Chapter 8:
The Appendicular Skeleton
BIO 210 Lab
Instructor: Dr. Rebecca Clarke
Appendicular Skeleton
 Allows us to move and manipulate objects
 Includes all bones besides axial skeleton:
 the limbs
 the supportive girdles
 Pectoral (shoulder)
 Pelvic
Appendicular Skeleton
Figure 8–1
Pectoral Girdle
 Also called the shoulder girdle
 Positions shoulder joints
 Connects the arms to the body
 Provides base for muscle attachment
 Helps move upper limbs
Pectoral Girdle
Figure 8–2a
Pectoral Girdle
 Consists of:
 2 clavicles
 2 scapulae
 Connects with axial skeleton only at the manubrium (clavicle
articulations)
Clavicle
 Also called collarbone
 Long, S-shaped bone
 Originates at manubrium (sternal end)
 Articulates with scapula (acromial end)
 Relatively fragile so fractures common
Clavicle
 Sternal End:
 Square, flat surface
 Articulates with
manubrium; only ones
between axial skeleton
and pectoral girdle
 Acromial End:
 Flatter, broader end
 Articulates with
acromion of scapula
Figure 8–2b, c
Scapula
 Also called shoulder blade
 Broad, flat triangle
 Articulates with arm and collarbone
 Skeletal muscles support/position 
 Extreme mobility
 Not much strength
Scapula: Posterior Surface
 Body
 Broad, flat, triangular area
 Has 3 borders/ margins
 Superior
 Medial
 Lateral
Figure 8–3c
Scapula: Posterior Surface
 Spine
 Large ridge across posterior
surface
 Shoulder blade
 Supraspinous fossa
 Depression superior to spine
 Infraspinous fossa
 Depression inferior to spine
Figure 8–3c
Scapula: Posterior Surface
 Acromion
 Large, posterior extension at
lateral end of spine
 Articulates with clavicle
(acromial end)
Figure 8–3c
Scapula: Lateral View
 Glenoid fossa (cavity)
 Cup-shaped, lateral depression
 Articulates with humerus
 Forms shoulder joint
Figure 8–3c
Scapula: Lateral View
 Coracoid process
 Smaller, anterior projection
superior to glenoid cavity
 Near clavicle vs coronoid process
on mandible near nose)
Figure 8–3c
Scapula: Anterior Surface
 Subscapular fossa
 Depression on smooth,
anterior side of body
Figure 8–3a
Bones of the Upper Limbs
 Brachium (arm)
 Antebrachium (forearm)
 Ulna
 Radius
 Carpals (wrist)
 Metacarpals (hand)
 Phalanges (fingers)
Humerus
 Only bone in brachium (arm)
 Extends from scapula to elbow
 Articulates with pectoral girdle
 on proximal end (head) – with glenoid fossa of scapula
 on distal end – with radius and ulna (bones of antebrachium)
Humerus
 Head
 Large, ball-shaped structure on
proximal end
 Greater tubercle
 Larger, rounded projection on
lateral/posterior surface of
epiphysis
 Lesser tubercle
 Smaller projection on
medial/anterior surface
 Intertubercular groove
 Separates tubercles
Figure 8–4
Humerus
 Anatomical neck
 Narrow groove between base of head
and tubercles
 Margin of joint capsule
 Surgical neck
 At metaphysis
 Where fractures often occur
 Deltoid tuberosity
 Rough ridge on-anterior surface of
shaft
 Where deltoid muscle attaches
Figure 8–4
Humerus
 Condyle
 = rounded projection for muscle
attachment
 Distal epiphysis where humerus
articulates with radius and ulna
 “Knuckles” on anterior surface of
humerus
Figure 8–4
Humerus
 Lateral epicondyle
 Medial epicondyle
 More prominent than lateral one
 Trochlea (“pulley” or “spool”)
 In center of condyle (middle
“knuckle)
 Where trochlear notch of ulna
rotates during forearm flexion
 Capitulum
 Forms a “cap” over the radius
