Appendicular Skeleton Overview

Overview

This lecture covers the anatomy of the appendicular skeleton from the pelvic girdle (hips) down through the upper and lower legs, ankles, and feet, focusing on key bones and their landmarks.

Pelvic Girdle (Hips)

• The pelvic girdle includes the ilium (upper bone), ischium (lower, posterior bone), and pubic bone (anterior bone).
• The pubic symphysis is a cartilage joint connecting the two pubic bones.
• The sacroiliac joint connects the ilium and sacrum.
• Key landmarks: ischial spine, pubic tubercle, iliac fossa, iliac crest, anterior/posterior superior and inferior iliac spines.
• The greater and lesser sciatic notches are located on the ischium.
• Obturator foramen is a large opening in the pelvis.
• The acetabulum is the hip socket for femur articulation.

Upper and Lower Leg Bones

• The femur (thigh bone) is the only bone in the upper leg; key parts: head (articulates with acetabulum), neck, greater/lesser trochanters, linea aspera (shaft ridge).
• Distal femur landmarks: medial/lateral condyles and epicondyles, intercondylar fossa, and patellar surface (anterior side for kneecap).
• The tibia (shin bone) is medial and larger in the lower leg; key features: medial/lateral condyles, intercondylar eminence, tibial tuberosity, anterior crest, medial malleolus (inner ankle bump).
• The fibula is lateral and much thinner; features the head and lateral malleolus (outer ankle bump).

Ankle and Foot Structure

• The main ankle bones are the calcaneus (heel bone) and talus (supports body weight).
• Other tarsal bones: navicular, medial/intermediate/lateral cuneiforms, cuboid.
• Foot bones: five metatarsals (long bones of the foot) and phalanges (toes), organized as proximal, middle, and distal phalanges.

Key Terms & Definitions

• Ilium — uppermost bone of the pelvis.
• Ischium — lower, posterior pelvic bone.
• Pubic Bone — front bone of the pelvis.
• Acetabulum — hip socket for femur articulation.
• Femur — thigh bone, largest in the body.
• Tibia — medial (inner) lower leg bone, weight-bearing.
• Fibula — lateral (outer) lower leg bone, non-weight-bearing.
• Malleolus — bony bumps on each side of the ankle (medial for tibia, lateral for fibula).
• Calcaneus — heel bone.
• Talus — uppermost ankle bone, articulates with tibia and fibula.
• Metatarsals — long bones of the foot.
• Phalanges — toe bones.

Action Items / Next Steps

• Review labeled diagrams of the pelvis, femur, tibia, fibula, and foot.
• Prepare for identification questions on key bones and features listed above.
• Next lecture will cover the axial skeleton.