COMPARATIVE ANATOMY HOME
COMPARATIVE ANATOMY TABLE OF CONTENTS
  OBL HOME OBL REFERENCES
TRUNK MUSCLES
The latissimus dorsi (and its derivative, the teres major) extend, adduct, and medially rotate the arm.
DRAWING
The latissimus dorsi is the only dorsal muscle acting on the limb to originate outside the limb.

FROG

frog

frog

ALLIGATOR

LATISSIMUS DORSI

LATISSIMUS DORSI

CHICKEN

LATISSIMUS DORSI

In mammals, the ancestral single sheet of the latissimus dorsi divides to form the latissimus dorsi, the teres major and cutaneous maximus. In most mammals the pectoralis splits and also forms part of the cutaneous maximus. (Webster, 1974, p.139; Hartman, 1933).

OPOSSUM

LATISIMUS DORSI

LATISIMUS DORSI

CAT

LATISIMUS DORSI

LATISIMUS DORSI

GOAT

LATISIMUS DORSI

SHEEP

LATISIMUS DORSI

COW

LATISIMUS DORSI

PIG

PIG

RHESUS MONKEY

LATISIMUS DORSI

In higher apes, the latissimus dorsi developed an additional origin on the iliac crest. (Hartman, 1933).

HUMAN MODEL

In higher apes, the latissimus dorsi developed an additional origin on the iliac crest.  (Hartman, 1933).

In higher apes, the latissimus dorsi developed an additional origin on the iliac crest.  (Hartman, 1933).
The ancestral muscles of the chest and shoulder have been adapted to a variety of lifestyles. Birds have adapted the pectoralis and suracoracoideus muscles for flight while bats have adapted to flight using the pectoralis, clavodeltoid, subscapularis, and serratus ventralis muscles. (Webster, 1974) In moles, the teres major one of largest muscles of shoulder, allowing them to burrow. (Webster, 1974, p.145-6).

The panniculus carnosus is a thin sheet of muscle which covers most of the trunk and limbs just deep to the skin in monotremes and marsupials. It is derived from pectoralis and latissimus muscles. In placental mammals it is reduced although remnants may persist in different body regions. The pectoralis abdominis and panniculus carnosus which are present in Old World monkeys are absent in humans. The panniculus gradually decreased in higher primates. In humans a few axillary slips and an occasional sternalis muscle over the pectoralis are remnants of this ancestral muscle. (Weichert, 1970, p. 528; Hartman, 1933)

PANNICULUS