kin 100 - muscles of the abdominal walls

what is the anterolateral abdominal wall made up of?

• external oblique

• internal oblique

• transverse abdominals

• rectus abdominus

what is the fiber direction of external obliques?

• anteroinferior (hands in pockets)

what does the inferior edge of the aponeurosis of the external oblique create?

• the inguinal ligament

what are the inguinal ligament’s attachmetn styles?

• anterior superior iliac spine to the pubic tubercle

internal oblique fiber direct

anterosuperior

transverse abdominal fiber pattern

horizontal fiber pattern

the 3 anterolateral muscles of the abdominal walls in order of superficial to deep

1. external obliques

2. internal obliques

3. transverse abdominals

what happens when 3 of the anterolateral abdominal wall muscles meet?

• so the aponeuroses all meet in the midline of the trunk and form the linea alba

what are the actions of the 3 layers of muscles of the anterolateral border?

• compression and support of the abdominal viscera (soft internal organs inside the abdominal cavity)

• flexion of the trunk

• rotation of the trunk

what is rectus abdominus? what does it run vertically between?

• its the abs

• its bilateral

• it runs vertically between the ribs and the pubic symphysis

what is the purpose of linea alba

• its a white line that seperates hte left and right rectus abdominus muscles

what are tendinous intersecitons?

• they are litearlly intersections between cunks of the rectus abdoninus, making the 6-8 pack we see.

• they seperate the rectus abdominus into 6-8 chunks

label this diagram of the obliques

1. external oblique (anteroinferior fiber direction)

2. internal oblique (anterosuperior fiber direction)

3. transverse abdominal (horizontal fiber direction)

label this diagram of the rectus abdominus

1. rectus sheath

2. rectus abdominus

3. tendinous intersection

4. linea alba

label this diagram of the rectus sheath

1. external oblique

2. internal oblique

3. transverse abdominal

4. aponeurosis of external oblique

5. aponeurosis of internal oblique

6. aponeurosis of transverse abdominal

7. rectus abdominus

8. linea alba

9. rectus sheath

what is the rectus sheath?

• when the aponeuroses of the external obliques + aponeuroses of internal oblique basicaly just combine, and create this sheath that covers the front of the rectus abdominus muscles

what are the 3 openings of the diaphragm?

• caval opening

• esophageal hiatus

• aortic hiatus

what structure comes out of the caval opening? and at what vertebrae?

• the inferior vena cava at level of T8

what structure comes out of the esophageal hiatus and at what vertebrae?

• esophagus, at T10

what structures comes out of the aortic hiatus and at what vertebrae?

• aorta, T12

where does the diaphragm attach?

• the periphery of the margins of the thoracic cage and superior lumbar vertebrae

what does the heart sit on?

• sits on the central tendon of hte diaphragm!!!

what is the diaphragm described as?

• a domed muscle that seperates the thoax from the abdomen

label this diagram of the diaphragmatic openings

1. caval opening

2. inferior vena cava

3. T8

4. esophageal hiatus

5. esophagus

6. T10

7. aortic hiatus

8. aorta

9. T12

mnemonics for diaphragmatic openings

1. I ate 10 eggs at noon (I, 8, 10, E, A, 12)

2. they open, and then they go on hiatus

what are the 5 ligaments of the diaphgram? what view can you see them from?

• 1: midline median arcuate ligament

• 2: bilateral medial arcuate ligaments

• 2: bilateral lateral arcuate ligaments

what structure does the midline median arcuate ligament arch over? what structure does it form?

• it arches over the aorta! specifically the abdominal aorta

• forms the aortic hiatus

what does the bilateral medial arcuate ligament arch over?

• the psaos major muscles!!

what do the bilateral lateral arcuate ligaments arch over?

• the quadratus lumborum muscles

label this diagram of the inferior view of the diaphgram

1. central tendon

2. median arcuate ligament

3. medial arcuate ligament

4. psoas major

5. lateral arcuate ligament

6. quadratus lumborum

what is the posterior abdominal wall made up of?

• psoas major

• iliacus

• quadratus lumborum

psoas major (attachments, actions)

• prox: lateral aspect of lumbar vertebrae/transverse processes of lumbar vertebrae

• distal: lesser trochanter of femur

• actions:

  • thigh flexion

  • trunk flexion (bilateral contraction)

  • trunk lateral flexion (unilateral contraction)

whats something interesting about psoas minor?

• its present in some individuals only

• vestigial muscle?

iliacus (prox, distal, actions)

• prox: iliac fossa

• distal: lesser trochanter of femur

• action: thigh flexion (doesn’t touch vertebrae so it doesnt do anything with the trunk)

what muscle does psaos major unite with? whats it called?

• psoas major unites with iliacus, makes iliopsoas

whats tenderloin in humans?

psoas major

quadratus lumborum (prox, distal, actions)

prox: 12th rib and transverse processes of lumbar vertebrae

distal: iliac crest

actions:

trunk extension (bilateral contraction)

trunk lateral flexion (unilateral contraction)

3 terminal branches of the lumbar plexus that we’ll be studying?

• femoral nerve

• obturator nerve

• lumbosacral trunk

label this diagram of the lumbar plexus

1. femoral nerve

2. lumbosacral trunk

3. obturator nerve