Figure 8–4
Humerus
 Coronoid fossa
 On anterior surface
 Articulates with coronoid process of
ulna
 Olecranon fossa
 On posterior surface
 Articulates with olecranon of ulna
Figure 8–4
Antebrachium (Forearm)
 Consists of 2 long bones:
 Ulna (medial)
 Radius (lateral)
 “Rotates”
 Site of radial pulse
Figure 8–5
Ulna
 Olecranon (process)
 Large, curved projection (like
cobra head) on proximal end
 “U” for ulna
 Articulates in olecranon fossa
of humerus
 Superior lip of trochlear notch
 Point of elbow
Figure 8–5
Ulna
 Trochlear notch
 Anterior curved surface of
proximal epiphysis
 Articulates with trochlea of
humerus
 Coronoid process
 Inferior lip of trochlear notch
 Articulates in coronoid fossa of
humerus
Figure 8–5
Ulna
 Head
 Much smaller, distal epiphysis
(near wrist)
 Articulates with radium and carpal
(wrist) bones
 Styloid process
 Medial pointed extension at distal
epiphysis
 On posterior, lateral surface of
head
Figure 8–5
Ulna: Articulations
with the Humerus
 Forearm extended:
 Olecranon enters olecranon fossa
 Forearm flexed:
 Coronoid process enters coronoid fossa
Radius
 Head
 Disc-shaped proximal epiphysis
 Articulates with humerus
 Neck
 Narrow region between head and
tuberosity
 Radial tuberosity
 Structure at proximal end of diaphysis
below neck
 Marks attachment site of biceps brachii
muscle
Figure 8–5
Radius
 Shaft
 Curves and broadens
 Distal portion much larger
than distal portion of ulna
 Styloid process
 Lateral pointed extension at
distal epiphysis
 Stabilizes wrist joint
Figure 8–5
Carpal Bones
 Allow wrist to bend and twist
 8 bones
 “Sam likes to push the toy car hard.”
Carpal Bones
 Scaphoid
 Trapezium
 Lunate
 Trapezoid
 Triquetrum
 Capitate
 Pisiform
 Hamate
Wrist and Hand Bones
Figure 8–6
Metacarpal Bones
 5 long bones of the hand
 Numbered I–V from lateral (thumb) to medial
 Articulate with proximal phalanges
Phalanges (Phalanx=singular)
 Finger bones
 I (lateral)
 Pollex (thumb):
 2 phalanges (proximal, distal)
 II -V
 3 phalanges (proximal, medial or middle, distal)
Pelvic Girdle
 Functions
 Weight-bearing
 Locomotion
 Bones more massive than those of pectoral girdle
 Strong to bear body weight
Pelvic Girdle
 Made up of 2 hip bones (coxal bones or pelvic bones)
 Each hip bone is made up of 3 fused bones:
 Ilium (articulates with sacrum)
 Ischium
 Pubis
Pelvic Girdle
Figure 8–7
Pelvic Girdle: Ilium
 Largest hip bone
 Superior part of coxae
 Fused to ischium
(posteriorly) and pubis
(anteriorly)
 Articulates with sacrum
– attaches pelvic girdle
to axial skeleton
Figure 8–7
Pelvic Girdle: Ilium
 Iliac crest
 Superior border
 Anterior superior iliac
spine (ASIS)
 Anterior inferior iliac
spine (AIIS)
 Posterior superior iliac
spine (PSIS)
 Posterior inferior iliac
spine (PIIS)
Figure 8–7
Pelvic Girdle: Ilium
 Iliac fossa
 Depression on anterior aspect
 Sacroiliac joint
 Between posterior superior and
inferior spines; where ilium and
sacrum articulate
 Greater sciatic notch
 Inferior to PIIS
 Passageway for large sciatic nerve
Figure 8–7
Pelvic Girdle: Ischium
 Posterior-inferior part of
coxae
 Ischial spine
 Inferior to greater sciatic notch
 At posterior-superior end
 Lesser sciatic notch
 Inferior to ischial spine
 Ischial tuberosity
 Thickened posterior-inferior part
 Bears body weight when seated
(“sit bone”)
Figure 8–7
Pelvic Girdle: Pubis
 Anterior-inferior part of
coxae
 Pubic symphysis
