A3 Back Muscles

Question 1

Base of Skull

Answer 1

External occipital protuberance (draw) (feel back of head)

mastoid process (draw)

nuchal lines (inferior and superior)

Question 2

Scapula Structures and Movements

Answer 2

Identify the medial border, spine, acromion process, and glenoid cavity (articulations with head of humerus)

movements: elevate depress, retract, progract, rotate up and down

Question 3

supercristal plate

Answer 3

line created by the iliac crests of pelvis

Across L4 lumbar section

Question 4

Types of Contraction

Answer 4

Isometric: no movement, tension increased: hold arm out

Isotonic” muscle changes in length

• concentric contraction (shortening)
• eccentric contraction (lengthening)

Question 5

Extrinsic back Muscles

Answer 5

Hypaxial muscle group (migrated here)

Superficial: mm or upper extremity

Intermediate- rib attachments

ANTERIOR PRIMARY RAMI

Question 6

Intrinsic Back Muscles

Answer 6

Epaxial muscle group

Vert-Vert, Vert Skull, Rib attachments

POSTERIOR PRIMARY RAMI

Question 7

Trapezius

Answer 7

EXTRINSIC SUPERFICIAL

top contract-elevate scapula

middle: retract the scapule

bottom, lower scapula

ascending & descending: rotate scapula

PA: Superior Nuchal Line, EOP, nuchal ligament, spinous process of C7-T12

DA: Spine and acromion of scapula, lateral 1/3 of clavicle

Act: elevates and rotates retracts depresses scapula, upward rotation of glenoid cavity

Innervation: Accessory Nerve: CN XI

Question 8

Latissimus Dorsi

Answer 8

EXTRINSIC SUPERFICIAL

PA: Spinous process of T7-T12, thoracolumbar fascia, iliac crest (midline)

DA: Humerus (intertubercular sulcus)

Acts: Extends, adducts and medially rotates humerus

Inn: Thoracodorsal Nerve

Question 9

Levator Scapulae

Answer 9

EXTRINSIC SUPERFICIAL

PA: Transverse Process of C1-C4
DA: Upper medial border of Scapula
Act: elevates scapula, downward rotation of glenoid cavity
Inn: Dorsal Scapular Nerve

Question 10

Rhomboid minor

Answer 10

SUPERFICIAL EXTRINSIC

PA: Nuchal lig, spinous process of C7, T1

DA: medial border of scapula

Act: retracts scapula, downward rotation of glenoid cavity (with levator scapula)

Inn; Dorsal Scapular nerve

Question 11

Rhomboid Major

Answer 11

SUPERFICIAL EXTRINSIC

PA: Spinous Process of T2-T5 spinous process

DA: Medial Border of Scapula

Act: Retracts Scapula, downward rot of glenoid cavity

Inn: Dorsal scapular nerve

Question 12

Serratus Posterior Superior

Answer 12

INTERMEDIATE EXTRINSIC

PA: Nuchal ligament, spinous process of C7-T3

DA: Ribs 2-4

Act: Proprioception (elevate ribs)

Inn: Intercostal nn (thoracic anterior rami)

Question 13

Serratus Posterior Inferior

Answer 13

INTERMEDIATE EXTRINSIC

PA: Spinous process of the T11-L2

DA: Ribs 8-12

Act: Proprioception (depress ribs)

Inn: Inferior thoracic anterior rami

Question 14

Thoracolumbar Fascia

Answer 14

Dense CT, supports/anchors muscles, invests/surrounds deep back muscles.

Question 15

Intrinsic Muscles of Back

Answer 15

Posterior Rami motor innervation

Epaxial, not migratory

movement of vertebral column, involved with abdominal muscles

eccentric contraction: controlled relaxation of antagonist muscles

Flexion ( head back)
Extension (bend forward)

Posture

Question 16

Splenius Muscles

Answer 16

DEEP INTRINSIC

Splenius Capitis

Splenius Cervicis

PA: hucal ligament, spinous process of C7-T4
DA: Mastoid process and superior nuchal line (sp cap) transfuse process of C1-C4 (sp cerv)

Act: bilateral: extend head/neck Unilateral: ipsilateral lateral flexion of neck and rotation of head

Inn: Posterior Primary Rami

Question 17

Erector Spinae

Answer 17

DEEP INTRINSIC

THREE LONG COLUMS (I love spaghetti)

Iliocostalis

longissimus

spinalis

ACT: bilateral: extension of vert column/head
Unilateral: ipsilateral lateral flextion of vertebral colum

Inn: PR

Question 18

DA & PA of Erector

Answer 18

PA: broad tendon form posterior part of iliac crest, posterior surface of sacrum, sacroiliac ligaments, sacral and inferior lumbar spinous processes, supraspinal ligament

DA:

• il: ribs, cervical transverse processes
• l: transverse processes, ribs, mastoid process
• s: spinous processes

INN: PR

Question 19

Transversospinal group

Answer 19

very small in “gutter space”

PA: transfverse process to spinous process DA

stabilize transverse process

Semispinalis capitis: Up to neck

Semispinalis Cervicis

Semispinalis Thoracis

ACt: unilateralL contralateral rotation of head and VC
Bilateral: extend vertebral column/head

Question 20

multifidus and rotatores

Answer 20

Intrinsic

member of transversospinal group

Mult:
thickest in lumbar region (look at image), span 2-4 vertebrae each

Unilateral: assist with same rotation

Bilateral: extend vert. column

rota:
span 1-2 vertebrae, just one vertebral level

UnilateralL assist with same, stabilize, and proprioception

bilateral: extend vert column

Question 21

levator costarum

Answer 21

Intrinsic

transverse processes to ribs

Question 22

segmental muscles

Answer 22

intranversarii, tranverse process to transverse process

InterspinalisL spinous process to spinous process

Question 23

sub occipital triangle

Answer 23

DRAW

Deep Posterior Cervical

-many palpable structures

landmark for arteries muscles and nerves

1. Rectus Capitis (posterior minor and major)
2. obliquus capitis superior and inferior

where was splenius?

ACT: postural, extension, lateral flexion, ipsilateral rotation.

Inn: SUB OCCIPITAL NERVE (posterior ramus of C1) in the triangle, motor for mm of triangle
-posterior ramus of C2: sensory, inferior to inferior oblique, courses to scalp.

vertebral artery in traingle

Question 24

Innervation of Back

Answer 24

superficial / extrinsic/ hypaxial- ANTERIOR RAMI (except trapezius-CN XI)

Intermediate back/ Extrinsic. hyp: ANT RAMI

DEEP/INTRINSIC/EPAXIAL: posterior rami