The Appendicular Skeleton

Appendicular Skeleton

• Bones involved in body movements.
• Includes upper and lower limbs and girdles.

Pectoral (Shoulder) Girdle

• Consists of clavicle and scapula.
  • Clavicle:
  • S-shaped.
  • Medial end articulates with manubrium of sternum.
  • Lateral end articulates with acromion of scapula.
  • Scapula:
  • Flat bone in posterior thorax between second and seventh ribs.
  • Glenoid cavity: attachment for humerus.

Upper Limb (Extremity)

• Humerus:
  • Articulates with scapula (glenoid cavity).
  • Articulates with radius and ulna (trochlea with ulna, capitulum with radius).
• Ulna and Radius:
  • Forearm bones.
  • Ulna: Olecranon and coronoid process form trochlear notch (elbow joint).
  • Radius: Located on thumb side; allows forearm rotation.
• Carpal Bones:
  • 8 small bones connected by ligaments.
  • Proximal row: scaphoid, lunate, triquetrum, pisiform.
  • Distal row: trapezium, trapezoid, capitate, hamate.
• Metacarpals:
  • 5 bones in palm and back of hand; numbered I-V (1-5) from thumb.
  • Bases articulate with distal carpals, heads with proximal phalanges.
• Phalanges:
  • 14 bones of digits.
  • Thumb: 2 (proximal, distal).
  • Other fingers: 3 each (proximal, middle, distal).

Pelvic (Hip) Girdle

• Two hip bones articulate with sacrum.
• Each hip bone: ilium, ischium, pubis.
• Articulate anteriorly via pubic symphysis.
• Femur head articulates with acetabulum.
• Pelvis divided by pelvic brim into superior (false) and inferior (true) pelvis.
• Male vs. female:
  • Male: Larger, heavier bones.
  • Female: Wider, shallower bones.

Lower Limb (Extremity)

• Femur: Longest, heaviest, strongest bone.
  • Head inserts into acetabulum.
  • Distal end articulates with tibia and patella.
• Patella: Triangular bone in quadriceps tendon; articulates with femur.
• Tibia and Fibula:
  • Tibia articulates with femur and talus.
  • Tibial tuberosity: Attachment for patellar ligament.
• Tarsus: 7 tarsal bones (talus, calcaneus, navicular, 3 cuneiforms, cuboid).
• Metatarsus: 5 metatarsal bones (I-V or 1-5 from big toe).
  • Articulate with cuneiforms and cuboid proximally and phalanges distally.
• Phalanges: Like hand; big toe (proximal, distal), other toes (proximal, middle, distal).
• Arches:
  • Longitudinal (medial and lateral parts) and transverse arches.
  • Support body weight, provide leverage, distribute weight.