Ortho/ Muscle Flashcards
Two exam test to check for hip laxity?
- Ortaloni Test
- Barden Test
Ortaloni test typically performed in lateral but consider in dorsal recumbency if sedated. Typically gone in older dogs due to fibrous and thickening.
What are the Ortaloni and Barden Test assessing?
Joint Laxity.
Normal amount of laxity that can be noted is 2 - 3 mm.
The design of the screw hole allows for a displacement of up to ___ mm per hole in the DCPs 3.5 and 4.5 and up to ___ mm in the DCP 2.7.
1.0 mm
0.8 mm
Screws in LC-DCP can be inclined sideways to a maximum of ___ degrees and in a longitudinal direction up to ___ degress.
7 degrees
40 degrees
As opposed to 25 degress for DCP
What are the different modes DCP/LC DCP plates may function as
- compression
- neutralization, bridging
- buttress
What influences implant bending strength and stiffness?
Area moment of inertia
The area moment of inertia is a geometrical property that reflects how a cross-section’s area is distributed about an axis.
For a nail, how is the moment of inertia calculated?
Using the radius to the fourth power
This calculation emphasizes how the distribution of material affects the nail’s resistance to bending.
For a plate, how is the moment of inertia calculated?
Using the thickness to the third power
This reflects the relationship between the thickness of the plate and its structural strength.
The area moment of inertia of a solid section of an 8 mm interlocking nail is approximately how many times that of a 3.5 mm dynamic compression plate (DCP)?
6.8 times
This indicates the significantly greater resistance to bending of the larger nail compared to the DCP.
The area moment of inertia of a solid section of an 8 mm interlocking nail is approximately how many times that of a 3.5 mm broad dynamic compression plate?
3.5 times
This comparison shows the difference in bending strength between the interlocking nail and the broad DCP.
Where are interlocking nails placed in relation to the bone?
Near the neutral axis
The neutral axis is the line in the cross-section of a beam or structural element where the material experiences no tension or compression.
What type of forces are interlocking nails subjected to during weight bearing?
Compressive forces
Compressive forces push the material together, as opposed to tensile forces that pull it apart.
What moments are interlocking nails less subjected to during weight bearing?
Bending moments
Bending moments occur when an external load is applied to a beam, causing it to bend.
What types of mechanical forces does the locking mechanism of interlocking nails provide stability against?
torsion and compression
Torsion refers to twisting forces, while compression refers to forces that push or pull an object together.
What does the intramedullary location of the nail eliminate the risk of?
screw pull-out
Screw pull-out is a mode of failure where screws become disengaged from the bone, which is more common with plates, especially in weaker bone.
What are the active (dynamic) stabilizers of the shoulder joint?
The active stabilizers of the shoulder joint include:
* infraspinatus
* supraspinatus
* subscapularis
* teres minor muscles
* biceps brachii
* long head of the triceps brachii
* deltoideus
* teres major muscles to a lesser extent
These muscles work together to provide stability and movement at the shoulder joint.
What are passive mechanisms for stabilization of the shoulder joint?
Passive mechanisms do not require muscle activity and include:
* limited joint volume
* adhesion/cohesion mechanisms
* concavity compression
* capsuloligamentous restraints
What does limited joint volume refer to in the context of shoulder stabilization?
limited joint volume is a stabilizing mechanism in which the humeral head is held to the socket by the relative vacuum created when they are distracted
What are adhesion/cohesion mechanisms in shoulder joint stabilization?
“adhesion/cohesion mechanisms” refer to the stabilizing effect created by the molecular attraction between the synovial fluid within the joint and the surfaces of the humeral head and glenoid, essentially acting like a “suction cup” effect that holds the joint surfaces together when they come into contact, providing stability to the shoulder joint; this stability is dependent on the fluid’s ability to adhere to the joint surfaces and its cohesive properties within itself.
What structures are included in capsuloligamentous restraints?
Capsuloligamentous restraints include:
* glenohumeral ligaments
* joint capsule
* labrum
* tendon of origin of the biceps brachii muscle
Where are the extensors of the carpus and digits located?
They are located at the craniolateral position on the forearm.
What is the common origin point for most extensors of the carpus?
lateral epicondyle of the humerus
Which nerve innervates the extensors of the carpus?
radial n.
C6- T2
Which extensor is the most medial?
Extensor carpi radialis
Where does the Extensor carpi radialis insert?
Insertion: Small tuberosity on metacarpals 2 and 3
Origin: Lateral epicondylar crest of the humerus
Which extensor is the most lateral?
