Lecture Notes: Skeletal System - Lower Extremity

Overview

• Focus on lower extremity: thigh, leg, pelvis.
• Begin with pelvis, the most superior part of the lower extremity.

Pelvis

Views and Structure

• Antero-superior view: Combination of anterior and superior views of the pelvis.
• Central piece: Sacrum in the middle.
• Innominate: Half of a pelvis, consisting of three bones:
  1. Ilium: Largest, superior part with iliac crest.
  2. Pubis: Includes superior and inferior pubic ramus.
  3. Ischium: Includes ischial spine.

Important Landmarks

• Sacrum: Central, deep teal color. Contains sacral foramen (holes for nerve roots) and sacral ala (wings).
• Iliac Spine: ASIS (Anterior Superior Iliac Spine) and AIIS (Anterior Inferior Iliac Spine).
• Sacral Foramen: Holes in sacrum for nerve passage.
• Sacroiliac Joint: Joint between sacrum and ilium.
• Coccyx: Tailbone.
• Pubic Symphysis: Joint in the front, composed of fibrocartilage like spinal discs.
• Other Features:
  • Iliac Fossa: Depression in the ilium.
  • Acetabulum: Hip joint socket for femur head.
  • Obturator Foramen: Large hole for nerve/muscle passage.

Lateral and Posterior Views

• Lateral View: Shows three parts of innominate.
• Posterior View: Highlights sacrum, coccyx, and ischial landmarks.

Femur

Structure

• Anterior and Posterior Views: Show the structure and landmarks.
• Head and Neck: Connects with acetabulum.
• Trochanters:
  • Greater Trochanter
  • Lesser Trochanter
• Linea Aspera: Posterior ridge for muscle attachment.

Condyles and Epicondyles

• Medial and Lateral Condyles: Form knee joint.
• Medial and Lateral Epicondyles: Above the condyles.
• Intercondylar Fossa: Depression between condyles.

Tibia, Fibula, and Patella

Anterior View

• Patella: Knee cap.
• Tibia: Main weight-bearing bone.
• Fibula: Lateral, smaller bone.
• Landmarks:
  • Condyles: Medial and lateral on tibia.
  • Tibial Tuberosity: Quadriceps attachment, common site for Osgood-Schlatter.
  • Malleoli: Medial (tibia) and lateral (fibula) extensions.
  • Head and Neck of Fibula: Upper part of fibula.

Foot

Superior View

• Tarsal Bones: Ankle bones including talus and calcaneus (heel).
• Navicular and Cuboid: Important for arch and lateral foot stability.
• Cuneiforms: Three bones labeled as medial, middle, and lateral.

Metatarsals and Phalanges

• Metatarsals: Long bones of foot.
• Phalanges: Toe bones, arranged similar to hand.
  • Proximal, Middle, and Distal Phalanges.

Terminology

• Hallux: Term used for the big toe, similar to pollux for thumb.

This concludes the overview of the skeletal system focusing on the lower extremity. Topics covered include the pelvis, femur, tibia and fibula, and foot along with their major anatomical landmarks critical for understanding their function and clinical relevance.