Intro to musculoskeletal system

Page 1

Intro to musculoskeletal system

Locomotor system

System that allows movement

Components

Bones - Osteology

Act as rigid structure

Joints - Anthrology

Allows movement between bones

Muscles - Myology

Produces movement between bones

Interaction between limbs and trunks

Flexion

Protraction

Extension

Retraction

Results in forward movement of animal

Gait- sequence of limb movements

Walk

4 beat gait

Trot

2 beat gait

Canter

3 beat gait

Gallop

4 beat gait

Contribution from trunk depends on species

Linked to diet

Herbivores with roughage diets and bulky abdomen viscera

Less flexible trunks

Rely on limbs elongation

Horse

Relatively rigid vertebral column

Most of propulsion results from limbs

Flexed suspension phase

Cats

Consume small vol of meat

Flexible vertebral column allowing limbs to swing more

Acts like bow to increase propulsion from limbs

Flexed and extended suspension phases

Suspension phase is where not touching ground

Skeleton

Domestic species

Vertebrates

Internal skeleton

Axial skeleton

Appendicular skeleton

Bones classified into 4 diff types

Flat

Scapula

Pelvis

Large SA for muscle attachment

Protect underlying organs

Long

Humerus

Femur

Support and leverage in limbs

Short

Carpus

Tarsus

Function in group

Large range of movement

Anti concussive

Sesamoid bones

Knee cap

Embedded in tendons

Change in angle over bony surface

Redirect forces

Reduce friction so prevent damage

Bone general features

Smooth surface areas

Passage of structures/ tendons

Articular surfaces

Hyaline cartilage at weight bearing surfaces

Resistant to deformation

No blood vessels and no nerves

Specific bony contours

Tuberosites/Tubers/Tubercles/Processes

Provide site for attachmet of important structures

Rough surface areas

General muscle attachment

Periosteum

Covers outer surface of bone

Contains blood and nerves

Important for fracture healing

Enters medullary cavity via nutrient foramen

Endosteum

RadiographsDiaphysis - Shaft

Medullary cavity -Hollow centre

Metaphysis - Transition zone

Epiphysics - end

Incorporated articular surfaces

Can be described as proximal or distal

Bone growth

Formed from centres of ossification

Short and sesamoid bones

usually one centre per bone

Flat and long bone

Usually more than one per bone

Attachments sites for important structures may have separate centre

Cartilage between centres appears black on radiographs

Young animals

Open physes/growth plates

Produce increase in bone length

Weakest place for damage/separation

Can cause premature closure of all or part of growth plate

Subsequent problems depend on timing /location

Mature animal

Closed growth plates =physeal scars

Weakest point for fractures

Time closure depends on contribution of specific physics to limb length

Can estimate age from growth plate closure times

Limb directional terminology

Proximal - Top

Distal- Bottom

Medial- towards median plane

Lateral- away from median plane

Cranial- towards animals head, becomes dorsal below carpus/tarsus

Caudal- towards animals tail, becomes palmar below carpus and plantar below tarsus

Skeletal muscle

Individual muscle fibres

Arranged in parallel lines

Collected into bundles

Covered by fibrous tissue

Deep fascia

Attached to rigid structures

Origin

Insertion

Classification

See slide 19

Attachments

Directly to bone

Size of area depends on muscle

Rough surface

Bony tubur

Via tendons

Condensation of deep fascia into cords

Less bulky across joints

Small area of attachment

May have separate centre of ossification

Via aponeurosis

Limited access to bone

Fibrous tissue arranged as a thin sheet of tissue

Condensation of deep fascia into sheets

Long area of attachment

Muscles in area with limited?

Skeletal muscle attachment

Cervico-thoraco-lumbar fascia

Superficial fascia

Subcutaneous

Loose connective tissue

Fat

Muscle action

Belly contracts and shortens muscle

Pulls points of attachment closer together

Pivot at joint

Decrease angle - flexion

Increase angle - extension

Action depends on

Which joints crossed

Aspect of joints crossed

Antagonistic pairs of muscles

Classification

Intrinsic

Origin and insertion with appendicular skeleton

Movement of limb joints

Flexion and extension

Extrinsic

Origin on axial skeleton

Insertion in appendicular skeleton

Movement of limb relative to trunk

Protraction and retraction of limb

In domestic animals no joint is present between forelimb and trunk

Muscular attachments only

Scapular glide over thorax pivotal point midway down scapula

Page 2

NSF of shoulder and brachial regions

Forelimb

Regions

Omo (shoulder)

Brachium (arm)

From shoulder to elbow

Antebrachium (forearm)

Region from elbow to carpus

Carpus (wrist)

Manus (hand)

Region distal to carpus

Digit (toe)

Bones

Scapula

Plus clavicle in cats

Humerus

Ulna

Radius

Carpal bones

Metacarpal bones

Phalanges

Joints

Shoulder

Elbow

Carpal/Intercarpal

M????? slide 3

Scapula

Flat bone

Body

Neck

Glenoid cavity

Spine

Supraspinous fossa (cranial)

Infraspinous fossa (caudal)