 Joint where anterior medial
surfaces of pubic bones are
interconnect by
fibrocartilage pad
 Limits movement between
pubic bones of left and right
hipbones
Figure 8–7
Pelvic Girdle: Acetabulum
 Also called the hip socket
 Large, concave socket on
lateral surface of os coxae
 Meeting point of ilium,
ischium, and pubis
 Articulates with head of
femur
Figure 8–7
Pelvic Girdle: Obturator Foramen
 Large space encircled by
pubis and ischium
 Closed by sheet of collagen
fibers
 Provides base for hip muscles
Figure 8–7
Pelvis
 Consists of:
 2 hip bones
 Sacrum
 Coccyx (of axial skeleton)
 Stabilized by ligaments of pelvic girdle, sacrum, and lumbar
vertebrae
Pelvis
Figure 8–8
Pelvic Openings
 Pelvic inlet – (anterior) space enclosed by pelvic brim
 Pelvic outlet – opening bounded by coccyx and ischial
tuberosities
Figure 8–9
Pubic Angle
 Inferior angle between pubic bones
Figure 8–10
Bones of the Lower Limbs
 Femur (thigh)
 Patella (kneecap)
 Tibia and fibula (leg)
 Tarsals (ankle)
 Metatarsals (foot)
 Phalanges (toes)
Femur
 Longest, heaviest bone
 Transfers body weight to ground
 Articulates with:
 coxae at acetabulum
 tibia at knee joint
Figure 8–11
Femur
 Head
 Large, round proximal end
 Articulates at acetabulum
 Neck
 Narrow connector between head and
shaft
 Joins shaft at angle
Figure 8–11
Femur
 Greater trochanter
 Large process at superior end of shaft
 Lesser trochanter
 Smaller process inferior to neck on
medial /posterior side
Figure 8–11
Femur
 Lateral condyle
 Large, rounded, lateral projection at
distal epiphysis
 Articulates with lateral condyle of
tibia
 Medial condyle
 Large, rounded, medial projection at
distal epiphysis
 Articulates with medial condyle of
tibia
Figure 8–11
Femur
 Intercondylar fossa
 Depression between condyles on
posterior side
Figure 8–11
Femur
 Patellar surface
 Flattened area between condyles on
anterior side
Figure 8–11
Patella
 Large sesamoid bone
 Forms within tendon of quadriceps femoris
(extends/straightens the knee)
Figure 8–12
Tibia
 Larger, medial bone; supports body weight
 Also called the shinbone
Figure 8–13
Tibia
 Lateral condyle
 Lateral projection at proximal
epiphysis
 Articulates with lateral condyle
of femur
 Medial condyle
 Medial projection at proximal
epiphysis
 Articulates with medial condyle
of femur
Figure 8–13
Tibia
 Tibial tuberosity
 Roughened area on anterior
surface
 Inferior to condyles
 Attachment for patellar
ligament
Figure 8–13
Tibia
 Anterior margin
 Ridge that begins at tibial
tuberosity and extends distally
along anterior surface (“shin
bone”)
 Medial malleolus (“little
mallet”)
 Projection on medial side at
distal epiphysis
Figure 8–13
Fibula
 Slender, lateral bone of lower leg
Figure 8–13
Fibula
 Head
 Articulates with proximal tibia
 Lateral malleolus
 Projection on lateral side at
distal epiphysis
 Articulates with distal tibia
 Provides lateral stability to
ankle
Figure 8–13
Tarsal Bones
 Allow ankle to bend and twist
 7 bones
Ankle and Foot Bones
Figure 8–14a
Tarsal Bones
 Talus
 Cuneiforms (3)
 Calcaneous
 Navicular
 Cuboid
Note: movement more
restricted than wrist/hand
Metatarsal Bones
 5 long bones of the foot
 Numbered I–V from medial (big toe) to lateral
 Articulate with proximal phalanges
Phalanges
 Toe bones
 I (lateral)
 Hallus (big toe):
 2 phalanges (proximal, distal)
 II -V
 3 phalanges (proximal, medial or middle, distal)