BIOH 411 Unit 1 OIAs

Back and shoulders

What are the scapulohumeral muscles innervated by?

Ventral (anterior) rami of the spinal nerves

Deltoid muscle group

Scapulohumeral muscle

Deltoid origin

• Anterior fibers- lateral clavicle

• Middle fibers- acromion

• Posterior fibers- scapular spine

Deltoid insertion

Deltoid action

• Anterior fibers- flexion and medial rotation

• Middle fibers- abduct arm

• Posterior- extension and lateral rotation

Deltoid nerve

Axillary nerve C5 & C6 posterior cord of brachial plexus

Deltoid blood

Posterior circumflex humeral artery and deltoid branch of thoracoacromial artery

Supraspinatus muscle group

Scapulohumeral muscles, (a SITS muscle)

Supraspinatus origin

Supraspinous fossa of scapula

Supraspinatus insertion

Greater tubercle of humerus

Supraspinatus action

Assist deltoid in abducting arm by starting the movement, fixes head of humerus in glenoid cavity

Supraspinatus nerve

Suprascapular nerve C5 & C6 superior trunk of brachial plexus

Supraspinatus blood

Suprascapular artery

Infraspinatus muscle group

Scapulohumeral muscles (a SITS muscle)

Infraspinatus origin

Infraspinous fossa of scapula

Infraspinatus insertion

Greater tubercle of humerus

Infraspinatus action

Laterally rotates the arm

Infraspinatus nerve

Suprascapular nerve off C5 and C6

Infraspinatus blood

Suprascapular artery

Teres major muscle group

Scapulohumeral muscle

Teres major origin

Dorsal surface of inferior angle of scapula

Teres major insertion

Medial lip of intertubercular sulcus of humerus

Teres major action

Adducts and medial rotation

Teres major nerve

Lower subscapular nerve of C5 and C6 posterior cord of brachial plexus

Teres major blood

Circumflex scapular artery

Teres minor muscle group

Scapulohumeral muscle (a SITS muscle)

Teres minor origin

Superior 2/3 of infraspinous fossa of scapula on axillary border

Teres minor insertion

Inferior facet of greater tubercule of humerus

Teres minor action

Laterally rotates arm

Teres minor nerve

Axillary nerve C5 & C6 posterior cord of brachial plexus

Teres minor blood

Circumflex scapular artery

Subscapularis muscle group

Scapulohumeral muscle (a SITS muscle)

Subscapularis origin

Subscapular fossa

Subscapularis insertion

Lesser tubercle of humerus

Subscapularis action

Adducts, medial rotation of humerus and stabilizes shoulder joint

Subscapularis nerve

Upper and lower subscapular nerves C5, C6 posterior cord of brachial plexus

Subscapularis blood

Subscapular artery and lateral thoracic artery

Trapezius muscle group

Posterior axio-appendicular muscles

Trapezius origin

Superior nuchal line, external occipital protuberance, ligamentum nuchae, spinous process of C7-T12

Trapezius insertion

Lateral 1/3 of clavicle, acromion and spine of scapula

Trapezius action

• Clavicular part (superior)- elevates scapula

• Acromial part (middle)- retracts

• Spine part (inferior)- depresses and rotates scapula

Trapezius nerve

Spinal accessory (XI) nerve and 3rd and 4th cervical nerves

Trapezius blood and what is unique?

Transverse cervical artery & dorsal scapular artery (DSA will sometimes come off the TCA as the deep branch of the TCA)

Latissimus dorsi muscle group

Posterior axio-appendicular muscles

Latissimus dorsi origin

Spinous processes of T7-T12 and L1-L5, posterior layer of thoracolumbar fascia, iliac crest, ribs 10-12, inferior angle of the scapula

Latissimus dorsi insertion

Floor of intertubercular groove of humerus

Latissimus dorsi action

Adducts, extends, and medially rotates humerus

Latissimus dorsi nerve

Thoracodorsal nerve, posterior cord C6-C8, mostly C7

Latissimus dorsi blood

Thoracodorsal artery, branches of posterior intercostals 10 & 11, subcostal artery, 1st three lum

