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Questions and Answers
What term is used to describe the scientific study of joints?
Which type of joint is characterized by lacking a joint cavity and being connected by dense regular connective tissue?
How are joints classified based on the extent of mobility?
Which of the following statements about the relationship between mobility and stability in joints is correct?
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What is a common characteristic of cartilaginous joints?
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What type of joint is formed from the connection of the Radius and Ulna?
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Which classification of joints is described as allowing for extensive movement?
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What is the term for fibrous joints that may eventually undergo ossification in adults?
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What type of cartilage is found between articulating bones in cartilaginous joints?
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Which of the following describes the costochondral joints?
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In what structural category do intervertebral joints fall?
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What is the primary role of synovial fluid in joints?
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What feature differentiates synovial joints from other joint types?
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Which type of sensory receptor is responsible for detecting damaging stimuli in joints?
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What is the function of the articular cartilage in synovial joints?
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What happens to some synchondroses over time?
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What is the primary function of the anterior cruciate ligament (ACL)?
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What injury is commonly associated with a hyperextended leg?
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Which structures are involved in the 'unhappy triad' injury?
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What is the result of a tibial collateral ligament injury?
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How do the medial and lateral menisci aid in knee function?
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What characterizes a sprain of the ankle?
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What occurs during a Pott fracture?
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Which type of joint allows for plantar flexion and dorsiflexion movements?
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What is the main purpose of the medial and lateral mallioli?
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What describes the common cause of meniscal injuries?
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What movements are primarily allowed at the elbow joint?
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What structure increases the stability of the elbow joint?
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Which ligament is crucial in maintaining the stability of the hip joint?
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What is the largest and most complex diarthrosis in the human body?
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Which of the following describes a subluxation?
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What occurs during an intertrochanteric fracture?
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What is a primary function of the cruciate ligaments in the knee joint?
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What is the role of the radial collateral ligament?
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Where does the articulation of the hip joint occur?
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How are the movements of the hip joint categorized?
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Which factor contributes to the stability of the humeroradial joint?
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What defines a complete dislocation compared to a subluxation?
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What contributes to hip joint stability aside from ligaments?
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Which of these describes a function of the articular capsule?
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What type of synovial joint is the elbow considered?
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Which joint allows for the greatest range of movement?
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Which statement accurately describes a saddle joint?
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Which joint is characterized by a convex surface fitting into a concave depression?
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What characteristic is unique to the temporomandibular joint (TMJ)?
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Which of the following movements is NOT associated with the TMJ?
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What type of joint is characterized by a rounded surface of one bone fitting into a ring formed by another bone?
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What type of synovial joint allows for movement in two planes?
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Which option describes the articular surfaces of a plane joint?
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Which of the following is NOT a characteristic of a ball-and-socket joint?
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What is the least mobile type of synovial joint?
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Which joint is an example of a biaxial joint?
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Which of the following statements about synovial joints is correct?
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What is the primary risk factor for developing skin cancer?
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What skin cancer type is known to have the highest 5-year survival rate if detected early?
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In which stage of melanoma does the cancer spread into the dermis below the epidermis?
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What is a common consequence of ozone layer depletion?
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What is a potential consequence of Vitamin D deficiency?
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What role do tight junctions play in the skin structure?
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What is the primary cause of the death of cells in the superficial strata of the skin?
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Which pigment contributes to yellow-orange color in the skin?
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What effect does keratohyalin have on keratinocytes?
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What is a common characteristic of psoriasis?
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What happens to blood vessels that leads to erythema?
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Which factor is NOT linked to skin color variation?
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What is a characteristic feature of desquamation?
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What is the major component of the dermis that provides tensile strength?
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What is indicated by skin turgor during hydration tests?
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Which layer of the skin lies deep to the epidermis?
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What type of glands lack ducts and release their products into the interstitial fluid?
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Which skin marking is formed due to tension lines in the skin?
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What is the primary function of the sebaceous glands in the dermis?
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What type of connective tissue is predominantly found in the dermis?
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Which of the following structures is NOT typically found in the dermis?
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What is the primary action involved in the treatment of burns that involves the removal of damaged tissue?
