The Appendicular Skeleton
The Appendicular Skeleton
• 2 pairs of limbs & 2 girdles
• Pectoral (shoulder) girdle attaches upper limbs
• Pelvic (hip) girdle secures lower limbs
• 3 Segmented limbs:
– Upper = arm
• Arm
• Forearm
• Hand
– Lower = leg
• Thigh
• Leg
• Foot
Pectoral Girdle
(Shoulder Girdle)
• Clavicle – anterior: collar bone
– Sternal end attaches to the manubrium medially
– Acromial end articulates with the scapula laterally
• Scapula – posterior: shoulder blade
Pectoral Girdle
• Attach the bones of
the upper limbs to the
axial skeleton
• The joints are freely
movable in many
directions
Scapulae: triangular, paired, but don’t connect
in back (adds thoracic flexibility)
Scapula
• Also known as the shoulder
blade
• Large, flat triangular bone
situated in the posterior part
of the thorax
• The glenoid cavity is a
depression inferior to the
acromion.
• It articulates with the
humerus head to form the
shoulder joint.
• The coracoid process is
where muscles attach.
Scapula
• Glenoid cavity
articulates with
the humerus
• Acromium
articulates with
clavicle
• Coracoid process
projects anteriorly
Clavicle
• Also known as the
collarbone
• Long, slender Sshaped bone that is
horizontally above the
first rib
Upper Limb
Upper extremity
• Arm = upper arm
– Between shoulder and
elbow (humerus)
• Forearm
- Radius & ulna
• Hand includes:
– Wrist (carpus)
– Palm (metacarpus)
– Fingers (phalanges)
Humerus
• Longest and largest
bone of the upper
limb
• Articulates with the
scapula at the
shoulder & both the
ulna and radius at the
elbow
Upper arm
– Humerus is the only
bone
– Head of humerus fits
into glenoid cavity of
scapula
– Articulates with the
ulna& with the radius
– Medial & lateral
epicondyles
Right
humerus,
anterior view
Forearm
• 2 bones:
• Ulna
• Radius
• Radius is thinner proximally &
wide distally
• Ulna is slightly longer
Ulna
• Located on the medial
side of the forearm
(pinky side)
• Longer than the radius
Radius
• Located on the lateral
side of the forearm
(thumb side)
Right forearm bones,
anterior view
In the anatomical position,
the radius is lateral
(thumb side)
Left forearm
prone
Anatomical
position
 with pronation the palm
faces posteriorly and the
bones cross
Proximal and distal joints of the forearm
proximal ulna
Carpus (Wrist)
• 8 carpals
• Held together by
ligaments with four
bones in each row
• Named for their
shapes
• Short bones
• The carpals in the top
row are the:
– Scaphoid, Lunate,
Triquetrum, and
Pisiform
• The carpals in the
bottom row are the:
– Trapezium, Trapezoid,
Capitate, and Hamate
Hand
•
•
•
•
Proximal is “wrist” – 8 carpal bones
Palm of hand - 5 metacarpals
Fingers (or digits) consist of long bones called phalanges
Thumb (“pollex”)
Right hand, 2 views:
Pelvic Girdle
(Hip Girdle)
•
•
•
•
•
Strongly attached to axial skeleton (sacrum)
Deep sockets
More stable than pectoral (shoulder) girdle
Less freedom of movement
Made up of the paired hip bones
– “Bony pelvis” is basin-like structure: hip bones &
the sacrum & coccyx
Hip bone: 3 separate bones in
childhood which fuse
• Ilium
• Ischium
• Pubis
• Iliac crest
• Anterior superior
iliac spine
Ilium
ilium
• Greater sciatic
notch
• Forms part of
“acetabulum”
(hip socket)
which receives
ball-shaped head
of femur
ilium
Hip bones
Pelvis and childbearing
• Male/female differences:
–
–
–
–
–
Large & heavy vs light & delicate
Heart shaped pelvic inlet vs oval
Narrow deep true pelvis vs wide & shallow
Narrow outlet vs wide
Less than 90 degree pubic arch vs more than 90 degree
Lower limb
• Thigh: femur
• Leg (lower
leg)
– Tibia
– Fibula
• Foot
Thigh
• Femur is largest, longest and
strongest bone in the body
• Head fits in socket
(acetabulum) of pelvis
• Neck is weakest
• Greater trochanter
• Distal: lateral & medial
condyles & epicondyles
• Patella: sesmoid bone
Right femur, anterior
view
Leg
• Tibia: shin bone
– Medial and lateral
condyles
– Tibial tuberosity
– Distal medial malleolus
(medial ankle)
• Fibula
– Distal lateral malleolus
(lateral ankle)
Right lower leg,
anterior view
Foot
• Tarsus: 7 tarsal bones
– Talus: articulates with tibia
and fibula anteriorly and
calcaneus posteriorly
– Calcaneus: heel bone
– Smaller cuboid, navicular,
and 3 cunieforms (medial,
intermediate and lateral)
• 5 metatarsals
• 14 phalanges
– Big toe = hallux
Right foot, superior (dorsal) view and inferior (plantar) view
Right foot,
lateral and
medial views