Superficial Back Flashcards
What are the main shoulder joints?
- Glenohumeral Joint
- Acromioclavicular Joint
- Sternoclavicular Joint
Glenohumeral Joint
Ball-in-socket joint, multiaxial
Movement of the arm
Extremely mobile, weak and not very stable
Acromioclavicular Joint
Relatively weak planar joint with limited mobility
Some rotation occurs with scapular movements
Sternoclavicular Joint
Mobile, saddle joint surrounded by strong ligaments
Movement occurs with all scapular motions
What are the three types of fascia?
Superficial fascia
Deep fascia
Investing fascia
Superficial fascia
Deep to skin, primarily adipose
Varies in thickness, often very thick in lower back
Deep Fascia
Dense connective tissue lying deep to superficial fascia
Investing Fascia
Extensions of deep fascia that surround muscles and neurovascular bundles
What does the extrinsic back muscles act on?
Primary action is on the upper limb and rib cage
What are the different movements of the scapula?
Elevation/Depression
Protraction/Retraction
Superior/Inferior Rotation
What are the superficial extrinsic back muscles?
- Trapezius
- Latissimus dorsi
- Levator scapulae
- Rhomboid major
- Rhomboid minor
What is the origin, insertion, and innervation of the trapezius muscle?
Origin - external occipital protuberance, nuchal ligament, spinous processes of lower cervical and thoracic vertebrae (C7-T12)
Insertion - Lateral 1/3 of clavicle, scapular spine, acromion process
Innervation - Accessory nerve (CN XI)
What are the actions of the trapezius muscle?
Descending fibers - elevate scapula (extend and laterally flex neck when shoulders are fixed)
Middle fibers - Retracts scapula
Ascending fibers - Depress scapula
Ascending and descending fibers - work together to superiorly rotate the scapula
Clinical correlate - Injury to Spinal Accessory Nerve (CN XI)
CN XI prone to injury and can cause paralysis of the trapezius and possibly sternocleidomastoid. Shoulder will noticeable lower at rest due to unresisted pull of gravity. Pt will be unable to abduct upper limb above shoulder due to weakened superior scapular rotation
What is the origin, insertion, action, and innervation of the latissimus dorsi?
Origin - Spinous processes of lower thoracic vertebrae (T7-T12), thoracolumbar fascia
Insertion - Anterior humerus (floor of intertubercular sulcus), sometimes angle of scapula
Action - Adducts, extends, and medially rotates humerus
Innervation - Thoracodorsal nerve
What is the origin, insertion, actions, and innervation of the levator scapulae?
Origin - Transverse processes of cervical vertebrae (C1-C4)
Insertion - Medial border of the scapula superior to scapular spine
Action - Elevates and inferiorly rotates scapula, assists in extension of neck
Innervation - Dorsal scapular nerve
What is the origin, insertion, action, and innervation of the rhomboid major?
Origin - Spinous processes of upper thoracic vertebrae (T2-T5)
Insertion - Medial border of scapula inferior to scapular spine
Action - Retract and elevate scapula, inferior rotation
Innervation - Dorsal scapular nerve
What is the origin, insertion, action, and innervation of the rhomboid minor?
Origin - Spinous processes of lower cervical and upper thoracic vertebrae (C7-T1)
Insertion - Medial border of scapula at root of scapular spine
Action - Retract and elevate scapula, inferior rotation
Innervation - Dorsal scapular nerve
What are the deep extrinsic muscles?
Serratus posterior superior
Serratus posterior inferior
What is the origin, insertion, action, and innervation of the serratus posterior superior?
Origin - Spinous processes of lower cervical and upper thoracic vertebrae (C7-T3)
Insertion - Super borders of upper ribs (ribs 2-5)
Actions - Elevate ribs (superior), proprioception
Innervation - Local intercostal nerves (ventral primary rami)
What is the origin, insertion, action, and innervation of the serratus posterior inferior?
Origin - Spinous processes of lower thoracic and upper lumbar vertebrae (T11-L2)
Insertion - Inferior border of lower ribs (ribs 8-12)
Actions - Depress ribs (inferior), proprioception
Innervation - Local intercostal nerves (ventral primary rami)
Clinical correlate: Triangle of Auscultation
Triangular space deep to which is devoid of large muscles making it an ideal place to listen to posterior lungs. Borders: Inferior is latissimus dorsi, medial is trapezius, and lateral is medial border of scapula
Clinical correlate: Lumbar Triangle
Triangular space between latissimus dorsi and external abdominal oblique, lacks muscular reinforcement making it prone to lumbar hernias
What innervates the superficial extrinsic back muscles (except trapezius)?
Brachial plexus - supplies the upper limb. Dorsal scapular and thoracodorsal nerves are branches of this plexus.
What kind of nerve innervates the trapezius?
Cranial Nerve - accessory nerve
What innervates the deep extrinsic back muscles?
Local intercostal nerves from ventral primary rami of spinal nerves
What innervates the skin of the back?
Posterior cutaneous branches of dorsal rami of spinal nerves - developed from dermatomes
What is the primary blood supply to the extrinsic back muscles?
From branches of subclavian and axillary arteries.
Transverse cervical and dorsal scapular are from subclavian
Blood also supplies by regional intercostal arteries