Acromion process

See slide 4

Glenoid cavity

Articular surface

Concave

Smooth surface

Supre

Slide 5

Medial / costal surface

Serrated

Rough bone

Attachment of

Serratus ventralis muscle

Subscapularis muscle

Slide 6

Scapula in cats

More rounded cranial angle than dogs

Suprahamate process

proximal to acromion process

Development of scapula

Centres of ossification

Body

Supreglenoid tubercule

Potential problems

Tendon of origin of biceps brachia muscle

Physis weak point so prone to avulsion fractures

Palpation

Dorsal border

Cranial

Caudal

Cranial angle

Spine

Acromion

Caudal border beneath muscle so not palpable

Extrinsic muscles

Brachiocephalic muscle

Cephalic- head

Brachium - arm

Origin - cervicothoracic fascia

Insertion - humerus

Function - protractor

3 parts

Cleidocervicalis

Cleidomastoideus

Cleidobrachialis

Dog

Clavicular insertion

Fibrous band

Cat

Clavicle

Bony remnant

Visible on radiographs

Cranial to shoulder

Latissimus dorsi

Latus - broad

Dorsi - back

Origin - thoracolumbar fascia

Retractor

Propulsion

Serratus ventralis

Origins

Thoracic wall

Cervical vertebrae

Insertion

Proximal scapula

Proximal to pivot point

Locates between forelimb and trunk

Function

Cranially - Retractor

Caudally - Retractor

Abductors -

Move limb away from midline

Muscles located proximal to PP and limb

Adductors

Moves limb towards midline

Located distal to PP and medial to limb

Limited movement

Trapezius

Origin - cervicothoracic fascia

Insertion - proximal to scapula spine

2 parts , cranial and caudal

No effect on shoulder

Rhomboideus muscle

Lies deep to trapezius

Origin?? slide 15

Pectoral muscles

Origin - sternum

Insertion - humerus

Deep and superficial groups

Adductor of limb

Recap slide 17

???

Humerus

Type of long bone

S shaped

Head

Articular surface

Convex

Smooth surface

Articulates with glenoid cavity of scapula at shoulder joint

Greater tubercle

Lesser tubercle

Intertubercular groove

Smooth bone surface

Condyle

Medial half larger than lateral

Medial epicondyle

Lateral epicondyle

Articular surface at dorsal end divided into 2

Throchlea

Capitulum

Olecranon / Ulna fossa

Radial fossa

Supratrochlear foramen

slide 25?

Cats don't have supratrochlear foramen

Supracondyloid foramen

Centres of ossification

Proximal epiphyses

Body

Chondyle

Medial epicondyle

Medial half of chondyle

Lateral half of condyle

Palpation landmarks

Slide 27?

Clinical considerations

Trauma

Supr??? 28

Intrinsic muscles

Both origin and insertion within appendicular skeleton

No effect on lib relative to trunk

Move joints within limb

Flexion

Extension

Page 3

Movements and support of shoulder joint

Nervous system

CNS

Brain

Spinal cord

PNS

Cranial nerves

Spinal nerves

Somites in embryo

Blocks of muscle tissue

Develops in pair alongside spinal cord

Group combines to form each forelimb

Drag nerves

Nerve supply therefore reflects origin

Spinal nerves

Leave spinal cord

Intervertebral foramen

Paired left and right

Branches

Dorsal branches supply dorsal structures

Ventral branches of these nerves from brachial plexus, located in axillary region

Emerging nerves supply forelimb

Nerves we need to know

Musculocutaneous nerve

Axillary nerve

Radial nerve

Median nerve

Ulnar nerves

Afferent supply

Efferent supply

Mixed nerves

Brachial plexus

Supplies some extrinsic muscles

Latissimus dorsi

Serratus ventralis

Pectorals

Supplies all intrinsic muscles

Joints

Fibrous

Little movement

Skull structures

Cartilagenous

Little movement

epiphysis/diaphysis in young animals

pelvic /mandibular

Synovial

Allows large range of motion between bones

Most limb joints

Typical features

Hyaline cartilage covers articular surfaces

Reduces friction

Flexible

Avascular

No nerve endings

Synovial fluid

Viscous

Nourishes cartilage

Lubricates

Synovial membrane

Produces synovial fluid

Physical barrier to contain fluid

Joint capsule

Fibrous layer

Incorporates synovial membrane

Attaches round osteochondral junction

Ligaments

Fibrous material condenses to form ligaments

Dense fibrous connective tissue

Run from bone to bone

Collateral ligaments support joint (medial and lateral)

Joint movement

Flexion

Decreased angle

Folded limb

Non weight bearing position

Extension

Increased angle

Stretching limb

Associated with weight bearing

Shoulder joints

Components

Scapula

Humerus

Palpable landmarks

Acromion process

Greater tubercle

All synovial joint features except poorly developed collateral ligaments lateral aspect.

Bicipital bursa

Joint capsule extends into inter tubercular groove

Wraps around tend of origin of biceps brachii

Held in place by transverse ligament

Lateral support

Supraspinatus muscle

Infraspinatus muscle

Suprascapular nerve

Medial support

Subscapularis muscle

Extensors

Cross cranial to shoulder. joint

Brachiocephalicus

Extrinsic muscle

Nerve supply not from brachial plexus

Biceps brachii muscle

Intrinsic

Supplied by musculocutaneous nerve

Bicipital bursa

??18

Flexors

Cross caudal to shoulder joint

Extrinsic

Supplied by brachial plexus

Deltoideus muscle

2 heads

??? 20

Teres Major

Teres Minor ?? 21

Triceps

4 heads

?