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What is the Rule of Nines primarily used for in burn assessment?
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Which type of burn is classified as a third-degree burn according to the severity percentages outlined?
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What physiological change is typically observed in a person experiencing severe burns?
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What refers to the death of most or all cells in an area due to damage from burns?
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What is a significant consequence of increased capillary permeability following a burn injury?
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What type of sweat glands are characterized by their secretions being released directly without loss of cellular material?
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Which type of skin graft involves using tissue from another individual?
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Which of the following statements is true regarding the function of dermal blood vessels?
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What is a common result when the body experiences significant burns?
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What is the main composition of the subcutaneous layer beneath the skin?
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How does the thickness of the subcutaneous layer generally differ between sexes?
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Which type of nerve cells are involved in the stimulation of myoepithelial cells in sweat glands?
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What condition is specifically related to pressure causing constriction of blood vessels in the skin?
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What is the primary role of the myoepithelial cells in sweat glands?
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Which of the following components does not form part of the subcutaneous layer?
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What is included as a derivative of the integumentary system?
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What percentage of body weight does the integument typically account for?
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What is the typical thickness range of the skin?
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Which part of the skin serves as a visual indicator of physiology and health?
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Which layer of the skin is primarily composed of connective tissue?
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What structure is responsible for anchoring hair follicles and causing hair to stand upright?
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What type of connective tissue is primarily found in the subcutaneous layer?
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Which type of glands are sweat glands considered?
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What is the primary purpose of using epidermal growth factor (EGF) in medical treatments?
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Which of the following describes a consequence of severe burns?
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What significantly affects the caloric needs of a patient who has sustained severe burns?
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Which method is used to estimate the severity of burns based on body surface area?
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What term is used to refer to the removal of damaged tissue from a wound?
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Which type of graft involves using tissue from the same individual?
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What is one of the critical factors that decreases blood delivery to tissue in burn injuries?
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What temperature indicates a resetting of the body’s thermostat following burns?
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What is the main function of melanin in the skin?
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How does the number of melanocytes in the skin vary?
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What triggers the release of Melanocyte stimulating hormone (MSH)?
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Which of the following conditions results from a lack of melanin production?
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What is the impact of UV exposure on melanin levels in individuals with darker skin?
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What is the normal daily hair loss for an individual?
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What hair color is associated with the presence of pheomelanin?
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Which term describes diffuse hair loss and is commonly associated with genetic factors?
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What determines the expression of the baldness allele in males?
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How long does hair typically remain in the growth phase for scalp hair?
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What type of sweat glands are primarily responsible for thermal regulation through sweating?
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Which type of blood vessel plays a critical role in thermoregulation by undergoing vasodilation?
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What is the primary function of the subcutaneous layer of the skin?
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What characterizes the distribution of adipocytes in men compared to women?
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What type of cells are involved in the contraction of sweat glands to facilitate sweating?
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Which of the following structures is NOT part of the general structure of a sweat gland?
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What potentially harmful condition can occur due to prolonged pressure on the skin?
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Which of the following statements about dermal blood vessels is true?
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What type of joint is the sternoclavicular joint classified as?
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Which ligament contributes significantly to the stability of the sternoclavicular joint?
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What is a common cause of shoulder separation?
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In which position is pain most likely experienced in cases of shoulder separation?
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Which muscle group plays a critical role in stabilizing the glenohumeral joint?
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What is the primary reason for the glenohumeral joint's instability?
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What type of joint is the acromioclavicular joint classified as?
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What typically happens to the shoulder during a dislocation of the glenohumeral joint?
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What structure is primarily responsible for maintaining the socket depth in the glenohumeral joint?
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Which of the following statements accurately reflects the relationship between joint mobility and stability?
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Which characteristic distinguishes cartilaginous joints from fibrous joints?
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What is a common injury mechanism for glenohumeral joint dislocation?
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What type of movement is primarily associated with synarthrosis joints?
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How are fibrous joints primarily categorized?
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What term describes joints that may become completely fused as a result of ossification?
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What classification would a joint be under if it allows limited movement?
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Which joint classification is characterized by having a joint cavity?