Levator scapulae muscle group

Posterior axio-appendicular muscle

Levator scapulae origin

Posterior tubercles of transverse process C1-C4

Levator scapulae insertion

Medial border of scapula from superior angle to spine

Levator scapulae action

Elevates scapula medially, inferiorly rotates glenoid fossa

Levator scapulae nerve

Dorsal scapular nerve C5 off of brachial plexus root, anterior rami of C3-C4

Latissimus dorsi blood

Thoracodorsal artery, branches of posterior intercostals 10 &11, subcostal artery, 1st three lumbar arteries

Rhomboid major muscle group

Posterior axio-appendicular muscle

Rhomboid major origin

Spinous processes of T2-T5

Rhomboid major insertion

Vertebral border of scapula, below base of scapular spine

Rhomboid major action

Fixes scapula to thoracic wall, retracts and rotates scapula downward to depress glenoid fossa

Rhomboid major nerve

Dorsal scapular nerve off C5

Rhomboid major blood

Dorsal scapular artery (or deep TCA), perforating branches of upper 5 or 6 posterior intercostal arteries

Rhomboid minor muscle group

Posterior axio-appendicular muscles

Rhomboid minor origin

Ligamentum nuchae, spine of 7th cervical and 1st thoracic vertebrae

Rhomboid minor insertion

Medial border of scapula at root of spine (superior to rhomboid major)

Rhomboid minor action

Fixes scapula to thoracic wall. Retracts and rotates scapula downward to depress glenoid fossa

Rhomboid minor nerve

Dorsal scapular nerve C5 root of brachial plexus

Rhomboid minor blood

Dorsal scapular (or Deep TCA), perforating branches of upper 5 or 6 posterior intercostal arteries

What are superficial extrinsic muscles used in?

Respiration

Serratus posterior superior muscle group

Superficial extrinsic muscle

Serratus posterior superior origin

Ligamentum nuchae, spinous processes of C7-T3

Serratus posterior superior insertio

Serratus posterior superior action

Elevates ribs (inspiration muscle)

Serratus posterior superior nerve

Ventral (anterior) primary rami of T2-T5

Serratus posterior superior blood

Posterior intercostal arteries

Serratus posterior inferior muscle group

Superficial extrinsic muscles

Serratus posterior inferior origin

Spinous processes of T11-L2

Serratus posterior inferior insertion

Inferior border of ribs 9-12

Serratus posterior inferior action

Fixes lower ribs, draws them down and back (expiration muscle)

Serratus posterior inferior nerve

Ventral (anterior) primary rami of T9-12

Serratus posterior inferior blood

Posterior intercostal arteries

Splenius capitis muscle group

Superficial intrinsic muscle

Splenius capitis origin

Ligamentum nuchae, spinous process of C7-T4

Splenius capitis insertion

Mastoid process of the temporal bone, lateral superior nuchal line

Splenius capitis action

• Bilaterally: Extends head

• Unilaterally: laterally bends (flexes) and ipsilateral rotation of head to same side

Splenius capitis nerve

Dorsal rami of C2-C3 (occasionally C4)

Splenius capitis blood

Descending branches of occipital artery and deep cervical artery

Splenius cervicis (colli) muscle group

Superficial intrinsic muscle

Splenius cervicis (colli) origin

Spinous process of T3-T6

Splenius cervicis insertion

Transverse processes C1-C3

Splenius cervicis action

• Bilaterally: Extends neck

• Unilaterally: laterally flexes head and neck, rotates head ipsilaterally

Splenius cervicis

Splenius cervicis blood

Descending branches of occipital artery and deep cervical artery

Where does the erector spinae group extend to?

Sacrum to skull

What are the sagittal divisions of the erector spinae group?

Capitis, cervicis, thoracic, and lumborum

What are the medial/lateral divisions of the erector spinae group?

Iliocostalis, longissimus, and spinalis

Iliocostalis muscle group

Erector spinae

Which column is iliocostalis?

Lateral column

Iliocostalis origin

• Cervicis- angles of ribs 3-6

• Thoracis- angles of ribs 7-12

• Lumborum- sacrum, iliac crest, and thoracolumbar fascia

Iliocostalis insertion

• Cervicis- posterior tubercles of transverse processes C4-C6

• Thoracis- angles of ribs 1-6 & transverse process of C7

• Lumborum- angles of ribs 6-12

Iliocostalis action

Extends and laterally bends vertebral column