A&P Lab Cat Muscle Quiz

Sternomastoid muscle

joined with the cleidomastoid muscle in humans to form the sternocleidomastoid. The large external jugular veins, which drain the head, should be obvious crossing the anterior aspect of these muscles.

Cleidomastoid muscle

joined with the Sternomastoid muscle in humans to form the sternocleidomastoid. The large external jugular veins, which drain the head, should be obvious crossing the anterior aspect of these muscles.

Mylohyoid muscle

parallels the bottom aspect of the chin

Digastric muscles

form a V over the mylohyoid muscle

Masseter muscle

flanks the digastric muscle laterally. Is NOT one of the neck muscles.

Pectoralis major

5 to 8 cm (2 to 3 inches) wide and can be seen arising on the manubrium, just inferior to the sternomastoid muscle of the neck, and running to the humerus. Its fibers run at right angles to the long axis of the cat's body.

Pectoralis minor

lies beneath the pectoralis major and extends posterior to it on the abdominal surface. It originates on the sternum and inserts on the humerus. Its fibers run obliquely to the long axis of the body, which helps to distinguish it from the pectoralis major. Contrary to what its name implies, the pectoralis minor is a larger and thicker muscle than the pectoralis major.

Xiphihumeralis

can be distinguished from the posterior edge of the pectoralis minor only by virtue of the fact that its origin is lower-on the xiphoid process of the sternum.

Its fibers run parallel to and are fused with those of the pectoralis minor.

Pectoantebrachialis

a thin, straplike muscle, about 1.3 cm (½ inch) wide, lying over the pectoralis major. Notice that the pectoralis major is visible both anterior and posterior to the borders of the pectoantebrachialis. It originates from the manubrium, passes laterally over the pectoralis major, and merges with the muscles of the forelimb approximately halfway down the humerus. It has no homologue in humans.

Rectus abdominis

a long band of muscle approximately 2.5 cm (1 inch) wide running immediately lateral to the midline of the body on the abdominal surface. Humans have four transverse tendinous intersections in the rectus abdominis, but they are absent or difficult to identify in the cat.

Linea alba

the longitudinal band of connective tissue that separates the rectus abdominis muscles. Note the relationship of the rectus abdominis to the other abdominal muscles and their fascia.

External oblique

a sheet of muscle immediately beside the rectus abdominis. Carefully free and then transect the external oblique to reveal the anterior attachment of the rectus abdominis.

Internal oblique

Reflect the external oblique; deeper muscle.

Transversus abdominis

Free and then transect the internal oblique muscle to reveal the fibers of the transversus abdominis, whose fibers run transversely across the abdomen.