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What feature is common to both fibrous and cartilaginous joints?
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What is the primary role of the posterior cruciate ligament (PCL)?
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Which condition describes the combination of injuries to the tibial collateral ligament, medial meniscus, and ACL?
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How does the meniscus function in the knee joint?
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What typically causes an ankle sprain?
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What happens to the medial malleolus during a Pott fracture?
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Which ligament helps prevent hyperextension of the knee?
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What type of injury could occur due to blows at the knee or extensiveness of activity?
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What is the function of the deltoid ligament in the ankle?
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When does a tibial collateral ligament injury often occur?
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Which of the following is NOT a characteristic of the lateral ligaments in the ankle?
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What type of joint primarily allows only flexion and extension?
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Which ligament helps prevent hyperadduction at the knee joint?
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What structure provides stability to the humeroradial joint?
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Which movement is least allowed by the elbow joint?
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Which type of hip joint fracture typically occurs in elderly individuals with osteoporosis?
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What is the primary characteristic of the knee joint?
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Which statement accurately describes the articular capsule of the hip joint?
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What is the role of the annular ligament in the elbow joint?
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The primary movements allowed at the hip joint are categorized how?
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Which of the following is a definitive feature of the knee joint's structure?
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In the context of joint dislocations, what does the term 'subluxation' signify?
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Which ligament is important in preventing hyperabduction of the knee?
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Which condition is commonly associated with a humeral epicondyle dislocation?
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Study Notes
Articulations & Joints
- Bones are rigid and meet at joints called articulations
- Different joints provide different ranges of movement
- A joint is a place where bones, cartilage, or teeth come together
- Arthrology is the scientific study of joints
- Joint names are derived from the bones they connect (e.g., radioulnar joint is between radius and ulna)
- Joints are classified by structure and mobility
Classifying Joints
-
Structural Classification is based on whether a space (joint cavity is present) exists between articulating bones and the type of connective tissue present
- Fibrous Joints have no joint cavity and are connected by dense regular connective tissue.
- Cartilaginous Joints lack a joint cavity and have cartilage between articulating bones.
- Synovial Joints have a joint cavity and are the most common type of joint
-
Functional Classification is based on the extent of movement allowed
- Synarthrosis allows no movement
- Amphiarthrosis allows limited movement
- Diarthrosis allows free movement
Fibrous Joints
- Dense regular connective tissue connects bones
- No joint cavity is present
- Can be Synarthroses or Amphiarthroses
- Can ossify in adults, becoming synostoses
Cartilaginous Joints
- Lack a joint cavity
- Classified as Amphiarthroses
- Cartilage (hyaline or fibrocartilage) is present between bones
Sympheses
- Shock absorbers
- Resist compression and tension stress
Synchondroses
- First sternocostal joint joins the rib to the manubrium
- Costochondral joins connect ribs to costal cartilage
- Costochondritis is inflammation of the costochondral joints
- Epiphyseal plate is a synchondrosis that ossifies over time
Synovial Joints
