Back Muscles Flashcards
What is the superficial group of muscles called, what is its function, and what muscles make up this group?
Posterior axio-appendicular muscles
Move/stabilize pectoral girdle or humerus
Superficial group: Trapezius & Latissimus dorsi
Deep group: Rhomboids (major/minor) & Levator scapulae
What movements does the scapulothoracic joint provide?
Scapula movements
Elevation/depression
Protraction/retraction
Upward/downward rotation
What muscle is the only one innervated by a CN?
Trapezius is innervated by CN XI (spinal accessory nerve)
What muscles make up the Auscultatory triangle and where is it located?
It is a muscle free window good for auscultation
Trapezius, rhomboid major and latissimus dorsi
It is medial to inferior scapular angle (6th intercostal space)
What muscles make up the lumbar triangle and what can occur in that area?
Latissimus dorsi, external oblique, iliac crest
Lumbar hernia is frequent here
What muscles make up the intermediate group and what are they often called?
Serratus posterior superior and Serratus posterior inferior
Accessory muscles of respiration
What is the deep back muscle group also called, what is its function, and what are these muscles all innervated by?
“intrinsic back muscles”
Maintain posture & move vertebral column
All segmentally innervated by dorsal rami of spinal nerves
What muscles make up the deep-superficial group?
Splenius capitis & splenius cervicis
What muscles make up the deep-intermediate group? What is another name for this group?
“erector spinae muscles”
Spinalis, longissimus, iliocostalis (medial to lateral)
What muscles make up the deep-deep group? What is another name for this group?
“Transversospinalis group”
Semispinalis (capitis/cervices/thoracis)- only view capitis & cervices in lab/ Multifidus/ Rotatores
What is the thoracolumbar fascia, what are its three layers, and where is it located?
It is the deep fascia of thoracic & lumbar regions
It is attached to the vertebral column medially and abdominal wall muscles laterally
Three layers are posterior, middle & anterior
Where do the three layers of the thoracolumbar fascia attach and what do they form a compartment for?
Posterior- attach to spinous processes
Middle & Anterior- attach to transverse processes
Posterior & middle for compartment for intermediate & deep layers
Anterior forms compartment for quadratus lumborum
(thoracic region = thin, transparent)
(lumbar region = thick, formidable)
Where is the erector spinae group located within the thoracolumbar fascia?
Its located between the posterior & medial layers
Where is the Transversospinalis group located within the thoracolumbar fascia?
It is located in the posterior layers
What pierces through the semispinalis capitis?
The greater occipital nerve (dorsal rami of C2)
Where is multifidus best developed?
Lumbar region
Where are the rotatores muscles best developed?
Thoracic region
What movements/function does the transversospinalis group perform?
extend & stabilize the vertebral column
What three muscles make up the sub occipital triangle?
rectus capitis posterior major (medial border)
obliquus capitis superior (lateral border)
obliquus capitis inferior (inferior border)
What muscle is the sub occipital region deep to?
semispinalis capitis
What nerve makes up the dorsal rami of C1?
Suboccipital nerve
What marking is the centerpoint of the suboccipital starfish?
Spinous process of C2
What is the fourth suboccipital muscle that is NOT involved in the triangle?
Rectus capitis posterior minor
If you follow the greater occipital nerve deep through the semispinalis capitis muscle, what landmark does it bring you to?
The inferior border of the suboccipital triangle (obliquus capitis inferior)
What landmark can you palpate through the suboccipital triangle?
posterior arch of C1
What artery is present deep in the center of the suboccipital triangle?
Vertebral artery
What nerve innervates all four suboccipital muscles?
suboccipital nerve
What sensation do the dorsal rami of spinal nerves provide?
sensory innervation of skin
What spinal nerves have sensory innervation to the back muscles?
T2-L2
What spinal nerves have sensory innervation to the posterior neck & scalp?
C2-C4
What is special about C1 spinal nerve and its innervation?
It does not have an afferent component (it does not provide sensory info through an afferent pathway to the spinal cord); it is purely motor
What nerve is most commonly injured iatrogenically? and what damage does that cause?
Spinal accessory nerve CN XI (supplies SCM & Trapezius/nearly subcutaneous in posterior triangle of neck)
weak/absent shoulder shrug & inability to abduct arm beyond horizontal
How can the Thoracodorsal nerve get damaged and how does this effect the body?
Damaged by axillary procedures (axillary node dissection), creates paralysis of latissimus dorsi; can’t climb or use axillary crutch
