4.4 Muscles of breathing/abdominal cavity Flashcards
What are the deep muscles of the thorax involved in breathing
- involved in breathing
- two phases of breathing: inspiration and expiration
Inspiration muscles: diaphragm and external intercostals
*contraction enlarges rib cage
*diaphragm divides thoracic and abdominal cavities
Expiration: bough on by relatation of inspiratory muscles and contraction of intercostals, decreases size of rib cage
external intercostal muscles
*inter = between, cost = rib
- 11 piars lie between rib fibers, run obliquely from rib to below rib
O: rib
action: pulls ribs towards one another to elevate rib cage
internal intercostals
11 pairs lie between ribs, ribers run deep and at right angles to external intercostals
- O: rib
- daw ribs together and depress rib cage
Diaphragm
- broad muscle, pierced by aorta, inferior vena cava, esophagus
- forms floor of abdominal cavity
O: rib cage and sternum, costal cartilages
I: central tendon
*PRIME MOVER of inspiration, flattens on contraction (when contracted dramatically inc intra abdominal pressure)
What are the muscles of the Abdominal Waal involved in tunk movements and compression of Abdominal Viscera
Four paired muscles: Rectus abdominis, external obliques, internal obliques, transverse abdominis
*fascicles run at angles to one another to provide extra strength
what are the actions of the muscles of the abdominal wall involevd in trunk movements and compression of abdominal viscera
Lateral flexion and rotation of trunk
help promote: urination, defection, childbirth, vomiting, coughing and screaming
Rectus abdominis
*muscle of anterior and lateral abdominal wall
*rectus = straight, adbom = abdomen
- medial superficial muscle
O: pubic crest
I: xiphoid process and ribs
*flex and rotate lumbar region of vertebal column: fix and depress ribs, stbalize pelvis during walking, inc intra-abdominal pressure *use in sit ups, curls
Externla oblique
*muscle of anteiror lateral abdominal wall
- largest and most superficial of three lateral muscles
0 fibers run downwards and medially
*forms inguinal ligament
O: ribs
I: linea alba and iliac crest
*flex vertebral column and compress abdominal wall
*rotating trunk and flexing laterally
internal oblique
*muscle of anterior and lateral abdominal wall
- fibers run up and medially
O: lumbar, iliac crest
I: linae alba, pubic crest, ribs
*same as external oblique, flexes vertebal column and compresses abdominal wall, rotates trunk and flexes laterally
Transversus abdominus
- deepest (innermost) muscle of abdominal wall - fibers run horizontally
O: lumbar
I: linae alba, pubic crest
*compresses abdominal contents
What are the muscles of the Pelvic Floor and Perineum and their funtions
Muscles of pelvic diaphragm: levator ani (inferior) and coccygeus (superior)
Functions;
- Seals inferior outlet of pelvis
- Supports Pelvis organs
- Lifts pelvic floor to help release feces
- Resists increased intra-abdominal pressure
Levator ani
*levator = raises, ani = anus
- has pobococcygeus, puborectalid and iliococcygeus
- forms a “sling” around male prostate ro female vagina, urethra, and anorectal junction
O: inside pelvis
*supports and maintains postion of pelvic organs
*resists downwards thrusts (coughing, vomiting)
Coccygeus
small triangular muscle that supports pevlic organs
Deep transverse perineal muscle
- in urogential diaphagm
*parine = near anus
- supports pelvic organs
what are the muscles of the superficial perineal space?
- Ischiocavernosus
- *ischi = hip, caverna = hollow chamber
- retands venous drainage and maintains erection of penis/clit
- Bulbospongiosus
- Empties male urethra
- Superificial transverse perineal muscles
- stabilizes and strengthens central tendon of perinum
what are the muscles of the urogenital diaphragm?
- anterior half of perineum, inferior to pelvic floor
- Deep transverse perineal muscle
- contrains external urethral sphinter (oluntary control of urination)
- External anal sphincter
Pectoralis minor
O: ribs 305
I: scapula
*with ribs fixed, drawls scpula foward and downwards
Serratus anterior
*serratus = saw
- fan shaped muscle lies deep to scapula, deep and inferior to pectial muscles on lateral rib
O: ribs 1-8
I: scapula
*rotates scapula so its inferior angles move
Subclavius
*subclavious = under clavical
- O: costal cartilage
I: clavical
*helps to stablize and depress pectoral girdle
Trapezius
- most superficial of posterior thorax, run inferiorly to scapula
- middle fibers run horizontally to scapula, lower superiorly, upper inferiorly (to scapula)
- O: occipital bone, C2, thoracic vertebrae
- I: scapula and calvical
*stabilzes, elevates, retracts and rotates scapula
lavator scapulae
- back and side of neck, deep to trapezius
O: C1- C4
I: scapula
*elevates/adducts scapula (in synergy w/ superior fibers of trapezius
Rhomboids
*has a major and minor
*rhomboid - diamond shaped
- ies deep to trapezius and inferior to levator scapulae
O: C7- T1 (minor) and T2-T5 (major)
I: scapula
*stablizies scapula acting w/ middle fibers of trapezius to adduct scapula
