Deep Dissection of the Back

Presented by: Angelie Melzer

Superficial to Deep Dissection: Structures to Look For

• PLATES: 542, 381, 544, 541, 375, 376• Nuchal Ligament• Accessory Nerve• 3rd and 4th cervical nerves and dorsal scapular nerve -C5• Thoracodorsal Nerve and Artery• Posterior Axillary Fold/Intertubercular Sulcus on the Humerus

• Levator Scapulae• Sternocleidomastoid • Splenus Capitus• Splenus Capitus Lateral and Medial• Masseter Muscle• Splenus Cervicis• Omohyoid Muscle• Latissimus Dorsi• Serratus posterior superior • Teres Major• Rhomboid Minor • Rhomboid Major • Supraspinatus, Infraspinatus and Teres Minor muscles (Rotator

Cuff)

KEY: ORIGIN, INSERTION, ACTION and NERVE

• O=Origin• I=Insertion• A=Action• N=Nerve

Biomechanical Actions: • Circumduction• Lateral Flexion• Rotation

MUSCLES OF THE NECK:

ORIGIN, INSERTION, ACTION and NERVE

• Splenius Capitus and Cervicis • Origin: Spinous processes of C7-T4• Insertion: Mastoid process and lateral portion of superior nuchal line• Action: Rotate the head and neck to the same side, laterally flex and extend the head and neck• Nerve: Cervical

• Levator Scapulae• Origin: Transverse processes of C1-4• Insertion: Medial border of scapula between superior angle and superior portion of spine of scapula• Action: Elevate and downwardly rotate the scapula, Laterally flex, rotate and extend the head and

neck• Nerve: Cervical 3-4 and Dorsal Scapular C4-5

• Sternocleidomastoid• Origin: Sternal Head-Top of Manubrium; Clavicular Head-Medial 1/3 of clavicle• Insertion: Mastoid process of temporal bone and lateral portion of superior nuchal line• Action: Lateraly flex head neck to same side, Rotate head and neck to opposite side and assist in

elevation of the ribcage during inhalation• Nerve: C1-3

MUSCLES OF THE SHOULDER: Cross Sectional View

ORIGIN, INSERTION, ACTION and NERVE

• Supraspinatus• Origin: Supraspinous fossa of scapula• Insertion: Greater Tubercle of humerus• Action: Adduct shoulder and stabilize head of humerus• Nerve: Suprascapular C4-6

• Infraspinatus • Origin: Infraspinous fossa of scapula• Insertion: Greater Tubercle of humerus• Action: Laterally Rotate and adduct shoulder, stabilize head of humerus• Nerve: Suprascapular C4-6

• Teres Minor• Origin: Upper 2/3 of lateral border of scapula• Insertion: Greater Tubercle of humerus• Action: Laterally Rotate and adduct shoulder, stabilize head of humerus• Nerve: Axillary C5-6

• Subscapularis• Origin: Subscapular fossa of scapula• Insertion: Lesser Tubercle of humerus• Action: Medially rotate the shoulder and stabilize the head of humerus• Nerve: Upper and Lower subscapular C5-7

MUSCLES OF THE SPINE

SPINE: Erector Spinae Group• Erector Spinae: Iliocostalis Cervicis, Thoracis and Lumborum

• Origin: Common tendon (cervicis, thoracis and lumborum, respectively)• Insertion: Cervical, Thoracic and Lumbar, respectively• Action: Extend and Laterally flex the vertebral column to the same side• Nerve: Spinal

• Erector Spinae: Longissiumus Cervicis and Capitis• Origin: Same as above• Insertion: Transverse process of cervical vertebra and Lower nine ribs of

transverse processes, respectively • Action: Same as above• Nerve: Spinal

• Spinalis: Cervicis and Capitis• Origin: Spinous processes of the upper lumbar and lower throacic vertebrae,

ligamentum nuchae and spinous processes of C7• Insertion: Spinous processes of upper thoracic and cervicals• Action: Latterally flex and Extend the vertebral column and head• Nerve: Spinal

SPINE: Transversospinalis Group• Semispinalis Capitis, Cervicis and Thoracis

• Origin: Transverse processes of C4-T5• Insertion: Between superior and inferior nuchal lines• Action: Extend the vertebral column and head• Nerve: Cervical