- Most joints in the body are synovial joints
- Bones are separated by a joint cavity
- All synovial joints are Diarthroses
- Synovial joints have specific features:
-
Articular Capsule - Strengthens joints to prevent bones being pulled apart
- Has two layers
- Articular Cartilage - Covers the ends of bones, lacks perichondrium, reduces friction during movement, acts as a shock absorber, prevents joint damage
-
Joint Cavity - Space between articulating bones
- Contains synovial fluid secreted by the synovial membrane
- Synovial fluid is viscous and oily, lubricating joint surfaces, acting as a shock absorber, nourishing chondrocytes, and removing waste
-
Sensory Nerves and Blood Vessels - Innervate and supply articular capsule and ligaments
- Proprioceptors - Detect joint stretch and movement
- Nociceptors - Detect damaging stimuli
-
Classification of Synovial Joints - Synovial joint classification is based on shape and movement:
- Uniaxial - Movement in one plane
- Biaxial - Movement in two planes
- Multiaxial - Movement in three planes
-
Articular Capsule - Strengthens joints to prevent bones being pulled apart
Classification of Synovial Joints: Subtypes
-
Plane Joints
- Simplest synovial joint
- Least mobile diarthrosis
- Articular surfaces are flat
- Example: Intercarpal and intertarsal joints
-
Condylar Joints
- Biaxial joint, with movement in two planes
- Oval convex surface articulates with a concave surface
- Example: Metacarpophalangeal joints (knuckles) of fingers and thumb
-
Saddle Joints
- Convex and concave surfaces resembling a saddle
- Biaxial
- Greater range of motion than condylar or hinge joints
- Example: Carpometacarpal joint of the thumb
-
Pivot Joints
- Bone with a rounded surface fits into a ring formed by a ligament from another bone
- Uniaxial joint
- Rotation on the longitudinal axis
- Example: Proximal radioulnar joint, dens of axis and anterior arch of atlas
-
Hinge Joints
- Convex surface articulates with a concave depression
- Movement confined to a single axis (uniaxial)
- Example: Elbow joint, knee, interphalangeal joints
-
Ball-and-Socket Joints
- Multiaxial joints permitting movement in three planes
- Spherical head of one bone fits into a cuplike socket
- Most freely mobile joint type
- Example: Coxal joint (hip) and glenohumeral joint (shoulder)
Temporomandibular Joint (TMJ)
- The only mobile joint in the skull
- Has a loose articular capsule and an articular disc of fibrocartilage
- Articular tubercle and ligaments (sphenomandibular, temporomandibular) are present
- Movements include:
- Depression & Elevation
- Protraction & Retraction
- Excursion
TMJ Disorders
- Alterations to ligaments securing the joint can lead to disorders
- The articular disc may be displaced
- Symptoms include clicking or popping sounds, pain in the joint, and pain radiating to other structures innervated by the trigeminal nerve
Shoulder Joint
- Contains the humeroradial joint (articulation between capitulum and radial head)
- Both joints are enclosed within a single articular capsule
- Stability of the shoulder joint is provided by:
- Interlocking bony surfaces
- Thick articular capsule
- Strong ligaments reinforcing the articular capsule
- Stable joint, but not as mobile as some other joints
Elbow Joint
- Contains two articulations within a single articular capsule:
- Humeroulnar joint
- Humeroradial joint
- Elbow joint stability is provided by:
- Bony surfaces of humerus and ulna interlock
- Thick articular capsule
- Ligaments (radial collateral, ulnar collateral)
- Primarily allows flexion and extension
- Stress to the elbow joint can lead to fractures or dislocations
- Subluxation of the radial head is an incomplete dislocation where the joint surfaces are in partial contact
Wrist and Hand Joints
- Wrist and hand joints are classified as:
- Saddle joints
- Plane joints
- Ball-and-socket joint
- Hinge joints
- Pivot joints
- Condylar joints
Coxal Joint (Hip)
- Articulation between the head of the femur and the acetabulum of the os coxa
- Acetabular labrum is a fibrocartilaginous ring that deepens the acetabulum
- Stable and less mobile than the glenohumeral joint (shoulder)
- Supported by the articular capsule, ligaments, and muscles
- Ligaments include ligament of the head of the femur and retinacular fibers
Hip Joint: Intracapsular Spiraling Ligaments
- The iliofemoral, ischiofemoral, and pubofemoral ligaments help to stabilize the hip joint
- Stability is greatest when the hip is extended
- Movements include:
- Flexion
- Extension
- Abduction
- Adduction
- Rotation
- Circumduction
Femoral Fractures
- Often called a "fractured hip," but this term refers to a fracture in the proximal femur
