Just Good Ol' Anatomy

Question 1

Trapezius

Answer 1

Broad flat and triangular
Attaches from skull, nuchal ligament and spinous processes of c7-t12
Inserts to the clavicle, acromion and scapula spine
Innervation - motor from accessory nerve and proprioceptor fibres from c3 and 4 spinal nerves
Upper fibres elevate and rotate scapula during arm abduction
Middle fibres retract scapula
Lower fibres pull scapula inferiorly

Question 2

Latissimus dorsi

Answer 2

Origin- lower back spinous process of t6-12, iliac crest, thoracolumbar fascia and inferior three ribs
Fibres converge into tendon inserting into intertubercular sulcus of humerus
Innervation from thoracodorsal nerve
Extends, adducts and medically rotates upper limb

Question 3

Lavator scapulae

Answer 3

Origin - transverse processes of c1-4
Inserts to medial boarder of scapula
Innervation from dorsal scapula nerve
Elevates scapula

Question 4

Rhomboids

Answer 4

Major - 
Origin from spinous processes of t2-5 
Inserts on medial boarder of scapula between spine of scapula and inferior angle 
innervation dorsal scapula nerve
Retracts and rotates scapula
Minor -
Origin spinous processes of c7-t1 
Inserts on medial boarder of scapula at level of scapula spine
Innervation dorsal scapula nerve
Retracts and rotates scapula

Question 5

Extrinsic superficial back muscles

Answer 5

Levator scapulae
Trapezius
Latissimus dorsi
Rhomboid major and minor

Originate from the torso and attach to the bones of the shoulder

Question 6

Extrinsic intermediate back muscle

Answer 6

Deep to rhomboids
Serratus posterior - split into serratus superior and inferior

Serratus superior - origin spinous processes and supraspinous ligament of C7-T2
Inserts into posterior aspect of 2-5th ribs
Elevates rib cage as accessory muscle of inspiration
Innervation from anterior primary rami of T2-5 and intercostal nerves

Serratus inferior - origin spinous processes and supraspinous ligament of T11-L2
Inserts into posterior aspect of 9-11th ribs
Depresses the spine in forced expiration
Innervation from anterior primary rami of T9-11 and intercostal nerves

Question 7

Intrinsic superficial back muscles

Answer 7

Known as spinotransversalis
Splenius capitis And splenius cervicis
Both act to rotate the head to the same side.

Capitis - origin from lower aspect of ligamentum nuchae and spinous processes of C7-T3/4
Inserts into mastoid process of occipital bone
Innervation posterior rami of spinal nerves C3/4

Cervicis - origin from spinous processes of T3-6
Inserts into transverse processes of C1-3/4
Innervated by posterior rami of lower cervical spinal nerves

Question 8

Intrinsic intermediate back muscles

Answer 8

Erector spinae - split into spinalis, longissimus and iliocostalis
Common origin from thoracolumnar fascia, sacrum, lumbar and thoracic vertebrae, sacroiliac and supraspinous ligaments and posterior iliac crest.
Common innervation from posterior rami spinal nerves
Acts bilaterally to extends the vertebral column and head
Acts unilaterally to flex the vertebral column

Iliocostalis - most lateral, inserts into the costal angle of all ribs and cervical transverse processes
Longissimus - middle muscles inserts into the transverse processes of T2-12 and mastoid process of occipital bone
Spinalis - most medial, inserts into spinous processes of T2-8 and occipital bone.

Question 9

Deep intrinsic back muscles

Answer 9

Collectively known as transversospinales

Semispinalis - most superficial, Origin from transverse processes of C4-T10
Inserts into C2-T4 and occipital bone
Extends and contralaterally rotates the head and vertebral column

Multifidus - underneath semispinalis, best developed in lumbar spine
Origin sacrum, posterior iliac spine, common tendon with erector spinae, mammillary processes of T1-3 and articular processes of C4-7
Inserts into spinous processes of vertebrae
Stabilises vertebral column

Rotatores - origin transverse processes of vertebrae
Inserts into laminar and spinous processes of immediately superior vertebrae
Most prominent in thoracic region

Question 10

Minor deep intrinsic back muscles

Answer 10

Interspinales - between adjacent spinous processes. Stabilises vertebral column

Intertransversari - between adjacent transverse processes acts to stabilise VC

Levatores costarum - origin C7-T11 inserts into rib immediately below acts to elevate ribs