humerus anatomy of domestic animals

vetrinary comparitive anatomy

1. VETERINARY COLLEGE HASSAN VETERINARY ANATOMY SUBMITTED TO: Dr Rajashailesh N M HOD Dept of Veterinary Anatomy SUBMITTED BY: Swaroop R Jr MVSc Dept of VSR

2. HUMERUS It is a  long bone  placed obliquely downward and backward between the  shoulder joint  above and the elbow joint below . The cylindrical shaft is twisted and presents four surfaces. Lateral surface is spiral ,smooth and presents a musculo spiral groove , which accomodates the brachialis muscle . Medial surface is rounded

3. At the middle there is a tubercle for the insertion of teres major and longisimus dorsi muscle This tubercle is known as teres tubercle The anterior surface is triangular, wide and smooth above and narrow & rough below Crest of humerus -Prominent border Prominance Deltoid tuberosity (Deltoid Muscle) Posterior surface : Round and smooth and nutrient foramen at the distal third

4. Proximal end

5. The head is circular, c onvex &articulates with the glenoid cavity of scapula. Neck is the constricted part below the head Tuberosites are lateral and media l s eparated by intertuberal groove Lateral tuberosity is large and prominent,as two parts i.e , Summit and Convexity The summit is placed anteriorly and is curved over the bicipital groove , infraspinatus muscle inserts at a circular rough area below and lateral to summi t.

6. Distal end It is articular ,expanded and a modified condyle, consists of trochlea (medial condyle),the capitulum (lateral condyle),the medial and lateral epicondyles, the olecranon fossa and coronoid fossa.(Radial) The trochlea is larger and is transversed by a groove: Cranially- Radial fossa Caudally- Olecranon fossa The radial fossa accommodates coronoid process of radius during flexion and olecranon fossa receives the anconeus process of ulna during extension of the joint.

7. Capitulum is small and situated further distally and caudally Medial and lateral epicondyles are small projections from the concerned condyles, Medial epicondyle gives rise to flexor muscles and the lateral one to extensor carpi radialis . The epicondyloid crest , part of lateral epicondyle forms the lateral boundary of the musculospiral groove.

8. Sheep and Goat  It is relatively longer and slender than that of ox. The deltoid tuberosity is closer to the proximal end and not as prominent. The lateral tuberosity is smaller and does not overhang the bicipital groove. Olecranon and coronoid fossa are shallower.

9. Horse The deltoid tuberosity is more prominent . The musculospiral groove is more deep and twisted. Bicipital groove is divided by a ridge The summit of lateral tuberosity does not arch inward . The nutrient foramen is situated at the distal third of the medial surface . The coronoid and the olecranon fossa are shallower.

10. Pig It has the appearance of italic letter ‘ f ’ minus the cross bar. The shaft is laterally compressed and flat on the medial side. The musculo -spiral groove is shallow and the deltoid tuberosity is small and there is a larger rounded eminence midway between it and the lateral tuberosity. Teres tubercle is absent. The condyles are of equal size. The coronoid fossa is prominent. The olecranon fossa is narrow and deep. Occasionally the suprtrochlear foramen is found.

11. Dog The bone is comparatively more long and less twisted Head is rounded and is more convex Radial and olecranon fossa are communicated by a large Supratrochlear foramen Deltoid tuberosity is in the form of a ridge. The nutrient foramen is situated at the posterior surface The musculospiral groove is not prominent

12. Rabbit Head is elongated Deltoid tuberosity is in the form of a ridge Musculospiral groove is shallow Supratrochlear foramen is present

13. Fowl Proximally this bone articulates with scapula and coracoid The pneumatic foramen is situated medially below the head The body is less twisted The Head is in ova l in form

14. Development The humerus ossifies from six centers Three primary centers for the shaft and epiphyses and three secondary centers for the external tuberosity, the deltoid tuberosity, and the internal condyle. The proximal end fuses with the shaft at about three and one-half years, the distal at about one and a half years of age.