Unit 1 Exam Anterior Abdominal Wall

Question 1

External oblique muscle

Answer 1

proximal attachment: lower ribs

distal attachment: iliac crest, linea alba, pubic tubercle

primary actions:
Bilateral: compress abdomen, stabilize spine, flex trunk, posterior pelvic tilt
Unilateral: lateral flexion, contralateral rotation

innervations: anterior rami of T7-T12

Question 2

Internal oblique muscle

Answer 2

proximal attachment: thoracolumbar fascia, iliac crest, inguinal ligament

distal attachment: lower ribs, linea alba, pubic crest, pectineal line

primary actions:
Bilateral: compress abdomen, stabilize spine, flex trunk, posterior pelvic tilt
unilateral: lateral flexion, ipsilateral rotation

innervations: Anterior rami of T7-T12, L1

Question 3

Transversus abdominis muscle

Answer 3

proximal attachment: thoracolumbar fascia, iliac crest, inguinal ligament, lower ribs

distal attachment: linea alba, pubic crest, pectineal line

primary actions: compress abdomen, stabilize spine

innervations: anterior rami of T7-T12, L1

Question 4

Rectus abdominis muscle
(has tendonous intersections on it)

Answer 4

proximal attachments: pubic crest, pubic tubercle, pubic symphysis

distal attachments: lower ribs, xiphoid process

primary actions: compress abdomen, flex trunk, posterior pelvic tilt

innervations: anterior rami T7-T12

Question 5

Pyramidalis muscle (variable)

Answer 5

proximal attachment: pubis, pubic symphysis

distal attachment: linea alba

primary actions: tense linea alba

innervations: anterior ramus T12

Question 6

Cremaster muscle (males)

Answer 6

proximal attachment: internal oblique

distal attachment: spermatic cord

primary actions: pulls testes upward

innervations: genital branch of genitofemoral n (L1-L2)