Skeletal Anatomy Flashcards
What is the skeletal system made up of?
- Cartilage (chondrocytes)
* Bones (osteocytes)
What are the common characteristics of cartilage and bones?
• Belongs and has characteristics of connective tissues
• Cells and extracellular matrix
o Presence of connective tissue fibres
Collagen, elastic, reticular
What are the features of cartilage?
• No blood supply
o Causes slow repair
- No nerve fibres
- Presence of large amount of water in extracellular matrix -> gives resilience and purpose
- Cartilage of embryos -> replaced by bones
What are the features of bone?
- Rich blood supply
- Nerve supply
- Presence of inorganic mineral calcium in matrix -> arise to bone hardness
What are the different kinds of cartilages?
- Hyaline
- Elastic
- Fibrocartilage
What are the functions of hyaline cartilage?
- Supports and reinforces
- Resilient cushioning properties
- Resists compressive stress
What are the locations of hyaline cartilage?
- Mostly all joints
- Articular cartilages of bone in synovial joint: provides springy pads that absorbs compression at joints
- Tip of nose: nasal cartilage
- Connects ribs to sternum: coastal cartilage
- Trachea
- Larynx
What are the cell properties of hyaline cartilage?
• Chondrocytes in lacuna (spherical cells)
• Homogenous matrix
(fine collagen)
What are the functions of the elastic cartilage?
- Maintains the shape of a structure
* Allows great flexibility
What are the locations of the elastic cartilage?
- External ear (pinna or oracle)
* Epiglottis
What are the cell properties of the elastic cartilage?
- Elastic fibres
- Chondrocyte in lacuna
- Matrix
What are the functions of the fibrocartilage cartilage?
- Tensile strength
* Ability to absorb compressive shock
What are the locations of the fibrocartilage cartilage?
- Intervertebral discs
- Pubic symphysis
- Meniscus: knee joint
What are the cell properties of the fibrocartilage cartilage?
- Chondrocytes in lacuna
* Collagen fiber
What are some features of the perichondrium cartilages?
- Has blood vessels -> nutrients diffuse that matrix to cartilage (made of nutrient delivery -> limits cartilage thickness)
- Cartilage surrounded by dense connective tissue -> girdle/perichondrium -> resist outward expansion of cartilage when it is compressed
What are the certain bone growth in youth and elderly?
• Cartilage can calcify due to calcium deposition
• Calcified cartilage is not bone
o Bone and cartilages are distinct and different
What are the classification of different shapes of bones?
- Long bone
- Flat bone
- Irregular bone
- Short bone
Examples of long bone
humerus
- length is more than width
Examples of irregular bone
Vertebra
- complicated shape
Examples of flat bone
- Sternum
- Ribs
- Iliac
- Thin, flattened, abit curved
Examples of short bone
- Carpus (hands)
- Tarsus (feet)
- Patella (knee caps)
- cube shape
What are the major divisions of skeletal system?
• Axial (vertebra, ribs, sternum, ribs)
o Lie centrally
• Appendicular
o Lie laterally
What are the bones of the skull?
- Facial
- Cranium
- Base of skull
Describe the facial bones of skull
o Paired: maxilla, palatine, lacrimal, nasal, zygoma, inferior nasal chonchae
o Single: mandible, vomer (nasal septum)
o Forms boundaries of opioid, nose and oral cavity
Describe the cranium bones of skull
o Encloses the brain
o 2 parts
Skull cap (calvarium) (upper part)
Cranial base (inferior)
Describe the base of the skull
o 3 cranial fossae (anterior, middle, posterior)
o Accommodate to various part of the brain
Describe the cranium bones of skull
• Cranium bones (4 single, 2 pair)
o Single: frontal, occipital, ethmoid, sphenoid
o Paired: parietal and temporal
What are the paranasal sinuses and its functions?
- Lighten skulls
- Enhances voice resonance
- Surround the noses and communicate with nasal cavity
- Bones of skull have mucosal line air filled spaces
What are the types of paired paranasal sinuses?
- Frontal sinuses (eyebrows, paired)
- Maxillary sinuses (cheeks, paired)
- Sphenoid sinus
- Ethmoid sinuses (posterior, middle, anterior)
What makes up the vertebral column?
- 26 pieces of separate bones (vertebra)
- Surrounds and protects spinal cord
- Flexible
- Cervical curvature (concave): C1-C7
- Thoracic curvature (convex): T1-T12
- Lumbar curvature (concave): L1-L5
- Sacral curvature (convex): S1-S5 (fused vertebrae)
- Coccyx (tailbone): 4 fused vertebrae
What makes up the thoracic cage?