Ulnaris lateralis
Where does the Ulnaris lateralis insert?
accessory carpal bone and 5th metacarpal
What is another name for the Extensor carpi obliquus?
abductor pollicis longus
What is the origin of the Extensor carpi obliquus (abductor pollicis longus)?
cranial radius
Where does the Extensor carpi obliquus (abductor pollicis longus) insert?
1st metacarpal
Where does the Common Digital Extensor insert?
extensor process of the distal phalanx of each digit
What does the Common Digital Extensor send to the dew claw?
a medial branch
Where does the Lateral Digital Extensor insert?
dorsal proximal phalanges of the 3rd to 5th digit
What is the origin of the flexor muscles of the carpus and digits?
Caudal medial epicondyle of the humerus
These muscles are positioned caudally on the forearm.
Which nerves innervate the flexor muscles of the carpus and digits?
Median or ulnar nerve of the brachial plexus
Median Nerve (C7-T1)
Ulnar Nerve (C8-T2)
What is the most medial flexor muscle of the carpus?
Flexor carpi radialis
Where does the flexor carpi radialis insert?
Upper 2nd/3rd metacarpal bone
What is the most lateral flexor muscle of the carpus?
Flexor carpi ulnaris
Where does the flexor carpi ulnaris insert?
Accessory carpal bone
What does the superficial digital flexor divide into?
Four branches
Where do the branches of the superficial digital flexor insert?
Middle phalanges of all digits
What structure does the deep digital flexor pass through before branching?
Carpal canal
Where does the deep digital flexor continue to after branching?
Palmar distal phalanges
What is the function of the interosseus muscles?
Support the metacarpophalangeal joints
Where do the interosseus muscles originate?
Palmar proximal metacarpal bones
Where do the interosseus muscles insert?
Sesamoid bones within the joints
The interosseus muscles are continued by ligaments to the _______.
Phalanges
What is the maximum time an Esmarch bandage/tourniquet should be applied?
1.5 to 2 hours
This is the point at which muscle adenosine triphosphate (ATP) stores are depleted.
How long does it take for mitochondrial changes to become visible after applying an Esmarch bandage/tourniquet?
1 hour
Mitochondrial changes indicate cellular stress due to lack of blood flow.
What is the time frame for microvascular damage to occur after applying an Esmarch bandage/tourniquet?
2 hours
Microvascular damage can lead to tissue necrosis if blood flow is not restored.
When should the placement time of an Esmarch bandage/tourniquet be reduced?
If significant trauma or sepsis is present
Reducing placement time is crucial to prevent further complications.
Exanguination or raising of the limb prior to application of an Esmarch bandage is not recommended with _______.
malignant neoplasia or infection
This practice can exacerbate conditions in patients with these diagnoses.
What are the 4 caudal hip muscles that externally rotate the hip/femur?
- Internal obturator
- External obturator
- Quadratus femoris
- Gemelli
What are ligaments?
Connective tissue bands that attach to bones (typically span a joint, may have 2 attachments on same bone)
Ligaments provide stability and support to joints.
What are intra-articular ligaments?
Ligaments that cross a joint within a synovial cavity
Examples include the cruciate ligaments.
What covers intra-articular ligaments?
A thin vascularized connective tissue sheath (epiligament)
This sheath merges with the periosteum at both attachments.
What are capsular ligaments?
Focal thickenings of the fibrous component of a joint capsule
An example is the collateral ligaments of the glenohumeral joint.
What is the primary composition collagen type of the extracellular matrix of tendon and ligament?
Densely arranged type I collagen fibers, with smaller quantities of types II, III, V, VI, IX, and XI
Type I collagen provides strength and support to ligaments and tendons.
What are tendons?
Collagen-rich fibers that connect muscle to bone or that form connections between muscles
Tendons play a crucial role in transmitting muscular forces to the skeletal system.
What are aponeuroses?
Flattened structures that connect muscles to bones or to other fascial elements (ex 1) or that form connective tissue leaves within the substance of a pennate muscle (ex 2).
Example 1 - fascia of the biceps femoris muscle
Example 1 - Rectus abdominis muscle
What is the function of positional tendons?
Transfer muscular forces to bones in such a manner as to cause joint motion
An example is the infraspinatus muscle tendon.
What are wrap-around tendons?
A type of positional tendon that change direction and engage specialized pulley-like grooves in bones as they traverse a joint
An example is the deep digital flexor tendons of the pes.
What are energy-storing tendons?
Tendons that have greater elastic fiber content and are adapted to respond to the forces of weight bearing by energy storage and elastic recoil
An example is the common calcaneal tendon.
What is the primary composition collagen type of the extracellular matrix of tendon and ligament?
Densely arranged type I collagen fibers, with smaller quantities of types II, III, V, VI, IX, and XI
This composition contributes to the mechanical properties of tendons and ligaments.
