Muscles of Respiration

internal intercostal muscles

(11 on each side). run almost perpendicular to externals.

function of the holes under the diaphragm

1. goes down to stomach 2. for blood vessels and nerves

how many external intercostal muscles are there on each side?

11

anterior scalenus insert

1st rib, anterior to other scalenus

posterior scalenus insert

2nd rib

how many scalenus muscles are there?

3 - anterior, medial, and posterior

transverse abdominal muscle action

compresses abdominal contents: appreciable effect on vertebral column--flex it ventrally or laterally.

what does the diaphragm separate?

creates seal between thoracic and abdominal cavities

rectus abdominis origin

crest of pubis medially to pubic symphasis

transverse abdominal muscle description

deepest or most internal of the flat abdominal muscles. fibers run horizontally.

name the muscles of respiration (15 not counting the abdominal muscles)

diaphragm, external & internal intercostals, transverse thoracic, costal elevator, pectoralis (major & minor), serratus anterior, sternocleidomastoid, scaleni (3 - anterior, medial, and posterior), trapezius, latissmus dorsi, quadratus lumborum

diaphragm (shape)

dome-shaped muscle

functions of serratus anterior

dual function: pull shoulder. if scapula is rigid, deep inhalation.

function of costal elevators

elevate ribs. muscles of inhalation

anterior scalenus action

elevate the first rib or fixate it to allow other ribs to be elevated

lumbar fascia description

facial sheath on lower part of back into which some of the muscles attach.

medial scalenus insert

first rib anterior to tubercule

trapezius action

fixates and moves scapula, fixates shoulder. when shoulder is fixed, moves head backwards and laterally.

trapezius shape & location

flat, triangular. extends over back of neck and upper thorax

rectus abdominis action

flexes the vertebral column. tenses the abdominal wall, compresses the abdominal wall for expressing contents as well as increasing abdominal pressure for expiration, pulls ribs down for expiration.

origin of transverse thoracic muscles

from sternum. upward and lateral, about ribs 5-7

sternocleidomastoid (origin)

from upper surface of sternum and medial end of clavicle - 2 heads. fibers run upwards, laterally and posteriorally.

boundaries of the external intercostal muscles (front and back)

front: bounded by costal cartilage (not up to sternum in front). back: very close to vertebrae itself - all the way around fibers run laterally to medially.

rectus abdominis description

horizontal fascial lines, separate the muscle into 4 or 5 groups. these + the aponeurosis, help contain the muscle during sever flexion

latissimus dorsi insert

humerous. forms posterior fold of axilla

quadratus lumborum origin

iliac crest and ligaments attached to lumbar vertebrae.

function of the diaphragm

increases inside volume of thoracic cavity. primary muscle used in inspiration. unique because it's partially controlled by autonomic nervous system, so it's always used when we're asleep.

transverse abdominal muscle origin

inguinal ligament, inner side of iliac crest, lumbar fascia, inner surfaces of ribs 6-12

origin/insertion of pectoralis major

insert along clavicle, humerus. other point: sternum. (ventral surface of sternal half of clavicle and from cartilages of true ribs).

location of transverse thoracic muscles

inside of thoracic cavity, near front. look like bat wings

latissimus dorsi description

large triangular flat muscle. extends over lumbar region and lower part of thorax

functions of external intercostal muscles

largely muscle of inhalation. squeeze ribs together a bit, as long as they're all attached, rib cage can elevate (swing outward). all stiffen chest wall.

trapezius insert

lateral 1/3 of clavicle, acromion, and crest of spine of scapula

linea semilunaris

lateral boundary of the abd. apo. - not as prominent as the linea alba

anterior scalenus location

lies deep in the neck, deep to the sternocleidomastoid

rectus abdominis location

long, thin muscle running vertically adjacent to the linea alba, enclosed by 2 parts of the abdominal aponeurosis

medial scalenus description

longest and largest muscle

what's good about the perpendicular direction of internal to external intercostal muscles?

makes the muscles overall more stiff.

sternocleidomastoid (insert)

mastoid process of skull

linea alba

middle of abd. apo. - a prominent line of tissue that is thicker than the rest

external oblique abdominal muscle description

most superficial of the flat abdominal muscles, forming a part of the abdominal wall

anterior scalenus innervation

nerves C3-4

what is unique about the insertion of the diaphragm?

not attached to skeleton

trapezius origin

occipital bone, nuchal ligament, spinous processes of 7th cervical vertebrae and all 12 thoracic vertebrae. all fibers converge on upper part of shoulder.

function of transverse thoracic muscles

one of the few muscles above diaphragm that causes exhalation. It is almost completely without function, but it separates the thoracic cage from the parietal pleura. It depresses the ribs. Contraction of this muscle aids in exertional expiration by decreasing the transverse diameter of the thoracic cage.

