Lab muscles part 2

What are the muscles of the neck and vertebral column?

• splenius

• erector spinae

  • ILIOCOSTALS

  • LONGISSIMUS

  • SPINALIS

• semispinalis

• quadratus lumborum

broad 2-part superficial muscle (capitis and cervicis parts) extending from upper thoracic vertebrae to skull: capities portion known as “bandage muscle” because it covers and holds down deeper neck muscles.

splenius

What is the origin and insertion of splenius? What is the action?

O- ligamentum nuchae, spinous processes of verterbra c7-t6

I- mastoid process of temporal bone and occipital bone (capities): transverse processes of C2-c4 vertebrae

action- extend or hyperextend head

Prime mover of back extension. Lifting a load or moving suddenly from a bent-over position can injure these muscles.

erector spinae

most lateral muscle group of erector spinae muscles; extend from pelvis to neck

iliocostalis

What is the origin and insertion of iliocostalis? What is the action?

O- iliac crest, thoracic ribs, and cervical ribs 3-6

I- ribs

Action- extend the vertebral column, laterally flex the vertebral column

intermediate 3-part muscle group of erector spinae; extend by many muscle slips from lumbar region to skull; mainly pass between transverse processes of verterbrae

longissimus

What is the origin and insertion of longissimus? What is the action?

O- transverse processes

I- transverse processes, and mastoid process

action- extend the vertebral column, laterally flex the vertebral column, extends and rotates the head

most medial muscle column of erector spinae; cervicis usually rudimentary and poorly defined.

spinalis

What is the origin and insertion of spinalis? What is the action?

O- spinous process

I- spinous process

action- extends vertebral column (no flexion!!)

composite muscle forming part of deep layer of intrinsic back muscles; extends from thoracic region to head (profound to longissimus)

semispinalis

What is the origin and insertion of semispinalis? What is the action?

O- transverse processes

I- spinous processes

action- extends vertebral column and head and rotates them to opposite side

fleshy muscle forming part of posterior abdominal wall

quadratus lumborum

What is the origin and insertion of quadratus lumborum? What is the action?

O- iliac crest and lumbar fascia

I transverse processes of lumbar vertebrae

action- laterally flexes vertebral column

What are the superficial muscles of the anterior and posterior thorax?

• Anterior:

  • Pectoralis minor

  • Serratus anterior

• Posterior:

  • Trapezius

  • Levator scapulae

  • Rhomboids

flat, thin muscle directly beneath and obscured by pectoralis major

pectoralis minor

What is the origin and insertion of pectoralis minor? What is the action? What is the nerve supply?

O- ribs 3-5 (or 2-4)

I- coracoid process of scapula

action- with ribs fixed, pulls scapula forward and downward

Nerve supply- medial and lateral pectoral nerves

fan-shaped muscle; lies deep to scapula, deep and inferior to pectoral muscles on lateral rib cage; forms medial wall of axilla;orgins hare serrates apperance; paraylysis results in “winging” of verterbral border of scapula away fro chest wall, making arm elevation impossible

serratus anterior

What is the origin and insertion of serratus anterior? What is the action? What is the nerve supply?

O- ribs

I- medial border of scapula

action- rotates scapula, prime mover to protract

nerve supply- long thoracic nerve (C5-C7)

upper fibers run inferiorly to scapula; middle fibers run horiontally to scapula; lower fibers run superiorly to scapula.

trapezius

What is the origin and insertion of trapezius? What is the action? What is the nerve supply?

O- occipital bone, ligamentum nuchae, spinous processes of c2 and all thoracic

I- acromion, spine of scapula, lateral 3rd of clavicle

action- stabilizes, elevates, retracts, and rotates scapula

nerve supply- accessory nerves (cranial nerve XI); C3 and C4

located at back and side of neck; deep to trapezius; thick straplike muscle

levator scapulae

What is the origin and insertion of levator scapulae? What is the action? What is the nerve supply?

O- transverse processes

I- medial border of scapula

action- elevates and adducts scapula

nerve supply- cervical spinal nervers and dorsal scapular nerve (C3-C8?)

