Thorax Flashcards
Trapezius
O: external occipital protuberance, nuchal ligament, medial superior nuchal line, spinous processes of vertebrae (C7-T12)
I: clavicle, acromion process, and spine of scapula
N: accessory nerve, cervical spinal nerves C3 and C4
A: rotation, retraction, elevation, and depression of scapula
Rhomboid major
O: spinous processes of T2-T5
I: Scapula
N: dorsal scapular nerve (C4 &C5)
A: Retracts scapula, rotates scapula to depress glenoid cavity, fixes scapula to thoracic wall
Rhomboid minor
O: nuchal ligaments and spinous processes of C7-T1
I: medial border of scapula
N: dorsal scapular nerve (C4-5)
A: Retracts and rotates scapula, fixes scapula to thoracic wall
Serratus posterior superior
O: nuchal ligament and spinous processes of C7-T3
I: 2nd-5th ribs
N: 2nd-5th intercostal nerves
A: elevates ribs (aids inspiration)
External intercoatals
O: lower border of ribs
I: upper border of ribs (rib below)
N: intercostal nerves
A: inhalation
Serratus anterior
O: upper 8 or 9 ribs
I: scapula
N: long thoracic nerve (from roots of brachial plexus C5-7)
A: protracts and stabilizes scapula, assists upward rotation
Levator scapula
O: transverse processes of C1-4
I: medial border of scapula
N: cervical nerve (C3-4) and dorsal scapular nerve (C5)
A: elevates and rotates scapula
Pectoralis Minor
O: 3rd-5th ribs
I: Coracoid process of scapula
N: medial pectoral nerve (C8, T1)
A: stabilizes scapula by drawing it inferiorly and anteriorly against the thoracic wall
Internal intercostals
O: inferior borders of ribs
I: superior borders of ribs
N: intercostal nerves
A: hold ribs steady
Diaphragm
O: xiphoid process, costal margin, fascia over the quadratus lumborum and psoas major, vertebral bodies L1-L3
I: central tendon of the diaphragm
N: phrenic nerve (C3-5)
A: pushes the abdominal viscera inferiorly, increasing vol of thoracic cavity
