Superficial Muscles of the Chest (Rat)

Xiphihumeralis

A long, thin, flat ribbon of muscle Originating: from the xiphoid process of the sternum, with its anterior part passing dorsal (interior) to the posterior portion of the pectoralis minor. Insertion: On the humerus; the insertion is probably covered by fatty tissue in the axilla.

Submaxillary Salivary Gland

At the angle of the jaw, adjacent to the ear. A large rounded pinkish body.

Posterior Facial Vein

Crosses the submaxillary salivary gland. (Maybe partially obscured by another lymph gland)

External Jugular Veins

Runs superficially along the sides of the throat.

Lymph Glands

Small, smooth, kidney bean colored bodies

Pectoralis Major

The large triangular muscle just posterior to the pectoantebrachialis. Origin: Sternum and median ventral raphe. Insertion: On the humerus (*to see the insertion, transect the pectoantebrachialis and fold the cut distal portion aside)

Pectoantebrachialis (Chest muscle in front of the arm)

The most anterior and superficial of the pectoral group. Origin: Manubrium Insertion: By flat tendon, on the deep fascia of the upper arm.

Pectoral Group

The muscles covering the ventral side of the thorax. Action: Adduction of arm

Pectoralis Minor

The next posterior muscle, appearing as a scalene triangle: its anterior portion is largely covered by the pectoralis major. Origin: Sternum Insertion: On the humerus (*if you transect the belly of the latter, you may see the extent and the subtle subdivisions of the pectoralis minor)