Anatomy: Bones and Muscles of the Lower limb Flashcards
What are the 3 portions of a long bone called, from joining end to long end?
Epiphysis
Metaphysis
Diaphysis
Describe 3 things about a sesamoid bone
Give an example of a sesamoid bone
Patella
Found within tendons
Reduce wear
Improve muscle efficiency
Describe 3 things about a flat bone
Give an example of a flat bone
Scapula
Large surface area for muscle attachment
Weight/force transfer region
Protection (pelvic girdle and skull)
What is Wolff’s Law?
Bone is deposited and reabsorbed in accordance with the stresses placed upon it (it is able to remodel)
Name the 2 types of bone?
within a single bone
Cancellous/trabecular/spongy bone
Cortical bone
What 6 things make up the axial skeleton?
Skull Ribs Sternum Vertebrae Sacrum Coccyx
What 3 things make up the appendicular skeleton
Hip bones (pelvic girdle)
Pectoral girdle
Limbs (upper and lower)
Define Amelia
No limb growth
Define Meromelia
Partial limb
Define Phocomelia
Seal-like limb/flipper
Define Polydactyly
Additional digits
Define Syndactyly
Webbing/joining of digits
Name the 2 large groups of bone to bone joint
Fibrous joints
Cartilaginous Joints
What are the 3 types of fibrous joints?
Give an example and characteristic of each type of joint
Suture
- do not move
- skull
Gomphosis
- small degree of movement
- teeth to jaw
Syndesmosis
- fibrous sheet of tissue that keeps 2 long bones in proximity to each other
- forearm
What are the 2 types of cartilaginous joints?
Give an example and characteristic of each type of joint
Epiphysis
- mainly in children
- growth plate of a bone
Symphysis
- movable discs between joints
- vertebral discs
Describe 3 things about hyaline cartilage
Found at the ends of 2 adjoining bones
Avascular, smooth and slippy
Sits withing a joint capsule
What lines a joint capsule and produces synovial fluid?
Synovium (serous membrane)
What is a bursae?
Pockets of synovium and synovial fluid found in regions of friction/wear
Inflammation of the bursae causes bursitis
Where are synovial sheaths found?
Around tendons at points of wear/friction/direction change
Inflammation of the synovium causes synovitis
Inflammation of the sheath and the tendon causes
What is a nerve plexus?
A region where the ventral rami of spinal nerves join and exchange neurons
What wraps the compartments in the forearms?
Connective tissue fascia
Wraps around the muscles and tissues to form anterior and posterior compartments
Anterior compartments are mainly responsible for….
Flexor function
Posterior compartments are mainly responsible for….
Extensor function
What does the anterior thigh compartment contain?
Hip flexor and knee extensor
Femoral nerve (L2, L3, L4)
Femoral artery
What is a retinacula?
Thick bands of fascia that connect tendons to bone and stop them lifting off when activated
Venous drainage runs from….
Superficial to deep
The origin site of a muscle is
Generally more fixed and proximal
The insertion site of a muscle is
Normally more mobile and distal
Give 5 roles of connective tissue
Structural support
Metabolic support
Cell adhesion
Medium of exchange
Defense, protection and repair
What 2 things is connective tissues made from?
Cells
Extracellular matrix
What 2 things is extracellular matrix formed of?
Give properties of each
Fibrous proteins
- collagen
- elastin
Ground substances
- transparent
- colourless
What 3 things is ground substance formed from?
Give properties of each
Proteoglycans
- repeated disaccharides (GAG) around a protein core
- GAG attracts water
Glycoproteins
-allow cells to adhere to the ECM
Water
-attracted by GAG
What provides the rigidity of bones?
Mineralised extracellular matrix (hydroxyapatite)
What provides the resilience of bones?
Type 1 collagen fibres
part of the fibrous proteins component of ECM, other component is ground substance remember
Name the 5 functions of bone
Movement
Mineral homeostasis
Support
Protection
Site of haematopoiesis
Describe the structure and function of the periosteum
Dense, irregular connective tissue layer covering the bones where tendons and ligaments insert
Out fibrous layer
Inner cellular layer
-osteoprogenitor cells and osteoblasts
Helps the bone grow in thickness, # repair nourishes bone tissue
Where is the endosteum?
Lines the inside of the bones
What are the 2 types of bone (mature/immature)
Woven bone
Lamellar bone (mature)
Describe the structure of woven (immature) bone
First bone formed at any site
Collagen fibres are arranged randomly
Occurs at site of # healing
Describe the structure of lamellar (mature) bone
Collagen fibres remodel into orderly arrangement
What are the 2 types of mature (lamellar) bone?