Fill in the blank: Positional tendons are discrete and relatively stiff structures that transfer muscular forces to bones in such a manner as to _______.
cause joint motion
Fill in the blank: The extracellular matrix of tendon and ligament is composed primarily of densely arranged type _______ collagen fibers.
I
What are Sharpey fibers?
Dense bands of collagen that merge with the periosteal membrane and penetrate deeply into the cortical bone
Sharpey fibers play a crucial role in anchoring the periosteum to the underlying bone.
What type of tissue are Sharpey fibers primarily made of?
Collagen
Collagen is a protein that provides strength and structure to various tissues in the body.
What membrane do Sharpey fibers merge with?
Periosteal membrane
The periosteal membrane is a dense layer of vascular connective tissue enveloping the bones except at the surfaces of the joints.
Where do Sharpey fibers penetrate?
Deeply into the cortical bone
Cortical bone is the dense outer surface of bone that forms a protective layer around the internal cavity.
What pathogens are associated with orthopedic surgery for elective procedures and closed fractures?
Staphylococcus spp.
Cefazolin is typically used for these pathogens.
What pathogens are associated with open fractures?
- Staphylococcus spp.
- Streptococcus spp.
- Anaerobes
Treatment options include cefazolin or clindamycin, possibly combined with aminoglycoside or fluoroquinolone.
Which antibiotic should be avoided with known or potential streptococcus canis infections?
Enrofloxacin
Fluoroquinolones like enrofloxacin should be avoided when treating Streptococcus canis infections in dogs because they can make the infection worse.
What is a Conditioning film?
- Thin layer of proteins (such as fibronectin, fibrinogen, vitronectin, thrombospondin, laminin, collagen, con Willebrand factor and polysaccharides) that forms on indwelling medical device or living tissues
- Allows for initial attachment of pathogenic organisms
Conditioning film is a surface coating that forms when biomolecules stick to a surface. It can affect the surface properties of a material and can lead to microbial attachment and biofilm formation.
What are some protiens make the thin layer of the conditioning film on medicl devices or living tissues?
- Fibronectin
- Fibrinogen
- Vitronectin
- Thrombospondin
- Laminin
- Collagen
- Von Willebrand factor
- Polysaccharides
What allow for initial attachment of pathogenic organisms on a indwelling medical device or living tissues?
Conditioning film
Conditioning film is a surface coating that forms when biomolecules stick to a surface. It can affect the surface properties of a material and can lead to microbial attachment and biofilm formation.
What is the first goal of fracture fixation?
Eliminate interfragmentary strain with anatomic reconstruction, compression of bone ends with rigid fixation & absolute stability
This approach focuses on achieving a stable environment for healing by eliminating movements at the fracture site.
What is the second goal of fracture fixation?
Maintain low strain environment through bridging techniques and implants that allow relative stability
This method involves using implants that can accommodate some movement while distributing strain among fracture fragments.
Fill in the blank: The first goal of fracture fixation is to _______.
Eliminate interfragmentary strain
Fill in the blank: The second goal of fracture fixation is to _______.
Maintain low strain environment
True or False: Rigid fixation is used to maintain a strain environment in fracture fixation.
False
Rigid fixation is associated with the goal of eliminating interfragmentary strain.
What techniques are used to maintain a low strain environment in fracture fixation?
Bridging techniques and implants that allow relative stability
These techniques can accommodate larger gaps in the fracture.
Define Strain
Bone strain
- Bone strain is a measure of how much a bone deforms when force is applied to it. It can also refer to an injury to a muscle or tendon that connects to a bone.
- Bone strain is calculated by dividing the change in bone length by its original length.
- Bone strain is a key variable between loading forces and bone remodeling.
- Dynamic loading, or cyclic changes in internal strain, can stimulate bone formation. However, repetitive loading can cause stress fractures.
What are the two types of Primary Bone Healing?
Contact and gap healing
Primary Bone Healing is also known as Direct Bone Healing.
What condition must be met for Primary Bone Healing to occur?
Absolute stability
This stability eliminates strain through anatomical reconstruction, compression, and rigid fixation.
True or False: Complete congruence of the entire bone surface is always possible.
False.
Complete congruence is impossible in practice. Will always occur through both contact and gap healing
Fill in the blank: Primary Bone Healing occurs under _______.
absolute stability
True or False: Primary Bone Healing can be achieved without any strain.
True
Strain must be functionally eliminated.
What type of bone healing is Contact Healing?
Primary (direct) bone healing
Contact Healing is characterized by the direct elongation of osteons to bridge a fracture.
What are the two requirements for Contact Healing to occur?