• Multifidus and Rotatores• Origin: Sacrum and transverse processes of lumbar through

cervical vertebrae• Insertion: Spinous processes of lumbar vertebrae through C2• Action: Rotate and Extend vertebral column• Nerve: Spinal

MUSCLES OF THE BACK:Cross Sectional View

ORIGIN, INSERTION, ACTION and NERVE

• Rhomboid Minor and Major Muscles• Origin: Spinous processes of T2-5 and C7-T1, respectively• Insertion: Medial border of scapula across spine of scapula• Action: Adduct, elevate and downwardly rotate scapula• Nerve: Dorsal Scapular C4-5

• Quadratus Lumborum• Origin: Posterior Iliac Crest• Insertion: Last rib and transverse processes of L1-4• Action: Laterally tilt pelvis, laterally flex to same side and

extend vertebral column• Nerve: Lumbar Plexus T12-L3

Arteries, Veins, Nerves and Lymph Nodes

• Accessory Nerve (Lies inferior on the trapezius muscle)• Arteries and Veins• Laterally:

– External Jugular Vein– Internal Jugular Vein– Lateral cutaneous branches of Ventral Rami-Intercostal Nerves of Ribs

• Posteriorly: – Occipital Artery and Vein– Great Auricular Nerve– Posterior Cutnaeous Branches of Dorsal Rami (C4-T6)– Posterior Cutaneous Branches of Ventral Rami (T7-12)

– Subclavian artery and vein– Superficial cervical artery and vein (descending branch)– Iliohypogastric Nerve (just superior to the Iliac Crest)

LYMPH NODES:

•Occipital •Mastoid•Sternocleidomastoid•External Jugular •Inferior Deep Lateral Cervical•Thoracic Duct•Transverse Cervical Chain•Supraclavicular

•Jugular Trunk•Subclavian Trunk and Node

Dissection Techniques• This week:• Latissimus Dorsi: Identify the Thoracodorsal Nerve and Artery along the deep surface of

the muscle. Locate the serratus posterior inferior, separate the Lats from it. Also locate the Teres Major muscle and follow it to the point of insertion for both the Lats and Teres Major on the intertubercular sulcus at the posterior axillary fold. Separate the two muscles from eachother. Locate T9 and the beginning of the Thoracolumbar Fascia. Make an arcing cut from the medial to the lateral border (just above the iliac crest) separating the Latissimus Dorsi from the Fascia.

• Rhomboids Major and Minor: ID the two muscles and separate them from underlying tissue. ID the dorsal scapular nerve and transverse cervical artery. Sever the rhomboids from the vertebral column and reflect laterally.

• Serratus Posterior Superior and Inferior: ID both portions along the spine at C7-T3 and T11-L3 respectively. Sever them both at their attachments on the vertebral column. Reflect them laterally to expose the thoracolumbar fascia.

• Thoracolumbar Fascia: The posterior layer is a thick aponeurosis that covers the erector spinae. A vertical incision will be made from the 12th rib to the iliac crest, cutting medially to the midline and laterally to the border of the erector spinae muscles. A vertical cut will be made along the line fo fusionto expose the underlying Quadratus Lumborum muscle.

UPCOMING DISSECTIONS• Quadratus Lumborum• Splenius Capitis and Cervicis• Levator Scapulae• Erector Spinae• Spinalis: Cervicis and Capitis• Transversospinalis: Semispinalis Capitis, Cervicis and

Thoracis• Multifidus• Rotatores• Interspinous and Intertransverse

BIBLIOGRAPHY• Biel, Andrew. Trail Guide to the Body, 4th Edition. Boulder, CO:

Books of Discovery. 2010. 66-85.• Clemente, Carmine D. Anatomy: A Regional Atlas of the Human

Body, 6th Edition. Los Angeles: Lippincott, Williams and Wilkins, 2011. 33-34, 38, 40, 44-45, 47, 53, 55, 65, 371-373.

• Clemente, Carmine D. Anatomy Dissector, 3rd Edition. Los Angeles: Lippincott, Williams and Wilkins, 2011.

• Netter, Frank. Atlas of Human Anatomy, 3rd Edition. New Jersey: Novartis. 1999. 148-150,160-163.

• Semenow, Bluhm and Oliver. . Rapid Review: Anatomy Reference Guide, 3rd Edition. Skokie, IL: Lippincott, Williams and Wilkins, 2010. 8-11, 18-21.