Anatomy Lecture 1 Flashcards
What are the bones of the Thoracic Limb?
- Scapula
- Humerus
- Radius
- Ulna
- Intermediate Carpus
- Ulnar Carpal
- Accessory Carpal
- Carpal Bones I, II, III, and IV
- Metacarpal Bones I, II, III, IV, and V
- Phalanges (proximal, middle and distal)
What are the extrinsic muscles of the Thoracic limb? (8)
- Superficial Pectoral
- Deep Pectoral
- Brachiocephalicus (Cleidobrachialis and Cleidocephalicus)
- Omotransversarius
- Trapezius
- Rhomboideus
- Latissimus Dorsi
- Serratus Ventralis
What is included in the Axial Skeleton?
bones of the axis of the body: skull, thorax, vertebral column
What is included in the Appendicular Skeleton?
bones of the appendages (limbs)
What are the shapes of bones? (5)
- Long
- Short
- Flat
- Irregular
- Sesamoid
What makes a bone a long bone? (what are the required characteristics?)
The length of the bone must be greater than its diameter
What is the Diaphysis?
the long, straight main body of a long bone.
- location of primary ossification
What is the Epiphysis?
End regions of long bones
- Location of secondary ossification
What is the Metaphysis?
region of bone lying between the epiphysis and diaphysis
Where is the Metaphyseal growth plate and what is it made of?
located between the epiphysis and diaphysis in young animals. Comprised of cartilage cells
What is a short bone?
a bone that has approximately equal dimensions (cube-shaped)
- Only one center of ossification and no growth plates
What is a flat bone?
bones that are centrally compressed which are present either when extensive protection or large muscle attachment is necessary.
What is an irregular bone?
bones that cannot be classified under any of the other categories.
- formed by both endochondral ossification (body of bone) and intramembranous ossification (bony processes)
What is a sesamoid bone?
a small, seed-like bone that is embedded in muscle tendons
What do sesamoid bones do?
- eliminated tendon shear
- redirects lines of force
- increases torque
What is the Periosteum?
lines the outer surface of the bone.
- source of osteoblast progenitor cells (healing fractures)
- rich in nerves -> very sensitive
- blood supply
What is the Endosteum?
Lines the inner surface of bone.
What is the Medullary Cavity?
Where bone marrow is stored.
How are most bones formed?
Endochondrial ossification which is the ossification of a cartilage model
What is Intramembranous Ossification?
when mesenchymal cells become osteoblasts directly rather than becoming chondroblasts
What bones form by intramembranous ossification?
Flat bones including bones of the calvaria (top of skull) and face.
What is Chondrodystrophy?
Cartilage Maldevelopment. A genetic condition that affects secondary centers of ossification, resulting in arrested growth of long bones.
DISPROPORTIONATE DWARVES!
Where do nutritional vessels enter the bone?
through the Diaphysis and epiphysis with the majority of long bones having a single nutrient foramen entering mid-diaphysis.
How does the cortical bone get supplied with blood?
Vessels in the periosteum supply it
What is Wolff’s Law?
Normal bone remodels in response to stress placed upon it.
- If load in a particular area increases, the bone will remodel to become stronger to resist those forces.
What are the three types of muscle?
- Smooth (Involuntary)
- Cardiac (Involuntary)
- Skeletal (Voluntary)
What is the Epimysium?
the outermost connective tissue envelope surrounding the muscle belly
What is the Perimysium?
extends from the epimysium into the muscle and divides the muscle into smaller units
What are muscle fascicles?
the smaller units of muscle that has been divided up by the perimysium
What is the Endomysium?
extends from the perimysium to envelop individual muscle fibers (Cells)
Epimysium, Perimysium and Endomysium are all types of what?
Connective Tissue
What is the constituent material of muscle tendons that are attached to the bone?
the same connective tissue seen in the Epimysium, Perimysium and Endomysium.
What is the Tendon of origin?
usually the more proximal and/or fixed point of muscle attachment
What is an Aponeurosis?
