Canine Thorax and Abdomen-Muscles

Question 1

Cervical Hypaxial Muscles (names and overall function)

Answer 1

Longus colli (ventral) and Longus capitis (lateral)

Function: flex head and neck

Question 2

Sublumbar hypaxial Muscles (names and overall function)

Answer 2

Quadratus lumborum, psoas major, psoas minor, iliacus, and iliopsoas

Function: flex lumber vertebrae

Question 3

Serratus dorsalis cranialis

Answer 3

Thoracic wall muscle, runs caudoventrally to ribs

Function: draws forward during inspiration

Question 4

Serratus dorsalis caudalis

Answer 4

Thoracic wall muscle, runs cranioventrally to ribs

Function: draws caudally during expiration

Question 5

External abdominal oblique

Answer 5

abdominal wall muscle, lateral ribs running craniodorsal to caudoventral, ends at midline in aponeurosis

Function: contract in inspiration and towards the end of expiration

Nerve: caudal intercostal and ventral lumbar nerves

Question 6

Internal abdominal oblique

Answer 6

abdominal wall muscle, origin on tuber coxae, runs caudodorsal to cranioventral, ends at midline

Function: inspiration and towards end of expiration

Nerve: caudal intercostal and ventral lumbar nerves

Question 7

Transverse abdominis

Answer 7

abdominal wall muscle, origin from last ribs and transverse processes of lumbar vertebrae, runs dorsal to ventral, ends in aponeurosis

Nerves: caudal intercostal and ventral lumbar nerves

*Thoracic and abdominal spinal nerves run alongside muscle fibers

Question 8

Rectus abdominis

Answer 8

abdominal wall muscle, origin from ventral rib cartilages, runs craniocaudal to pubic rim

Nerve: caudal intercostal and ventral lumbar nerves

Question 9

Coccygeus

Answer 9

pelvic muscle, ischiatic spine to lateral surface of tail on 2-5 coccygeal vertebrae

Function: tail against anus and genitalia, or between rear legs (with depressors), wag tail with lateral flexion (unilateral involvement)

Nerve: caudal rectal nerve

Question 10

Levator ani

Answer 10

pelvic muscle, medial shaft of ilium, dorsal surface of pubis, and pelvic symphysis to 3-7 coccygeal vertebrae, connects to external anal sphincter

Function: tail against anus and genitalia, sharp angulation of tail during defecation, cranial and lateral tail wag (unilateral involvement)

Nerve: caudal rectal nerve