ANT 1003 Back Muscles

What are the extrinsic muscle groups and what does it innervate

innervation: anterior rami of spinal nerves

groups:

1. superficial group- upper limb movement

2. intermediate group- respiration (rib attachments)

What are the intrinsic muscle groups and what does it innervate

innervates: posterior rami of spinal nerves

group (only one)

1. Deep, related to vertebral column movements

What are the superficial back muscles

1. trapezius

2. latissimus dorsi

3. levator scapulae

4. rhomboid major AND minor

What are the groups that the superficial muscles can be separated into and what muscles in each?

2 groups:

1. vertebral column to scapula: trapezius, rhomboid major, rhomboid minor, levator scapulae

2. vertebral column to humerus: latissimus dorsi

Trapezius Origins and Insertions

Origins (less mobile):

• superior nuchal line (on occipital bone)

• external occipital pertrubance

• nuchal ligament

• spinous process

Insertion (mobile):

• lateral 1/3 of clavicle

• spine of scapula

• acromion

Trapezius actions and innervation

actions:

• scapula rotation during abduction of humerus above horizontal

• fibers:

  • superior - elevate

  • middle adduct

  • inferior: depress

innervation:

• spinal accessory (motor)

• c3-c4 (proprioception)

Levator scapulae orgin, insertion, action, innervation

origin: transverse process of CI-CIV

insertion: medial border of scapula

action: elevate scapula

innervation: dorsal scapular nerve (c4-c5)

Rhomboid major origin, insertion, actions, innervation

Origin: spinous process of TII-TV

insertion: medial border of scapula at spine of scapula

actions: adduct and elevate scapula

innervation: dorsal scapular nerve

Rhomboid minor origin, insertion, actions, innervation

Origin: ligamentum nuchae, spinous process

insertion: medial border of scapula (at the spine)

actions: adduct and elevate scapula

innervation: dorsal scapular nerve

Latissimus Dorsi orgin, insertion, action, innervation

origin: spinous process, sacrum, iliac crest, ribs

insertion: intertubercular sulcus (humerus)

actions: externd, adduct, medially rotate humerus

innervation: thoracodorsal nerve

TIII vertebrae lines up with what bone/ area

root of the spine of the scapula

TVII vertebrae lines up with what bone and area

scapula, inferior part of it

LIV vertebrae lines up with what bone/ area

highest point of iliac crest

SII vertebrae lines up with what bone/ area

iliac crest and sacral dimple

What are the three groups of deep muscles

1. spinotransversales (superficial of the deep)

2. erector spinae (intermediate of the deep)

3. Transversospinales (deep of deep)

What are the muscles of the spinotranversales (superficial of the deep)

function: look up

1. splenius capitis: Originates at nuchal ligament

2. splenius cervicis

erector spinae (intermediate of the deep) functions

mid back area:

• Bilateral movement: Primary extensor of vertebral column,

straighten back and head

• Unilateral movement: bend vertebral column laterally

transversospinales (deep of deep) function

rotate the trunk (the two are semispinalis cervicis and semispinalis capitis)

What is the action of the suboccipital triangle

look up and to the right/ left at the same time