- Distance between bone ends <0.01mm
- Strain functionally eliminated (<2%)
These conditions allow for the direct connection of bone ends without significant movement.
What are cutting cones in the context of Contact Healing?
Structures at the ends of each fracture where osteoclasts and osteoblasts operate
Cutting cones are essential for the remodeling process during bone healing.
What is the sequence of cells involved in the formation of lamellar bone during Contact Healing?
Osteoclasts followed by osteoblasts
Osteoclasts resorb bone, allowing osteoblasts to lay down new bone matrix.
What is the rate of bone healing in Contact Healing?
50-100 μm/day (slow)
This slow rate reflects the meticulous nature of primary bone healing.
How long is it estimated to take for Contact Healing to fully restore normal structure and mechanical properties?
Up to 18 months
This duration indicates the complexity of the healing process and the need for complete structural integrity.
What type of bone healing is Gap Healing classified as?
primary
What interfragmentary strain percentage functionally eliminates in Gap Healing?
<2%
What is the maximum gap width for effective Gap Healing?
gap width < 1 mm
What fills the gap during the initial stage of Gap Healing?
fibrin matrix and vascular sprouts
What components rapidly remodel from the initial fibrin matrix in Gap Healing?
collagen type I, type III & other bone formation components
How long does it typically take for lamellar bone to fill the gap in Gap Healing?
days to weeks
What does the early repair in Gap Healing mimic?
intramembranous ossification
What is the orientation of lamellar bone in the early stages of Gap Healing?
TRANSVERSE to long axis
How long does it take for cutting cones to cross the fracture in Gap Healing?
3-4 weeks
From where do cutting cones originate in Gap Healing?
osteons within and adjacent to fracture
How is the orientation of lamellar bone reoriented over time in Gap Healing?
longitudinally
What is secondary bone healing?
Healing process for fractures that are not anatomically reconstructed
Also known as indirect bone healing, typically occurs without surgical intervention.
What tissues are involved in secondary bone healing?
Periosteum and surrounding soft tissue envelope
These tissues are other than bone/fracture.
What is the hallmark of secondary bone healing?
Formation of CALLUS
Callus formation involves accumulation of reparative cells and extracellular matrix (ECM).
How is interfragmentary strain decreased during secondary bone healing?
Osteoclasts remove dead bone on fracture margins
This process widens the fracture gap within the first few weeks, allowing granulation tissue formation.
Where does the external callus form during secondary bone healing?
On abaxial surface of bone
The external callus provides stability to the fracture.
What is the relationship between the radial distance of callus from the fracture and stability?
The greater the radial distance of callus from fracture, the greater the stability
This is due to an increase in area moment of inertia.
How does stiffness increase in cylindrical structures during secondary bone healing?
Exponential increase in stiffness due to radius affecting stiffness to the 4th power
This principle applies to the callus structure as it forms.
List the five overlapping phases of secondary bone healing.
- Inflammation
- Intramembranous Ossification
- Soft Callus Formation (Chondrogenesis)
- Hard Callus Formation (Endochondral Ossification)
- Bone Remodeling
Each phase plays a critical role in the healing process.
Four functions of bone grafts?
- Osteogenesis
- Osteoinduction
- Osteoconduction
- Osteopromotion
- Osteogenesis: This process occurs when osteoblasts actively produce new bone matrix. Only living bone cells (present in autogenous grafts) can perform true osteogenesis.
- Osteoinduction: This is the stimulation of cells to become osteoblasts, essentially “triggering” bone formation. Bone morphogenetic proteins (BMPs) are key growth factors that can stimulate the differentiation of mesenchymal stem cells into osteoblasts.
- Osteoconduction: This refers to the ability of a bone graft material to provide a scaffold for new bone to grow upon. A porous bone graft material provides a surface for new bone cells to adhere to and grow upon.
- Osteopromotion: This term encompasses the combined effects of stimulating osteogenesis, osteoinduction, and osteoconduction to promote overall bone regeneration.
What is the gold standard for osteogenesis in bone grafts?
Osteogenesis
Fresh, Autogenous Cancellous bone graft
Considered the most effective type of bone graft for supporting bone formation.
What types of cells are contained in fresh, autogenous cancellous bone graft?
Osteogenesis
Osteoblasts lining bone to mesenchymal stem cells in marrow
This mixture is crucial for effective bone healing.
Mesenchymal stem cells can differentiate into _______.
Osteogenesis
ANY cellular component need in secondary bone healing
This versatility is essential for the healing process.
Do fresh, autogenous cancellous bone grafts revascularize more rapidly or more slowly than cortical grafts?
Osteogenesis
More rapidly
This rapid revascularization is beneficial for effective healing.
What functions do bone grafts provide?
