Thorax/Abdomen

Question 1

Serratus Posterior Superior

Answer 1

Elevates ribs - inspiration

Question 2

Levatores Costorum

Answer 2

Raises the ribs

Question 3

External Obliques

Answer 3

Anterior Fibers
Bilaterally - flex vertebral column, support and compress abdominal visceral, depress the thorax, and assist in respiration
Unilaterally with the ant fibers of internal oblique on opposite side - rotate vertebral column, bring thorax forward when pelvis is fixed or pelvis backward when thorax is fixed

Lateral Fibers
Bilaterally - flex vertebral column with major influence on lumbar spine, tilting pelvis posteriorly
Unilaterally - with IO on same side, laterally flex vertebral column
Narrows subcostal angle

Question 4

Internal Obliques

Answer 4

Lower Fibers
Compress and support lower abdominal visceral in conjunction with the transverses abdominis

Upper Fibers
Bilaterally - flex vertebral column, support and compress the abdominal visceral, depress the thorax and assist in respiration
Unilaterally with EO on opposite side - rote vertebral column, bringing thorax backward or pelvis forward

Lateral Fibers
Bilaterally - Flex vertebral column, depress thorax
Unilaterally with EO on same side - laterally flex vertebral column
Widens subcostal angle

Question 5

Transverse Abdominal

Answer 5

Acts like a girdle to flatten the abdominal wall and compress the abdominal viscera
Upper portion helps to decrease the infrasternal angle of ribs as in expiration
No action in lateral trunk flexion except that it acts to compress the visceral and to stabilize the linear alba permitting better action by the anterolateral trunk muscles

Question 6

Rectus Abdominis

Answer 6

Flexes vertebral column by approx thorax and pelvis anteriorly
Pelvis fixed - thorax moves toward pelvis
Thorax fixed - pelvis moves toward thorax
May be short with depressed chest

Question 7

Transversus thoracis

Answer 7

Draws ribs down

Question 8

Subcostals

Answer 8

Draws ribs togethers

Question 9

External intercostals

Answer 9

Elevates ribs by pulling them closer together

Question 10

Internal Intercostals

Answer 10

Draws ribs together and if supported from above, elevates ribs

Question 11

Innermost Intercostals

Answer 11

Draws ribs together and if supported from above, elevates ribs

Question 12

Diaphragm

Answer 12

Main muscle for inspiration

Question 13

Levator ANI - Puborectalis

Answer 13

Critical for maintaining normal function of external anal sphincter

Question 14

Pubococcygeus

Answer 14

Critical for maintaining normal function of external anal sphincter

Question 15

Iliococcygeus

Answer 15

Supports and raises pelvic floor increasing intra-abdominal pressure and draws anus forward constricting it

Question 16

Coccygeus

Answer 16

Draws coccyx forward, supports pelvic floor

Question 17

Pyramidalis

Answer 17

Tenses linea alba

Question 18

Cremasteric

Answer 18

Pulls testes up toward superficial inguinal ring

Plays a role in testicular thermoregulation