3. Superficial Back

Lecture 3 - miller

surface landmarks of the superficial back

external occipital protuberance

vertebral prominens (C7)

fold of trapezius

spine of scapula

medial border of scapula

intrinsic back muscles

L4 vertebra

iliac crest

posterior superior iliac spines

posterior skull attachment sites

temporal bone - mastoid process

occipital bone - external occipital protuberance, superior nuchal line, inferior nuchal line

how many vertebrae in the vertebral column

33

how many cervical vertebrae

7

how many thoracic vertebrae

12

how many lumbar vertebrae

5

how many sacral vertebrae

5 (fused)

how many coccygeal vertebrae

varies person to person. typically 4 fused

functions of the vertebral column

support body weight, posture, locomotion, protection of spinal cord and spinal roots

parts of a typical vertebrae

body

vertebral arch - laminae and pedicales

processes (7) - spinous (1), transverse (2), and articular (4)

clavicle medial end joint (sternal end)

sternoclavicular joint (SC) joint

clavicle lateral end (acromial) joint and importance

acromioclavicular joint (AC)

attachment site of trapezius

conoid tubercle of clavicle

attachment of coracoclavicular ligament

groove of clavicle importance

attachment site of subclavius

scapula parts

superior angle, coracoid process, acromion process, spine of scapula, glenoid cavity, lateral border of scapula, medial border of scapula, and inferior angle of scapula

humerus features

head, anatomical neck and surgical neck, greater tubercle and lesser tubercle, and intertubercular groove

surgical neck of humerus importance

common fracture location

arteries and nerves

greater and lesser tubercles of humerus importance

attachment sites for rotator cuff muscles

intertubercular groove of the humerus importance

attachment site for 3 muscles:

pectoralis major, latissimus dorsi, and teres major

vertebral ligaments of the superficial back (dorsal)

interspinous ligaments

supraspinous ligaments

ligamentus flavum

Ligamentum nuchae superficial back

occipital protuberance

spinous process C7

role of deep facia of superficial back

postural (aids extensors)

keeps trapezius from bowing during contraction

Thoracolumbar fascia

invests the intrinsic back muscles and separates the deep (intrinsic) and superficial (extrinsic) back muscles

Intrinsic (deep) back muscles function

postural and movement of the spine

extrinsic (superficial) back muscles

attach pectoral girdle to the axial skeleton, movement of the scapula or humerus

superficial back innervation

innervation of muscles occur early in development

muscles are innervated by spinal nerves from cord segments near where they begin to develop

innervation of the back muscles

skeletal muscles of the trunk and limbs are innervated by segmental spinal nerves (mixed)

segmental spinal nerves split into dorsal and ventral rami (mixed)

dorsal rami innervate intrinsic (deep) back muscles and suboccipital muscles

ventral rami innervate all other skeletal muscle (including the superficial back muscles

what does dorsal rami innervate

innervate intrinsic (deep) back muscles and suboccipital muscles

what does ventral rami innervate

all other skeletal muscle (including the superficial back muscles

(except cranial face muscles)

superficial back muscles (posterior axioappendicular muscles)

trapezius, latissimus dorsi, levator scapula, rhomboid minor, rhomboid major, serratus posterior superior, serratus posterior inferior

trapezius (origin, insertion, innervation, and movements)

origin: external occipital protuberance and superior nuchal line, nuchal ligament, and spinous process of C7-T12 vertebrae

insertion: spine of scapula, acromion process, and lateral third of clavicle

innervation: spinal accessory nerve (CN XI)

movements: descending fibers elevate the scapula, transverse fibers adduct/retract the scapula, the ascending fibers depress the scapula

the descending and ascending fibers together cause upward rotation of the scapula

clinical correlation: damage to spinal branch XI, partial paralysis of trapezius, shoulder drop, weakness in shoulder, difficulty lifting upper limb

latissimus dorsi (origin, insertion, innervation, and movements)

origin: spinous processes of T7-T12, inferior portion of ribs 9-12, thoracolumbar fascia, sacrum, posteromedial 1/3 to ½ of the iliac crest

insertion: medial floor of the intertubercular groove (anterior surface of humerus) between teres major and pectoralis major

Innervation: thoracodorsal nerve (C6,7,8)

Movements: arm extension, adduction of the upper arm, medial (internal) rotation of the arm, moves trunk forward (toward the upper limb) when the humerus, “climbers muscle”

Levator Scapulae (origin, insertion, innervation, and movements)

Origin: transverse process of C1-C4

Insertion: superior angle of the scapula and superior portion of the medial border

innervation: dorsal scapular nerve (C5), branch of the root of C5 ventral rami. some fibers from C4 spinal nerves but know C5

Movements: elevation of the scapula, downward rotation of the scapula