Muscles of the abdominal wall Flashcards
what is the ori and ins of Obliquus externus abdominis
Ori: external surface of lower 8 ribs
Ins: Linea alba (midline of the rectus sheath)
Pubic tubercle
Anterior half of iliac crest
function of obliquus externus abdominis
contralateral rotation, flexion of the trunk, compresses the abdominal contents
innervation of obliquus externus abdominis
Intercostal nerves (T7 to T12)
what is the ori and ins of Obliquus internus abdominis
Ori: lateral 1/3 of Inguinal ligament
- Anterior 2/3 of iliac crest,
- Thoracolumbar fascia
Ins: Linea alba
Lower 3 ribs
function of obliquus internus abdominis
ipsilateral rotation, flexion of the trunk, compression of abdominal contents
innervation of obliquus internus abdominis
Intercostal nerves (T6 to T12) & L1
which muscle is the largest and most superficial of the three flat muscles in the anterior abdomen
Obliquus externus abdominis
which muscle is irregularly quadrilateral form and situated at the lateral and anterior parts of the abdomen
Obliquus internus abdominis
which muscle is the most internal of the flat muscles of the abdomen
transverses abdominis muscle
Transversus abdominis muscle Ori and Ins
Ori:
Inguinal ligament
Iliac crest
Thoracolumbar fascia
Cartilages of the lower 6 ribs
Ins:
Linea alba
Transversus abdominis muscle function
compresses the abdominal contents (think corset)
innervation of Transversus abdominis
Intercostal nerves (T6 to T12) & L1
which muscle is long flat and extends the whole length of the front of the abdomen
Rectus abdominis
the Rectus abdominis is seperated from its fellow of the opposite side by what?
linea alba
the Rectus abdominis is cross by fibrous brands, three in number, which are named the ?
tendinous intersections
Ori and Ins of Rectus abdominis
Ori: pubic crest, and symphysis pubis.
Ins:
Xiphoid process
Cartilages of ribs 5,6,7
the function of Rectus abdominis
flexion of the trunk @ the spinal joints, posterior tilt of pelvis, compresses the abdominal contents
innervation of Rectus abdominis
Nerve: Intercostal nerves (T6 – T 12)
what is the fatty layer of the abdominal wall?
Campers Fascia
The Campers Fascia is a superficial layer of
adipose and areolar connective tissue
where is the Campers Fascia more prominent
in the lower aspect of the abdomen (below the umbilicus)
What is the deep membranous layer of the abdominal wall?
Scarpa’s Fascia
the Scarpa’s Fascia is anchored laterally to the __________ of the external oblique and medially to the ______ of the rectus sheath
aponeurosis, linea alba
what is the protective covering (deepest layer) of the rectus abdominus
the rectus sheath
what is the rectus sheath compose of
Composed of the aponeurosis of the three flat muscles as they converge in the midline to form the median linea alba
where does the composition of the rectus sheath change?
inferior to the umbilicus
- The composition and arrangement of muscle layers differs depending on location with respect to an area known as the Arcuate line
why is it harder to build strength in the lower abdomen
the composition of the rectus sheath changes
what is the line located 1/2 of the distance between the umbilicus and pubic symphysis called?
Arcuate line
Inferior to the arcuate line the aponeuroses of all 3 lateral abdominal muscles pass ______ to the rectus abdominis muscle
anterior
At this level, the internal aspect of rectus abdominis muscle is in direct contact with the transversalis facia
A thin layer of CT located between the posterior surface of the TA muscle a the extraperitoneal fat of the parietal peritoneum
name the layers of the abdominal wall (7)
- skin
- camper’s fascia
- scarpa’s fascia
- rectus sheath
- Anterior lamina
- Posterior lamina - transversalis
6, extraperitoneal fat - parietal peritoneum
describe the anterior and posterior lamina of the rectus sheath above the arcuate line
Anterior lamina (sheet) – full aponeurosis of external oblique and ANTERIOR 1/2 of the aponeurosis of the internal oblique
Posterior lamina (sheet) – POSTERIOR 1/2 of the aponeuroses of the internal oblique and full aponeurosis of transversus abdominis
describe the anterior and posterior lamina of the rectus sheath below the arcuate line
Anterior lamina (sheet) – aponeuroses of all 3 abdominal muscles
- external oblique
- interal oblique
- transversalis facia
Posterior lamina (sheet) – no layer!
Transversalis facia now directly meets the posterior aspect of rectus abdominis mm.
name the layers of the anterolateral abdominal wall (9)
- Skin/Superficial fascia
- Camper’s fascia – fatty layer
- Scarpa’s fascia – membranous layer
- External oblique m.
- Internal oblique m.
- Transversus abdominis m.
- Transversalis fascia
- Extraperitoneal fat
- Parietal layer of peritoneum
Quadratus lumborum Ori and Ins
Ori:
- Iliac crest
- Iliolumbar ligament
Ins:
- Rib 12
- TPs of L1 – L4
Quadratus lumborum function
Extends the trunk, lateral flexion of the trunk, fixes Rib 12 during inspiration
which muscle is a powerful stabilizer of the lumbar spine
Quadratus lumborum
innervation of Quadratus lumborum
Ventral rami of spinal nerves T12, L1, 2, 3, 4
Psoas Major Ori and Ins
Ori: Bodies and TPs of L1 – L5
Ins: Lesser trochanter of femur
function of Psoas Major (4)
flexion of the thigh (more to stabilize the lumbar), lateral rotation of the thigh, flexion of the trunk (bilateral action), lateral flexion of the trunk
innervation of Psoas Major
Nerve: Nerve: Lumbar plexus (L1, L2, 3)
Iliacus Ori and Ins
Ori:
Iliac fossa
Sacral ala
Ins: Lesser trochanter of femur
function of iliacus (2)
Function (2): Flexion of the thigh, lateral rotation of the thigh
which two muscles are often considered to be the iliopsoas M.
psoas major and the iliacus muscles
because of their common distal attachment onto the lesser trochanter of femur.
- not reasonable to refer to these two as one unit -> you can injure one and not the other
Psoas typically causes the problem
innervation of Iliacus
Nerve: Femoral N.
It is an oblique canal about 4 cm. long, directing downward and medial ward, and placed parallel with and a little above the medial half of the inguinal ligament. It extends from the deep inguinal ring to the superficial inguinal ring.
The Inguinal Canal:
what does the The Inguinal Canal contain in men
It contains the spermatic cord (containing ductus (vas) deferens, testicular vessels, autonomic nerves and lymphatic) and the ilioinguinal nerve
what does the inguinal canal contain in females?
the round ligament of the uterus and the ilioinguinal nerve in females.
A triangular gap in the external oblique aponeurosis
Superficial inguinal ring
an oval shape opening in the fascia transversalis; situated half an inch above the midinguinal point (and immediately lateral to the stem of the inferior epigastric vessels)
- Deep inguinal ring
is formed by the fusion of the lowest aponeurotic fibers of the internal oblique and of the transversus abdominis muscles
Conjoint tendon
the conjoint tendon lies behind __ ?
It lies behind the superficial inguinal ring and strengthens the abdominal wall at this point.
