Spinal muscles Flashcards
Why are the superficial and intermediate back muscles defined as extrinsic muscles?
They don’t develop embryologically in the back
Why are the deep back muscles defined as intrinsic muscles?
They develop embryologically in the back
Generally, where do all of the superficial back muscles originate and attach to, and why?
Originate from vertebral column
Attach to shoulder bones
Because they are associated with movements of upper limb
Where is trapezius, and what are its sites of origin and attachment?
1
Originates from skull, nuchal ligament (ligament at back of neck that is continuous with supraspinous ligament), spinous processes C7-T12
Attaches to clavicle, acromion process, scapula spine
What nerve innervates trapezius, and what are its 3 motor actions?
Innervated by accessory nerve
Upper fibres: Elevate and rotate scapula during arm abduction
Middle fibres: Retract scapula
Lower fibres: Pull inferiorly/depress scapula
What is the nuchal ligament, and which superficial back muscle originates from here?
ligament at back of neck that is continuous with supraspinous ligament
Origin site of trapezius
Where is latissimus dorsi, and what are its sites of origin and attachment?
5
Originates from iliac crest, spinous processes T6-T12, thoracolumbar fascia
Attaches to bicipital groove/intertubercular sulcus of humerus
Which nerve innervates latissimus dorsi, and what are its 3 motor actions?
Thoracodorsal nerve
Upper arm extension, adduction, medial rotation
Where is levator scapulae, and what are its origin and attachment sites?
11
Originates from transverse processes of C1-C4
Attaches to scapula medial border
Which nerve innervates levator scapulae, and what is its motor action?
Innervated by dorsal scapular nerve
Elevates scapula
Is rhomboid minor or major more superficial?
Rhomboid minor is superficial to rhomboid major
Where is rhomboid minor, and what are its origin and attachment sites?
10
Originates from spinous processes C7-T11
Attaches to scapula medial border at level of scapula spine
Which nerve innervates rhomboid minor, and what are its 2 motor actions?
Dorsal scapular nerve
Retracts/pulls inferiorly scapula
Rotates scapula
Where is rhomboid major, and what are its origin and attachment sites?
7
Originates from spinous processes T2-T5
Attaches to medial border of scapula
Which nerve innervates rhomboid major, and what are its 2 motor actions?
Dorsal scapular nerve
Rotates scapula
Retracts/pulls inferiorly scapula
What are the 2 intermediate back muscles, and what nerve innervates them and what is their motor action?
Serratus posterior superior: Elevates ribs 2-5
Serratus posterior inferior:
Depresses ribs 9-12
Innervated by intercostal nerve