Osteogenesis
Multiple functions of bone formation
These functions are critical for successful bone repair.
What do bone marrow grafts contain?
Osteogenesis
Mesenchymal stem cells
Bone marrow grafts are less effective than autogenous cancellous bone grafts.
True or False: Bone marrow grafts are as effective as autogenous cancellous bone grafts.
Osteogenesis
False
Autogenous cancellous bone grafts are generally more effective.
What is osteoinduction?
Osteoinduction
Capacity to induce bone formation when placed into a site where it will otherwise not occur
Osteoinduction refers to the process of promoting bone formation in areas that would not typically support it.
What type of cells does osteoinduction recruit?
Osteoinduction
Mesenchymal stem cells or differentiated cells
These cells are essential for the process of bone healing and regeneration.
What processes are induced during osteoinduction?
Osteoinduction
Proliferation and differentiation
These processes are crucial for the development of new bone tissue.
What is the best example of an osteoinductive material?
Osteoinduction
Decalcified bone matrix
This material is used in various medical applications to promote bone healing.
Name two naturally occurring initiators and mediators of bone healing.
Osteoinduction
TGF-B and BMP-2, -4, & -7
These growth factors play significant roles in bone regeneration and healing processes.
What role do eicosanoids play in bone formation?
Osteoinduction
Critical for bone formation
Eicosanoids, such as PGE2, are important signaling molecules that influence bone metabolism.
What inhibits the role of PGE2 in bone formation?
Osteoinduction
Chronic NSAID use
Nonsteroidal anti-inflammatory drugs (NSAIDs) can negatively affect bone healing by inhibiting eicosanoid synthesis.
What is osteoconduction?
Osteoconduction
Provides scaffold for mesenchymal stem cells and their progeny to migrate into and proliferate
Osteoconduction is a key property of bone grafts that facilitates healing and regeneration.
What types of structures can provide osteoconduction?
Osteoconduction
Biologic (trabecular cancellous matrix) or synthetic (porous bioceramics) 3D structure
Biologic scaffolds are derived from natural tissues, while synthetic scaffolds are engineered materials.
What are the two main functions of osteoconductive materials?
Osteoconduction
- Framework for adherence of cells
- Interconnecting porosity for cell proliferation and vascular ingrowth
These functions are critical for successful bone healing and integration.
What are the +/- functions associated with osteoconductive materials?
Osteoconduction
- +/- load bearing
- +/- absorbable
These characteristics can vary depending on the specific material used in bone grafting.
What is the primary function of osteopromotion?
Osteopromotion
Enhances bone regeneration without cells or scaffold
Osteopromotion is a technique used to improve the healing process of bone tissue.
True or False: Osteopromotion can induce bone formation.
Osteopromotion
False
Osteopromotion enhances regeneration but does not directly induce the formation of bone.
Give three examples of osteopromotion materials.
Osteopromotion
- Platelet-rich plasma
- Hydrogels
- Biphasic Calcium Phosphate
These materials are commonly used to enhance bone healing.
What percentage of the thoracic limb weight-bearing force is carried by the proximal radial articular surface at the level of the elbow?
51%
The remaining force is borne by the ulna.
What is the sole responsibility of the proximal ulnar physis?
Only olecranon elongation
This indicates that the proximal ulnar physis does not contribute to other growth.
What does the distal ulnar physis account for in terms of growth?
100% of growth distal to elbow joint of the ulna
This means that all growth below the elbow is due to the distal ulnar physis.
What percentage of growth is each of the proximal and distal radial physes responsible for?
30-50% each
This shows that both radial physes contribute significantly to the limb’s growth.
What are Type I muscle fibers also known as?
Slow-twitch
Type I muscle fibers are rich in _______.
mitochondria
What type of contraction is associated with Type I muscle fibers?
Sustained contraction of low velocity & low force
Type I muscle fibers are fueled primarily by _______.
oxidative metabolism
What are Type II muscle fibers also known as?
Fast-twitch
Type II muscle fibers are rich in _______.
myofibrils
What type of contractions are associated with Type II muscle fibers?
Transient, high-velocity & high-force contractions
Type II muscle fibers are subclassified based on capacity for _______.
oxidative metabolism
In most species, high-intensity training leads to hypertrophy of Type _______ muscle fibers.
II
What is a Type I fracture?
Open fracture with a small laceration (< 1 cm) and clean
Type I fractures are characterized by minimal soft tissue injury.
What characterizes a Type II fracture?
Open fracture with a larger laceration (> 1 cm) and mild soft-tissue trauma, with no flaps or avulsions
Type II fractures indicate more significant soft tissue involvement than Type I.
Describe a Type III (a) fracture.