- The leg appears shorter and rotated laterally
- Fractures can occur in the:
- Intertrochanteric region: Extracapsular, usually in younger and middle-aged individuals due to trauma
- Subcapital region: Intracapsular, usually in elderly people with osteoporosis, may damage retinacular arteries leading to avascular necrosis
Knee Joint
- Largest and most complex diarthrosis in the body
- Primarily a hinge joint
- Composed of two articulations
- Tibiofemoral joint
- Patellofemoral joint
- No single unified capsule or joint cavity
- Ligaments reinforce the knee joint:
- Patellar Ligament
- Tibial Collateral Ligament (prevents hyperabduction)
- Fibular Collateral Ligament (prevents hyperadduction)
- Cruciate Ligaments (anterior and posterior) - Prevent anterior and posterior displacement of the tibia
Knee Ligaments and Cartilage Injuries
-
Anterior Cruciate Ligament (ACL):
- Extends from posterior femur to anterior tibia
- Prevents tibia from moving too far anteriorly on the femur
- Prevents hyperextension of the knee
-
Posterior Cruciate Ligament (PCL):
- Runs from anteroinferior femur to posterior tibia
- Prevents posterior displacement of the tibia
- Prevents hyperflexion
-
Medial and Lateral Menisci:
- C-shaped fibrocartilage pads positioned on the condyles of the tibia
- Act as cushioning between articular surfaces
- Change shape to conform to articulating surfaces
-
Common Injuries:
- Tibial collateral ligament injury: Common
- ACL injury: Very common, often injured during hyperextension of the leg
- Meniscus injury: Can occur due to blows to the knee or overuse
- Unhappy triad: Triple injury of tibial collateral ligament, medial meniscus, and ACL, often occurring in football players due to lateral blow to the knee, causing the leg to abduct and laterally rotate
Ankle Joint
-
Talocrural (Ankle) Joint:
- Highly modified hinge joint
- Includes two articulations within one joint
-
Structure:
- Medial and lateral malleoli of tibia and fibula prevent talus from sliding
- Articular capsule covers distal tibia, medial malleolus, lateral malleolus, and talus
-
Ligaments:
- Deltoid ligament
- Lateral ligament
- Tibiofibular ligaments
- Posterior tibiofibular ligament
- Anterior tibiofibular ligament
-
Ankle Sprains and Pott Fractures:
- Sprain: Stretching or tearing of lateral ligaments due to overinversion, occurring without fracture or joint dislocation, resulting in localized swelling and tenderness anteroinferior to lateral malleolus. Overeversion sprains are rare due to the strong deltoid ligament.
- Pott fracture: Occurs with overeversion, when medial malleolus of tibia is pulled off and fibula fractures, while deltoid ligament remains intact
Joint Types
-
Plane:
- Found between carpal bones
- Found between tarsal bones
-
Ball and Socket:
- Example: Shoulder joint
-
Hinge:
- Elbow joint
- Ankle joint (talocrural joint)
-
Cartilaginous:
- Found between vertebrae
-
Syndesmosis:
- Found at the distal tibiofibular joint
-
Condyloid:
- Found between radius and carpal bones
-
Saddle:
- Found between trapezium and first metacarpal
-
Pivot:
- Found between atlas and axis
- Found between radius and ulna
Keratinization
- The process of keratinization is visible in the strata of the skin.
- Keratinization involves the accumulation of keratin, keratohyalin, and eleidin in keratinocytes.
- Keratin, a fibrous protein, causes cells to become flatter and less permeable.
- Keratohyalin dehydrates cells and precipitates keratin.
- The process results in a water-resistant barrier.
Desquamation
- The cells of the superficial strata die and are shed through desquamation.
- This process occurs every 15-30 days.
Skin Barrier
- The skin barrier is composed of keratin, lipids secreted by lamellar bodies, and tight junctions between keratinocytes.
- The barrier is described as dry and brittle, and is uninhabitable by most microbes.
Psoriasis
- Psoriasis is a chronic autoimmune disease characterized by an overgrowth of new skin cells.
- The condition results from T-lymphocytes attacking keratinocytes.
- Symptoms include cracked, scaly, and raw skin.
- Treatment options include corticosteroids, UV light therapy, and medications that interfere with skin cell production.
Skin Color
- Skin color is determined by pigments and hemoglobin.
- Carotene: a yellow-orange pigment that accumulates in subcutaneous fat and keratinocytes of the stratum corneum.
- Hemoglobin: gives skin its pink hue, visible when blood vessels dilate.
- Erythema: abnormal redness of the skin.
- Contusion: bruise caused by damage to blood vessels.
- Cyanosis: blueness of the skin due to low oxygen levels, indicative of respiratory or cardiovascular disorders.
