Back Musculature Flashcards
Trunk ROM is limited by
- IV discs- elasticity, compressibility
- facet joint orientation
- facet joint capsular tightness
- back muscle & ligamentous resistance
- thoracic (rib) cage attachment
What are the 2 main classifications of back muscles?
intrinsic & extrinsic
What is the general function of the intrinsic back muscles?
maintain posture and control movements of the vertebral column
What are the 3 groups of intrinsic back muscles? What are the muscles within each group?
- superficial group (splenius capitus, splenius cervicis)
- intermediate group (erector spinae)
- deep group (transversospinales)
What are the 2 groups of extrinsic back muscles? What are the muscles within each group?
- superficial group (trapezius, latissimus dorsi, levator scapule, rhomboids)
- intermediate group (serratus posterior superior, serratus posterior inferior)
Extrinsic superficial group:
1) What is their skeletal-spatial relationship?
2) Function?
3) Innervation?
1) posterior axioappendicular muscles
2) produce and control movements of upper limbs
3) innervated by ventral rami of cervical nerves (except trapezius)
Extrinsic intermediate group:
1) What is their skeletal-spatial relationship?
2) Function?
3) Innervation?
1) attached to thoracic wall
2) superficial respiratory muscles & proprioception
3) innervated by ventral rami of intercostal nerves
Innervation of intrinsic back muscles?
dorsal rami of spinal nerves
Blood supply of intrinsic back muscles?
thoracic area: posterior intercostal arteries
lumbar area: subcostal and lumbar arteries
in general:
-multiple sources
-arteries generally supply structures they contact
Attachments of the splenius?
proximal: nuchal ligament & spinous processes C7-T4
distal:
-for splenius capitis, mastoid process & superior nuchal line
-for splenius cervicis: transverse processes of C1-C4
Actions of the splenius?
unilateral: laterally flex neck & rotate head side to side
bilateral: extend head and neck
What are the 3 subdivisions of the erector spinae?
spinal thoracis
longissimus
iliocostalis
Attachments of the erector spinae?
proximal: iliac crest, posterior sacrum, lumbar and sacral spinous processes
distal: angles of the ribs, thoracic and cervical transverse processes, mastoid process
Actions of the erector spinae?
bilaterally: extends vertebral column & head
unilaterally: flexes vertebral column
What are the 3 subdivisions of transversospinales?
semispinalis
multifidus
rotatores
Proximal attachments of the transversospinales?
proximal: mainly transverse processes
- semispinalis: thoracic & lower cervical t. processes
- multifidus: sacrum, ilium, lumbar t. processes
- rotatores: t. processes
Distal attachments of the transversospinales?
fibers run superomedially and attach to spinous processes of more superior vertebrae
- semispinalis: spans 4-6 segments
- multifidus: spans 2-4 segments
- rotatores: spans 1 (brevis) - 2 (longus) segments
What is exceptional about the trapezius’ innervation?
only extrinsic back muscles not innervated by ventral rami of spinal nerves;
innervated by CN XI, spinal accessory nerve
Attachments of the trapezius?
proximal: nucal ligament, spinous processes of C2-T12
distal: clavicle, acromion (shoulder blade), spine of scapula
Innervation of the trapezius?
spinal accessory nerve, CN XI
Blood supply of the trapezius?
superficial branch of the transverse cervical artery
Actions of trapezius?
scapular elevation, retraction, & depression
Proximal attachments of latissimus dorsi?
- spinous processes of inferior 6 thoracic vertebrae
- inferior 3 or 4 ribs
- thoracolumbar fascia
- iliac crest
Distal attachments of latissimus dorsi?
floor of the intertubercular groove of humerus