Open fracture with vast soft-tissue laceration or flaps or high-energy trauma, but soft tissue is available for wound coverage
Type III (a) fractures occur in high-energy impacts.
What is a Type III (b) fracture?
Open fracture with extensive soft-tissue injury loss and bone exposure, with periosteum stripped away from bone
Type III (b) indicates severe soft tissue damage and poses high risks for complications.
What defines a Type III (c) fracture?
Open fracture with arterial supply to the distal limb damaged and arterial repair required for limb salvage
Type III (c) fractures are the most severe and require immediate vascular intervention.
What is the Salter-Harris classification system used for?
It is used for fractures involving the physis, metaphysis, and/or epiphysis.
What characterizes Type I fractures in the Salter-Harris classification?
Type I fractures are confined to the physis.
What is the main feature of Type II fractures in the Salter-Harris classification?
Type II fractures involve a portion of the physis and adjacent metaphysis.
Which type of Salter-Harris fractures is the most common?
Type II fractures are the most common types of Salter-Harris fractures.
What distinguishes Type III fractures in the Salter-Harris classification?
Type III fractures involve a portion of the physis and epiphysis.
Describe Type IV fractures in the Salter-Harris classification.
Type IV fractures involve the metaphysis, physis, and epiphysis.
What defines Type V fractures in the Salter-Harris classification?
Type V fractures are a compression fracture of the physis without obvious radiographic displacement.
What type of fracture is caused by tensile load?
transverse fracture
Tensile load leads to a fracture that occurs straight across the bone.
What type of fracture results from compressive load?
oblique fracture
Compressive load causes a fracture that occurs at an angle across the bone.
What type of fracture is associated with torsional load?
spiral fracture
Torsional load creates a fracture that spirals around the bone.
What is the result of bending load on a bone?
transverse fracture +/- butterfly fragment (especially when combined with compressive loads)
Bending can lead to a straight fracture along with possible butterfly fragments.
How many individual bones compose the complete tarsal joint?
Seven
The seven bones are crucial for the structure of the tarsal joint.
Name the bones that compose the complete tarsal joint.
- the talus (tibial tarsal bone)
- the calcaneus (fibular tarsal bone)
- the central tarsal bone
- the fourth tarsal bone
- the first tarsal bone
- the second tarsal bone
- the third tarsal bone
These bones work together to facilitate movement and stability in the foot.
How many main tarsal articulations have been identified?
Six
The main tarsal articulations are tarsocrural, talocalcaneal, talocalcaneocentral, calcaneoquartal, centrodistal, and tarsometatarsal.
Name the main tarsal articulations.
- Tarsocrural
- Talocalcaneal
- Talocalcaneocentral
- Calcaneoquartal
- Centrodistal
- Tarsometatarsal
These articulations are essential for foot movement and stability.
What are the talocalcaneocentral and calcaneoquartal collectively referred to as?
Proximal intertarsal joint
This term highlights their function and location within the tarsal structure.
The centrodistal joint is also known as the _______.
Distal intertarsal joint
This joint plays a role in the articulation of the central tarsal bone with adjacent tarsal bones.
What does the centrodistal joint articulate with?
- Central tarsal bone
- First tarsal bone
- Second tarsal bone
- Third tarsal bone
Understanding this articulation is important for studying foot mechanics.
What is the source of blood supply to the tarsus?
- Cranial tibial artery
- Plantar branch of the saphenous artery
These are the two primary vessels supplying the tarsus.
The cranial tibial artery becomes which artery at the tarsocrural joint?
Dorsal pedal artery
This artery subsequently forms the dorsal metatarsal arteries.
What areas does the dorsal pedal artery supply?
Dorsal and lateral aspects of the tarsus
It runs alongside the tendon of the long digital extensor muscle.
Which artery supplies the medial and plantar areas of the tarsus?
Plantar branch of the saphenous artery
This artery runs within the tarsal canal.
How does venous drainage occur in the tarsus?
Via the medial and lateral saphenous veins
These veins are responsible for draining the tarsal region.
Which nerve supplies innervation to the tarsus?
Branches of the sciatic nerve
Specifically, the tibial nerve and the common peroneal nerve.
What does the tibial nerve divide into near the tarsocrural joint?
Medial and lateral plantar nerves
These nerves provide innervation to the plantar aspect of the foot.
What are the branches of the common peroneal nerve?
Superficial and deep peroneal nerves
These branches innervate the dorsal aspect of the foot.
Which nerve provides cutaneous innervation to the dorsomedial part of the tarsus and metatarsus?
Saphenous nerve
This nerve is a branch of the femoral nerve.
What is the figure demonstrating?
Normal Strain
What is each figures demonstrating?
