Lecture Notes: The Appendicular Skeleton - Upper Limbs and Pectoral Girdle

Overview of the Appendicular Skeleton

• Comprises 126 bones
  • Upper limbs, arms, wrists, hands
  • Pectoral girdle, pelvic girdle
  • Lower limbs, ankles, feet
• Typically in pairs (two of each)
• Functions:
  • Works with muscles for body movement
  • Calcium storage and blood cell formation

Pectoral Girdle

• Also known as the shoulder girdle
• Consists of two pairs of bones:
  • Clavicle (Collarbone):
    • Anterior side, under the neck
    • Articulates medially with the manubrium of the sternum
    • Lateral/acromial side articulates with the acromial process of the scapula
  • Scapula (Shoulder Blade):
    • Posterior side, includes the spine
    • Features:
      • Glenoid cavity: Articulates with the head of the humerus
      • Acromium: Superior projection, articulates with scapula
      • Coracoid process: Muscle attachment for biceps brachii, pectoralis minor
      • Spine: Ridge on the posterior
      • Supraspinous and infraspinous fossa: Muscle attachment

Upper Limb Bones

• Humerus (Upper Arm Bone):

  • Articulates proximally with scapula (shoulder joint)
  • Articulates distally with radius and ulna (elbow joint)
  • Features:
    • Head: Forms ball and socket of shoulder joint
    • Greater and lesser tubercles: Muscle and ligament attachment
    • Deltoid tuberosity: Deltoid muscle attachment site
    • Olecranon fossa: Indentation for olecranon of ulna
    • Capitulum: Articulates with head of radius
    • Trochlea: Part of elbow joint

• Forearm Bones:

  • Radius:
    • Lateral side (thumb side)
    • Head: Articulates with capitulum of humerus
    • Styloid process: Ligament attachment, wrist stabilization
  • Ulna:
    • Medial side (opposite thumb)
    • Olecranon: Forms hinge of elbow joint
    • Coronoid process: Part of trochlear notch
    • Styloid process: Ligament attachment, wrist stabilization
  • Connected by interosseous membrane: Prevents separation

Wrist and Hand Bones

• Carpals (Wrist Bones):

  • Eight bones in two rows (proximal and distal)
  • Acronym: "Stop Letting Those People Touch The Cadaver's Hand"
    • Proximal Row: Scaphoid, Lunate, Triquetrum, Pisiform
    • Distal Row: Trapezium, Trapezoid, Capitate, Hamate

• Metacarpals (Hand Bones):

  • Numbered 1-5 starting with thumb

• Phalanges (Finger Bones):

  • 14 total, three per finger (proximal, medial, distal)
  • Two in the thumb (proximal and distal)
  • Thumb also known as pollex

Key Anatomical Terms

• Pollux: Anatomical term for thumb
• Interosseous membrane: Connective tissue between radius and ulna