Diaphragm, Abdominal Wall and Pelvic Floor

Question 1

what are the boundaries of the abdominopelvic cavity?
superiorly: ??
inferiorly: ??
posterior abdominal wall: ??
anterolateral abdominal wall: ??
anterior: ??

Answer 1

superiorly: diaphragm
inferiorly: pelvic floor
posterior abdominal wall: psoas major, quadratus lumborum
anterolateral abdominal wall: external oblique abdominals, internal oblique abdominals, transverse abdominis
anterior: rectus abdominis

Question 2

what is the shape of the diaphragm?

Answer 2

dome shape with a central tendon

Question 3

what are the attachments of the diaphragm?

Answer 3

L1, 2 + 3; lower 6 cartilages + ribs; superiorly= central tendon

Question 4

what are the openings of the diaphragm?

Answer 4

inferior vena cava (T8), oesophagus (T10), descending aorta passes behind (T12)

Question 5

what is the innervation of the diaphragm?

Answer 5

phrenic nerve (C3,4,5)

Question 6

what muscles are in the pelvic floor?

Answer 6

levator ani + coccygeus

Question 7

what is the function of the pelvic floor?

Answer 7

support contents of the pelvic cavity

Question 8

psoas major attachments?

• anterior = ?
• posterior = ?
• insert onto = ?

Answer 8

• anterior = from the vertebral bodies/ iv discs
• posterior = from the transverse processes
• insert onto = less trochanter of femur

Question 9

what is the orientation, action and moment arm of the psoas major?

Answer 9

• vertical orientation ( + close to joint axis)
• action- primarily a hip flexor, also compression of lumbar spine
• small moment arms for flexor or extension

Question 10

what are the attachments of quadratus lumborum?

Answer 10

12th rib, lumbar transverse processes, posterior iliac crest

Question 11

what are the moment arms for quadratus lumborum?

• sagittal movements (F/E)= ??
• coronal movements (LF)= ??

Answer 11

• sagittal movements (F/E)= minimal

- coronal movements (LF)= large

Question 12

what are the EMG activity for quadratus lumborum?

Answer 12

• active during flexion and extension activities

- active during axial loading activities

Question 13

what is the innervation of quadratus lumborum?

Answer 13

thoracolumbar ventral rami

Question 14

what are the attachments of rectus abdominis?

• superior attachment= ??
• inferior attachment= ??

Answer 14

• superior attachment= xyphoid process + adjacent rib cartilages
• inferior attachment= pubic crest + symphysis

Question 15

what is the innervation of rectus abdominis?

Answer 15

T7-12 ventral rami

Question 16

what is the action of rectus abdominis?

Answer 16

trunk flexion

Question 17

what are the attachments + insertion of transverse abdominis?

• posterior attachment = ??
• superior attachment = ??
• inferior attachment = ??
• insertion = ??

Answer 17

• posterior attachment = thoracolumbar fascia
• superior attachment = internal aspect of lower ribs/cartilages
• inferior attachment = iliac crest and inguinal ligament
• insertion = linea alba (and lower fibres onto pubic crest)

Question 18

what is the innervation of transverse abdominis?

Answer 18

T7-L1 ventral rami

Question 19

what is the action of transverse abdominis?

Answer 19

increase IAP

Question 20

what are the attachments of internal oblique abdominal?

• posterior attachment= ??
• superior attachment= ??
• inferior attachment= ??
• anterior attachment= ??

Answer 20

• posterior attachment= TLF
• superior attachment= lower 4 ribs and cartilages
• inferior attachment= anterolateral iliac crest, inguinal ligament
• anterior attachment= linea alba via aponeurosis

Question 21

what is the innervation of internal oblique abdominal?

Answer 21

T7-L1 ventral rami

Question 22

what is the action of internal oblique abdominal?

Answer 22

B= trunk flexion and increase IAP, U= ipsilateral rotation and LF

Question 23

what are the attachments of external oblique abdominal?

• superior attachment= ??
• inferior attachment= ??

Answer 23

• superior attachment= external surface posterior lower 8 ribs
• inferior attachment= linea alba via aponeurosis and anterolateral iliac crest

Question 24

what is the innervation of external oblique abdominal?

Answer 24

T7-12 ventral rami

Question 25

what is the action of external oblique abdominal?

Answer 25

B= trunk flexion and increase IAP, U= contralateral rotation and ipsilateral LF

Question 26

what is the arcuate line?

Answer 26

midline between umbilicus and pubic symphysis

Question 27

what is upper 3/4 of the rectus sheath made up of? - anterior= aponeuroses of ?? - posterior= aponeuroses of ??

Answer 27

- anterior= aponeuroses of: external oblique abdominal; 1/2 internal oblique - posterior= aponeuroses of: 1/2 internal oblique, transverse abdominis

Question 28

what does the lower 1/4 (below arcuate line) of the rectus sheath made up of?

Answer 28

- aponeuroses all anterior | - posterior= transversalis fascia

Question 29

what does the anterior and middle layer of the thoracolumbar fascia consist of? - attach to: ?? - envelope: ?? - posterior attachment for: ??

Answer 29

- attach to: lumbar transverse processes - envelope: quadratus lumborum - posterior attachment for: transverse abdominis and internal oblique abdominal

Question 30

what does the posterior layer of the thoracolumbar fascia consist of? - attaches to: ?? - encloses: ?? - laterally fuses with: ??

Answer 30

- attaches to: T/L/S spinous processes - encloses: erector spinae group - laterally fuses with: middle layer

Question 31

what does the thoracolumbar fascia blend with?

Answer 31

erector spinae aponeurosis (caudal tendons of longissimus thoracis PT and iliocostalis lumborum PT), latissimus dorsi, gluteus maximus

Question 32

how can muscles of the abdominopelvic cavity contribute to stability of the lumbar spine? (give explanation) 1. ? 2. ? 3. ?

Answer 32

1. increasing intra-abdominal pressure: - belts around the abdomen and rib cage maximised the pressure increase - increased IAP, extensor moment and increased the force required to flex the lumbar spine - contributes to spinal stability 2. abdominal muscle co-contraction - muscular co-contraction can 'stiffen' the vertebral motion segment - contraction of the muscles that act across vertebral motion segments imposes compression across the joint -> makes it more difficult to move the joint "increases stability" 3. TLF (abdominopelvic muscle attachments - extensive muscular attachments into the thoracolumbar fascia which, in turn, attach to lumbar transverse and spinous processes - possible contributions to motion segment stability

Question 33

what are the 2 diaphragm function?

Answer 33

1. respiration | 2. trunk postural control