- Jaundice: yellowness of the skin due to excess bilirubin in the blood.
Skin Cancer
- Skin cancer is the most common type of cancer.
- It is most prevalent on the head and neck.
- Individuals with fair skin are at the highest risk.
- Basal cell carcinoma and squamous cell carcinoma are common types of skin cancer.
- Melanoma is a more aggressive type of skin cancer.
- Early detection of melanoma is crucial for survival.
- Metastasis of melanoma can drastically decrease survival rates.
Melanomas
- Melanomas are increasingly occurring due to ozone layer depletion.
- They have a significant impact in Australia, the US, Europe, and Canada.
- Limiting UV exposure through protective clothing and sunscreen is essential.
Integument: Metabolic Regulation
- Limited exposure to sunlight is beneficial as it aids in the production of Vitamin D.
- Vitamin D, considered a hormone, regulates blood calcium and phosphate levels.
- Deficiency in Vitamin D leads to impaired bone maintenance and growth, and can also contribute to depression.
Dermis: Composition
- The dermis, located deep to the epidermis, ranges in thickness from 0.5mm to 3.0mm.
- It is composed primarily of connective tissue.
- Major components include collagen, elastic, and reticular fibers.
- Collagen fibers provide tensile strength.
- Elastic fibers allow for stretching and recoiling.
- Skin turgor, indicated by a pinch test, is a sign of hydration.
- The dermis also contains blood vessels, sweat glands, sebaceous glands, hair follicles, nail roots, sensory nerve endings, and arrector pili.
Skin Markings
- Wrinkles: formed by folds and creases in the skin.
- Striae: stretch marks.
- Friction Ridges: fingerprints.
- Tension Lines: lines of cleavage in the skin.
Glands
- Glands are composed of epithelial tissue and secrete substances for use elsewhere or elimination.
- Serous glands: secrete watery fluids.
- Mucous glands: secrete viscous fluids.
- Mixed glands: secrete both serous and mucous fluids.
- Endocrine glands secrete hormones directly into the bloodstream.
- Exocrine glands release secretions through ducts.
- Unicellular exocrine glands are single cells that secrete substances.
- Some organs possess both endocrine and exocrine functions.
Exocrine Glands of the Skin
- Sweat glands: exocrine glands responsible for producing sweat.
- Merocrine glands: secrete sweat through exocytosis.
- Apocrine glands: secrete sweat through a process involving the pinching off of portions of the cell.
- Myoepithelial cells are present in sweat glands and help to contract the gland.
Dermal Circulation
- Dermal blood vessels are responsible for supplying nutrients to the epidermis and dermis.
- They play a role in temperature and blood pressure regulation.
- Vasodilation: expansion of blood vessels causes increased blood flow to the skin.
- Vasoconstriction: narrowing of blood vessels decreases blood flow to the skin.
- Decubitus ulcers: pressure sores caused by prolonged pressure on the skin.
Subcutaneous Layer
- The subcutaneous layer is located beneath the dermis and consists of fibroblasts, adipocytes, and macrophages.
- It acts as an energy reservoir, pads and protects the body, and provides thermal insulation.
- Thickness and distribution of subcutaneous fat vary between sexes.
Hair Follicle
- The hair follicle is a tubular structure that houses a hair shaft.
Hair Color and Texture
- Hair color is determined by melanin.
- Hair texture (straight, wavy, curly) is determined by cross-sectional shape.
Burns
- Burns can cause a variety of injuries, including tissue damage, shock, and death.
- Burns increase capillary permeability leading to fluid and electrolyte loss.
- They can also lead to decreased blood delivery to tissues, infection, and necrosis.
- Burns increase metabolic rate, causing increased caloric needs and a need for additional protein.
- Treatment of burns may involve debridement, antibiotics, and tissue grafts.
- Rule of Nines: a tool used to estimate the percentage of the body surface area affected by burns.
Burn Characteristics
- 1st Degree: superficial, damages the epidermis, heals within a few days.
- 2nd Degree: damages the epidermis and dermis, blistering, takes weeks to heal.
- 3rd Degree: damages all layers of the skin, often requires skin grafts.
