MS1 Musculature of the Back- Extrinsic Flashcards
What is a dermatome
region of skin supplied by 1 level of spinal nerves
What features are on the surface anatomy of the back?
External occipital protuberance Site of nuchal ligament Scapula Iliac crest Prominent spinous processes Muscles: trapezius, latissimus dorsi, deltoid, erector spinae, teres major
What are the extrinsic muscles of the back
Superficial and Intermediate muscles of the back
What functions doe the extrinsic muscles have
movement of upper limbs and scapula
movement of ribs
What are the extrinsic muscles innervated by
anterior rami
What are the superficial muscles of the back
trapezius latissimus dorsi rhomboid minor rhomboid major levator scapulae
What are the intermediate muscles of the back
serratus posterior superior
serratus posterior inferior
What is the proximal origin of the trapezius
spinous process of C7-12
What is the distal insertion of the trapezius
acromion
spine of the scapula
lateral 1/3 of the clavicle
What is the action of the trapezius
elevate and depress the scapula
retraction of scapula
abduction of upper limb above 90 degrees
What is the blood supply to trapezius
superficial branch of transverse cervical artery
What is the innervation of the trapezius for motor function
spinal acessory nerve (CN XI)
-thing SANd TRAP
What is the innervation of the trapezius for proprioception
C2, C3, and C4
What are the three portions of the trapezius
superior
middle
inferior
Where does the superior portion attach
external occipital protuberance, ligamentum nuchae, spinous process of C7
to
1/3 of clavicle/ acromium
Where does the middle portion of the trapezius attach
spinous process of T1-T5
to
medial border of acronium and lip of spine of scapula
Where do the inferior portion of the trapezius attach
T6-T12 spinous processes
to
tubercle of spine
What is the function of the anterior portion of the trapezius
elevate scapula
unilateral: flex and rotate head to opposite side
bilaterally, extend neck
lateral rotate upwards
What is the function of the middle portion of the trapezius
adduct scapula, bring closer to the spine
What is the function of the posterior portion of the trapezius
depress scapula, glide inferiorly
laterally rotate scapula upwards
What is the proximal origin of the latissimus dorsi
Spinous process of T7-12, thoracolumbar fascia, iliac crest
Where is the distal insertion of the latissimus dorsi
floor of intertubercle groove of the humerus (bicipital groove)
What is the action of latissimus dorsi
extension
medial rotation
adduction of the upper limb (pull up muscle)
What is the innervation of the latissimus dorsi
Thoracodorsal nerve (C6-C8) off the brachial plexus
What is the blood supply of latissimus dorsi
thoracodorsal artery
What muscles are involved in the 2nd layer of superficial back
serratus posterior superior and serratus posterior inferior
Axillary dissection of lymph nodes can affect the latissimus dorsi how
dissection leads to risk of damaging thoracodorsal nerve, which will affect the latissimus dorsi if cut
weakness in adduction, extension, and medial rotation
How does the latissimus relate to breast cancer
you place a slip of latissimus dorsi and vasculature to support an implant after a mastectomy
What is the proximal origin of the levator scapulae
Transverse processes of C1-C4
Where is the distal insertion of the levator scapulae
Superior angle and medial border of the scapula
What is the action of levator scapulae
elevates scapula
What is the proximal orgin of the rhomboid minor
nuchal ligament
spinous process C7-T1
What is the proximal origin of the rhomboid major
spinous process of T2-T5
What is the distal insertion of the rhomboid minor
Medial border of scapula at level of the spine
What is the distal insertion of the rhomboid major
medial border of scapula inferior to spine
What are the actions of the rhomboids
retract and fix scapula
What is the innervation of the rhomboids
dorsal scapular nerve C4-C5
What is the innervation of the levator scapulae
dorsal scapular nerve and cervical nerve
What is the blood supply to the rhomboids
deep cervical artery
What is the blood supply to the levator scapulae
deep cervical artery
What is Petit’s Hernia
herniation through inferior lumbar triangle
What is the lumbar triangle
space below latissimus dorsi above the iliac crest
What is triangle of auscultation
area at the 6th intercostal space with very little tissue that makes auscultation easy
What are the borders of the triangle of auscultation
trapezius–medial
latissimus dorsi–inferior
medial border of scapula–lateral
What borders the lumbar triangle
latissimus dorsi medially
external oblique laterally
iliac crest inferiorly
What is the proximal origin of the serratus posterior inferior
Spinous process of T11-L2/L3
What is the distal insertion of serratus posterior inferior
Ribs 9-12, lateral to angles
What is the proximal origin of serratus posterior superior
nuchal ligament
spinous processes C7-T3
What is the distal insertion of serratus posterior superior
ribs 2-5, lateral to angles
What are the actions serratus posterior inferior and superior
to elevate and depress ribs
accessory respiratory muscle
What is the innervation for serratus posterior inferior and superior
segmental anterior rami (intercostal nerves)
What is the blood supply of serratus posterior inferior and superior
intercostal arteries