Name the labels
Stress Strain Curve
A. Stress
B. Yield point
C. Toughness
D. Strain
True or False: The osteonal structure of cortical bone in the tibia and femur is well adapted to handle the tensile axial loads required to support body weight.
False.
The osteonal structure of cortical bone in the tibia and femur is well adapted to handle the axial compressive loads required to support body weight.
True or False: The mechanical performance of long bones is highly dependent on the type of loading (e.g., tensile vs. compressive) and the orientation of the load.
True
True or False: When a load is applied to a material, it experiences internal stresses, leading to deformation (strain), and the magnitude of this deformation is directly related to the applied load and the material’s properties.
True
Fill in the Blank: Young’s modulus is a specific measure of ____.
Stiffness
Young’s modulus = σ : ε
Ratio of tensile stress (σ) to tensile strain (ε)
The Young’s modulus (E) is a property of the material that tells us how easily it can stretch and deform and is defined as the ratio of tensile stress (σ) to tensile strain (ε).
Identify the forces.
On the stress strain graphs is cortical bone line closer to stress or strain?
Stress
Described Material A and D.
Material [A] - A very strong and stiff material that is also very brittle and fails with very little plastic deformation.
Material [D] - A very compliant material with a very small elastic region.
What happens to the extracellular matrix in cartilage injury?
It degrades by MMP and aggrecanases (ADAMTs 4 and 5)
MMP stands for matrix metalloproteinases, which are enzymes that break down proteins in the extracellular matrix.
What is the chondrocyte response to cartilage injury?
Enhanced proliferation and metabolic activity (anabolic response)
Chondrocytes are the cells responsible for maintaining cartilage.
What occurs when chondrocytes are unable to keep up with cartilage repair?
Complete loss of cartilage tissue
This can lead to significant joint problems and pain.
What is the end-stage result of cartilage degradation?
Eburnation of subchondral bone
Eburnation refers to the polishing or hardening of bone under the cartilage.
What type of response occurs when chondrocytes fail to repair cartilage?
Catabolic response
This response leads to further degradation of cartilage.
What is the composition of the synovium?
A discontinuous layer of fibroblasts and macrophage-like cells
The synovium is the lining of the joint that secretes synovial fluid.
What cytokines are released by macrophages in the synovium?
IL-1B and TNF-a
These are catabolic cytokines that promote the degradative cascade in cartilage.
Can osteophytes form without cartilage damage?
Yes, at the junction between cartilage and bone
Osteophytes are bony growths that can occur in response to joint injury.
What types of nerve fibers are present in cartilage structures?
A-Beta, A-delta, C-fibers
A-beta fibers primarily mediate touch and proprioception, while A-delta and C fibers transmit pain and temperature sensations, with A-delta fibers being faster and C fibers being slower and unmyelinated.
Name the types of arthritis?
- Osteoarthritis (degenerative joint disease) MC
- Rheumatoid arthritis
- Septic arthritis
- Immune-mediated polyarthritis
What are the two main types of IMPA?
- Nonerosive (MC)
- Erosive
Non
IMPA stands for immune-mediated polyarthritis.
What kind of arthritis is Rheumatoid?
Name a subtype of Erosive IMPA.
Rheumatoid is a type of Erosive IMPA.
Which species is associated with periosteal proliferative Erosive IMPA?
Cats
This refers to a specific manifestation of Erosive IMPA.
What breed is mentioned in relation to potentially infectious Erosive IMPA?
Greyhound
Greyhounds may experience this type of IMPA, especially when young.
What drug and breed are associated with Nonerosive IMPA?
Sulfas (Dobermans)
This indicates a specific drug that can induce Nonerosive IMPA in Dobermans.
Which systemic condition is associated with Nonerosive IMPA?
Systemic lupus
This can lead to granulation or pannus in the joint.
What is Polymyositis in relation to IMPA?
A subtype of Nonerosive IMPA
Polymyositis is an inflammatory condition affecting muscle tissue.
Name two breeds associated with Nonerosive IMPA.
Akitas and Shar Pei
These breeds are noted for their association with Nonerosive forms of IMPA.
What percentage of Type 1 Nonerosive IMPA cases involve one joint?
50%
Type 1 is characterized by involvement of a single joint.
The most responsive type to Pred.
What is the percentage for Nonerosive IMPA are type 2?
25%
Reactive/infectious
Type 2 cases are linked to reactive or infectious causes.
What percentage of Nonerosive IMPA cases are type 3?
15%
Related to gastrointestinal issues?
Type 3 cases are associated with GI problems.
What percentage of Nonerosive IMPA cases are type 4?
10%
linked to cancer
Type 4 cases indicate a connection to cancer.
