Muscles Flashcards
Sternocleidomastoid
Position: anterior part of neck and is a paired superficial muscle
O: sternal head - anterior upper surface of the manubrium of the sternum
Clavicular head - upper anterior surface 2/3 clavicle
I: superior nucheal line
A: ipsilateral - side flexion and contralateral rotation
Bilateral - protraction and flexion of neck
Diaphragm
Position: unpaired dome-shaped muscle that is located in the trunk and separates the thoracic and abdominal cavities
Attachments: peripherally diaphragm is attached to xiphoid process and ligaments that extend over posterior aspect of the lumbar wall and the vertebrae of the lumbar region
A: primary muscle of inspiration, during inspiration it contracts and flattens increasing vertical diameter of thoracic cavity this produces lung expansion and air is drawn in
F: labour, urinating, vomiting
External oblique
Position: situated on the lateral and anterior part of abdomen
O: 5th-12th ribs and costal cartilages
I: rectus sheath via linea Alba, pubic tubercles to ASIS, anterior 2/3 iliac crest
A: fixed pelvis - contralateral rotation, trunk flexion, lateral flexion
fixed shoulders - ipsilateral side flexion, posterior pelvic tilt
Rectus Abdominus
Position: paired muscle running vertical each side anterior wall of abdomen
O: xiphoid process, 5th-7th costal cartilages
I: pubic symphysis, pubic crest
A: trunk flexion, contralateral rotation, ipsilateral lateral flexion, posterior pelvic rotation
Internal oblique
Position: lateral side of abdomen and forms one of the layers of the lateral abdominal wall
O: lower border of the 10th-12th ribs, linea Alba via rectus sheath, pectin pubis
I: lateral 2/3 inguinal ligament, thoracolumbar fascia
A: fixed shoulders - posterior pelvic tilt, ipsilateral side flexion, bilateral trunk rotation
Fixed pelvis - contralateral rotation, bilateral posterior rotation of pelvis
Transversus Abdominus
Position: under internal obliques on the anterolateral abdominal wall, it’s fibres run transversely perpendicular to linea Alba
O: internal surface 7th-12th ribs and their costal cartilages, thoracolumbar fascia, iliac crest and lateral 1/3 inguinal ligament
I: linea alba via rectus sheath and pectin pubis
A: raises intra-abdominal pressure and stabilising muscle of lumbar spine/ trunk
Quadratus lumborum
Position: deepest abdominal muscle on lower back either side of lumbar spine
O: medial 1/2 lower border 12th rib
I: transverse process of lumbar vertebrae, iliolumbar and iliac crest
A: muscle of inspiration, ipsilateral side flexion, lumbar extension
Levator scapulae
Position: located at the back and side of the neck, posterior axial appendicular muscle
O: posterior tubercle of transverse processes C1-4
I: vertebral margin scapula between superior angle and spine of scapula
F: elevate scapula, tilt glenoid cavity inferiorly
A: fixed scapula - lateral flexion of c spine and stabilised during rotation
External Intercostal muscles
O: inferior margin of the rib above
I: superior margin of the rib below
A: inspiration
F: stabilise chest wall
Internal intercostal muscles
intercostal space
Innermost intercostal muscles
O: inferior margins & internal surfaces of costal cartilages of 2nd-6th ribs & inferior aspect of deep surface of body of sternum
I: xiphoid process & costal cartilages of ribs 4-7
A: act within internal intercostals
Scalene
Position: three paired muscles anterior, middle and posterior scalene on lateral aspect of neck collectively form part of the floor of the posterior triangle of the neck
O: ant - TP C3- C6, med - TP C1- C7, post - TP C4- C6
I: upper surfaces ribs 1&2
A: flexes and rotates neck, ipsilateral flexion
F: elevate 1st and 2nd ribs, accessory muscles of respiration
Accessory muscles of respiration
Sternocleidomastoid Scalene Serratus anterior Pectoralis major Quadratus lumborum Abdominal muscles Latissimus Dorsi
Upper Trapezius
Position: large paired surface muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae of the spine and laterally to the spine of scapula
O: occipital protuberance, superior nucheal line, spinous processes C7-T12, supraspinous ligament
I: lateral 1/3 clavicle
A: extension and side flexion of skeleton, elevates shoulder girdle
F: rotates scapula upwards, cervical extensor muscles counterbalance pull of gravity on head
Longus capitis & coli
Bilateral flexion of c spine
Flexion of neck
Coli - flexes neck
Capitis - flexes head and neck
