The Back and Thorax Flashcards
Trapezius
Origin: superior nuchal line, external occipital protuberance, ligament nuchae, and spinous process of T1-T12
Insertion: spine of the scapula, acromion process, and lateral 1/3 of the clavicle
Action: head rotation, elevation and retraction of the pelvic girdle, and superior rotation of the scapula
Innervation: spinal accessory nerve (Cranial Nerve XI)
Latissimus Dorsi
Origin: spinous process of T7 - L5, thoracolumbar fascia, sacrum, and iliac crest
Insertion: inter-tubercular sulcus of the humerus
Action: extension, adduction, and medial rotation of the humerus, depression and retraction of the pectoral girdle, and inferior rotation of the scapula
Innervation: thoracodorsal nerve
Rhomboid major
Origin: spinous process of T2-T5
Insertion: medial border of the scapula
Action: retraction and elevation of the pectoral girdle, and inferior rotation of the scapula
Innervation: dorsal scapular nerve
Rhomboid minor
Origin: spinous process of C7-T1
Insertion: medial border of the scapula
Action: retraction and elevation of the pectoral girdle, inferior rotation of the scapula
Innervation: dorsal scapular nerve
Levator scapulae
Origin: transverse process of C1-C4
Insertion: superior angle of the scapula
Action: elevation of the pectoral girdle and inferior rotation of the scapula
Innervation: dorsal scapular nerve
Serratus posterior superior
Origin: spinous process of C7 - T3
Insertion: ribs 2-5
Action: elevation of ribs 2-5
Innervation: ventral primary rami (intercostal nerves)
Serratus posterior inferior
Origin: spinous process of T11-L3
Insertion: ribs 9-12
Action: depression of ribs 9-12
Innervation: ventral primary rami (intercostal nerves)
Splenius capitis and cervicis
Origin: ligamentum nuchae and spinous process T1-T4
Insertion:
Capitis: superior nuchal line and mastoid process
Cervicis: transverse process of C1-C4
Action:
Unilateral: ipsilateral rotation of head and neck
Bilateral: extension of the head and neck
Erector spinae muscles
Origin: iliac crest, sacrum, and lumbar spinous process
Insertion:
Iliocostalis: ribs, spinous process of C1 and C7
Longissimus: cervical and thoracic transverse processes, ribs, and mastoid
process
Spinalis: thoracic spinous processes, ligamentum nuchae, and occipital bone
Action:
Unilateral: lateral flexion and ipsilateral rotation of trunk
Bilateral: extension of the trunk and head
Transversospinalis muscles
Origin: iliac crest, sacrum, and transverse process of C4 - L5
Insertion:
Semispinalis capitis: spans upper transverse processes to occipital bone
Semispinalis cervicis: spans upper thoracic transverse processes to upper
cervical spinous processes
Multifidus: spans 2-4 segments
Rotator: spans 1-2 segments
Action:
Unilateral: lateral flexion and contralateral rotation of the trunk
Bilateral: extension of the trunk
Intersegmental Muscles
Intertransverarii: spans the transverse processes
Interspinales: spans spinous processes
Levatores costarum
Origin: transverse processes of thoracic vertebrae
Insertion: ribs - 1-2 segments inferior to origin
Action: elevation of ribs
Rectus capitis posterior major
Origin: spinous process of C2
Insertion: inferior nuchal line
Action:
Unilateral: ipsilateral rotation of the head
Bilateral: extension of the head
Innervation: dorsal rami of C1
Rectus capitis posterior minor
Origin: posterior tubercle of C1
Insertion: inferior nuchal line
Action:
Unilateral: ipsilateral rotation of the head
Bilateral: extension of the head
Innervation: dorsal rami of C1
Obliquus capitis superior
Origin: transverse process of C1
Insertion: between nuchal lines
Action:
Unilateral: ipsilateral bending of the head
Bilateral: extension of the neck
Innervation: dorsal rami of C1
