Anterolateral Abdominal Muscles (Quiz 2/Exam 2) Flashcards
What is the origin/proximal attachment of the external oblique?
external surfaces of ribs 5-12
What is the largest anterolateral abdominal muscle?
external oblique
What are the insertions/distal attachments of the external oblique?
-linea alba
-pubic tubercle
-anterior half of iliac crest
What innervates the external oblique?
thoracoabdominal nerves and subcostal n.
What are the actions of the external oblique?
-compresses and supports abdominal viscera
-flexes and rotates trunk
What are the origins/proximal attachments for the internal oblique?
-thoracolumbar fascia
-anterior 2/3 of iliac crest
-lateral 3rd of inguinal ligament
What are the insertions/distal attachments for the internal oblique?
-inferior border of ribs 10-12
-linea alba
-pectin pubis via conjoint tendon
What innervates the internal oblique?
thoracoabdominal nerves
What are the actions of the internal oblique?
-compresses and supports abdominal viscera
-flexes and rotates trunk
What are the origins/proximal attachments for the transversus abdominis?
-internal surface of 7th-12th costal cartilages
-thoracolumbar fascia
-iliac crest
-lateral 3rd of inguinal ligament
What are the insertions/distal attachments of the transversus abdominis?
-linea alba with aponeurosis of internal oblique
-pubic crest
-pectin pubis via conjoint tendon
What innervates the transversus abdominis?
thoracoabdominal nerves
What are the actions of the transversus abdominis?
compresses and supports abdominal viscera
What is the origin/proximal attachment for the rectus abdominis?
pubic symphysis and pubic crest
What is the insertion/distal attachment for the rectus abdominis?
xiphoid process and 5th-7th costal cartilages
What are the actions of the rectus abdominis?
-flexes trunk (lumbar vertebrae) and compresses abdominal viscera
-stabilizes and controls tilt of pelvis (antilordosis, helps prevent hyperlordosis)
Which abdominal muscle is absent in 20% of the population?
test q
pyramidalis
What is the origin/proximal attachment of the pyramidalis?
linea alba
What is the insertion/distal attachment for the pyramidalis?
anterior surface of the pubis and the anterior pubic ligament
What is the action of the pyramidalis?
tenses linea alba
The rectus abdominis muscle is enclosed in the rectus sheath and is divided right and left by the linea alba and transversely by the…..
tendinous intersections
All the layers of the anterolateral muscles fuse at the….
test q
umbilicus
The aponeurosis of the anterolateral abdominal muscles forms the _____________ rectus sheath and linea alba
anterior and posterior
The external and internal oblique form which sheath?
rectus sheath
The internal oblique and transversus abdominis form which sheath?
posterior rectus sheath
The arcuate line demarcates the ________ rectus sheath and the transversalis fascia covering the inferior quarter
posterior
Superiorly, the posterior rectus sheath continues as the…..
transversus thoracis m.
The ________________ abdominis form a neurovascular plane of the anterolateral abdominal wall that contains nerves and arteries
test q
internal and transversus
The contralateral external and internal oblique muscles form a ____________, a 2 bellied muscle sharing a common central tendon that works as a unit
“digastric muscle”
What are the 4 main functions of the anterolateral abdominal muscles?
1) combined action produces the force required for defecation, vomiting, child birth, and heavy lifting
2) supports the abdominal viscera and protect them from injuries
3) rectus abdominis is a powerful flexor of the thoracic wall
4) the oblique muscles assist in posture and movement of the trunk like rotation and flexion
