Appendicular Skeleton Study Notes

Shoulder Girdle

  • Also called the pectoral girdle; attaches the upper limb to the axial skeleton.
  • Composed of two bones: the clavicle and the scapula.
  • Light, poorly reinforced girdle; Allows the upper limb exceptional flexibility.

Clavicles

  • Provide attachment for muscles.
  • Hold the scapulae and arms laterally.
  • Transmit compression forces from the upper limbs to the axial skeleton.

Scapulae

  • Have three borders: Superior, Medial (vertebral), Lateral (axillary).
  • Have two angles: Superior and Inferior.
  • Lateral border features include the glenoid cavity at the lateral angle.
  • Notable processes/landmarks: Acromion, Coracoid process.
  • Suprascapular notch.
  • Spine of the scapula; Medial border (vertebral) and Lateral border (axillary) are separated by the borders noted above.
  • Superior angle and Inferior angle are the two angular points on the scapula.

Bones of the Upper Limbs

  • Humerus: forms the arm; single bone.
  • Proximal end articulation: head articulates with the glenoid cavity of the scapula.
  • Distal end articulation: trochlea and capitulum articulate with the bones of the forearm.
  • Major landmarks include: Head of humerus; Greater tubercle; Lesser tubercle; Anatomical neck; Surgical neck; Intertubercular sulcus; Deltoid tuberosity; Radial groove; Medial epicondyle; Lateral epicondyle; Trochlea; Captiulum; Olecranon fossa.

Forearm

  • The forearm has two bones: Ulna and Radius.
  • Ulna (medial bone):
    • Proximal end articulation via the coronoid process and olecranon with the humerus.
    • Distal end is separated from carpals by fibrocartilage.
    • Ulna features include the Ulnar styloid process; Trochlear notch; Olecranon; Coronoid process; Head; Neck; Radial notch (proximal relation to radius).
  • Radius (lateral bone):
    • Proximal end articulation via the head articulating with the capitulum of the humerus.
    • Distal radioulnar joint.
    • Radius features include the Radial tuberosity; Radial styloid process; Head; Neck.
  • Interosseous membrane links Ulna and Radius.
  • Proximal radioulnar joint and Distal radioulnar joint provide forearm rotation.

Elbow region (anterior view reference)

  • Radius and Ulna form the elbow joint with the distal humerus.
  • Head of the radius articulates with the capitulum of the humerus.
  • The superior surface of the head of the radius articulates with the capitulum; the head also articulates with the radial notch of the ulna.
  • Key distal features around the elbow include the Capitulum, Trochlea, Medial epicondyle, and Coronoid fossa.
  • Common articulations to remember: Proximal radioulnar joint; Distal radioulnar joint.

Bones of the Hand

  • Carpals (wrist bones): 8 bones arranged in two rows of 4 bones in each hand.
  • Proximal row (lateral to medial): Scaphoid, Lunate, Triquetral, Pisiform.
  • Distal row (lateral to medial): Trapezium, Trapezoid, Capitate, Hamate.
  • Metacarpals (palm bones): 5 per hand.
  • Phalanges: Fingers and thumb.

Pelvic Girdle (Coxal bones)

  • Each hip bone (coxal bone) is formed by fusion of three bones: Ilium, Ischium, Pubis.
  • The two coxal bones contribute to the pelvic girdle.
  • Key landmarks include: Ilium, Pubis, Ischium; Iliac crest; Sacroiliac joint; Acetabulum; Pubic symphysis; Pubic arch; Pelvic brim.
  • Notable processes and features include: Ischial spine; Ischial tuberosity; Obturator foramen; Inferior pubic ramus; Body of pubis; Pubic arch; Anterior superior iliac spine; Anterior inferior iliac spine.
  • The bony pelvis involves the ilium, ischium, and pubis bones together with the sacrum and coccyx.

The Bony Pelvis (Figure 5.24b references)

  • Ilium with landmarks: Iliac crest; Anterior superior iliac spine; Posterior superior iliac spine; Posterior inferior iliac spine; Greater sciatic notch.
  • Ischium: Ischial body; Ischial spine; Ischial ramus; Ischial tuberosity.
  • Pubis: Body; Pubic symphysis; Inferior pubic ramus; Pubic arch.
  • Acetabulum is the socket for the head of the femur.
  • Obturator foramen is formed by the pubis and ischium.

Male vs Female Pelvis (Table 8.2 overview)

  • Sacrum (left lateral view):
    • Female: Wider; shorter; sacral curvature accentuated; More movable; Straighter.
    • Male: Narrower; longer; sacral promontory more ventral; Less movable; curves ventrally.
  • Pelvic inlet (brim):
    • Female: Wider; oval from side to side.
    • Male: Narrow; basically heart-shaped.
  • Pelvic outlet (posteroinferior view):
    • Female: Wider; Ischial tuberosities shorter, farther apart, and everted.
    • Male: Narrower; Ischial tuberosities longer, sharper, and point more medially.

Bones of the Femur

  • The heaviest, strongest bone in the body.
  • Proximal end articulation: Head articulates with the acetabulum of the coxal (hip) bone.
  • Distal end articulation: Lateral and medial condyles articulate with the tibia in the lower leg.
  • Major landmarks include: Head; Lesser trochanter; Greater trochanter; Intertrochanteric line; Intertrochanteric crest; Surgical neck; Neck; Patellar surface; Medial and Lateral condyles.

Bones of the Right Thigh and Leg (summary references)

  • The right thigh and leg include features such as: Head; Lesser trochanter; Greater trochanter; Intertrochanteric line/crest; Lateral and Medial condyles; Intercondylar fossa; Patellar surface; Gluteal tuberosity.

Bones of the Lower Leg

  • Tibia: Proximal end articulates with the femur via medial and lateral condyles to form the knee joint.
  • Distal end forms the medial malleolus (inner part of the ankle).
  • Fibula: Has no role in forming the knee joint.
  • Distal end features: Lateral malleolus forms the outer part of the ankle.
  • Key joints noted: Proximal tibiofibular joint; Distal tibiofibular joint; Interosseous membrane.
  • Tibia and fibula together support the ankle and leg.

Tibia and Fibula (Figures 5.25c reference)

  • Proximal tibiofibular joint connects the tibia and fibula proximally.
  • Distal tibiofibular joint connects the tibia and fibula distally.
  • Critical landmarks include: Intercondylar eminence; Head of tibia; Lateral condyle; Medial condyle; Tibial tuberosity; Interosseous membrane; Anterior border; Medial malleolus (tibia); Lateral malleolus (fibula).

This set of notes covers the major and minor points presented in the transcript, including anatomical terms, joint articulations, and key structural landmarks across the shoulder girdle, upper limb, hand, pelvic girdle, and lower limb. The relationships between joints (e.g., head of the humerus with the glenoid cavity, acetabulum with the femoral head, radioulnar joints) and the practical implications (e.g., how the girdles transmit forces to the axial skeleton, or how pelvic morphology differs by sex) are highlighted to connect this material to clinical and real-world context.