ForeLimb

Question 1

What is locomotor system and what are the components

Answer 1

The musculoskeletal system that allows wide range of animal movement.
components:
1. Osteology (BONES)
2. Arthrology (joints)
3. Myology (muscles)

Question 2

What are adaptations of locomotor system in cursors?

Answer 2

ALL TO INC STRIDE LENGTH
1. reduced pectoral skeleton: not full pectoral girdle of clavicle, scapula and coracoid.
domestic species = no collar bone (clavicle) cats do have but it is vestigial.
2. Elongation of proximal end of limb - scapula lies laterally rather than at back
3. elongation at distal end of limb to inc stride length = energy efficient

Question 3

What are the 4 forms of locomotion

Answer 3

1. flexion - folding
2. extension - stretching
3. protraction - moving limb forward
4. Retraction - moving limbs backwards

Question 4

What are 2 types of skeleton

Answer 4

1. Axial skeleton: bones of vertebral column, skull and ribcage
2. Appendicular skeleton: all bones of fore and hind limb

Question 5

What are the types of bone:

Answer 5

1. Long- support and leverage in limbs. Medullary cavity
2. Flat- large SA 4 muscle attachment, protection of underlying structures
3. Short - large range of movement, anticoncussive and shock absorption
4. Seasmoid - embedded in tendons, change in angle over bony surface, redirect forces and reduces friction to prevent damage

Question 6

Bone features:

Answer 6

1. proximal - top
2. body
3. distal - bottom
   allow passage of structures/ tendons
4. articular surfaces - where skeletal surface makes direct contact with another = hayline cartilage at weight bearing surfaces = don’t want nerve/ blood supply to be crushed. C = deprived of nerve and blood supply

Question 7

4. Describe how bones of the limb are formed from centres of ossification and explain the bone growth

Answer 7

a. Develop from cartilaginous template = mesenchyme tissue which forms the shape of the entire bone
b. Ossifies due to blood supply from centre in fetal life = replaced by bony matrix rather than cartilaginous matrix
c. Osteoblasts inc in number into cartilaginous template, than calsify to harden strucutre
d. Primary ossification centre elongates
e. One point extremities ossify separately (secondary ossification)
f. Cartilaginous matrix between extremities = growth plates = between centres of ossification

Question 8

5. Recognise the growth plates on a radiograph and distinguish between the radiograph of a young and mature animal

Answer 8

a. Soft tissue structure = dark = radiolucent
b. Bone = opaque = white = ability to divert Xray as hard structure
c. Hollow centre = medullary cavity
d. Epiphysis = end
e. Metaphysis = transition zone
YOUNG: growth plates produce inc in bone length as ossify and close
MATURE= closed = physeal scars

Question 9

Bones of forelimb:

Answer 9

1. scapula
2. Humerus
3. Radius (cranial)
4. Ulna (caudal)
5. Carpal bones
6. Metacarpal bones
7. Phalanges

Question 10

Regions of the forelimb

Answer 10

1. OMO = shoulder joint = scapula
2. Brachium = shoulder joint to elbow joint (arm) = humerus = elbow joint
3. antebrachium = elbow joint to carpal = forelimb = radius and ulna
4. Carpus = wrist = carpal bones (carpal joint)
5. Manus = hand = carpal bone to digits = metacapal bones and inter phalanges joint
6. Digits = toes

Question 11

Explain the basic structures and function of the nervous system supplying the forelimb

Answer 11

CNS - brain and spinal cord (vertebral column)
Vertebral formula: C7, T13, L7, S3, Cd20.
Between 2 adjacent vertebrae = intervertebral foramen = wheere spinal nerves origionate form. they divide into dorsal branch (innovates dorsal musculature) ventral innovate C6, C7, C8, T1, T2. These form the brachial plexus
PNS - Cranial nerves (connect with structures of the head and body) and spinal nerves (connect spinal cord to neck, trunk, tail and limbs)

Question 12

Which 5 nerves form the brachial plaxus?

Answer 12

C6, C7, C8, T1, T2

Question 13

what nerves does the PNS contain

Answer 13

axons that conduct impulses TO the CNS: Sensory, afferent axons = carry impulses from structure to brain and
axons conduct impulses FROM CNS motor, Efferent = carry impulses from brain to muscle or organ: motor neurones

Question 14

what does the brachial plexus supply?

Answer 14

all intrinsic muscles (muscles in appendicular skeleton) , some extrinsic (Lat dorsi (refractor), pectoral (Adductor), serratus ventralis (protractor and retractor)

Question 15

What is a somatic efferent neurone?

What is visceral efferent neurones?