• 12 pairs of ribs and coastal cartilages –> attached posterior to vertebrae
o True ribs (1-7)
Attached directly to their own coastal cartilage to sternum
o False ribs (8-12)
Attached indirectly
11 and 12 -> floating ribs -> not attached to sternum
• Xiphoid process
o No ribs attached
• Manubrium
o Attached to clavicle and 1-2nd ribs
What is the hyoid bone?
- Front of the neck
- Does not articulate with any other bone
- Is a site of attachment for muscle in swallowing and speech
What is the appendicular skeleton?
• Bones of pectoral girdle
o Clavicle
o Scapula
• Upper limb
o Humerus: arm bone
o Radius: forearm
o Ulna: forearm
o Carpals: 8 bones, arranged in proximal to wrist
o Metacarpals: palm
o Phalanges: fingers, digits (thumb 2, fingers 3)
• Lower limb (pelvic gird) o Bones of pelvic girdle (hip bones) – iliac, ischium, pubis o Femur o Patella o Tibia o Fibula o Tarsals o Metatarsals o Phalanges
What is a broken hip?
- Fracture of the neck of the femur
* Common in elderly -> due to osteoporosis weakens the neck of femur
What are some example of the joined bones?
- 2 pubic join -> forms pubic symphysis
- Iliac and sacrum -> forms sacroiliac joint
- Sacrum and coccyx -> forms sacrococcygeal
What are the functions of the bone?
- Framework for the body and soft organs
- Protection of soft tissues (ribs for lungs)
- Attachment for lungs
• Storage site (calcium, phosphorus, magnesium)
o Can release osteominerals in response to body
o Provides homeostasis
• Haematopoiesis: production of blood cells
o In red bone marrow (found in internal cavities of most bones)
What is the structure of a long bone?
• Epiphysis: ends of the bone
o Proximal and distal
- Epiphyseal line/plate: remnant of epiphyseal growth plate -> cartilage that grows in a child -> becomes a line when adult
- Metaphysis: between epiphysis and diaphysis
- Diaphysis: middle of the bone
- Distal diaphysis: helps to understand blood supply
- Articular cartilage: caps joint surface of each epiphysis, cushioning movements and shock absorber
- Inner spongy bone
- Outer compact bone: surrounds the medullary cavity
- Medullary cavity: consists of yellow bone marrow
What is a haematopoietic tissue?
• Red marrow
• Trabecular cavities of spongy bone of long bones
o Trabecular: means small, often microscopic
• Diploe (thin) of flat bones and hip bones
What are the connective tissues associated with the bone?
- Periosteum
* Endosteum
What is the periosteum?
- Layer of connective tissue
- Covers the external surface of the bones, except neat joint surfaces
- Secured to underlying bone via Sharpey’s fibres
- Rich nerve and blood supply -> nutrients, arteries, lymphatic vessels
- Tendons and ligaments attached to periosteum
• 2 layers:
o Outer fibrous layer
o Inner cellular layer (osteogenic layer: contains stem cells -> give rise to osteogenic cells)
What is endosteum?
- Inner lining layer of connective tissues
- Lines the bony cavity
- Lines the medullary cavity
- Between bone tissue and bone marrow
- One cellular layer (osteogenic cells)
- Covers spongy and trabeculae bones -> lies inner layer of periosteum
What is a compact bone?
• Dense + outer layer of solid bone + defines the shape of the bone
• Presence of Haversian/central canal
o Has neurovascular structure, vein, artery, nerve
• Presence of Volkman’s canal -> connect medullary cavity to central canal
What is a spongy bone?
- Inner layer, contains struts and plates, formed by spicules
- Presence of trabeculae -> open spaces -> Forms medullary cavity -> filled with red and yellow bone marrow
What is an osteon?
- Structural unit of compact bone (aka lamellae bone)
* Organized as a column like matrix tubes -> arranged one outside the other
What are the features of osteon?
- Lamellae: each matrix tube
- Central canal: lies parallel to axis of the bone -> contains vein structures (BV and nerves)
- Lacunae: small cavities containing osteocytes
• Canaliculi:
o Hair like canals
o Connect to lacunae to lacunae -> lacunae to central canal -> make sure all bone cells are adequately nourished
What are flat bones made up of?
• Layer of spongy and sandwich of 2 different kinds of compact bone
What are compact bones covered with?
