AGR 282 Lecture 6: Skeletal System

Long, short, flat, irregular, and sesamoid bones

What are the five classifications of bones?

The main trunk of the body, including the torso, skull, spinal column, and rib cage

What is the axial skeleton?

The appendages of the body, including the arms, legs, and pelvis

What is the appendicular skeleton?

The study of joints

What is arthrology?

Inflammation of the joints

What is arthritis?

By the number of articulating bones, structural classification, and functional classification

What are the three ways joints can be classified?

A joint involving two bones

What is a simple joint?

A joint involving three or more bones

What is a compound joint?

Fibrous, cartilaginous, and synovial.

What are the three structural classifications of joints?

A joint with fibrous tissue between the bones and little to no movement.

What is a fibrous joint?

No.

Do fibrous joints have a joint capsule?

They usually ossify, causing the bones to fuse together

What usually happens to fibrous joints during adulthood?

Skull sutures, the tibia/fibula, and teeth attached to the jaw socket.

What are examples of fibrous joints?

A joint connected by fibrocartilage and/or hyaline cartilage that allows slight movement

What is a cartilaginous joint?

No

Do cartilaginous joints have a joint capsule?

The epiphyseal plate in long bones, first rib with the sternum, intervertebral joints, and pubic symphysis.

What are examples of cartilaginous joints?

A freely movable joint

What is a synovial joint?

Joint cavity with synovial fluid, articular cartilage, synovial membrane, outer fibrous membrane, and ligaments

What are the five major components of a synovial joint?

It is found in the joint cavity and helps the joint move freely.

What is the function of synovial fluid?

Hyaline cartilage located where the bones meet

What is articular cartilage?

Produces synovial fluid

What does the synovial membrane do?

The outer layer surrounding and supporting the joint.

What is the outer fibrous membrane of a synovial joint?

Structures that are components of synovial joints and help support the joint.

What are ligaments?

Fibrocartilage structures that partially divide the synovial cavity.

What are menisci?

The knee, wrist, sternum/clavicle joint, and temporal/mandible joint.

Where are menisci found?

Decreasing the angle between two bones, bringing them closer together

What is flexion?

Increasing the angle between two bones, straightening the joint

What is extension?

A twisting movement around a fixed axis

What is rotation?

Movement away from the body's midline.

What is abduction?

Movement toward the body's midline

What is adduction?

Circular movement of a body part where the distal end draws a circle

What is circumduction?

All types of movement

What movements can a ball-and-socket joint perform?

Hip and shoulder joints.

What are examples of ball-and-socket joints?

A joint capable of pretty much all movements but with reduced rotation

What is a saddle joint?

The carpal/metacarpal joint of the thumb

What is an example of a saddle joint?

A joint that allows all movements except rotation.

What is an ellipsoidal joint?

Radius/carpal and metacarpal/phalange joints

What are examples of ellipsoidal joints?

All movements except circumduction

What movements does a plane joint allow?

Intercarpal and intertarsal joints

What are examples of plane joints?

Flexion and extension only

What movement does a hinge joint allow?

Knee/stifle and elbow joints

What are examples of hinge joints?

Rotation only.

What movement does a pivot joint allow?

The radius/ulna joint.

What is an example of a pivot joint?

A joint with limited or no movement; it is also called a fibrous joint

What is a synarthrotic joint?

Skull sutures

What is an example of a synarthrotic joint?

A joint that allows slight movement; also called a cartilaginous joint.

What is an amphiarthrotic joint?

Intervertebral joints

What is an example of an amphiarthrotic joint?

A joint that allows considerable movement and can have 1-, 2-, or 3-dimensional movement

What is a diarthrotic joint?

Synovial joint.

What is another name for a diarthrotic joint?

Mandible, maxilla, incisive, and nasal bones.

What are some major facial bones?

Frontal, parietal, temporal, and occipital bones

What are some major skull bones?

C1-C7

What are the cervical vertebrae?

Atlas

What is C1 called?

Axis

What is C2 called?

Incisive, nasal, mandible, frontal, parietal, occipital, maxilla, temporal, atlas (C1), axis (C2), and C3-C7

What are the major head and neck bones shown in the lecture?

Chewing

What is the function of the masseter?

Sucks in the cheeks

What does the buccinator do?

Shows the teeth

What does the levator labii do?

Pulls the forelimb forward and flexes the neck

What does the brachiocephalicus do?

Thoracic vertebrae, scapula, sternum, and costal bones.

What are the major skeletal structures of the thorax?

13

How many thoracic vertebrae do cows, dogs, and cats have?

14-15

How many thoracic vertebrae do pigs have?

18

How many thoracic vertebrae do horses have?

Elevates the shoulder

What does the trapezius muscle do?

Assist with breathing

What do the intercostal muscles do?

Adduct the limbs

What do the pectoral muscles do?

Assists with breathing

What does the diaphragm do?

Humerus, radius, ulna, carpals, metacarpals, and phalanges

What are the major bones of the forelimb?

Retracts the forelimbs

What does the latissimus dorsi do?

Extends the elbow

What does the triceps brachii do?

Flexes the elbow.

What does the biceps brachii do?

Extends the carpus

What does the extensor carpi radialis do?

Lumbar vertebrae and pelvis

What are the major skeletal structures of the abdomen and pelvis?

L1-L6/7, depending on species

What is the vertebral range for the lumbar vertebrae?

Ilium, ischium, and pubis

What three major bones make up the pelvis?

Extends the hip and moves the hindlimbs backward.

What does the gluteus medius do?

Moves the tail

What does the coccygeus muscle do?

Assists with breathing

What does the external abdominal oblique do?

Acts in the abdominal press

What does the rectus abdominis do?

Femur, patella, tibia, fibula, tarsals, metatarsals, and phalanges

What are the major bones of the hind limb?

Extends the stifle

What does the quadriceps femoris do?

Flexes the stifle.

What does the biceps femoris do?

Extends the hock

What does the gastrocnemius do?

Flexes the hock

What does the tibialis cranialis do?