A3 Back Muscles Flashcards
Base of Skull
External occipital protuberance (draw) (feel back of head)
mastoid process (draw)
nuchal lines (inferior and superior)
Scapula Structures and Movements
Identify the medial border, spine, acromion process, and glenoid cavity (articulations with head of humerus)
movements: elevate depress, retract, progract, rotate up and down
supercristal plate
line created by the iliac crests of pelvis
Across L4 lumbar section
Types of Contraction
Isometric: no movement, tension increased: hold arm out
Isotonic” muscle changes in length
- concentric contraction (shortening)
- eccentric contraction (lengthening)
Extrinsic back Muscles
Hypaxial muscle group (migrated here)
Superficial: mm or upper extremity
Intermediate- rib attachments
ANTERIOR PRIMARY RAMI
Intrinsic Back Muscles
Epaxial muscle group
Vert-Vert, Vert Skull, Rib attachments
POSTERIOR PRIMARY RAMI
Trapezius
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
Latissimus Dorsi
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
Levator Scapulae
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
Rhomboid minor
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
Rhomboid Major
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
Serratus Posterior Superior
INTERMEDIATE EXTRINSIC
PA: Nuchal ligament, spinous process of C7-T3
DA: Ribs 2-4
Act: Proprioception (elevate ribs)
Inn: Intercostal nn (thoracic anterior rami)
Serratus Posterior Inferior
INTERMEDIATE EXTRINSIC
PA: Spinous process of the T11-L2
DA: Ribs 8-12
Act: Proprioception (depress ribs)
Inn: Inferior thoracic anterior rami
Thoracolumbar Fascia
Dense CT, supports/anchors muscles, invests/surrounds deep back muscles.
Intrinsic Muscles of Back
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
Splenius Muscles
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
Erector Spinae
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
DA & PA of Erector
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
Transversospinal group
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
multifidus and rotatores
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
levator costarum
Intrinsic
transverse processes to ribs
segmental muscles
intranversarii, tranverse process to transverse process
InterspinalisL spinous process to spinous process
sub occipital triangle
DRAW
Deep Posterior Cervical
-many palpable structures
landmark for arteries muscles and nerves
- Rectus Capitis (posterior minor and major)
- 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
Innervation of Back
superficial / extrinsic/ hypaxial- ANTERIOR RAMI (except trapezius-CN XI)
Intermediate back/ Extrinsic. hyp: ANT RAMI
DEEP/INTRINSIC/EPAXIAL: posterior rami