Trabecular
Cortical
Describe the characteristics of trabecular bone and how structure is related to function
Looks like beams and struts.
Orientated along the lines of stress and redistributes stress along the bone.
Spaces make the bone lighter and give space for bone marrow as well
Describe the characteristics of cortical bone and how structure is related to function
Dense and compacted bone
Arranged into Haversian systems (osteons)
What is a lamellae?
A bony plate made up of collagen fibres arranged in parallel
Describe the composition of lamellar bone
And outer circumferential lamellae runs along the shape on the bone
Concentric lamellae form around Haversian canals, which contain blood vessels, lymph vessels and nerves.
Collagen fibres in the Haversian systems (osteons) form around the Haversian canals in parallel to each other
Volkmann’s canals run transversely and allow communications between the Haversian systems and between the periosteum and the osteons
What type of cell are osteoprogenitor cells derived from?
Mesenchymal stem cells
What do osteoprogenitor cells turn into?
Osteoblasts
What do osteoblasts mature into?
Osteocytes
What type of cell produces osteoid?
Osteoblasts
What is in osteoid?
Type 1 collagen
Proteoglycans
Glycoproteins
List 2 features of osteocytes
Mature bone cells
Do not undergo cell division
Give 2 functions of osteocytes
Mechanotransduction (detecting stresses and triggering action of other bone cells)
Calcium homeostasis
Name the space that an osteocyte sits in within the bone
Lacunae
What are the channels within bone called?
What sits within these channels?
Canaliculi
Dendritic processes of osteocytes
What role do osteoclasts have?
Remodeling, growth and repair of bones
What do osteoclasts derive from?
Monocyte-macrophage system
What do osteoclasts secrete?
Enzymes and acid
Name the space the osteoclasts sit in
Howship’s lacunae
Which type of cell secretes RANKL?
Osteoblasts
When do osteoblasts secrete RANKL?
In response to calcitrol and PTH
Where is the RANK receptor located?
Osteoclasts
What 2 things do osteoblasts secrete?
RANKL
OPG
Which hormone increases the amount of OPG?
Oestrogen
What does OPG do?
Mops up excess RANKL so that bone re-absorption does not get out of control
Fill in the gaps:
Many different hormones regulate bone remodelling. Osteoblasts secrete _____ in response to ______ and ___. RANKL binds to ____ receptors on ______ and stimulates bone reabsorption. _____ secrete OPG: this mops up excess ______ so that bone reabsorption does not get out of control.
Many different hormones regulate bone remodelling. Osteoblasts secrete RANKL in response to calcitriol and PTH. RANKL binds to RANK receptors on osteoclasts and stimulates bone reabsorption. Osteoblasts secrete OPG: this mops up excess RANKL so that bone reabsorption does not get out of control.
What are the 2 types of bone development?
Intramembronous ossification
Endochondral ossification
Draw out the pathways for the 2 types of ossification
Intramembranous:
mesenchyme –> bone
Endochondral:
mesenchyme –> cartilage –> bone
What is mesenchyme?
Undifferentiated embryonic connective tissue
Which bones undergo intramembronous ossification?
Flat bones of the skull, clavicle and mandible
How are the flat bones of the skull, clavicle and mandible formed?
Intramembranous ossification
Which enzyme leads to calcification of the ECM?
Hydroxyapatite
Where are primary ossification centres found?
Diaphysis of weight bearing bones
In endochondral ossification, what does the mesenchyme develop into?
Chondroblasts (cartilage building cells)
Where are secondary ossification centres found?
Epiphyses of weight bearing bone
What is the difference between primary and secondary ossification sites
Primary found at diaphysis and forms bony structure all around. Develop as a foetus.
Secondary found and epiphysis and doesn’t lay bone down on articular surfaces and epiphyseal growth plate. Develop after birth
What are the 6 stages of fracture healing?
Haematoma
Granulation tissue
Callus
Woven bone
Lamellar bone
Remodelling
What are the 2 types of bone growth?
Longitudinal growth
Appositional growth
Where does longitudinal growth occur?
At the epiphyseal growth plates of weight bearing long bones
Name the 5 zones in the epiphyseal growth plate
Resting zone
Proliferation zone
Hypertrophic zone
Calcification zone
Ossification zone
In which zone of the epiphyseal growth plate to chondrocytes undergo mitosis?
Proliferation zone
What are cartilage cells called?
Chondrocytes
In which zone of the epiphyseal growth plate are chondrocytes stacked like coins in columns?
Proliferation zone
In which zone in the epiphyseal growth plate do chondrocytes die?
Calcification zone
In which zone in the epiphyseal growth plate do osteoprogenitor cells invade?
Ossification zone