• Covered by externally and internally by connective tissue membranes -> periosteum or endosteum
What are the different kinds of bone cells?
- Osteogenic/osteoprogenitor
- Osteoblast
- Osteocyte
- Osteoclast
Description of Osteogenic cells
- Stem cells
- Mitotically active
- Cellular layer of periosteum and endosteum
Description of Osteoblast cells
- Immature bone forming cells
- Mitotically active
- Matrix-synthesizing cell responsible for bone growth
Description of Osteocyte cells
- Mature bone cell
- Maintains the bone matrix
- Surrounded by matrix
- Reside in lacunae
- Interconnected through canaliculi
Description of Osteoclast cells
- Bone-resorbing cell
- Multinucleated
- Motile cells
- Originate from macrophages
Role of Osteogenic cells
Repairs and fractures
Role of Osteoblast cells
Secretion of bone matrix and matrix calcification
Role of Osteocyte cells
Maintains matrix
Role of Osteoblast cells
Osteolysis and modelling, bone breakdown (osteolysis/remodel)
What are the types of bone development?
- Intramembranous model
* Endochondral model
What happens during intramembranous development?
- Fibrous tissue -> bone
- Bone develops directly from fibrous membrane at ossification centre -> arises from fibrous tissue
- Direct transformation of fibrous tissue -> to bone
- Eg: flat bone of skulls and clavicle of upper limb
What happens during endochondral model?
- Fibrous tissue -> cartilage -> bone
- Form by replacing hyaline cartilage
- Has intervening cartilage model from which bones are formed
- Forms most bones in body
What are the different types of bone growth?
- Linear
* Width
What happens during linear bone growth?
• Occurs at the age of 18 (F), 21 (M)
• Longitudinal bone growth -> mimics endochondral ossification
o Ends when epiphysis fuses with diaphysis = epiphyseal plate closure
• Depends on epiphyseal plate cartilage
o Next to diaphysis -> organizes a pattern for continuous remodeling of epiphyseal end -> to maintain proportion between diaphysis and epiphysis
• Continuous remodeling of epiphyseal end
What happens during width bone growth?
• Appositional growth
• Osteoblasts beneath periosteum secrete bone matrix on external surface
o More building > breaking down -> unequal process producing thicker and stronger bones -> prevents bone from becoming brittle
• Osteoclasts on endosteal surface of diaphysis removes bone
What are joints?
- Holds bones together for mobility
- Articulation site
- Two or more bones meet with or without movement
What are the functional classification of joints?
• Classified based on: movement allowed by the joint
- Synarthroses (immovable)
- Amphiarthroses (slightly movable)
- Diarthroses (freely movable) (most joints in our body)
What are the structural classification of joints?
• Based on the material binding bones together + whether joint cavity is present
- Fibrous
- Cartilaginous
- Synovial
What are fibrous joints?
- Dense and connective
- No movements
- Eg: suture line on skull, inferior tubule of fibula joint
What are cartilaginous joints?
• Bones joined by cartilage
• 2 types o Synchondroses (primary type) Immovable joints Bones united by hyaline cartilage
o Symphases (secondary type) Strong, flexible with slight movements
What are synovial joints?
• Most joints of our body
• Lined by synovial membrane
o Internal surface of capsule
o Secretes synovial fluid (viscous slippery filtrated plasma -> lubricates joints)
• Has a joint cavity -> with synovial fluid
o Potential space -> allow inside of joint to be viewed during scopy
• Articular cartilage (caps part of bone -> form joints)
• Fibrous capsule
o Dense layer of connective tissue -> attached to bones
What are the other features of synovial joint?
• Ligaments (band of connective tissue -> connects bones
o Intrinsic – part of fibrous capsule (eg: glenohumeral of shoulder)
o Extracapsular – outside the capsule (eg: patella ligament of knee)
o Intracapsular – deep to the capsule (eg: cruciate ligament of knee)
• Rich in nerve and blood vessel supply
• Articular discs: wedges of fibrocartilage
o Found in complex joints (meniscus of knee)
o Function: stabilisers
• Bursae: friction reducing structures
o Flattened fibrous sac -> in synovial membrane -> containing synovial fluid
o Extension of synovial cavity
o Present where ligaments, muscles, tendons, bones wrapped together
• Tendon sheath:
o Elongated bursa -> wraps completely around a tendon
What is osteoarthritis?
• Targets the articular cartilage of a joint
What is rheumatoid arthritis?