Nerve supply is radial nerve

Only long head for shoulder

Clinical considerations

Osteochondrosis

Developmental disease

Erosion of articular cartilage

Subchondral bone may be affected

Visible on radiograph

Characteristic location

Pain causes lameness

Leads to degeneration joint disease - arthritis

New bone formation

Around joint capsule attachment

Osteochondral junction

Characteristic locations on radiographs

Painful while forming

Persistent lameness if affects movement of joint

Soft tissue conditions

Bicipital burtisis

Ultrasound for diagnosis

Page 4

Antebrachial Region

Radius and Ulna

Paired and crosses each other obliquely

Long bones

Radius

Shorter

Main weight bearing

Ulna

Longer

Leverage

Radius

Head

Fovea capitis

Articular surface

Neck

Body

Trochlea

Articular surface

Styloid process

Medial

Attachment medial collateral ligament of carpus

Ulnar notch

Note transverse section

Ulna

Olecranon process

Anconeal process

Beak shaped

Fits into ulnar fossa of humerus

Trochlear notch

Articular surface

slide 6

slide 7

Evolution

Toes rotated cranially

Elbows rotated caudally

Radius and Ulna therefore rotate around each other

Proximal

Ulna most medial protection

Distal

Ulna most lateral projection

Cat

Square olecranon

Radius and Ulna similar diameter

Palpation

Ulna

Olecranon process

Lateral styloid process

Radius

Medial stolid process

Development

Radius

Proximal epiphyses

Body

Distal epiphyses

Ulna

Olecranon process

Anconeal preocess

Body

Distal epiphyses

Clinical considerations

Fractures

Radius bears most weight

Requires fixation

Ulna not as important

Primary bone tutors

Predilection sites

Proximal humerus

Distal radius

Distal ulna

Elbow joint

Humerus

Trochlea

Capitulum

slide 13

Typical features of synovial joint

Extensive joint capsule

Osteochondral junction

Incorporates proximal radio-ulnar articulation

Stability

??? 14

Movement

Limited to flexion and extension

Ulna acts as lever

Elbow extensors insert onto olecranon

Joint between radius and ulna

Rotation possible

Annular ligament

Interosseous ligament

Fibrous joint distally

????

Clinical considerations

Elbow dysplasia

Osteochondrosis

Ununited anconeal process

??? 17

Elbow joint muscles

Elbow extensors

Caudal to elbow joint

Triceps muscle

All 4 heads

No effect on shoulder

Supplied by radial nerve

Flexors

Cranial to elbow joint

Biceps brachii muscle

O - supraglenoid tubercle

I- proximal radius

Motor nerve supply

Musculocutaneous nerve

slide 20

Rotators

supinator muscle

Radial nerve ??

slide 21

Clinical considerations

Surgical access to humerus

Dissect between muscles rather than cutting them

Less damage faster healing

Proximal humerus

Disec?????? 23

Blood supply

Limb naturally extended

Blood vessels cross flexor aspect of joints

Avoids stretching of vessels

NV bundle

Arterial supply

Oxygenated blood from heart to peripheral tissues

Major vessels runs down limb

Changes name according to region

Slide 25 need. to know major branches :(

I've stopped taking notes so 26-29

Page 5

Structures and functions of distal forelimb

Carpus

Composed of carpal bones

Short bones

Proximal row

Radial/Intermediate carpal bone

Ulnar carpal bone

Accessory carpal bone

Distal Row

1st 2nd 3rd 4th carpal bones

Development

Most have single centre of ossification

ACB has 2

Fused RCB has 2

Joints

Antebrachio-carpal joint

Between ante brachium and carpus

Radius --

Ulna ---

Middle carpal joint

Proximal and distal rows

Carpo-metacarpal joint

Distal row and metacarpal bones

Intercarpal joints

Movements

Standing position

Extension

Large range of flexion

Most movement ant antebrachio-carpal joint

Least movement at carbo-metacarpal joint

Some movement between carpal bones

ACB acts as lever for distal limb

Insertion of major carpal flexor muscle

Counteraction by palmar ligament

Typical synovial joint

Single joint capsule extending

Proximally between radius and ulna

Distally between metacarpal bones

Poor communications between compartments

Collateral ligaments

Lateral

Ulna to 5th metacarpal bone

Medial

Radius to 2nd metacarpal bone

Styloid processes vulnerable intracarpal ligaments

Support

Palmar aspect

Fibrocartilagenous reinforcements

Functions

Friction free surface for passage of tendons

Passive maintenance of joint extension

Retinaculum

Sleeve of deep fascia, encloses the carpal region both at Palma and dorsal surface

Attaches to lateral aspect of the accessory carpal bone

Crosses from ACB to medial act carpus

Forms carpal canal

Carpal canal

Dorsal boundary

Fibrocartilagenous reinforcement of palmar aspect of carpal joint capsule

Lateral boundary

ACB

Palmar boundary

Palmar/flexor retinaculum

dog ??

Palpation

ACB

joint spaces

???

