Exam 2 Abdominal Muscles and Mediastinum Objectives

External Obliques

O: 5th - 12th Ribs

I: Linea alba, pubis, anterior iliac crest

A: Lateral flexion, compression, and opposite side rotation of the trunk

Internal Obliques

O: Thoracolumbar fascia, iliac crest

I: 10th - 12th ribs, linea alba

A: Lateral flexion, compression, and opposite side rotation of the trunk

Rectus Abdominis

O: Pubis and pubic symphysis

I: Xiphoid process and costal cartilages of ribs 5-7

A: flexes trunk, compresses abdomen

Transverse Abdominis

O: Inner 7-12 costal cartilages, thoracolumbar fascia, iliac crest

I: Linea alba, pubis

A: Rotates trunk to the same side, compression of the abdomen

External oblique

The external oblique is superficial to the internal oblique

Internal oblique

The internal oblique is deeper than the external oblique

Rectus abdominis

Rectus abdominis is medial to transverse abdominis

Transverse abdominis

The transverse abdominis is the deepest layer under the internal oblique and is lateral to the rectus abdominis

What innervates the abdominal muscles?

All abdominal muscles are innervated by the intercostal nerves

What is your core?

- Core refers to all borders of the abdominal cavity

- The abdominal muscles for the anterior and inferior regions of the core.

What are the borders of your core?

- The diaphragm forms the superior border

- The perineum forms the inferior border

Why is your core important?

Provides great reinforcement (support) to your lumbar spine

Takes the "heat" off your lower spine

A strong core helps offset lordosis

Pathway of the superior epigastric artery:

Continues from the internal thoracic artery. Starts at the level of the costal cartilages.

Pathway of the inferior epigastric artery:

Continues from the superior epigastric artery. Starts at the level of the umbilicus. Drains into the external iliac artery.

Define mediastinum

The cavity is located medially between the lungs.

borders of the mediastinum

Bordered anteriorly by the sternum/costal cartilages, posteriorly by the thoracic spine, laterally by the mediastinal pleura, and superiorly by the thoracic inlet and inferiorly by the diaphragm.

All structures in the mediastrinum

Contains major blood vessels, the heart, vagus, and phrenic nerves.

Divisions of the Mediastinum

Superior

Inferior

Anterior

Posterior

Middle

Structures within the Mediastinum Divisions

Superior: Structures that pass from head/neck to thorax (aorta arch, trachea, esophagus, Superior Vena Cava, Vagus N

Anterior: Branches of internal thoracic A and N

Middle: Heart and great vessels, Ascending aorta, pulmonary trunk,

Posterior: Esophagus, Thoracic aorta

Phrenic Nerve

phrenic nerve originnates Cervical plexus C1 - C4 and innervates diaphragm

Runs lateral to the vagus nerve and deep to the subclavian vessels.