Extrinsic forelimb muscles (medial)

Question 1

M. pectoralis profundus (origin, insertion & action)?

Answer 1

ORIGIN - 1st to last sternebrae
INSERTION - Lesser & greater tubercle of humerus
ACTION - adducts & retracts the forelimb

Question 2

M. pectoralis superficialis (origin, insertion & action)?

Answer 2

ORIGIN - 1st & 2nd sternebrae
INSERTION - whole crest of greater tubercle of humerus
ACTION - draw back limb inward, forward or back, and draw trunk sideward

Question 3

M. serratus ventralis (origin, insertion & action)?

Answer 3

ORIGIN - 1. transverse processes of last 5 cervical vertebrae, 2. 1st 7 to 8 ribs
INSERTION - serrated face of scapula (sub scapular)
ACTION - support trunk & depress the scapula

Question 4

M. Rhomboideus (origin, insertion & action)?

Answer 4

ORIGIN - 1. occipital bone (bottom of skull), 2. Raphé of neck, 3. spinous process of T4 to T6
INSERTION - medial surface of dorsal border of scapula
ACTION - elevate forelimb & draw scapula against trunk