The document summarizes the main bones that make up the appendicular skeleton in humans. It describes the two pairs of girdles - the pectoral (shoulder) and pelvic (hip) girdles - that connect the upper and lower limbs to the axial skeleton. It then outlines the major bones that comprise each segmented limb, including the arm, forearm, hand, thigh, leg, and foot. For each bone, it identifies key anatomical features and points of articulation with other bones.

1. The Appendicular Skeleton
By- Dr. Armaan Singh

2. THE SKELETAL SYSTEM
The Appendicular Skeleton
 2 pairs of limbs and 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

3. 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

4. Scapulae: triangular, paired, but don’t
connect in back (adds thoracic flexibility)

5. Scapula
 Glenoid cavity
articulates with
the humerus
 Acromium
articulates with
clavicle
 Coracoid
process projects
anteriorly

6. Upper extremity
 Arm or Brachium =
upper arm
 Between shoulder
and elbow (humerus)
 Forearm or
Antebrachium
 Radius & ulna
 Hand includes:
 Wrist (carpus)
 Palm (metacarpus)
 Fingers (phalanges)

7. Arm
 Humerus is the only
bone
 Head of humerus fits
into glenoid cavity of
scapula
 Distal & medially,
trochlea articulates
with the ulna
 Distal & laterally
capitulum articulates
with the radius
 Medial & lateral
epicondyles

8. Right
humerus,
anterior view

9. Right
humerus,
posterior view

10. Forearm
 2 bones: articulate with each
other proximally and distally
 Interosseous membrane
between them
 Ulna
 Olecranon hinges with the
humerus forming elbow
 Styloid process distally
 Radius
 Contributes to wrist joint
 Styloid process anchors a
ligament to wrist (thumb side)
Radius is thinner proximally, like a spool
of thread, and wide distally; ulna is
slightly longer and looks like a monkey
wrench (supposedly!)

11. Right forearm bones,
anterior view

12. Right forearm bones,
posterior view

13. In the anatomical
position, the radius is
lateral (thumb side);
with pronation the palm
faces posteriorly and
the bones cross
Left forearm
Prone: body lying face down
Suppine: body lying face up
(you can remember prone if you think
about how you would fall forward onto
your face if you passed out)
Anatomical
position
prone
pronation moves the forearm into the
prone position and supination moves
it back to the anatomical position

14. proximal ulna
Proximal and distal joints of the forearm

15. Hand
 Proximal is “wrist” – 8 carpal bones
 Palm of hand - 5 metacarpals
 Fingers (or digits) consist of miniature long bones called
phalanges: thumb (“pollex”) has 2; fingers have 3:
proximal, middle, distal
Right hand, 2 views:

18. 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
plus the axial sacrum and coccyx

19. Hip bone (os coxae): 3 separate
bones in childhood which fuse
 Ilium
 Ischium
 Pubis

20. Ilium
 Iliac crest
 Anterior
superior iliac
spine
 Greater sciatic
notch
 Forms part of
“acetabulum”
(hip socket)
which receives
ball-shaped
head of femur
ilium
ilium

21. Ischium
 Body
 Ramus
 Ischial spine
 Ischial
tuberosity
 Part of socket
ischium
ischium

22. Pubis
 Joins
medially in
pubic
symphysis
 Forms
“obturator
foramen”
(large hole)
with ischium
 Part of socket
pubis
pubis

23. Hip bones with labels

24. Ligaments
False (greater) and
true (lesser) pelvis

25. 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
 Birth canal changes shape as baby descends:
head turns ¼
 Higher: pelvic inlet (brim) - side to side largest
 Lower: pelvic outlet - largest in AP direction

26. Lower limb
 Thigh:
femur
 Leg (lower
leg)
Tibia
Fibula
 Foot

27. 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 and epicondyles
 Patella: sesmoid bone

28. Right femur,
anterior view

29. Right femur,
posterior view

30. Leg
 Tibia: shin bone
 Medial and lateral
condyles
 Tibial tuberosity
 Distal medial malleolus
(medial ankle)
 Fibula
 Distal lateral malleolus
(lateral ankle)
 Interosseous
membrane

31. Right lower leg,
anterior view

33. 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
 Great toe is hallux

34. Right foot, superior (dorsal) view and inferior (plantar) view

35. Right foot,
lateral and
medial views

36. Arches