Answer 15

motor neurones supplying voluntary, striated, skeletal muscles.
VEN- motor neurones supplying involuntary, smooth muscle of viscera, blood vessels, cardiac muscle and glands

Question 16

what are 3 types of joint

Answer 16

1. Fibrous= little movement (skull)
2. cartilagenous (little movement)
3. Synovial - allows large range of movement between bones

Question 17

Elucidate the components of a TYPICAL SYNOVIAL JOINT

Answer 17

1. Hyaline cartilage covers articular surface to reduce friction. Avascuar and no nerve endings
2. Synovial fluid in joint cavity = viscous/ sticky, nourishes cartilage, lubricates
3. Synovial membrane contains the fluid also produces the synovial fluid.
4. Joint capsule: fibrous layer, incorporates synovial membrane. Attaches around osteochondral junction (interface between bone and cartilage)

Question 18

describe any bursae or synovial sheaths that are related to specific joints.

Answer 18

• ****(ligaments condensed fibrous material)

1. collateral ligaments support the joint medial and laterally

Question 19

Describe various movements of SHOULDER JOINT.

Answer 19

1. Flexion: decreased angle, folded limb, non weight bearing position.
2. Extension: inc angle, stretching limb, weight bearing

Question 20

Describe various support of SHOULDER JOINT.

Answer 20

Bicipital bursa

Question 21

what is the bicipital bursa?

Answer 21

Bicipital bursa - tendon sheath. A joint capsule that extends into the inter tubercular groove between the greater and lesser tubercles. Transverse ligament holds tendon of bicep brachii in place in intertubercle groove

Question 22

Identify EXTENSORS muscle groups involved in shoulder joint movements along their origins, insertion and innervation.

Answer 22

1. Brachiocephalicus = protractor of limb, extensor of shoulder.
Cross cranial to shoulder
Innovation = brachial plexus
2. Biceps brachii (1 head in dog).
Crosses cranially
O = supraglenoid tubercle
I= ulna and radial tuberosities
Intrinsic muscle
Also elbow flexor/ shoulder extensor
Innovation = musculocutaneous nerve (motor nerve only).
Bicipital bursa

Question 23

Identify FLEXORS muscle groups involved in shoulder joint movements along their origins, insertion and innervation.

Answer 23

Latissimus dorsi: cross caudal to shoulder
Also limb retraction, Innovation = brachial plexus
2. Teres major
O = caudal border of scapula
I = medial humerus
Innovation = axillary nerve, motor adn sensory fibres
3. Teres Minor
O = infraglenoid tubercle
I = lateral aspect of humerus
4. Deltoideus:
2 heads
O = scapular spine
O = acromion process
I = lateral aspect of humerus
Innovation = axillary, mixed type of nerve = motor adn sensory fibres.
5. Tricep muscle, caudal aspect of brachial region
4 heads
long head = only flexor of shoudler
O = caudal border of scapla
I = olecranon of ulna
(also elbow extensor)
Innovation = radial nerve adn motor adn sensory fibres

Question 24

what are the antagonistic muscle pairs in the shoulder joint
E = 2
Flexors = 4

Answer 24

Extensor = cranial to shoulder: brachiocephalicus and biceps brachii
Flexors = caudal to shoulder = latissimus dorsi, deltoideous, teres major and tricep long head

Question 25

Whats clinical issues can arise at the shoulder joint?

Answer 25

1. Osteochondrosis: - developmental disease - causes erosion of articular cartilage = stem exposed to underlying structures (which have nerves). - can lead to degenerative joint disease (DJD) - additional bone formation - pain causes lameness 2. Degenerative joint disease (DJD) - new bone formation around joint capsule attachment. - Osteochondral junction - painful when forming = persistent lameness 3. conditions related to soft tissue structures e.g. tendons = bicipital bursitis = inflammation of bursa - ultrasound to identify soft tissue damage

Question 26

What is a osteochondral junction

Answer 26

interface between bone and cartilage

Question 27

what is the palpation landmark of the shoulder joint?

Answer 27

1. Acromion and greater tubercle

Question 28

what are the palpation landmarks of the radius and ulna?

Answer 28

``` Ulna: 1. olecranon process 2. Lateral styloid process Radius: 1. Medial Styloid process ```

Question 29

Discuss stability of elbow joint

Answer 29

1. strong collateral ligaments that extend from humerus to R adn U 2. discuss bony structures on U that limits extension ability of joint hence bringing stability

Question 30

what are the elbow joint antagonistic paris

Answer 30

``` 1. Extensors = caudal to joint = 4 tricep heads I= olecranon process of ulna n = radial nerve FLEXORS = cranial to joint a. biceps brachii Brachialis I = radius n = musculocutaneous nerve ```

Question 31

What are the bones called in the carpus region?

Answer 31

1. proximal row = radial/ intermediate carpal bone, ulnar carpal bone, accessory carpal bone 2. Distal row = 1st, 2nd, 3rd, 4th carpal = labelled from medial aspect