A sheet-like tendon that allows muscles to have a broader attachment
What are structures that ease the effect of excessive pressure or friction associated with tendons?
- Sesamoid Bones
- Synovial Subtendinous Bursa
- Synovial Sheath
What is a Synovial Subtendinous Bursa?
A synovial fluid-filled bag positioned between a tendon and a bony process
What is a Synovial Sheath?
A synovial fluid-filled bag that wraps around a tendon
What do Tendons attach?
attach muscle to bone
What do Ligaments attach?
attach bone to bone
What is the tendon of insertion?
the more distal, peripheral or movable point of muscle attachment
How are fibers in a strap-like muscle arranged? Why?
The fibers run parallel to the long axis
- greater displacement
How are fibers in a spindle shaped muscle arranged?
the fibers are fusiform
What are three types of fiber arrangements that join the tendons at an angle?
- pennate
- bipennate
- multipennate
Why do more muscle fibers mean that the muscle is more powerful?
it has a greater cross sectional area
How do fibers end?
they form flat layers ending in broad tendinous sheets (Aponeuroses)
What are some muscle arrangements?
- Muscles arise by two, three or four heads that merge into one tendon of insertion
- Two or more fleshy units are separated by an intermediate tendon forming digastric (two bellies) or polygastric units
- Muscle fibers are arranged into rings that surround natural openings such as the eye, mouth, or anus.
What do Fascia/ Fascial planes do?
they allow the muscles to function as units.
What is superficial fascia?
loose connective tissue
What is deep fascia?
dense collagenous connective tissue from which some muscles may originate or insert; attached to bone.
What does deep fascia do?
surrounds and compartmentalized muscles; distinct fascial septa separate groups of muscles from one another and result in fascial planes
What are two types of contraction?
- Isometric
- Normal
What is Isometric contraction?
contraction/tension with no change in length
What is Normal contraction?
isotonic; involves changes in the angle of the joint(s)/bones by that specific muscle
What is an Agonist or Prime Mover?
any muscle that produces the specified effort
What is an Antagonist?
any muscle capable of actively opposing the specified movement of the agonist
What is a Synergist?
a muscle that acts in unison with another muscle
What is a Fixator?
muscles that are used to stabilize a joint rather than promote its movement
What is the origin of the Biceps Brachii Muscle?
the supraglenoid tuberosity of the scapula
What is the insertion of the Biceps Brachii Muscle?
The tuberosities of the radius and ulna
What is the function of the Biceps Brachii Muscle?
To flex the elbow joint and extend the shoulder joint
What is a joint?
The point of contact, or articulation, between two or more bones/cartilages
What do joints do? (Function)
Provide support and movement to the skeleton
- Not all joints are movable however
What is the the functional classification of joints?
Physiological classification based on the amount of movement permitted
What is the structural classification of joints?
Anatomical classification based on structure which is based on the type of connective tissue present between the bones
What are the three types of functional joints?
- Synarthroses
- Amphiarthroses
- Diarthroses
What are Synarthroses Joints?
Immovable joints
- Includes: synostosis
What are Amphiarthroses Joints?
Semimoveable joints
-Includes: suture, syndesmosis, synchondrosis
What are Diarthroses Joints?
Freely moveable joints
- Includes: synovial joints
What are the three types of Structural joints?
- Fibrous
- Cartilaginous
- Synovial
What are Fibrous joints?
Strong fibrous connective tissue (dense irregular) between articulating bones = little to no movement
What is a Synostosis?
A type of Fibrous joint in which the bones fuse resulting in a bony joint.
What is a Cartilaginous joint?
Cartilage, either hyaline or fibrocartilage, between articulating bones = limited movement
What is a Synovial joint?
Joint cavity between articulating bones lined with synovial membrane = free movement
What are the types of fibrous joints?