What treatment resulted in a complete cure for 56% of dogs with Type 4 Nonerosive IMPA?
Chemotherapeutic immunosuppression
This treatment approach has shown significant effectiveness.
What is the response rate to pred for Type I Nonerosive IMPA?
Most responded, 1/3 relapsed
This highlights the treatment response variability.
What are the most common etiologic agents in septic arthritis in dogs?
- Staphylococcus aureus
- Staphylococcus intermedius
- beta hemolytic Strep
These bacteria are typically associated with infections in dogs.
What are the most common etiologic agents in septic arthritis in cats?
- Pasteurella
- Bacteroides
These bacteria are part of the oral flora and are usually transmitted during cat fights.
Fill in the blank: The most common etiologic agent in septic arthritis in dogs is _______.
Staphylococcus aureus
True or False: Beta hemolytic Strep is a common etiologic agent in septic arthritis in cats.
False
Beta hemolytic Strep is primarily associated with dogs.
Fill in the blank: In cats, septic arthritis is commonly caused by _______ and bacteroides.
Pasteurella
What is the most abundant GAG?
Chondroitin sulfate
GAG” refers to Glycosaminoglycans, which are long, unbranched polysaccharides found in the extracellular matrix of connective tissues, playing roles in hydration, cell signaling, and structural support.
GAG types
Sulfate GAG:
* Chondroitin sulfate (Most abundant)
* Dermatan sulfate
* Heparan sulfate
* Keratan (prevalent in bone and cartilage)
Non-sulfated GA:
* Hyaluronic Acid
Bioavailability of Chondroitin and Glucosamine?
- Chondroitin = 5%
- Glucosamine = 90%
Role of Ca in muscle contraction?
Ca + binds to troponin to change its shape so that the actin filament is exposed
This process is initated by ACh. Ach binds to sarcolemma and depolarize. The Sarolemmaticulum release the Calcium.
DOES the diameter of the Collagen fibril affect the tensile strength?
Yes.
Collagen fibrils in healed ligament/tendon remain of smaller overall diameter and more uniform distribution than in the native ligament
Inferior mechanical properties
Covalent cross-linking configuration of collagen provides significant tensile strength to the healing tissues?
Yes
Tensile properties of collagen arrangement and load in longitudinal/ transversely?
- Parallel arrangement + dense packing underlie high tensile stiffness
- High stiffness and strength in longitudinal loading (tendons)
- Poor when loaded transversely
Myofibrils are?
Myofibrils are rod-like, contractile units within muscle cells, composed of repeating segments called sarcomeres, which are the fundamental units of muscle contraction.
Contractile unit
Filaments -> Myofibril -> muscle fibers -> Fascicles -> skeletal muscle
What type of muscle fibers are rich in mitochondria?
Type I: Slow-twitch fibers
Slow-twitch fibers are known for their endurance and are suitable for prolonged activities.
What characterizes Type I muscle fibers?
Rich in mitochondria, oxidative metabolism, more blood vessels, low velocity, low force, smaller fibers and nerves, red muscle from myoglobin
Type I fibers are often referred to as endurance fibers.
What type of muscle fibers are known for high-velocity and high-force contractions?
Type II: Fast-twitch fibers
Fast-twitch fibers are used for quick bursts of strength and speed.
What are the main characteristics of Type II muscle fibers?
Rich in myofibrils, transient contractions, high velocity, high force, larger fibers, less blood supply, energy by glycolytic process, fewer mitochondria
Type II fibers are primarily used in activities requiring short bursts of energy.
What is the energy source for Type II fast-twitch fibers?
Glycolytic process
This process allows for rapid energy production but is less efficient than oxidative metabolism.
True or False: Type II fibers have a greater blood supply than Type I fibers.
False
Type II fibers have less blood supply compared to Type I fibers.
Fill in the blank: Type I fibers are associated with _______ metabolism.
oxidative
Oxidative metabolism is used for sustained energy production.
What are ligaments?
Fibrous connective tissues that connect bones to other bones
Can ligaments originate and insert on the same bone?
Yes
Ex. transverse humeral ligament as it stabilizes the biceps tendon within the bicipital groove.
What is the transverse humeral ligament?
A ligament that stabilizes the biceps tendon within the bicipital groove
What are capsular ligaments?
Focal thickening of the fibrous component of the joint capsule
What is the role of collateral ligaments in the glenohumeral joint?
They provide stability to the joint
What are intra-articular ligaments?
Ligaments that cross the joint with a synovial cavity and are covered with a thin vascularized connective tissue sheath
What is the epiligament?
The thin vascularized connective tissue sheath that covers intra-articular ligaments and merges with the periosteum