Manus

Components

Metacarpal bone

Digit

Proximal phalanx

Middle phalanx

Distal phalanx

Long bones

Sesamoids

Dogs and cats

Digitigrade

4 weight bearing

1 vestigial

Numbered medial to lateral

1st digit

Dew claw

Vestigial

Medial aspect

Non weight bearing

3 elements - debate as to which is missing

Commonly removed in puppies

Distal phalanx

Long bone

Ungual process

Ungual crest

Round root of claw

Very vascular

Extensor process

Extensor tendons

Palmar process

Flexor tendons

Manus development

MC 2

PP 2

MP 2

DP 1

Joints of manus

Metacarpo-phalangeal joint

2x proximal sesamoids

Palmar aspect

Either side of sagittal ridge

Protect flexor tendons

1x dorsal sesamoid

Protect extensor tendons

Resting position extended

Interosseous muscle nd próximas sesamoids

Sling configuration - suspends MCP joint

Supported by metacarpal foot pad

Proximal interphalangeal joint

Distal interphalangeal joint

Deep digital flexor tendon

Common digital extensor tendon

Dorsal elastic ligament

Proximal end MP

Extensor process DP

Dogs

Forces balanced to maintain tip of claw above horizontal

Problem if DDFT severed

All typical synovial joints

Flexion and extension

Stability

Collateral ligaments

Sagittal ridge

Cat

Very strong elastic ligament

DIP joint hyperextended

Claw rests in skin fold

Remain sharp for hunting/climbing

Exposure of claw

DDFTT flexes joint

Manual pressure to distal digital pad

Clinical considerations

Complex radiographic anatomy

Species recognition

Muscles of antebrachium

Affects carpus and digit

Muscle belly in ante brachium

Tendon of insertion distal to carpus

Extensors of distal limb

Originate lateral epicondyle of humerus

Run over dorsal aspect of carpus

Radial nerve

Flexors of distal limb

Originate medial epicondyle

Run over palmar aspect carpus

Median and Ulnar nerves

Extension of carpus

Origin Lateral epicondyle

Innervated by radial nerve

Extensor carpi radialis

I metacarpal

Abductor polices longus/Extensor carpi obliquus muscle

Crosses at level of carpus

Sesamoid in tendon of insertion

Extensor carpi ulnaris/ Ulnaris lateralis muscle

I 5th metacarpal bone and ACB

Flexion or extension depending on position of limb

Extension of carpus and digits

Origin = lateral epicondyle

I- radial nerve

Common digital extensor

I - all digits

Distal phalanx - extensor process

Lateral digital extensor muscle

I 4th and 5th digits

Distal phalanx extensor process

Flexion of carpus

O = medial epicondyle

I = median and ulnar nerves

Flexor carpi claris muscle (2 heads)

O - olecranon / epicondyl of humerus

I- Accessory Carpal Bone

For carpi radialis muscle

I - Metacarpal bones

Flexion of carpus and digits

O- median epicondyle

Innervation - median and ulnar nerves

ve stopped taking notes

Page 6

Structural modifications of footpad and nerves supply

Foot pads

Carpal/ stopper pad

Protects ACB

Metacarpal pad

Overlies MCP joints

Digital pads

Overlie DIP joints

Functions

Resistance to trauma

Traction

Anti-concussive

Protect deep structures

Support digit

Skin

Epidermis

Cells produced by germinative layer

Cells age as move outwards

Dead at surface + slough

Constant replacement

No blood supply

No nerve supply

Dermis

Blood supply

Nerve supply

Supports germinative layer

Image

Modifications of footpads

Inc skin thickness

Increased turnover of cells

Deposition of keratin

Rough surface

Sweat glands

Variable pigmentation

Components

Skin

Epidermis

Germinative layer

Dermis

Superficial fascia

Digital cushoin

Shock absorber

Fat

Vascular supply

Rich in fibre-elastic tissue

Clinical considerations

Wounds

Elastic tissue

Vascular channels

Sweat

Bandaging

Damage DDFT

'Stubbed toe'

Claw

No superficial fascia

Dermis

Fused directly to periosteum of ungual process of DP

Germinative layer

Active in 2 area only

SLIDE 8

Epidermis

Heavily keratinised

Stratum tectorum

Waterproof surface layer

Produced by skin in ungual recesses

Normal claw - tip touches ground

Position maintained by

Extensor tendons

Dorsal elastic ligament

Balanced by DDFT

Continuous growth

Tip wears naturally

Reduced wear /????

slide 9

Triming

Horn insensitive so can cut

Dermis contains blood and nerve -- don't cut

Non pigmented claws easier to clip

Cat

Same number of pads and claws

Same components and function

May be pigmented

Pressure on footpad unsheath claw

Reamin sharp for hunting /climbing

Lymphatic system

Cardiovascular system

Continuous system

Leaky capillary pad

Exchange of material

Net loss

Fluid accumulation

recovery/ scavenging system

Series of individual vessels

Thin walled

Run from periphery to thoracic duct

Thoracic duct empties into caudal vena cava

Transports lost material back into systemic circulation

Lymph nodes

Filters

Located where lymph vessels converge

Prevent contaminants reaching systemic circulation

Remove invading organisms

Containing defence cells

Forelimb nodes

Prescapular L.n

Axillary L.n

Enlarged in response to infection

Can use to differentiate between locallised/generalised disease

Important for meat inspection

Nervous system

Brachial plexus supplies

Selected extrinsic muscles

Pectoral muscles

Latissimus dorsi

Serratus ventralis

All intrinsic muscles

Subscapular nerve

Motor nerves only

Lateral shoulder support

Supraspinatous muscle

Infraspinatous muscle

Suprascapular nerve

Motor nerves only

Medial shoulder support

Subscapularis muscle

Musculocutaneous nerve

Sensory

Cutaneous sensation to cranial and medial aspect of elbow and medial aspect of antebrchium

Motor

Elbow flexors

Brachial muscle

Biceps brachii muscle

If damaged

No compensation

Loss of elbow flexion

Axillary nerve

Motor supply

Dedicated shoulder flexors

Deltoideus muscle

Teres major muscle

Sensory fibres

Cutaneous sensation to lateral aspect shoulder and brachium

Damage

Compensated by latissimus doors and long head triceps

Median and Ulnar nerve

Sensory fibres

Cutaneous sensation to caudal and palmar aspect of limb and dorsal aspect 5th digit

Motor supply

Carpal and digital flexors

Flexor carpi ulnaris muscle

Flexor carpi radialis muscle

??? slide 8

Radial nerve

Sensory fibres

Motor supply

Slide 19

Image slide 19

Radial nerve route

Starts medial

Passes caudal to shoulder

Passes through triceps

Supplies triceps

Follows musculospiral groove

Branch

Lateral epicondyle

Supplies distal limb extensors

Cranial / dorsal aspect of limb

Runs alongside cephalic vein

Supples cutaneous sensation

Humeral fracture most common cause of damage

Deficits depend on level of damage

Radial nerve damage

Proximal level

All extensor muscles affected

Cannot extend below elbow

Cannot weight bear

Limb appears longer than opposite

Distal level

Extensors or carpus/digits can't extend carpus/digits

Triceps intact

Can extend elbow

Can weight bear if limb extended

Can swing leg to compensate

Slide 22

Brachial plexus damage

slide 23

Page 7

Equine forelimb anatomy

Slide 3 image

Above!