- Suture
- Gomphosis
- Syndesmosis
What is a Suture?
the seams (interdigitations) of the bones of the skull that are gradually eliminated via ossification (results in synostosis)
What is a Gomphosis?
Tooth in an alveolus, united by peridontal ligament.
- not technically a joint by classic definition because teeth are technically not considered bones
What is a Syndesmosis?
Bones joined by ligaments (eg: radius and ulna, tibia and fibula)
- Interosseous ligaments
What is the connecting medium of Fibrous Joints?
dense irregular connective tissue
What are the types of Cartilaginous Joints?
- Synchondrosis
- Symphysis
What is a Symphysis?
Occurs in the midline of the body where articulating bones are connected via a flat disc of fibrocartilage
What is a Synchondrosis?
Hyaline cartilage union
What is the connecting medium of cartilaginous joints
Hyaline or fibrocartilage
What are Synovial Joints?
freely movable joints (diarthrotic) in which the articulating bone surfaces are enclosed within a fluid-filled cavity.
- Joint capsule is multilayered and may have multiple compartments
What are diarthrotic joints?
freely movable joints
What are the bony articulating surfaces of Synovial joints covered with?
by an articular (hyaline) cartilage
What is the structure of a Synovial Joint?
it consists of an outer fibrous layer and an inner synovial membrane. The fibrous layer may blend with the periosteum and is thickened in some joints to form ligaments
What is the sturcture of the inner synovial membrane?
it is highly vascularized, has nerves, and the synoviocytes (cells) produce synovial fluid for lubrication and nutrition of the bone surfaces
What are the accessory structures of the synovial joint?
- Meniscus/Menisci
- Ligaments
- Fat pads
What are the Menisci of the synovial joints?
- fibrocartilage located within the synovial cavity
Where are the ligaments of the synovial joints?
Extracapsular ligaments located outside of the joint capsule and Intracapsular ligaments that occur within the joint capsule but are excluded from the synovial cavity by folds of the synovial membrane
Where are the fat pads of the synovial joints?
between fibrous and synovial layers, may protrude into the joint cavity
What is a simple joint?
a joint formed by two bones
What is a compound joint?
a joint formed by more than two bones
What is a congruent joint?
a joint with two articular surfaces that fit each other
What is an incongruent joint?
a joint with two articular surfaces that do not fit each other
What is a hinge joint?
a joint that permits angular motion in one plane eg: humeroradioulnar (elbow), metacarpophalangeal (fetlock) joints
What is a spheroidal joint?
A joint that permits rotation and other movements
- Ball and socket
eg: glenohumeral (shoulder), coxofemoral (hip) joints
What is a Plane joint?
a joint that permits angular motion in one plane eg: carpal, tarsal joints, vertebrae
What is a condylar joint?
a joint formed by two condyles of one bone fitting into concavities of another bone eg: femorotibial (stifle) joint
What is a Pivot joint?
a joint that permits rotation around the longitudinal axis of a bone eg: atlantoaxial, radioulnar joints
What is a Ellipsoidal joint?
A joint with an oval surface that nestles within a depression in the opposing surface eg: temporomandibular, antebrachiocarpal joints
What is a Saddle joint
A joint with the articular surface of the two bones concave in one direction and convex in the other direction. eg: distal interphalangeal joint
What is the gliding/translational motion of the synovial joint? What are some joints that do this?
two surfaces that slide past each other
eg: carpus and tarsus
What is Flexion?
decreasing angle between bones
What is Extension?
increasing angle between bones
What is Hyperextension?
increasing angle past anatomical position
What is Abduction?
moving away from the medial plane
What is Adduction?
Moving towards the medial plane
What is Circumduction?
movement circumscribing a cone shape
What is pronation of the forearm?
the palmar surface is rotated to touch the ground
What is supination of the forearm?
the palmar surface is rotated to face medially (only in carnivores)
What is the purpose of intra-articular injections?
- anesthetics for lameness evaluations
- treatment for osteoarthritis (corticosteroids, glycosaminoglycans
