Muscles of Back Flashcards
Thoracolumbar Fascia
invests the deep muscles of back
attaches to the Sp and Tp of T/L regions
provides origin for latissmus dorsi, transverse abdominal, and internal oblique
Superficial Layers of the back
Extrinsic (controls upper limbs)
trapezius, latissmus dorsi, rhomboids and levator scapula
Intermediate Layer of the back
Extrinsic, controls respiration
serratus posterior superior and inferior
Superficial layer of the deep back muscles
splenius capitus and cervicis
Intermediate layer of the deep back muscle
erector spinae (3 columns-iliocostalis, longissimus, spinalis)
Deep layer of the deep back muscles
transversospinal muscle group (semispinalis, multifidi, rotatores)
Trapezius
O: medial 1/3 of the superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous processes of vertebrae C7-T12
I: lateral 1/3 of the clavicle, medial side of the acromion and the upper crest of the scapular spine, tubercle of the scapular spine
N: motor: spinal accessory (XI)
A:elevates and depresses the scapula (depending on which part of the muscle contracts); rotates the scapula superiorly; retracts scapula
Latissimus Dorsi
O: vertebral spines from T7 to the sacrum, posterior third of the iliac crest, lower 3 or 4 ribs, sometimes from the inferior angle of the scapula
I: floor of the intertubercular groove
N:thoracodorsal nerve (C7,8) from the posterior cord of the brachial plexus
A:extends the arm and rotates the arm medially
Rhomboid Minor
O:inferior end of the ligamentum nuchae, spines of vertebrae C7 and T1
I:medial border of the scapula at the root of the spine of the scapula
N:dorsal scapular nerve (C5)
A:retracts, elevates and rotates the scapula inferiorly
Rhomboid Major
O: spines of vertebrae T2-T5
I: medial border of the scapula inferior to the spine of the scapula
N: dorsal scapular nerve (C5)
A: retracts, elevates and rotates the scapula inferiorly
Levator Scapula
O:transverse processes of C1-C4 vertebrae
I:medial border of the scapula from the superior angle to the spine
N:dorsal scapular nerve (C5); the upper part of the muscle receives branches of C3 & C4
A:elevates the scapula
Serratus Posterior Superior
O:ligamentum nuchae, spines of vertebrae C7 -T3
I:superior borders of ribs 2-4
N: intercostals nerves 2-5 (branches of the ventral primary rami)
A:elevates the upper ribs
Serratus Posterior Inferior
O:thoracolumbar fascia, SP’s of vertebrae T11-L2
I: ribs 8-12 (inferior borders near their angles)
N:branches of the ventral primary rami of spinal nerves T9-T12
A:pulls down lower ribs
Splenius Capitis
O: ligamentum nuchae and spines of C7-T4 vertebrae
I:mastoid process and lateral end of the superior nuchal line
N: dorsal primary rami of spinal nerves C2-C6
A:Bilateral: extends neck/head
Unilateral: lateral flex and rotate head/neck to same side
Splenius Cervicis
O: ligamentum nuchae and spines of C7-T4 vertebrae
I: posterior tubercles of the transverse processes of C1-C3 or 4 vertebrae
N: dorsal primary rami of spinal nerves C2-C6
A:Bilateral: extends neck/head
Unilateral: lateral flex and rotate head/neck to same side
Iliocostalis- lumborum, thoracis, and cervicis
O: broad tendon from posterior part iliac crest and sacrum, SP’s of lower L and S, supraspinus ligament
I: angles of the ribs and cervical TP’s
N:dorsal primary rami of spinal nerves
A:Bilaterally: extends the vertebral column, assist with flexion (eccentric contraction)
Unilateral: laterally bends the vertebral column
Longissimus- thoracis, cervics, capitis
O:broad tendon from posterior part iliac crest and sacrum, SP’s of lower L and S, supraspinus ligament
I:ribs, TP’s at superior vertebral levels, mastoid process
N:dorsal primary rami of spinal nerves
A:Bilaterally: extends the vertebral column, assist with flexion (eccentric contraction)
Unilateral: laterally bends the vertebral column
Spinalis- spinalis thoracis, spinalis cervicis
O: broad tendon from posterior part iliac crest and sacrum, SP’s of lower L and S, supraspinus ligament
I: spinous processes at superior vertebral levels and base of the skull
N:dorsal primary rami of spinal nerves
A:Bilaterally: extends the vertebral column, assist with flexion (eccentric contraction)
Unilateral: laterally bends the vertebral column
Semispinalis-thoracics, cervicis, capitis
O:TPs of C4-T12
I:capitis: back of skull between nuchal lines; cervicis & thoracis: SP’s 4-6 vertebrae above origin
N:dorsal primary rami of spinal nerves
A:Bilaterally: extends the head and vertebral column in C and T region, stabilize vertebrae during local or isolated movements of vertebral column, assit with extension of vertebral column
Unilateral: rotates the vertebral column to opposite side (contralateral rotation)
May have proprioceptive function
Multifidus
O:sacrum,TPs of T1-L5 and articular pillars (AP’s) of C4-7
I:spinous processes 2-4 vertebral levels superior to their origin
N:dorsal primary rami of spinal nerves
A:Bilaterally: extends the head and vertebral column in C and T region, stabilize vertebrae during local or isolated movements of vertebral column, assit with extension of vertebral column
Unilateral: rotates the vertebral column to opposite side (contralateral rotation)
May have proprioceptive function
Rotatores
O:TPs of vertebral column
I:long rotatores: SP’s (lamina) 2 vertebrae above origin
short rotatores: SP’s (lamina) 1 vertebrae above origin
N:dorsal primary rami of spinal nerves
A:Bilaterally: extends the head and vertebral column in C and T region, stabilize vertebrae during local or isolated movements of vertebral column, assit with extension of vertebral column
Unilateral: rotates the vertebral column to opposite side (contralateral rotation)
May have proprioceptive function
Rectus Capitis Posterior Major
O: SP of C2 (axis)
I:inferior nuchal line (lateral portion)
N: suboccipital nerve (DPR of C1)
A: extends the head, rotate head to same side (ipsilateral rotation)
Rectus Capitis Posterior Minor
O: posterior tubercle of C1 (atlas)
I: inferior nuchal line (medial portion)
N: suboccipital nerve (DPR of C1)
A:extends the head, rotate head to same side (ipslateral rotation)
Oblique Capitis Inferior
O: SP of the C2 (axis)
I: TP of C1 (atlas)
N: suboccipital nerve (DPR of C1)
A: rotates the head to the same side (ipslateral rotation)