rectus abdominis insertion

outer surface of xiphoid process and costal part of ribs 5-7

innervation of diaphragm

phrenic nerve (exits vetebral column between C4 & C5)

internal oblique abdominal muscle origin

pubic crest, inguinal ligament, and iliac crest. fibers run diagonally upwards and medially

quadratus lumborum action

pulls lumbar vertebrae laterally, bending to the side. fixes lower rib and assists in expiration by allowing the intercostals to pull against the lower rib

posterior scalenus action

raises 2nd rib or fixates it. bends and rotates neck. all three of these can and do work together for inspiration

medial scalenus action

raises first rib or fixates it. active during quiet respiration. can also bend and slightly rotate the neck

name all the abdominal muscles (4)

rectus abdominis, external, internal, and transverse abdominal muscles

sternocleidomastoid (action)

rotate head contralaterally and downward. during heavy breathing: raise sternum and clavicle. raise head from supine position. important for tilting head.

origin & insertion of pectoralis minor

scapula. insert more vertically in ribs 3-7

external oblique abdominal muscle origin

several parts--broadly. external surfaces and inferior borders of lower ribs--like a line running from top to bottom and front to back

internal oblique abdominal muscle description

situated underneath external oblique on lateral and ventral parts of abdominal wall. fibers run almost perpendicularly to those of the ext. obliq

posterior scalenus description

smallest and most deeply seated

innervation of costal elevator

spinal nerves

innervation of pectoralis major

spinal nerves in cervical region (C5-7)

innervation of transverse thoracic muscle

spinal nerves. decrease thoracic volume

innervation (intercostal)

spinal nerves. exit between vertebrae, go around chest into costal groove, travel and gives strength to muscles.

sternocleidomastoid (innervation)

spinal part of accessory and C2-3. torticolis is where the muscle is contracted permanently (spasmodic torticolis affects this muscle).

latissimus dorsi origin

tendons from spinous processes of lower 6 thoracic vertebrae and from lumbar fascia that is attached to spinous process of lumbar and sacral vertebrae. also from crest of ilium and from 3 or 4 lower ribs. fibers run laterally and converge into thick fasciculus--it spiralizes

external oblique abdominal muscle insertion

the fibers of the last 2 ribs run almost vertically to insert into the iliac crest. the remaining fibers are directed caudally and ventrally to insert on the abdominal aponeurosis.

shape of transverse thoracic muscles

thin plate of muscles on inner wall

quadratus lumborum description

thin sheet of muscle on back

abdominal aponeurosis description

thin sheets of fascia along the ventral surface of the abdomen. extends from sternum to pubis.

anterior scalenus origin

transverse process of C3-6 vertebrae. fibers run almost vertically downward.

posterior scalenus origin

transverse processes of 4, 5, & 6. 3 cervical v

medial scalenus origin

transverse processes of last 6 vertical vertebrae, also atlas

quadratus lumborum insert

transverse processes of lumbar vertebrae 1-4 and 12th rib

internal oblique abdominal muscle action

compresses abdominal contents, pulls ribs down for expiration

external oblique abdominal muscle action

compresses abdominal contents, flexes vertebral column, pull lower ribs down to assist in expiration

tendonous insertions/inscriptions

ab lines (each muscle fiber runs from one to the next)

2 non-muscular tissue forming muscle attachments in abdominal muscles

abdominal aponeurosis and lumbar fascia

internal oblique abdominal muscle insertion

abdominal aponeurosis, costal parts of ribs 8-12

latissimus dorsi action

adduct the arm. helps fixate arm for respiration. active in coughing and sneezing and in deep inspiration.

costal elevators (aka...? and how many?)

aka levator costarum. 12 on each side.

location of serratus anterior

along blade of scapula to ribs, close to bottom of rib cage.

sternocleidomastoid (location)

anterior and lateral part of neck

scaleni muscles (3 of them)

anterior, medial, and posterior

transverse abdominal muscle insertion

aponeurosis

location of costal elevators

arise from transverse processes of vertebrae 7-11. between tubercule and angle of rib below transverse process.

where does the diaphragm originate?

at xyphoid process and ribs 7-12 (lower thoracic/upper lumbar vertebrae. all around rib cage)

lumbar fascia attachment location

attaches to posterior part of iliac crest and spines of lumbar vertebrae. 2 layered structure allowing for 2 different muscle groups to attach

location of internal intercostal muscles

begin right next to sternum and terminate at about angle of rib in back (not all the way to the vertebrae like external muscles)

where is the diaphragm located?

bottom of thorax

pectoralis major (shape and location)

broad, fan-shaped. covers upper part of chest.

origin/insertion of external intercostal muscles

caudal of top rib to rostral of rib under it

where is the insertion for the diaphragm

central tendon (whitish underbelly) - aponeurosis