Lecture 12

Question 1

What are the Anterior Throacic muscles?

Answer 1

internal intercostals (interosseus portion)

Question 2

What are the posterior throacic muscles?

Answer 2

serratus posterior inferior

Question 3

What is the origin and insertion of the internal intercostal (interosseus portion)?

What is the Innervation?

What is the Location and Action?

Answer 3

Origin: inferior margin of ribs 1-11 from teh costal end of the rib to the angle of the rib

Insertion: upper surface of the rib immediately beneath that of the origin

Innervation: Intercosal nerve T2-T12, segments of the spinal nerves

Location: deeper than the external intercosals between the ribs **only between the bony parts of the ribs

Action: EXPIRATION, depresses the ribs and supports expiration, decreases the space between the ribs depressing the ribs and shrinks the volume o fthe thoracic cavity

Question 4

What is Origin and insertion of the serratus posterior inferior?

What is it’s course and action?

Answer 4

Origin: spinous processes of T11, T12 and L1-L3

Insertion: lower margins of ribs 7-12

Course: upward and lateral

Action: holds down lower ribs when contracted

Question 5

What are the Abdominal Muscles?

Answer 5

rectus abdominus

external abdominal oblique

internal abominal oblique

transverse abdominus

Question 6

What is the origin, insertion, innervation of rectus abdominus?

Answer 6

Origin: crest of pubis medially to the pubic symphasis

Insertion: sternum (xypohoid process) and costal parts of ribs 5-7

Innervation: lower thoracic spinal nerves (7-12)

Question 7

What is the course and action of the Rectus Abdominus?

Answer 7

• Course: up to tendinous inscription above

Action:

Compresses abdominal contents for increased pressue to reduce size of thoracic cavity during exhalation

Helps pull ribs down for exhalation

Flexes vertebral column

Compresses the viscera/gut

Question 8

What is the Origin, Insertion and Innervation fo the External Abominal Oblique

Answer 8

• Origin: bony surface and inferior borders of lower 8 ribs
• Insertion:

liac crest
• inguinal ligament
• abdominal aponeurosis- linea semilunaris costal parts of lower 8 ribs

• Innervation: lower thoracic spinal nerves 7-12

Question 9

What is the course and Action of the external Abdominal Oblique?

Answer 9

• Course: fan downward and medially
• Action:
• Encloses and compresses abdominal contenst for increased abdominal pressure and decreased thoracic volume during EXHALATION
• Pulls lower ribs down for EXHALATION
• Flexes vertebral column (bilateral contraction)

Trunk rotation, unilateral contraction

Question 10

What is the Origin, Insertion and Innervation of the Internal Abdominal Oblique?

Answer 10

• Origin:
• Inguinal ligament
• Iliac Crest
• Insertion
• Abdominal aponeurosis at linea semilunaris
• Costal parts of ribs 7-12

• Innervation: thoracic and lumbar spinal nerves T7- T12 L1

Question 11

What is the action and Course of the Internal Abdominal Oblique?

Answer 11

• Action:
• Encloses and compresses abdominal contents for increased abdominal pressure and decreased thoracic volume during EXHALATION

pushes up the diaphragm

• Course:
• Fibers urn perpendicular to the external abdominal oblique
• Fibers run diagonally upwards and medially

Question 12

What is the Origin, Insertion, Action and Innervation of the transverse abdominus?

Answer 12

• Origin:
• Lumbodorsal fascia (connective tissue forming the posterior abdominal wall at the vertebral column
• Insertion:
• Linea semilunaris
• Inner surface of ribs 6-12
• Pubis
• Action: encloses and compresses the abdominal contest for increased abdominal pressue and decreased thoracic volume during EXHALATION
• Innervation: thoracic and lumbar spinal nerves

Question 13

Where does the abdominal wall run?

Answer 13

From the diaphragm superiorly to the pelvis inferitorly

Superior limit- diaphragm

Inferior limit: pelvis

Question 14

What is the abdominal Aponeurosis?

Answer 14

flat tendonous structure that serves as an insertion point for various abdominal muscles

• Sheet of tendon allowing muscles to attach here

this fills the abdomen from the sternum and costal coartilages of ribs 5-12 to the pubis and inguinal ligament

Question 15

What are the non muscular structurels of the abdominal wall?

Answer 15

abdominal aponeurosis

linea alba

linea semilunaris

inguinal ligament

transervse inscriptions

lumbodorsal facia (thoracolumbar facia)

Question 16

What are the three main connective tissue types in the abdomen?

Answer 16

Facia: sheet like membranes that surround organs or muscles (least dense)

Ligament: connects bone to bone or holds organs in place (middle density)

Tendon: connects muscles to bone or in some cases, muscle to muscle. A sheet like tendon that is thicker than fascia is callse aponeurosis. (most dense)

Question 17

What is

1?

2?

3?

4?

6?

7?

8?

Answer 17

1. external abdominal oblique
2. transverse facia
3. transversus abdominus muscle
4. Internal abdominal oblique
5. Rectus Abdominus
6. Linea Alba

8, Linea Semilunaris