I. LANDMARKS
A. Vertebral furrow - median line of the back
B. External occipital protuberance
C. Vertebra prominens - spine of C7
D. Iliac crest - L4 vertebral level
E. Acromion - tip of shoulder, part of scapula
F. Spine of scapula - opposite T3
G. Inferior angle of scapula - T7
H. Superior angle
II. SUPERFICIAL TISSUES OF THE BACK
A. Skin - thick, particularly in the neck
B. Subcutaneous tissue - thicker and more fat in shoulder
C. Subcutaneous nerves - branches (medial and lateral) of dorsal primary rami, above midthoracic levels medial branches are cutaneous, below, the lateral branches are sensory
1. C1 - no cutaneous innervation
2. C2 = Greater occipital nerve - large medial branch
3. C3 = third occipital nerve (occipitalis tertius)
4. Lateral cutaneous branches - thoracic nerves with medial and lateral branches
5. Superior cluneal nerves - L1-3, distribute to gluteal region
III. MUSCLES
A. Organization by layers
1. Superficial muscles
a. do not act on vertebral column
b. connect upper limb to body
c. innervated by ventral primary rami of spinal nerves (due to developmental migrations)
2. Respiratory
a. very thin accessory muscles of respiration
b. innervated by ventral primary rami
3. Deep back muscles
a. act on vertebral column including neck
b. innervated by dorsal primary rami
c. Divisions
i. Erector spinae
ii. Transversospinalis
iii. Segmental
iv. Suboccipital
B. Trapezius
1. Attachments: external occipital protuberance, superior nuchal line, spines of C7 and all thoracic vertebrae to clavicle and spine of scapula, acromion
2. Nerve: Spinal accessory n (CN XI, spinal portion), C3-4 - form subtrapezial plexus
3. Artery: Dorsal scapular, transverse cervical, suprascapular
4. Action: ADducts and rotates scapula, tilts chin
C. Latissimus dorsi
1.Attachments: spines of lower thoracic vertebrae, lumbar fascia, crest ilium to biceptal groove of humerus
2. Nerve: Thoracodorsal (from brachial plexus)
3. Artery: Thoracodorsal (br. of subscapular), dorsal scapular
4. Action: adduct, extends and medial rotates humerus
D. Rhomboideus major
1. Attachments: spine T2-5 to medial border of scapula
2. Nerve: Dorsal scapular
3. Artery: Dorsal scapular
4. Action: ADducts and rotates scapula
E. Rhomboideus minor
1. Attachments: lig. nuchae, spine C7 and T1 to spine of scapula at medial border
2. Nerve: Dorsal scapular
3. Artery: Dorsal scapular
4. Action: ADducts and rotates scapula
F. Levator scapulae
1. Attachments: transverse process of atlas and axis, C3-4 to medial border of scapula
2. Nerve: Dorsal scapular, C3-4 to upper portion
3. Artery: Dorsal scapular
4. Action: raises scapula
F. Serratus posterior superior - inspiratory muscle of thorax
1. Attachments: lig. nuchae and spines of C7, T1-3 to ribs 2-5
2. Nerve: intercostals
3. Artery: intercostals
4. Action: respiratory
G. Serratus posterior inferior
1. Attachments: spinous processes of T11-12, L1-2 to last four ribs
2. Nerve: intercostals
3. Artery: intercostals
4. Action: respiration
H. Triangle of Auscultation
1. Borders
a. latissimus dorsi – inferior border
b. trapezius – medial border
c. rhomboideus major – floor/lateral border
2. Ribs 6 & 7, ICS 6 free of overlying muscles
3. well suited for auscultation of thoracic organs
I. Lumbar triangle
1. Borders
a. latissimus dorsi
b. external oblique
c. iliac crest
d. internal oblique - floor
2. may be site of lumbar hernia