Equine forelimb

Unguligrade

Perissodactyla

Weight bearing distal phalanx of 3rd digit

Same bones

Same joints

Same muscles as dog

Superficial structures

Chestnut

Vestigial horn pad

1st Metacarpal bone

Ergot

Horny lump in skin

Palmar aspect of MCP joint

Hidden by feathers

Remnant of metacarpal pad

Biceps brachii muscle

Function = extends shoulder / flexes elbow

origin = supraglenoid tubercle

Separated from glenoid cavity

Insertion - proximal radius

Double tendon of origin

Humerus

Intermediate tubercle

Two intertubercular grooves

Bicipital bursa

Separate from shoulder joint capsule

Lacertus fibrosis

Fibrous extension

Joins extensor carpi radialis

Inserts proximal MC3

Maintains shoulder and carpus in extension

Elbow joint

Radius and ulna fused

No rotation

No annular ligament

Collateral ligaments present

Triceps only have three heads

Bursa

Fluid filled cushion

Protection of tendons

Tricipital bursa

Between tendon and olecranon process

Subcutaneous bursa

Between skin and tendon of insertion of triceps

Clinical significance

Capped elbow (poor bedding)

Deeper swelling - true bursitis

Carpus

Carpal bones

All present except 1st CB

3rd bone largest

Movement

Most at antebrachio-carpal joint

Least at carpometacarpal joint

Collecting joint fluid samples

Synovial joint

Separate compartments

Support

Collateral ligaments

Palmar fibrocartilagenous plate

Origin of check ligament for DDFT

Palmar ligament

Retinaculum

Carpal canal

Palmar fibrocartilagenous plate

Palmar/Flexor retinaculum

Accessory Carpal Bone

Dogs DDFT only

Horses both DDFT and SDFT

Tendon sheath

Protects tendon in confiner spaces

Dorsal aspect

Surrounds extensor tendons

Carpal canal

1 seats for both DDFT and SDFT

inflammation - increased pressure

Thoroughpin bulges proximally and distally

Clinical considerations

Broken knees

Skin

Dorsal /Extensor retinaculum

Tendon sheath

Joint capsule

Penetration into joint space most likely if flexed during trauma

Metacarpal bones

Metacarpal bones

3rd MC = cannon bone

Wright bearing

Distal articular surface

Sagital ridge

2nd and 4th = splint bones

Vestigial -non weight bearing

Button at distal end - palpable

Joints between MCs

Fibrous joints

Mineralise as age

'Splints'

Palanges

Proximal phalanx

Long pastern bone

Raised V on palmar surface

Attachment oblique distal sesamoidean ligament

Middle Phalanx

Short pastern bone

Bony Contours

Attachment collateral ligaments

Ringbone

Distal phalanx

Pedal/coffin bone

Complex shape

Extensor process

Attachment common digital extensor tendon

Palmar processes

Support lateral cartilages

Solar surface

Attachment Depp digital flexor tendon

Dorsal surface

Striations

Blood vessels

Hoof attachment

Vascular channel

Manus bone development

Centres of ossification

MC 3

Body and distal epiphysis (2)

MC 2 and 4

Proximal epiphysis and body (2)

PP

Po??

MP

??

DP/

????

Proximal sesamoids

No dorsal sesamoid

Proximal sesamoid bones

Triangular

Distal end MC 3

Either side of sagittal ridge

Embedded in suspensory ligament

Protect SDFT and DDFT

Digital sesamoid

Navicular bone

2 flat articular surfaces

Covered with hyaline cartilage

Cancellous centre

Vascular channels

Located palmar aspect of DIP joint

Dorsal surface

Articulates with MP and DP

Palmar surface

Guides DDFT over DIP joint

Under large amount of pressure

Clinical considerations

Navicular disease syndrome

Erodes with age

Bone dissolves- visible on radiographs

Poor correlation between clinical signs and radiographic changes

Metacarpo-phalangeal joint

Fetlock

MC3 and PP

Synovial joint ??

Slide 19

Natural position = extension

Limited to flexion and extension

Sagittal ridge distal MC3

Sagittal groove Proximal PP

Collateral ligaments MC-PP

Tendency to collapse into hyper...

Suspensory ligaments

Entirely ligamentous

Origin

Proximal palmar MC3

Fills area between splint bones

Branches

Abaxial aspect proximal sesamoids

Pas.... slide 21D

Sesamoidean ligaments

Inter-sasemoidean ligament

Reinforced fibrocartilage

Proximal scutum

Passage of DDFT and SDFT over sesamoids

Coll...

Distal

Crucial

Short

Proximal sesamoids PP

Oblique

Proximal sesamoids PP

v shaper through on PP

Straight

??