2 roughly diamond-shaped muscles lying deep to trapezius and inferior to levator scapulae; rhomboid is the more superior muscle

rhomboids

What is the origin and insertion of rhomboids? What is the action? What is the nerve supply?

O- spinous processes

I- medial border of scapula

action- stabilize scapula, to retract (addict), rotate downward

Nerve supply- dorsal scapular nerve (C4-C5)

What are the deep muscles of the thorax?

• External intercostals

• Internal intercostals

• Diaphragm

11 pairs lie between ribs; fibers run obliquely (down and forward) from each rib to rib below; in lower intercostal spaces, fibers are continuous with external oblique muscle, forming part of abdominal wall

external intercostals

What is the origin and insertion of external intercostals? What is the action? What is the nerve supply?

O- inferior border of rib

I- superior border of rib

action- pulls ribs toward one another to elevate rib cage

nerve supply- intercostal nerves

11 pairs lie between ribs; fibers run deep to and at right angles to those of external intercostals; lower internal costal muscles are continuous with fibers of internal oblique muscle of abdominal wall

internal intercostals

What is the origin and insertion of internal intercostals? What is the action? What is the nerve supply?

O- superior border of rib

I- inferior border of rib

action- pull ribs together and depress rib cage

Nerve supply- intercostal nerves

broad muscle pierced by the aorta, inferior vena cava, and esophagus; forms floor of thoracic cavity; dome shaped in relaxed state; fibers converge from margins of thoracic cage toward a boomerang shaped central tendon

diaphragm

What is the origin and insertion of the diaphragm? What is the action? What is the nerve supply?

O- surface of rib cage and sternum, cartilages, lumbar vertebrae

I- central tendon

action- prime mover of inspiration; flattens on contraction

nerve supply- phrenic nerves

What are muscles of the abdominal wall?

• rectus abdominis

• external oblique

• internal oblique

• transverse abdominis

medial superfical muscle pair; extend from pubis to rib cage; ensheathed by aponeuroses of lateral muscles; segmented by 3 tendinous intersections

rectus abdominous

What is the origin and insertion of rectus abdominous? What is the action? What is the nerve supply?

O- pubic crest

I- xiphoid process & costal cartilages

Action- flex and rotate lumbar region of verterbral column

Nerve supply- intercostal nerves (T6 or T7-T12)

inguinal ligament

external oblique

What is the origin and insertion of external oblique? What is the action? What is the nerve supply?

O- lower 8 ribs

I- linea alba, pubic crest, iliac crest

action- flex verterbral column and compress abdominal wall, trunck rotation and lateral flexion

nerve supply- intercostal nerves (T7-T12)

most fibers run upward and medially; however the muscle fans so its inferior fibers run downward and medially

internal oblique

What is the origin and insertion of internal oblique ? What is the action? What is the nerve supply?

O- lumbar fascia, iliac crest, inguinal ligament

I- linea alba, pubic crest, ribs

action- flex verterbral column and compress abdominal wall, trunck rotation and lateral flexion

Nerve supply- intercostal nerves (T7-T12) and L1

deepest (innermost) muscle of abdominal wall: fibers run horizontally

transversus abdominis

What is the origin and insertion of transversus abdominis ? What is the action? What is the nerve supply?

O- lumbar fascia, inguinal ligament, iliac crest, cartilages, ribs,

I-linea alba, pubic crest

action- compresses abdominal contents

nerve supply- intercostal nerves (T7-T12) and L1

What are muscles of the pelvic diaphragm?

• levator ani

• Ischiococcygeus

broad, thin, 3-part muscle: its fibers extend inferomedially, forming a muscular “sling” around prostate (male) or vagina (female), urethra, and anorectoral junction before meeting in the median plane.

levator ani

What is the origin and insertion of levator ani ? What is the action?

O- pubis to ischial spine

I- coccyx, opposite side of levator ani

action- supports and maintains position of pelvic organs

small triangular muscle lying posterior to levator ani, forms posterior part of pelvic brim.

Ischiococcygeus (coccygeus)

What is the origin and insertion of ischiococcygeus? What is the action?

O- spine of ischium

I- sacrum and coccyx

action- supports pelvic organs