Integumentary System
- The integumentary system is the skin and its appendages.
- The skin is the largest organ, covering the body.
- It accounts for 8-15% of body weight and ranges from 1.5mm to 4.0mm in thickness.
Skin Layers
- Epidermis - Outermost layer of skin.
- Dermis - Middle layer of skin.
- Subcutaneous Layer - Deepest layer of skin, made of fat.
Epidermis
- Composed of stratified squamous epithelium.
- Contains keratinocytes, melanocytes, Langerhans cells and Merkel cells.
- Keratinocytes: Produces keratin, a tough protein that gives skin its strength.
-
Melanocytes: Produces melanin, a pigment that gives skin its color.
- Melanin is produced in different shades - black, brown, tan, yellow-brown.
- Number of melanocytes is consistent but melanin production varies depending on genetics and sun exposure.
- Melanosomes transfer from melanocytes to keratinocytes where they absorb UV light until broken down by lysosomes.
- Langerhans Cells: Immune cells that help fight infections.
- Merkel Cells: Sensory receptors that help with touch.
- Stratum Basale: Basal layer where cells divide and migrate upwards differentiating into different layers.
- Stratum Spinosum: Layer with spiny appearance due to desmosomes, where cells divide and produce keratin.
- Stratum Granulosum: Where cells produce granules and keratinization begins.
- Stratum Lucidum: Clear layer found only on thick skinned areas like palms of hands and soles of feet.
- Stratum Corneum: Outermost layer, composed of dead keratinocytes.
Dermis
- Dense connective tissue that supports the epidermis.
- Contains blood vessels, nerves, hair follicles, glands, and other structures.
- Two layers:
- Papillary layer: Consists of areolar connective tissue and dermal papillae which house capillaries, nerve endings, and sensory receptors.
- Reticular layer: Consists of dense irregular connective tissue, collagen and elastin fibers.
- Dermal blood vessels: Supply nutrients to the epidermis and dermis, help regulate temperature, and function as a blood reserve.
Subcutaneous Layer
- Consists of areolar connective tissue and adipose tissue.
- Acts as an energy reservoir, pads and protects the body, and provides thermal insulation.
Skin Cancer
- Ultraviolet (UV) radiation from the sun and tanning beds can cause sunburns and skin cancer.
- UV radiation accelerates aging, wrinkles, and other skin damage.
- Sunscreens can help block UVA and UVB rays.
Exocrine Glands of the Skin
-
Sweat glands: Release sweat to help regulate body temperature.
- Merocrine sweat glands: Secrete watery sweat onto the skin surface.
- Apocrine sweat glands: Secrete thicker sweat into hair follicles.
- Myoepithelial cells contract to release sweat from the glands.
- Sebaceous glands: Secrete sebum, an oily substance, into hair follicles.
Hair
- Hair follicle: Structure in the dermis that produces hair.
- Hair shaft: Visible part of the hair.
- Hair root: Part of the hair embedded in the skin.
Hair Growth Cycle
- Anagen phase: Growth phase of hair.
- Catagen phase: Transitional phase of hair growth.
- Telogen phase: Resting phase of hair growth.
Hair Loss
- Alopecia: General term for hair loss.
- Male pattern baldness: Hair loss from specific regions of the scalp.
- Eyebrows: Have a 30-day growth phase followed by a 105-day resting period.
Burns
- Burns are injuries to the skin caused by heat, chemicals, radiation, or electricity.
- First-degree burns: Damage the epidermis.
- Second-degree burns: Damage the epidermis and dermis.
- Third-degree burns: Damage all layers of the skin.
- Burns can cause:
- Increased capillary permeability
- Increased fluid and electrolyte loss
- Lower blood volume
- Tissue damage, shock, and death
- Debridement is removing damaged tissue.
- Tissue grafts can be used to replace damaged skin.
- The Rule of Nines is used to estimate the body surface area affected by a burn.
General Notes
- Dermatology: The study of the skin.
- Decubitus ulcer: Bed sores caused by pressure.
- Necrosis: Cell death.
- Hypothermia: Low body temperature.
- Hyperthermia: High body temperature.
- Vasodilation: Widening of blood vessels.