MCP joint

Function relies on

Suspensory ligament

Proximal ligaments

Common digital extensor tendon

Page 8

Proximal Interphalangeal joint

Pastern joint

Limited to flexion and extension

Distal PP - sagittal ridge

Proximal MP - sagittal ridge

Collateral ligaments

PP-MP

Extension runs to navicular bone

Distal interphalangeal joint

Coffin joint

Buried in hoof

Components

MP and DP

Distal sesamoid and DP

Digital sesamoid MP

Extensive joint capsule

Forms bursa

Protects extensor tendon

Accessible for injection

Dorsal aspect

DIP joint

Restricted to flexion and extension

Sagittal ridge and groove

Some rotation possible

Collateral ligaments

MP - DP

Movement

Common digital extensor tendon

Deep digital flexor tendon

No dorsal elastic ligament

Digital sesamoid

Ligaments

Collateral

PP - distal sesamoid

Impar

NDP - distal sesamoid

Navicular/ podotrochlear bursa

Fluid filled pocket

Between sesamoid and DDFT

Separated from DIP joint by imparting ligament

Protects DDFT

Lateral/ ungual cartilages

Cartilage plates

Palmar processes DP

medial and lateral

Protect above level of hoof

Shock absorption

Palpable feature

Radiography

Cartilage not visible

Mineralise as age

Side bone

Radiograph

Extensor tendons

Below carpus - fibrous connective tissue

Muscle bellies in antebrachium

Common digital extensor

Crosses dorsal aspect carpus

Joined by 2 branches of suspensory ligament

Inserts PP , MP and DP

Lateral digital extensor

Inserts PP

Separate from CDE

Flexor tendons

Superficial digital flexor tendon

Accessory check ligament

Origin Proximal to carpal canal

Passes through carpal canal

Splits to allow DDFT pass through it

Insets MP

Deep digital flexor tendon

Passes through carpal canal

Accessory check ligament

Originates from fibrocartilage plate on palmapalmar aspect of carpus

Fuses with DDFT

Passes through split in SDFT

Runs over navicular bursa

Inserts DP

Metacarpal region

Dorsal aspect = extensor tendons

Palmar aspect=

Skin

SDFT

DDFT

Check ligament

Suspensory ligament

Clinical relevance

Tendon trauma / injuries common

Ultrasound examination ideal for soft tissue damage

Distal region

Scutum

Cartilage shield

MCP joint = intersesamoidean ligament

Smooth passage for tendons

Annular ligaments

Hold DDFT and SDFT against bones

3 parts

Proximal AL

Proximal phalanx AL

Distal AL

Tendon sheath

Shared by SDFT and DDFT

Extends from AL distally

Inflammation - increased pressure

Clinical considerations

Palpation of swellings

Bony swellings -splints

Sort swellings

Articular ....

Tendon sheath

....

Stay apparatus

Most of weight borne on forelimb

Mechanism for passive weight bearing

Serratus Ventralis

Suspends weight of body between forelimbs

Maintenance of extension / prevention of flexion

Shoulder

Biceps brachii

Elbow

Collateral ligaments

Alignment of bones

Carpus

Lacertus fibrosis

Prevention of hyper extension

Carpus

MCP joint

MCP, PIP , DIP joints

???

Blood supply

Arterial supply

Similar to dog

Brachial artery

Palpable pulse

Medial aspect elbow

Medial and lateral digital arteries

Palpable pulse

Abaxial aspect proximal sesamoids

Venous drainage

Similar to dog

Nerve supply

Brachial plexus

Similar to dog

Nerve damage uncommon

Suprascapular nerve

Runs round neck of scapula

Supplies

Supraspinatous

Infraspinatous

No cutaneous sensation

Damage causes joint insatiability

Different sensory areas

Distal to carpus

Median and Ulna nerves combine

Supply pastern and foot

Combined with Musculocutaneous nerve

Medial aspect metacarpal area

Image

Median and Ulna nerves

Combine distal to carpus

Branches

Palmar metacarpal nerves

Paired (Medial and lateral)

Run between MC. 3 and splint bones

Emerge at distal end of splint bones

Supply dorsal aspect of digit

Palmar nerves

Paired (Medial and lateral)

Between suspensory ligament and SDFT

Cross abaxial aspect proximal sesamoids

Communicate at level of metacarpal

Become

Dorsal and palmar digital nerves

Dorsal and palmar branches

Supples hoof contents

Clinical considerations

Nerve blocks

Routinely used in equine practise to help localise area of lameness

Predictable locations

Inject Local anaesthetic

Desensitise structures supplied by nerve

Palmar Digital nerve block

Palmar digital nerves

Run adjacent to distal arteries

1cm above coronary band

2/3 of the way to palmar aspect

Medial and lateral injections

Blocks caudal 1/2 of foot

Abaxial sesamoid nerve block

Palmar digital nerves and dorsal branches

Run adjacent to digital arteries

Abaxial aspect sesamoids

Medial and lateral injections

Blocks entire foot

Palmar metacarpal nerve block

Palmar nerves

Palmar metacarpal nerves, Distal end splint bones

Medial and lateral injections

Blocks enter digit

Page 9

Comparative anatomy

Lameness

Production loss

Less food intake therefore weight loss

Abattoir

Meat inspection

Signs of infection

Forensics

Evaluation of bones

Look for growth plates

Estimate age

Horse v cow

Sheep v Pig

Horse

Yellow fat

Pig

Greasy bones

Scapula

Dog

Acromion process

Tuber spine absent

Supraglenoid tubercle part of glenoid cavity

Horse

Narrow supraspinous fossa

Acromion process is absent

Prominent tuber spine

SGT separate from glenoid cavity

Glenoid notch present

Cow

Broad dorsal border

Larger infraspinous fossa

Acromion process blunt and doesn't reach level of glenoid cavity

Tuber spine less prominent/ Absent

Indistinct glenoid notch

Pig

Rounded cranial margin

Poorly defined acromion

Prominent tuber

Humerus

Horse

Greater tubercle

Cranial and caudal parts

Level with humeral head

Lesser tubercle

Similar size

Intermediate tubercle

Double inter tubercular groove

Suprathrochlear foremen absent

Very prominent deltoid tuberosity

Dog

Since greater tubercle

Supratrochlear foramen

Cow

Greater tubercle

Cranial and caudal parts

Much higher level than humeral head

Pointed

Cranial part is v big and overhangs the interlobular groove medially

Single interlobular groove

Circular area for infraspinatus insertion

Small deltoid tuberosity compared to horse

No supratrochlear foramen

Pigs

Greater tubercle

Cranial and caudal parts

Higher than humeral head

Rounded

Almost encloses inter tubercular groove

Single inter tubercular grove

No supratrochlear foramen

No flattened thumb print

Radius and ulna

Dog and Cat

2 separate complete bones

Rotation

Horse

????

