Class # 11 Thoracic and Abdominal Walls

• Articulation: head of each rib with the body of at least one thoracic vertebra
• aka: costovertebral joints
• kind: plane synovial joint

• Articulation: tubercle articulates with the transverse process of a single thoracic vertebra
• aka: costovertebral joint
• kind? plane synovial joint

• Direction: down towards pockets; anteroinferiorly
• Pairs: 11
• Origin:
• Insertion:
• innervation: 1-11 intercostal nerves
• action: keep the intercostal spaces rigin during breathing; most active during inspiration elevating ribs

• Direction: perpendicular to external fibers; run inferoposteriorly from the floor of the costal grooves to the ribs below
• Pairs: 11
• Origin:
• Insertion:
• innervation: 1-11 intercostal nerves
• action: keep the intercostal spaces rigin during breathing; most active during expiration depressing ribs

• origin: inner surface of costal cartilage of 2-6 ribs
• insertion: inner surface of sternum and xiphoid process
• innervation: 2-7 intercostal nerves
• action: lowers ribs(in expiration)

• origin: internal surfaceof lower ribs near their angles
• insertion: superior borders of 2 or 3 ribs below
• innervation:
• action: same as internal costal muscles; keep spaces rigid during breathing; most active during expiration depressing ribs

• Arteries of the thoracic wall
• The post. intercostal arteries arise from the thoracic aorta.
• The ant. intercostal arteries aris from indirect or
• direct branches of the internal thoracic artery.
• Nerves of the thoracic wall
• The intercostal nerves are the ventral rami of the
• T1-T11 nerves
• the subcostal nerve arises from is the ventral ramus of the T12 nerve

• origin:
• insertion: central tendon
• innervation: phrenic nerve of cervical plexus (C3-C5)
• action: for respiration

• encased in: rectus sheath formed by aponeurosis of 3 pairs of anterolateral abdominal muscles
• divided by: tendinous inscriptions
• origin: pubis
• insertion: xiphoid process & costal cartilages 5-7
• innervation: thoraco-abdominal nerves
• action: flexes trunk, comresses abdominal viscera

• origin: external surfaces of 5-12 ribs
• insertion: linea alba, pubic tubercle, ant. half of iliac crest
• innervation: thoraco-abdominal nerves (ant. rami T7-T11) & subcostal nerve
• action: compress & support abdominal viscera; flex & rotate trunk
• Q: infer edge of each muscle from ASIS to pubic tubercle

fibers: run perpendicular to thos of the external oblique, they vary along the length of the muscle.

origin: spine via thoracocolumbar fascia, ant. 2/3 of iliac crest, connective tissue dep to the inguinal ligament

insertion: inferior borders of 10-12 ribs, linea alba, and pubis via conjoint tendon

innervation: thoraco-abdominal nerves (ant. rami T7-T11) and first lumbar nerve

action: compress and support abdominal viscera; flex and rotate trunk

origin: post. to thoracocolumbar fascia, internal surfaces of 7-12 costal cartilages, iliac crest, connective tissue deep to inquinal lig.

insertion: linea alba w/ aponeurosis of internal oblique, pubic crest, and pectin pubis via conjoint tendon

innervation: thoraco-abdominal nerves (ant. rami of T7-T11) and first lumbar nerve

action: compression and support abdominal viscera