4.1. APPENDICULAR SKELETON

Thoracic Limb and Pelvic Limb

Thoracic girdle (clavicle and scapula)

Arm/brachium (humerus)

Forearm/antebrachium (radius and ulna)

Forepaw/manus ( carpal bones, metacarpal bones, phalanges)

bones of the thoracic limb is composed of?

Pelvic girdle (Ilium, Ischium, Pubis)

Thigh (Femur, Patella)

Leg or Crus (Tibia and Fibula)

Hindpaw or Pes ( Tarsal bones, Metatarsal bones, Phalanges)

bones of the pelvic limb is composed of?

clavicle

• Small, oval-plate located cranial to the shoulder within the clavicular tendon in the brachiocephalicus muscle

• This is frequently absent in canines

• This is described as a “vestigial bone”

• It is present in felines, but it does not articulate with other bones

Scapula

• Large, flat, triangular bone seen at the lateral surface of the trunk at the junction between the neck and ribs

• It possess two surfaces, three border, and three angles

• Also known as “shoulder blade”

• Paired bone which makes up the shoulder girdle

Spine

Supraspinous fossa

Infraspinous fossa

Acromion

Subscapular fossa

Serrated face

Glenoid cavity

Supraglenoid tubercle

Infraglenoid tubercle

Coracoid process

Scapular notch

Enumerate the parts of the scapula (11)

Spine

is a prominent ridge running down the middle of its lateral surface.

area cranial to the spine for the attachment of the supraspinatus muscle

Supraspinous fossa

area caudal to the spine for the attachment of infraspinatus muscle

Infraspinous fossa

expanded distal end of the scapular spine.

Acromion

located on the medial side of the scapula for the attachment of the subscapularis muscle

Subscapular fossa

a small proximal and rectangular area in which serratus ventralis muscle is attached.

Serrated face

a shallow articular socket which forms the shoulder joint with the head of the humerus.

Glenoid cavity

is a process near the cranial aspect of the glenoid cavity for the attachment of the biceps brachii muscle.

Supraglenoid tubercle

caudal border in which the teres minor and long head of the triceps arises

Infraglenoid tubercle

is a small process on the medial side of the supraglenoid tubercle for the attachment of the coracobrachialis muscle

Coracoid process

forms the distinct neck of the scapula; this is where suprascapular nerve lies.

Scapular notch

Humerus

• Largest bone of the thoracic limb.

• It articulates proximally with scapula forming the shoulder joint

• It articulates distally with the radius and ulna forming the elbow joint

Humeral head

Greater tubercle

Lesser tubercle

Bicipital groove/intertubercular groove

Body/shaft

Deltoid tuberosity

Lateral epicondyle

Medial epicondyle

Enumerate the parts of the humerus (8)

Humeral head

round process at the medial side of the bone articulating with the glenoid cavity of the scapula.

Greater tubercle

• lateral/major tubercle

• is a large process craniolateral to the head of humerus.

Lesser tubercle

• medial/minor tubercle

• process at the medial side of humeral head.

Bicipital groove/intertubercular groove

is a sulcus between the greater and lesser tubercle through which the tendons of the biceps brachii runs

Body/shaft

connects the two extremities or epiphysis of the humerus.

Deltoid tuberosity

large tuberosity at the lateral side of the humerus

Lateral epicondyle

lateral side of the condyle giving rise to the extensors muscle of the forearm

Medial epicondyle

medial side of condyle giving rise to the flexors muscle of the forearm.

Radial Nerve Paralysis

• this occurs because the animal is unable to use the extensor muscles to bring the limb into its normal position.

• the damaged nerve may recover but if it has been severed the only treatment may be to amputate the forelimb

Radial Nerve Paralysis

a condition where an animals forelimb will knuckle over on its forepaw, leading to excessive wear of the skin on the dorsal surface of the paw; the ventral surface is protected from normal wear by the pads.

Musculo-spiral groove

• it refers to when the shaft of the humerus has a slight twist on it

• If the humerus is broken, the resulting fracture is often in the form of a spiral and may affect the radial nerve that runs within the spiral, causing temporary or permanent radial nerve paralysis.

• this is indicated by the animal knuckling over on its lower forelimb

Radius

shorter and more massive and it is located medially.

Ulna

• longer and slender compared to radius and is located laterally.

• is located on the caudal part of the forearm

Head

Body

Medial styloid process

Fovea capitis

Radial tuberosity

Trochlea

Ulnar notch

Styloid process

Groove for abductor digiti I longus

Groove for extensor carpi radialis

Groove for common digital extensor

Enumerate the parts of the radius (11)

Head

proximal end of the radius

Body

also called shaft of the radius

Medial styloid process

pointed projection on the distal end of radius.

Fovea capitis

oval, depressed articular surface, which articulates with humerus

Radial tuberosity

lies distal to the neck on the medial border of the bone of the radius.

Trochlea

distal extremity of the radius.

Ulnar notch

slight concave area with facet for the articulation with ulna

Styloid process

rounded projection in the distal end of ulna on the medial border.

Groove for abductor digitiI longus

small, short, and oblique; the most medial groove of the radius

Groove for extensor carpi radialis

middle and longest groove of the radius

Groove for common digital extensor

the most lateral groove of the radius, wide, and with variable distinctness

Olecranon process

Trochlear notch/semilunar notch

Anconeal process

Ulnar tuberosity

Medial and lateral coronoid process

Lateral styloid process

Medial styloid process

Interosseous space

Enumerate the parts of the ulna (8)

Olecranon process

• proximal end of the ulna; acts as a lever for the attachment of the extensor muscles of the forearm.

• This is the point of the elbow

Trochlear notch/semilunar notch

depression for the articulation with the humerus and ending in the anconeal process

Anconeal process

proximal end of the trochlear notch which fits in the olecranon fossa of the humerus when the elbow is extended.

Ulnar tuberosity

elongated eminence of the ulna on the medial surface of the bone at its proximal end.

Medial and Lateral coronoid process

are the larger distal end of the trochlear notch

Medial is larger than the lateral

In Medial and Lateral coronoid process, which is larger?

Lateral styloid process

where ulna narrows to a point distally.

Medial styloid process

pointed projection at the distal end of radius

Interosseous space

border between the radius and ulna

Elbow Dysplasia

• is a common condition of the heavier breeds of dog (e.g., Newfoundland, St Bernard, Rottweiler, Basset Hound).

• It encompasses a number of developmental conditions, such as an ununited anconeal process and detached olecranon process, which result in instability of the elbow joint, leading to osteoarthritis.

Elbow dysplasia

abnormal development of the elbow

Fragmented or Ununited Medial Coronoid Process (FMCP/ UMCP)

Osteochondrosis Dissecans (OD)

Ununited Anconeal Process (UAP)

what are the primary lesions of elbow dysplasia in canine

CARPALS/CARPUS

Composed of seven short bones and are arranged into two rows( proximal row and distal row)

proximal row

distal row

two rows of the carpus

radial carpal bone

intermediate carpal bone

ulnar carpal bone

accessory carpal bone

bones of the proximal row of the carpus

radial carpal bone and intermediate carpal bone

Intermedioradial carpal bone

which bones of the proximal row of the canine and feline carpus are fused? What is it called?

Radial carpal bone

most medial, articulates proximally with the radius

Intermediate carpal bone

also known as lunate bone

Intermedioradial carpal bone

• located on the medial side and articulates proximally with the radius;

1st carpal bone

2nd carpal bone

3rd carpal bone

4th carpal bone

bones of the distal row of the carpus