Ruminant

2 complete bones

Fuse as animal ages

No rotation

Pig

2 complete bones

???

Carpus

Dog and Cat

Radial and intermediate fused

Distal row all present

Horse

All present except 1st CB

Pig

All bones present

Ruminant

Proximal row all present

Distal row

1st CB absent

2n and 3rd CB fused

Carpal canal

Dog and cat

DDFT passes through

Horse

Both DDFT and SDFT

Ruminant and pig

???

Manus

Dog

Horse

Ruminants

slide 13

Metacarpal bones

Ruminants

MC 1 and 2 absent

MC 3 and 4

Fuse in uterus

2 medullary cavities

Axial bony septum

Proximal end 1 articular surface

Distal end 2 articular surfaces

4 centres of ossification

MC 5 vestigal spur

Digits

slide 15

MCP joint support

Medial and lateral collateral ligaments

Inter sesamoidean ligaments

Interdigitl intersesamoidean ligaments

Distal sesamoide ligaments

Short and cruciate

Interdgital phalangeal sesamoidean ligament

Axial aspectsesamoid opposite PP

Helps hold PPs together

Digits

Manus

Pig

Clinical considerations

Page 10

Muscles of the forelimb

Extrinsic

Have origin on neck and thorax

Have insertion on the limb

Superficial pectoral

Deep pectoral

Brachiocephalicus

Omotransversarius

Trapezius

Lattismus dorsi

Serratus ventralis

Trapezius

2 parts

Cervical part originates ...

Omotransversarius

O - 1st cervical vertebrae

I - distal part of scapula spine and acromion

Action - protraction of limb

Innervation - accessory nerve

Rhomboideus

2 parts

Cervical - originates from median raphe of neck and extends to the spinous process of the....

Serratus Ventralis

O - transverse processes of last 5 cervical vertebrae and ventral part of first 8 ribs

I - facies errata of scapula

Action - retractor/ protractor

...

Brachiocephalicus

3 parts

cleidomastoideus from head

...

O

I

Innervation

Action -

Superficial Pectoral

O - cranial end of sternum to third costal cartilage

I- major tubercle of humerus

Action - adducts the limb

Innervation - cranial pectoral nerve

Deep pectoral

????

Intrinsic muscles

Have both origin and insertion on the limb

?

Deltoideus

2 part

Scapular part arises a wide aponeurosis from of scapula covering infraspinatus muscle

O- the spine and acromial process of scapula

Deltoid tuberosity ???

Triceps

4 heads

I -

Long head

Lateral head

?

3 heads

Long and lateral heads

Accessory head

Medial head

Supraspinatus

O - supraspinous fossa

I - Major tubercle of humerus

Action- extension of shoulder and...

Innervation -suprascapula nerve

Infraspinatus

O

I

Action

Innervation

Teres Minor

O- distal 3rd of caudal

I

Action

Innervation

Subscapularis

???

Theres Major

O

I

Action- flexor of shoulder

Innervation- axillary nerve

Biceps brachii

O

I

Action - flexor of elbow, extensor of shoulder

Innervation- musculocutaneous nerve

Brachialis

O

I

Action- flexor of elbow

Innervation - musculocutaneus nerve

Coracobrachialis

O- coracoid process

I- minor tubercle of humerus

Action

Innervation

Anconeus

O - distal third of humerus

I-

Action- extensor of elbow, capsular muscle of elbow

Innervation- radial nerve

Tensor Fascia Antebrachii

??

Extensor carpi radialis

O lateral distal humerus

I -Carpal bones

Action- extensor of carpus , flexor of elbow

Innervation - radial nerve

Common digital extensor

O

I

Action

Insertion

Lateral digital extensor

O

I- distal phalanges of digits 23 and 4

Action - Extension of digits 2 3 and 4

Insertion - radial nerve

Ulnaris lateralis

??

Supinator

O

I

Action

Innervation

Absuctor pollicis longus

O

I

Action - Abductor of first digit

Innervation - Radial nerve

Pronator teres

O

I

Action

Innervation

Flexor carpi radialis

Superficial digital flexor

O

I

Action

Innervation

Flexor Carpi Ulnaris

O

I

Action

Innervation

Prodator Quadratus

O

I

Action

Innervation

Interosseousei

O -

I -

Action - metacarpophalangeal joints

Innervation - ulnar nerve

10 other small muscles we don't need to know

Page 11

Hoof

Overall structures

Wall

Weight bearing

Periople

Round coronary region

Produces boundary between skin and hoof

Sole

Raised, doest touch ground

Frog

Anticoncussive

Central sulcus

Collateral sulci

White line

Bars

Bulbs of heal

Coronary band

Transition between skin and hoof wall

Contents

Middle phalanx

Distal phalanx

DIP joint

Navicular bone

DDFT

Navicular bursa

Digital cushions

Deep to frog

Elastic tissue

Blood vessels

Fat

Functions

DDFT

Distal phalanx

Navicular bone

Navicular bursa

Clinical significance

Penetration injuries

Abscess formation

Must dig

May need to apply poultice to soften horn

Lateral/ ungual cartilages

Cartilage plates

Palmar processes DP

Medial and lateral

Shock absorption

Mineralize with age (Sidebone)

