AN2.1-6 | General features of bones & Joints — Summary & Reflection

REFLECT

You have now studied bones, cartilage, and joints as separate topics. Take a moment to integrate: Pick any joint you can palpate on yourself (e.g., your own knee or elbow). Identify (1) the type of bones forming it, (2) the cartilage type on its articular surfaces and any associated fibrocartilage, (3) the type of synovial joint, (4) the movements possible, and (5) using Hilton's Law, predict which nerves supply it. Write a short paragraph connecting all five concepts for your chosen joint.

KEY TAKEAWAYS

Key takeaways from this module:

1. Long bones have three regions (diaphysis, metaphysis, epiphysis) with distinct blood supply from nutrient, periosteal, and epiphyseal arteries.
2. Bones are classified into 5 types by shape: long, short, flat, irregular, and sesamoid.
3. Ossification occurs by two mechanisms: intramembranous (flat skull bones, clavicle) and endochondral (most bones). The growing end of a bone is where the secondary centre appears first and fuses last.
4. Epiphyses are classified as pressure (articular), traction (apophysis), atavistic, or aberrant.
5. Three cartilage types: hyaline (most common, avascular), elastic (pinna, epiglottis), fibrocartilage (menisci, discs — no perichondrium).
6. Joints are classified structurally (fibrous, cartilaginous, synovial) with synovial joints further classified into 6 types by articular surface shape.
7. Hilton's Law: the nerve to a muscle also supplies the joint it acts on and the overlying skin — enabling you to predict joint innervation and understand referred pain patterns.