ANHB2212 Study Guide - Final Guide: 2Degrees, Lubricant, Coracoid Process
3 Jun 2018
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Course
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Articular System
Joint Classification:
• Functional category
o Immovable joint → synarthroses
▪ Bone edges are close together and may interlock (e.g.
cranial suture)
▪ Growing bones include cartilgenous synarthroses (e.g.
epiphyseal plate synchondrosis) that sometimes fuse
▪ 2 once separate bones unite and boundary between
disappears and creates a synostosis → totally rigid
immovable joint
o Little joint movement → amphiarthroses
▪ Permits little movement
▪ Bones (connected by fibers or cartilage) are usually further
apart than they are at a synarthrosis
▪ Symphysis → bones separated by a pad of fibrocartilage
▪ Ligamentous amphiarthrosis (e.g. between tibia and fibula)
is known as a syndesmosis
o Free joint movement → diarthroses
▪ Synovial joint → permits a wide range of movement
▪ Typically articulates long bones of upper/lower limb
▪ Bony surfaces are not in contact as they are separated by
articular cartilage → shock absorber, reduces friction
• Structural category
o Bony fusion → synostosis
o Fibrous → suture, gomphosis, syndemosis
o Cartilaginous → synchondrosis, symphysis
o Synovial → monoaxial, biaxial, multiaxial
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Nerve and Blood Supply of Joints:
• Nerve/blood supply follows normal rule → where there is a nerve there is
an artery
• Some nerves supplying the joints are sensory, others are mixed
• Hilton’s Law → if a nerve supplies a muscle that crosses a joint, it will also
supply sensory fibers to that joint
• Parts with no nerve supply
o Articular cartilage
o Menisci
• Parts with a nerve supply
o Joint capsule
o Ligaments
o Tendons
o Pain sensation → particularly when capsule/ligament is torn
o Proprioceptive → conscious (stretch, pressure) and unconscious
(muscle length)
• Joints are surrounded by a rich network of arteries and veins
• Arteries give off subdivisions that form anastomoses on outer surface
• Network branches to fibrous capsule, ligaments and synovial membrane
• Vessels reaching subsynovial membrane proliferate to form another
anastomotic network
o Capillaries go to all parts of the membrane
o Capillaries ramify to the fatty pads and non-articulating parts of
articular cartilage, discs and menisci
o None go to articulating part of the articular cartilage → depends
on synovial fluid for nourishment
• Periarticular anastomoses ensure an alternative route for blood to supply
a joint when arterial supply is cut off due to joint position
The Synovial Joint:
• 3 types defined by plane of movement
o Monoaxial
▪ 1 degree of freedom
▪ Shape → bicondylar or pivot
o Biaxial
▪ 2 degrees of freedom
▪ Shape → condylar or saddle
o Multiaxial
▪ 3+ degrees of freedom
▪ Shape → ball and socket
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find more resources at oneclass.com
