GA: The Back Muscles
What mm. make up the suboccipital triangle?
RCP major (medial), Obliquus capitis superior (lateral), Obliquus capitis inferior (inferior)
What are the Suboccipital mm.?
RCP major / minor, Obliquus capitis inferior / superior
Another name for the intermediate group of back muscles
Respiratory group
Action of Rhomboid Major
Retraction (adduction), elevation (of scapula)
Action of Rhomboid Minor
Retraction (adduction), elevation (of scapula)
Serratus posterior superior is deep to which muscles?
Rhomboids
The intermediate group of muscles are attached to the _____ & their function is:
Ribs & Respiratory function
What actions do the superior and inferior fibers of the traps perform?
Rotate the lateral aspect of the scapula upward (elevation)
Transversospinalis muscles
Semispinalis, multifidus, rotatores
What is the largest group of intrinsic back muscles?
The erector spinae mm.
The superficial & intermediate (extrinsic) back muscles are innervated by:
Anterior rami of spinal nerves
Another name for the superficial group of back muscles is:
Appendicular group
Middle layer of the thoracolumbar fascia (lumbar region):
Attached medially to TVPs & intertransverse legatments, (Inferiorly) attached to iliac crest
Where are the multifidus mm. most developed?
Lumbar region
Regions of Iliocostalis
Lumborum, thoracis, cervicis
Where is the spinalis mostly absent?
Cervical region
Anterior layer of the thoracolumbar fascia (lumbar region):
Covers anterior surface of QL, attached to TVPs, superiorly forms lateral arcuate ligament for attachment of diaphragm
Neurovascular bundle of the levator scapulae & rhomboids
Dorsoscapular n., a., v.
Actions of the Serratus Posterior Inferior & Superior
Elevate (superior) & depress (inferior) the ribs
Actions of trapezius
Elevation, Adduction, Depression, assists in rotating scap during abduction of humerus
Primary extensors of the vertebral column and head
Erector spinae group / Sacrospinales group
What action occurs when the SOT muscles contract?
Extension of the head at the atlanto-axial joint
Action of Lat Dorsi
Extension, adduction, medial rotation, depression (of shoulder)
Px shows a lateral shift in the position of the scapula (affected side). What is the cause?
Injury to the dorsal scapular n.
Neurovascular bundle of the Serratus Posterior mm.
Intercostal n., a., v.
Innervation of Serratus Posterior mm.
Intercostal nn.
Px presents with drooping of the shoulder, inability to raise arm above the head, &/or weakness in attempting to raise the shoulder. What is the cause?
Interruption of CN XI (spinal accessory n.)
What are the two true segmental muscles of the back?
Interspinales & the intertransversarii
Serratus posterior inferior is deep to which muscles?
Latissimus dorsi
What 2 muscles blend into the thoracolumbar fascia?
Latissimus dorsi & Serratus posterior inferior
Where does the thoracolumbar fascia attach medially & laterally?
Medially: SP's of the thoracic vertebrae Laterally: angles of the ribs
Where do the semispinalis mm. attach?
Occipital bone at the base of the skull
The intrinsic muscles of the back are innervated by ___ & involve movements related to the:
Posterior rami of spinal nerves & vertebral column and head
What does the Suboccipital triangle contain?
Posterior ramus of C1 Vertebral artery, & Associated veins
Innervation of Trapezius
Spinal Accessory n. / CN XI
Blood supply of Trapezius
Superficial branch of the transverse cervical a.
Rhomboid minor is _____ to rhomboid major
Superior
Splenius cervicis attachment:
TVP of upper cervical vertebrae
The thoracolumbar fascia in the thoracic region
covers the deep muscles & separates them from the superficial & intermediate groups
The superficial group of muscles involve movements of:
The upper limb
Why are the muscles of the deep group classified as intrinsic muscles?
They develop in the back
Why are the muscles of the superficial and intermediate groups classified as extrinsic?
They originate embryologically from locations other than the back
Posterior thoracolumbar fascia layer (in lumbar region):
Thick, attached to SPs & supraspinous ligament, covers the erector spinae
Where are semispinalis mm. found?
Thoracic & cervical regions
Where are the rotatores mm. best developed?
Thoracic region
Where is the spinalis most constant?
Thoracic region
Regions of Longissimus
Thoracis, Cervicis, Capitis
Regions of Spinalis
Thoracis, Cervicis, Capitis
Px is unable to use the latissimus dorsi / cannot pull the body upward while climbing or doing a pull up. What nerve is diminished?
Thoracodorsal n.
Neurovascular bundle of the Latissimus Dorsi
Thoracodorsal n., a., v.
How many layers of thoracolumbar fascia are present in the lumbar region?
Three
What muscles are included in the superficial group?
Trapezius, Latissimus dorsi, Rhomboid(s), Levator scapulae
Action of Levator Scap
elevation (scapula)
The extensors & rotators of the vertebral column:
erector spinae & transversospinales mm., & interspinales & intertransversarii
Actions of spinotransversales mm. (splenius cervicis & capitis)
extension of neck, rotation of head to one side
Splenius capitis attachment:
occipital bone & mastoid process of temporal bone
Superiorly, the thoracolumbar fascia:
passes anterior to the serratus posterior m. & is continuous w/ the deep fascia in the neck
The extensors & rotators of the head & neck:
splenius capitis & cervicis (spinotransversalis mm.)
