunate
surface
The Pelvic Girdle
 The Pelvic Girdle

 Marks of the Ilium

 Greater sciatic notch
 For sciatic nerve

 Iliac crest
 Upper brim
The Pelvic Girdle
 The Pelvic Girdle

 Marks of the Pubis

 Pubic symphysis
 Gap between pubic tubercles
 Padded with fibrous cartilage
 Obturator foramen
 Formed by ischial and pubic rami
 Attaches hip muscles
 The Pelvic Girdle
 Coxal Bones
 Articulations of the pelvic girdle
 Sacroiliac joint
–With the sacrum
–Stabilized by ligaments of iliac
tuberosity
 The Pelvis
 Consists of two coxal bones, the sacrum, and
the coccyx
 Stabilized by ligaments of pelvic girdle,
sacrum, and lumbar vertebrae
 The Pelvic Girdle

.
The Pelvic Girdle
The Pelvic Girdle
The Pelvic Girdle
 The Pelvic Girdle
 Comparing the Male Pelvis and Female Pelvis
 Female pelvis
 Smoother and lighter
 Less prominent muscle and ligament attachments
 Pelvis modifications for Childbearing
– enlarged pelvic outlet
– broad pubic angle (>100°)
– less curvature of sacrum and coccyx
– wide, circular pelvic inlet
– broad, low pelvis
– ilia project laterally, not upwards
The Pelvic Girdle
 8-4 The Lower Limbs

 Functions of the lower limbs

 Weight bearing
 Motion

Note: leg = lower leg; thigh = upper leg

 The Lower Limbs

 Bones of the Lower Limbs

 Femur (thigh)
 Patella (kneecap)
 Tibia and fibula (leg)
 Tarsals (ankle)
 Metatarsals (foot)
 Phalanges (toes)
 The Lower Limbs
 The Femur
 The proximal epiphysis
 Femoral head:
–articulates with pelvis at acetabulum
–attaches at fovea capitis
 The neck:
–Narrow area between head and
trochanters
–Joins shaft at angle
 The Lower Limbs
 The Femur
 The proximal epiphysis

 Trochanters:

– greater trochanter and lesser trochanter:

» tendon attachments
 The Lower Limbs
 The Femur
 The shaft
 Linea aspera:
– most prominent ridge of shaft
– attaches hip muscles
– joins epicondyles
 The distal epiphysis
 Medial epicondyle and lateral epicondyle:
– above the knee joint
 Medial condyle and lateral condyle:
– separated by intercondylar fossa and patellar
surface
– form part of knee joint
The Lower Limbs
 The Lower Limbs

 The Patella
 Also called the kneecap

 A sesamoid bone

 Formed within tendon of quadriceps femoris

 Base attaches quadriceps femoris

 Apex attaches patellar ligament

 The Lower Limbs

 The Tibia
 Also called the shinbone

 Supports body weight

 Larger than fibula

 Medial to fibula
 The Lower Limbs
 The Tibia
 The proximal epiphysis

 Medial and lateral tibial condyles:

–separated by intercondylar eminence

–articulate with medial and lateral

condyles of femur

 Tibial tuberosity:

–attaches patellar ligament

 The Lower Limbs
 The Tibia
 The shaft

 Anterior margin/ tibial crest:

–sharp ridge of shinbone

 The distal epiphysis

 Medial malleolus:

–medial projection at the ankle

 The Lower Limbs

 The Fibula
 Attaches muscles of feet and toes

 Smaller than tibia

 Lateral to tibia
The Lower Limbs
 The Lower Limbs
 The Fibula
 Articulations with tibia
 Fibula/tibia articulations:
–head
–inferior tibiofibular joint
 Interosseous membrane:
–binds fibula to tibia
 Lateral malleolus:
–lateral projection of ankle
 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
The Lower Limbs
 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
 Individual Skeleton Variation

 Studying the Skeleton

 Reveals characteristics
 Muscle strength and mass (bone ridges, bone
mass)
 Medical history (condition of teeth, healed
fractures)
 Sex and age (bone measurements and fusion)
 Body size
Individual Skeleton Variation
Individual Skeleton Variation
Individual Skeleton Variation
Individual Skeleton Variation