Details of bone

1. Anatomy-4
Appendicular Skeleton
Forelimb
Comparative Aspects

2. Forelimb (Horse)

3. Scapula-1
Roughly triangular in shape and flat
Lies against the thoracic wall in a
cranioventral direction
Does not form a true articulation with
the trunk, instead forming a synsarcosis;
meaning it is attached only by muscles

4. Scapula-2
Two surfaces (lateral and Medial)
Three borders (Dorsal, Cranial and
Caudal)
Three angles (Cranial, Caudal and
Ventral)

5. Scapula-3
Lateral Surface:
Divided into two parts (Supraspinous and Infraspinous
fossa) by a spine (Scapular Spine)
Supraspinous fossa – Origin Supraspinatus muscle
Infraspinous fossa – Origin Infraspinatus muscle
Scapular Spine - Origin Omotransversarius, Trapezius
& Deltoideus muscle

6. Right Scapula (Horse)

7. Left Scapula (Dog)

9. Scapula-4
Medial Surface:
Proximal serrated part - Origin
Serratus ventralis
Ventral part (Subscapular fossa) –
Origin subscapularis

11. Scapula-5
Ventral angle;
Glenoid Cavity; (forms shoulder joint with
humeral head)
Supraglenoid tubercle;
a large prominence, cranial to glenoid cavity
origin - Biceps brachii

12. No definite joint ligaments;
Tendons of muscles crossing
the joint act as ligaments and
stabilize the articulation

14. Scapula-6
Coracoid Process;
a medial process on supraglenoid tubercle for
origin of coracobrachial & Teres minor muscle
Infraglenoid tubercle;
a small prominence at the caudal bordel dorsal to
the ventral angle, for the origin of Long head of
Triceps brachii

16. Left Scapula

17. Scapula-7
Dorsal Border – attached with Scapular
Cartilage and gives attachment to Rhomboideus
muscle
Cranial Border has a prominent “Scapular
Notch” just above the supraglenoid tubercle and
is converted into a foramen by transverse
scapular ligament; through which passes
the suprascapular nerve

18. Scapula-8
Caudal Border and Tricipital crest –
Gives origin to
Triceps Brachii and
Teres major
presents nutrient foramen in the
lower third

19. Scapula (Comparative Anatomy)-1
Point Horse Ox Dog
Acromion
Process - + +
Spine Less sinuous Sinuous/Straight
Tuber
Spine Prominent Less prominent

20. Scapula (Comparative Anatomy)-2
Point Horse Ox Dog
Supra/infra
Fossa ratio 1:2 1:3
Glenoid Notch + -
Subscapular
Fossa Deep Shallow

21. Humerus-1
A long and compact bone
Consists of two extremities (Proximal and
Distal) and a shaft
Proximal extremity consists of
Head which articulates with the glenoid of
the scapula to comprise the scapulohumeral
(Shoulder) joint
Neck

22. Equine Humerus

23. Humerus Ox

24. Humerus (Dog)

25. Humerus-2
Adjacent to the head, is the greater,
intermediate, and lesser tubercle
Between greater and lesser tubercle there is
intertubercular (Bicipital) groove in which
the bicipital bursa is located and over which
the biceps brachii tendon glides

26. Humerus-3
The shoulder joint does not have
collateral ligaments
The lateral stability of the shoulder
joint is provided by the supraspinatus
and infraspinatus muscles, both of
which insert on the greater tubercle

27. No definite joint ligaments;
Tendons of muscles crossing
the joint act as ligaments and
stabilize the articulation

28. Humerus-4
The deltoid tuberosity is located on the
craniolateral surface of the humerus at the
junction of the proximal and middle third of
shaft of the bone
The deltoid tuberosity serves as the origin
of the deltoideus muscle and insertion of
Superficial pectoral muscle

29. Humerus-5
Distal to the deltoid tuberosity, the bone
shaft has a well defined musculospiral
(Brachialis) groove which is occupied by
brachialis muscle
Immediately adjacent to the caudal border
of the brachialis muscle lies the radial nerve.
Clinical Significance: Damage during fracture

30. Equine Humerus

31. Humerus-6
The distal extremity consists of
Two condyles and two epicondyles
Lateral epicondyle has a smooth slope
Medial epicondyle is more prominent
and square shaped

32. Humerus-7
The space between the lateral and medial
epicondyles forms the olecranon fossa
caudally
The humeral condyles allows transfer of
weight bearing to the radial head
Medial condyle larger & massive

34. Humerus-8
The olecranon fossa allows intimate
articulation with the trochlear notch of the
proximal ulna; all together they form the
cubital (elbow)joint
Trochlea (pulley like structure b/t condyles)
Capitulum (a small flat area lateral to
trochlea)- articulates with head of radius

35. Elbow Joint

36. Equine (Shoulder and Elbow Joint)

37. Humerus (Comparative Anatomy)-1
Point Horse Ox Dog
Head Well defined Clear
Radialis groove Deep Shallow
Deltoid
Tuberosity Prominent Less prominent

38. Humerus (Comparative Anatomy)-2
Point Horse Ox Dog
Nutrient
Foramen Med shaft Caudal Shaft
Lat/Major
Tuberosity Level wd head Higher from head
Greater
Tuberosity Divided Undivided

39. Humerus (Comparative Anatomy)-3
Point Horse Ox Dog
Intertubercular
Groove Divided Undivided
Radial Fossa Narrow Deep
Olecranon
Fossa Less deep More deep
Supratrochlear
Foramen - - +