Hoof production

Dermis

Covers DP and digital cushion

Blood and nerve supply

Sensitive

Supplies germinative layer

Germinative layer

Produces epidermis

Active in 2 areas

Coronary band

Solar surface

Coronary band

Dermis formed into conical papillae

Produce epidermis

Extend distally towards ground

Grow 5-6mm/ quarter of an inch per month

Gaps filled by intertubular horn

Form hoof wall

Weight bearing surface

Dermis

Fused to DP

Surface forms laminae

Primary laminae

Secondary laminae

Sensitive - contains blood and nerve vessels

Hoof wall

Epidermal horn tubes glide distally

Internal surface interdigitates with dermal laminae

Forms corresponding primary and secondary laminae

White line

Prevents separation of epidermis from DP

Transfers weight from hoof wall to DP

Solar surface

Active germinal layer

Sole

Keratinised flakes

No tubular horns

Frog

Incomplete keratinisation

Soft and elastic

Weight bearing ?

Clinical considerations

??

Farrier

Foot trimming

Horn grows continuously

Shoeing

Protects weight bearing wall

Shape doesn't restrict heel

Therapeutic shoes

Nails

Insensitive laminae

Outwith white line

Sledge tipped nails

Tips clipped and flattened

Raise clenched berfore remove shoe

Hoof shape

Front

Weight bearing

Broad

Rounded

1or 2 toe clip

Medial wall

More upright

Straighter

Usually 3 nails

Back

Propulsion

Narrow

Pointed

2 toe clips

Lateral wall

More angled

Rounded

Usually 4 nails

Ruminants

Cloven hoof

Medial and lateral claws

Interdigital cleft

Sole

Heel

o frog.....

Hoof growth

??

Shock absorber

Bulbous heels

Digital cushion

Digits splay

No lateral cartilage

No frog

Clinical considerations

Horn overgrowth

Solar ulcers

Interdigital dermatitis

White line disease

Laminitis

Sheep and Goats

Goats well adapted for climbing

Softer soles for traction

Same as cattle

Skin gland proximal to interdigital cleft

Over growth is a problem

Regularly trimmed

Pig

Similar to ruminants

No frog

No lateral cartilages

Page 12

Vertebral column

Functions

Stiffens the body axis and contribute to the maintenance of posture

Facilitates locomotion by muscle attatchment

Encloses and protects spinal cord and accessory structures within central canal

Protects soft structures of neck thorax abdomen and pelvis

SEE slide 4

Cervical region

7 vertebrae

Thoracic

13 vertebrae

Lumbar region

7 vertebrae

Sacral

3 vertebrae

Caudal

15-20

SEE table

Typical vertebra

Body

Vertebral foramen

Neural arch

Pedicle

Lamina

Cranial and caudal notches

Dorsal spinous process

Transverse processes

Articular facets

Mamillary processes

See image

Adjacent vertebrae

Vertebral foramen

Vertebral canal

Spinal cord

Intervertebral foramen

Cranial and Caudal notches

Spinal nerve roots

Articulations

Synovial joints

Causal articular facets sit inside cranial ones

Variable movement depending on region

Intervertebral disc

Nucleus pulposus

Gelatinous cushion

Provides shock absorption

Annulus fibrosis

Concentric fibrous rings

Attached to adjacent vertebrae

Provides stability

Appears as black spaces on radiograph

Cervical vertebrae

7 in all domestic species

Most varied in shape of vertebrae

C1 and C2 atypical

C3-C7 typical

C1 (Atlas)

Reduced body

No spinous process

Large transverse process (wings)

Articulates with occipital condyles of skull (Atlanto-occipital joint)

Movement of head (Yes joint )

Articulates with C2 causally (No joint )

Image

C2 Axis)

2 bodies

Dens + body of C1

Large palpable dorsal spinous process

Articulates with C1 forming ATLANTO-AXIAL joint

(No joints)

No flexion and extension

Image

C3-C7

c3-c7 = typical vertebrae

C6-C7 ventral extension of transverse process

Cervical spine

Mobile

Flexion and extension

Lateral movement

Disc protrusion

C6 also has distinct expanded platelike transverse process

?? some shit about nerves

C7 lacks transverse foramen

NB There are 7 cervical vertebrae but 8 nerves

One leaves via foramen between C7 and T1

Thoracic vertebrae

Ribs limit motion

There is some flexion and extension

Most movement at thoracolumbar junction

Dist protrusion

Short body

Large dorsal spinous process

Transverse process much reduced to accommodate ribs

Costal fovea

image

T1- T10

Caudal angulation of dorsal processes

T11

Dorsal process short and vertical

Beyond T11

Cranial angulation of dorsal processes

Image

Lumbar vertebrae

Longer bodies

Large transverse proceses

Abdominal muscle attachment

Flexion and extension

images

Sacral vertebrae

Vertebrae fused

No movement

No discs

Articulates with pelvis

Sacroiliac joint = S1-ilium

Sacrotuberous ligament

image

Caudal vertebrae

First few resemble small lumbar ve`rtebraE

Large amount of movement possible

First few have heal arches

Small chevrons of bone run on the ventral aspect of bodies to protect the coccygeal artery

Vertebral canal disappears after Cy 5-7

Image

Ribs and sternum

Number of ribs corresponds with number of thoracic vertebrae

Each rib has dorsal bony part and ventral cartilage

Meet at costo-chondral junction

Each rib articulates proximally with 2 successive vertebrae

Each rib rib articulates ventrally with sternum

7-12 attach by costal arch

13th rib is floating

Sternum made up of sternebrae

First is manubrium

Last is xiphoid

Has diploid cartilage

Ligaments of vertebral column

Costotransverse ligament

Intercapitular ligament

Dorsal longitudinal ligament

Page 13