Canine Forelimb Extrinsic Muscles

Question 1

Superficial Pectoral

Answer 1

two parts: pectoralis transversus and pectoralis descendens (don’t need to distinguish)

• origin: first three sternebrae and raphe of ventral midline
• insertion: entire crest of greater tubercle of humerus
• action: prevents limb abduction when bearing weight, adducts limb when not

Question 2

deep pectoral

Answer 2

• covers large about of ventral torso, cranial portion covered by superficial pecs
• origin: ventral part of sternum and raphe at ventral midline
• insertion: lesser tubercle of humerus and its aponeurosis attaches to great tubercle/crest
• action: pull trunk cranially limb weighted or advanced (moves body forward), extends shoulder, and draws limb caudally when not weighted

Question 3

brachiochephalicus parts

Answer 3

cleidobrachialis and cleidocephalicus

-cleidocephalicus parts: cleidocervicalis/pars cervicalis and cleidomastoideus/pars mastoideus

Question 4

cleidobrachialis

Answer 4

origin: clavicular intersection
insertion: distal end of cranial border of humerus
action: advance the limb

Question 5

cleidocervicalis aka pars cervicalis

Answer 5

• origin: clavicular insertion
• insertion: middorsal raphe of neck
  action: extend the shoulder

Question 6

cleidomastoideus aka pars mastoideus

Answer 6

• origin: clavicular insertion
• insertion: mastoid process of skull
  action: draw head and neck to the side

Question 7

omotransversarius

Answer 7

omo-=shoulder; transver process of atlus=transversarius
-superficial cervical lymph nodes lie dorsally to this muscle

• origin: wing/transverse process of atlas (most cranial vertebra
• insertion: distal end of spine of scapula
• action: advance the limb or flex the neck laterally

Question 8

sternocephalicus

Answer 8

origin: first sternebra/sternum
- insertion: mastoid part of temporal bone (behind the ear); similar insertion to pars mastoideus of cleidocephalicus
- action: to draw the head and neck to the side

Question 9

sternohyoideus

Answer 9

• lies on the trachea, covered by the sternocephalicus caudally
• origin: first sternabra and first costal cartilage (?)
• insertion: basihyoid bone
• action: pull the tongue and larynx caudally

Question 10

sternothyroideus

Answer 10

covered at origin by sternohyoideus

• origin: first costal cartilage
• insertion: caudolateral surface of thyroid cartilage
  action: same as sternohyoideus-to pull tongue and larynx caudally