External occipital protuberance
projection on the external surface of the squamous part of the occipital bone in the midline
Long spinous process of C7. Disappears when head is extended
T1 Spinous Process
Another prominent spinous process. Does not disappear when head is extended
Fusion of 5 sacral vertebrae. Large triangular bone
Superior lateral boundaries of pelvic girdle
medial rotator and adductor of the humerus and assists the latissimus dorsi in drawing the previously raised humerus downward and backward (extension, but not hyper extension). It also helps stabilize the humeral head in the glenoid cavity
Area of the skin innervated by fibers from a single spinal nerve or spinal cord segment. Dermatome maps have been developed from clinical studies. Adjacent dermatomes have some area of overlap. Dermatome maps can be used for clinical sensory testing.
Subcutaneous tissue (tissue immediately below the skin). Found between the skin and the deep fascia. Covers most of the body, storage area for body fat. Not very well organized
Strong, dense, well organized layer of connective tissue. Located deep to the superficial fascia and contains NO fat. Where muscles attach to bones the deep fascia becomes continuous with periosteum. Helps form compartments in the body. Divides into different layers: Investing layer of deep fascia, intermuscular septa, and retinaculum
Investing layer of deep fascia
AKA Superficial layer of deep fascia. Invests (covers) deeper structures. Extensions from the deep surface of the deep fascia invests deeper structures such as muscles and neurovascular bundles
separates muscles into groups
thickening of the deep fascia across tendons of muscles at joints
Muscles of the back
Three types of muscles of the back: superficial back muscles, intermediate back muscles, and deep back muscles
Superficial back muscles
Also known as axioappendicular muscles. Attach to upper limb (appendicular skeleton) to axial skeleton. muscles of the superficial group originate from the bony structures of the back and insert on the bones of upper limb. Since they act to move the upper limb and not the back, they are, therefore, EXTRINSIC back muscles. Since they are upper limb muscles they are supplied by the VENTRAL PRIMARY RAMI and not by the dorsal primary rami. Included in these are Trapezius, latissmus dorsi, levator scapulae, and rhomboid major and minor.
Intermediate back muscles
Extrinsic muscles. Involved in the act of respiration by acting on the chest wall. Innervated by ventral primary rami.
Deep back muscles
The deep back muscles are the true (intrinsic) muscles of the back. These muscles are the primary movers of the back. Innervated by the DORSAL primary ramus.
Superficial back muscle. Provides direct attachment of pectoral girdle to the axial skeleton (trunk). Flat triangular muscle. Helps to suspend the upper limb from the trunk. The two muscles, one on each side of the vertebral column, form a trapezoid (4 sided) structure. Covers back of neck and upper half of the trunk. Attaches the pectoral girdle to the skull and vertebral column. Muscle fibers are divided into three parts.
Occipital Bone, Ligamentum nuchae, Spinous process of C7 - T12
Clavicle (lateral 1/3), Acromion and spine of scapula
Trapezius Nerve Supply
Motor: Cranial nerve XI (spinal accessory nerve). Sensory: C3, C4 (ventral primary rami) - pain and proprioception
Trapezius Blood Supply
Superficial branch of the transverse cervical artery. Located on the deep surface of the muscle
Holds upper limb to trunk. Adducts (retract) scapula (middle fibers). Raises scapula (upper fibers). Depresses scapula (lower fibers). Rotates scapula so that the inferior angle is moved laterally for abduction of upper limb above horizontal position.
Trapezius Clinical Correlations
Nerve injury results in drooping of scapula (shoulder) also known as shoulder drop. To test its strength, the shoulder is shrugged against resistance
Superficial back muscle. Very broad and flat muscle. Covers inferior half of the back (T6 to iliac crest). Attaches from upper limb to trunk. Acts on the shoulder joint
Latissmus Dorsi Origin
Spinous process of lower 6 thoracic vertebrae, thoracolumbar fascia, iliac crest and lower 3/4 ribs
Latissmus Dorsi Insertion
Humerus (at intertubercular groove) between Teres major and Pectoralis major
Latissmus Dorsi Nerve Supply
Thoracodorsal Nerve (C6, C7, C8 level of spinal cord) from brachial plexus
Latissmus Dorsi Blood Supply
Latissmus Dorsi Action
Pulls arm posteriorly (extends the arm) and rotates medially. Used in chopping wood or crawl stroke in swimming. Adducts, extends, and medially rotates the humerus at the shoulder joint. Along the pectoralis major, it is a powerful adductor of the arm.
Latissmus Dorsi Clinical Correlation
Nerve damage results in an inability to raise the trunk with upper limbs during climbing
Triangle of auscultation
Small triangular gap between muscles near inferior angle of scapula. Bounded by trapezius, latissmus dorsi, and medial border of scapula. Good place to listen for respiratory sounds with stethoscope as sounds are less muffled.
Superficial back muscle. A strap-like muscle located in the neck and the upper part of the thorax. The upper part lies deep to the sternocleidomastoid and the inferior part lies deep to the trapezius muscle.
Levator scapulae origin
Transverse processes of first three or four cervical vertebrae
Levator scapulae insertion
Superior angle of scapula and along its upper medial border
Levator scapulae blood supply
Dorsal scapular artery (branch of axillary a) or deep branch of transverse cervical artery
Levator scapulae nerve supply
Dorsal scapular nerve (C5) and 3rd & 4th cervical nerves
Levator scapulae action
Elevates scapula. Rotates scapula to move the glenoid cavity and shoulder joint inferiorly
Rhomboid Major and Minor
Superficial back muscle. One sheet of muscle, lies deep to the trapezius muscle. Upper portion is the rhomboid minor, lower bigger portion is the rhomboid major.
Rhomboid Major and Minor origin
Spines of lower cervical (C7) and upper thoracic (T1-T5) vertebrae
Rhomboid Major and Minor Insertion
Medial border of scapula
Rhomboid Major and Minor Blood Supply
Dorsal scapular artery
Rhomboid Major and Minor Nerve Supply
Dorsal scapular nerve (ventral ramus of C5) and some fibers from C4
Rhomboid Major and Minor Action
Adduct scapula. Rotate scapula so the glenoid cavity moves inferiorly
Rhomboid Major and Minor Clinical Correlation
Injury to the dorsal scapular nerve results in inability to adduct the scapula
Serratus Posterior Superior
Intermediate back muscle. Located deep to the rhomboid muscles.
Serratus Posterior Superior Origin
Ligamentum nuchae and spines of C7 to T3 vertebrae
Serratus Posterior Superior Insertion
2nd to 4th ribs
Serratus Posterior Superior Nerve Supply
First three thoracic spinal nerves. VENTRAL primary rami.
Serratus Posterior Superior Action
Serratus Posterior Inferior
Intermediate back muscle. Located at junction of thoracic and lumbar regions.
Serratus Posterior Inferior Origin
T11 to L2 Vertebral spines
Serratus Posterior Inferior Insertion
Lower four ribs
Serratus Posterior Inferior Action
Aids in respiration by holding ribs steady when diaphragm moves up
Serratus Posterior Inferior Nerve Supply
Last 4 thoracic nerves