- Vasoconstriction: Narrowing of blood vessels.
- Melanocyte-stimulating hormone (MSH): Hormone that stimulates melanin production.
- **Tyrosinase: ** An enzyme that catalyzes the conversion of tyrosine into melanin.
- Nevus: Birthmark.
- Freckles: Small, flat, pigmented spots on the skin.
- Vitiligo: Condition where melanocytes die and cause loss of pigmentation.
- Albinism: Genetic condition where the body does not produce melanin.
Articulations
- Joints are where bones, cartilage, or teeth meet
- Articulate is when two bones meet at a joint
- Arthrology is the scientific study of joints
- Joints are classified based on structural characteristics and range of movement
Fibrous Joints
- Connected by dense regular connective tissue
- There is no joint cavity in fibrous joints
- Synarthrosis and Amphiarthrosis are classes of fibrous joints
- Examples:
- Syndesmoses: Found between tibia and fibula
- Suture: Found in skull
- Gomphosis: Tooth in socket
- Fibrous joints can ossify and become synarthrosis
- Synarthroses become a solid mass of bone
Cartilaginous Joints
- Classified as Amphiarthroses
- No joint cavity
- Connected by cartilage
- Two types:
- Synchondroses: Hyaline cartilage present, like epiphyseal plate
- Symphyses: Fibrocartilage present, like intervertebral discs
Synovial Joints
- Free movement
- Joint cavity is present
- Fluid inside the joint cavity
- Joint capsule surrounds the joint
- Articulating surfaces covered in thin layer of hyaline cartilage
- Examples:
- Knee
- Shoulder
- Elbow
- Hip
Shoulder Joint
- Comprised of three joints:
- Sternoclavicular (saddle)
- Acromioclavicular (plane)
- Glenohumeral (Ball and Socket)
- Glenohumeral joint has the greatest range of motion of any joint in the body
- Glenohumeral joint is the most unstable due to minimal ligament support
- Strength of the glenohumeral joint comes mainly from the surrounding muscles, the rotator cuff muscles
Shoulder Separation
- Displacement of the acromioclavicular joint
- Often occurs due to a hard blow to the joint
- Pain may occur when the arm is abducted over 90°
- The acromion may appear prominent
Elbow Joint
- A hinge joint comprised of two articulations:
- Humeroulnar joint
- Humeroradial joint
- Stabilized by:
- Bony surfaces, interlocking well
- Thick articular capsule
- Strong ligaments
- Stability of the elbow joint, limits mobility
Hip Joint
- Articulation between the head of the femur and a socket in the os coxa
- The socket is called the acetabulum
- The acetabular labrum is a ring of fibrocartilage that deepens the socket
- Strong articular capsule, multiple ligaments, and muscles support the hip joint
- The capsule is reinforced by retinacular fibers: thick bands of ligamentous fibers
- Stronger and more stable joint than the glenohumeral joint
Knee Joint
- Largest and most complex diarthrosis in the body
- Primarily a hinge joint
- Comprised of two articulations:
- Tibiofemoral
- Patellofemoral
- The anterior surface of the articular capsule is reinforced by the quadriceps tendon
- Ligaments strengthen the joint:
- Tibial collateral ligament
- Fibular collateral ligament
- Cruciate Ligaments:
- Anterior Cruciate Ligament (ACL)
- Posterior Cruciate Ligament (PCL)
- Menisci:
- Medial meniscus
- Lateral meniscus
Ankle Joint
- Highly modified hinge joint
- Structure:
- Tibia
- Fibula
- Talus
- The joint is supported by ligaments:
- Deltoid ligament
- Lateral ligament
- Anterior tibiofibular ligament
- Posterior tibiofibular ligament
Subluxation
- Incomplete dislocation
- Joint surfaces lose contact momentarily but remain partially together
Dislocation
- Full displacement of the joint surfaces
- Joint surfaces are completely separated
- Bones are no longer in contact
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Description
Explore the structure and function of joints in the human body. This quiz covers the classifications of joints, including fibrous, cartilaginous, and synovial joints. Additionally, learn about the significance of arthrology in understanding joint mobility.