• Targets the synovial membrane of a joint
What is the factors needed for the stability of a joint?
- Shape and size of articular surfaces of bones
- Ligaments
- Muscle Tone
How are shape and size of articular surfaces of bones important for stability of joints?
o Hip joint is more stable than shoulder joint
Hip joint: Large femur head fits tightly in deep socket of acetabulum of hip bone
Shoulder joint: small, shallow, glenoid fossa for the large head of humerus -> misfit -> frequently dislocated joint
How are ligaments important for stability of joints?
Ligaments (elastic ligament, fibrous)
o Fibrous: uniting bones -> prevent undesirable movement and reinforce joint
o Eg: cruciate ligaments in knee
o More ligaments = more stable the joints
How are muscle tone important for stability of joints?
o Extremely important in reinforcing shoulder joint -> rotator cuff muscles -> helps to keep humeral head against gleroid fossa -> stabilizing shoulder joint
o Knee joint -> quadriceps femoris
What are the types of synovial joints?
- Plane Joints
- Hinge Joints
- Pivot Joints
- Condyloid/ellipsoid Joints
- Saddle Joints
- Ball and Socket Joints
Describe the types of synovial joints
• Plane joints
o Non-axial joints, short gliding movements
o Eg: acromioclavicular joint
• Hinge joints
o Uniaxial joints, flexion, extension movements
o Eg: elbow, knee, ankle
• Pivot joints
o Uniaxial joints, rotation movement
o Eg: atlantoaxial joint, radioulnar joint
• Condyloid/ellipsoid joints
o Bi-axial joints
o Eg: wrist, metacarpophalangeal joint
• Saddle joints
o Bi-axial joints
o Eg: carpometacarpal joint of thumb
• Ball and socket
o Multi-axial joints, most free moving synovial joints
o Hip, shoulder joint
What are some special joints?
- Knee joint
- Ankle joint
- Shoulder joint
- Elbow joint
- Superior radioulnar joint
- Wrist joint
- Inferior tibiofibular joint
Describe the knee joints
o fibula is not included
o patella-femoral complex: between femoral condyle + patella
o femoral-tibial complex: between femoral condyle + tibial condyle
o associated with number of busae -> busae communicate with knee joint
o intracapsular ligament -> most commonly injured
o menisci -> stabilisers
Describe the ankle joints
o uniaxial heel joint -> formed by tibia, fibula and talus
o stable hinge joint -> by nature of bony articulating bone and surfaces
Describe the shoulder joints
o head of humerus with glenoid cavity of scapula (most commonly dislocated joint)
o stability is affected by freedom of mobility
o mobility -> due to large size of head -> does not fit in small, shallow size of glenoid fossa of scapula
Describe the elbow joints
o humerus, radius and ulna
o describe as humeral-radial, humeral ulna complexes
Describe the superior radioulnar joints
o aka proximal radioulnar joint
o elbow joint
o share a common joint cavity with elbow joint
Describe the wrist joints
o radiocarpal joint – radius with scaphoid, lunate (carpus)
o ulna does not take part
o has articulation between radius and scaphoid lunate of carpal bones
Describe the inferior tibiofibular joints
only fibrous join in appendicular skeleton (present in lower limb)
What are the movements of the synovial joint?
- by muscles attached to the joints
- muscle contraction causes insertion to move towards the origin
• movements occurs along different planes
o transverse
o frontal
o sagittal
What are the muscles attached to the joint?
- Origin – proximal attachment
* Insertion – distal attachment
What are the movements of the lower limb?
• Ankle joint:
o dorsiflexion, plantar flexion = extension, flexion
• Tarsal joints of foot: inversion and eversion
• Hip joint:
o abduction and adduction
o flexion and extension (hyperextension)
o medial and lateral rotation
What are the movements of lower limb?
• Radioulnar joint:
o Supination and pronation of forearm
• Elbow joint:
o Flexion
o Extension
• Wrist joint
o Abduction and adduction
o Flexion and extension
• Interphalangeal joint (distal)
o Flexion and extension
• Metaphalangeal joints
o Abduction and adduction
o Flexion and extension
• Thumb o Opposition - Thumb approximates itself with bands of outer fingers - Opposing another finger with thumb - Movement of pinching, holding pen
What are the movements of neck?
• Lateral flexion and rotation: occurs at the uniaxial pivot joint
What are the movements of the vertebral column?
- Flexion, extension and hypertension
* (R&L) Lateral flexion, rotation
