Muscles of Respiration

Linea Semilunaris

2 layers from rectus sheath join to form a vertical line of aponeurosis

Levator Costarum Brevis

Considered thoracic muscles; contribute to the elevation of the rib cage; muscle of inspiration

Transversus Abdominis

Deepest layer of the anterior abdominal muscles; muscle of expiration

Quadratus Lumborum

Located on the dorsal (back) portion of the abdominal wall; muscle of expiration

Rectus Abdominis

Midline muscles on sides of linea alba made up of 3 fibrous bands that cross stomach; muscle of expiration

External Abdominal Oblique

Most superficial and largest of this group of abdominal muscles; muscle of expiration

Scalenes

Muscles of the neck which provide stability for the head and assist in facilitating rotation; includes anterior, medial, and posterior; muscle of inspiration

Subcostals

Origin - inner thorax; inner surface of rib near angle Insertion - inner surface of 2nd or 3rd rib below Action - depresses thorax

Transverse Thoracis

Origin - lower third of sternum at inner surface Insertion - constal cartilage at ribs 2-6 Action - pulls ribs down and inward

Internal Intercostals

Origin - ribs 1-11 Insertion - superior surface of rib below Action - depresses ribs 1-11

Serratus Posterior Superior

Origin - spinous process of C7 and T1-T3 Insertion - ribs 2-5 Action - elevates ribs 2-5 specifically

Serratus Posterior Inferior

Origin - spinous processes of T11-T12 and L1-L3 Insertion - lower margin of ribs 7-12 Action - muscles pull the rib cage down

Diaphragm

primary muscle of inspiration; separates the abdominal and thoracic cavities; central tendon, muscle of inspiration

Pectoralis Minor

Lies under pectoralis major; muscle of inspiration

Pectoralis Major

Large fan-shaped muscle that originates from 2 heads; muscle of inspiration

Serratus Anterior

Similar to serrated knife; muscle of inspiration

External Intercostals

Accessory muscles of inspiration that contribute to forced inspiration; significant muscles for speech; assist in respiratory capacity and unique speech functions; muscle of inspiration

Trapezius

Broad muscle of upper back; muscle of inspiration

Levator Costarum Longis

Considered thoracic muscles that contribute to the elevation of the rib cage; muscle of inspiration

Rectus Sheath

Continuous layer of connective tissue from the linea alba to the external oblique muscles; splits into 2 layers at the linea alba to cover the abdominal muscles

Subclavius

Courses under the clavicle; muscle of inspiration

Internal Abdominal Oblique

Found between external and transverse oblique; muscle of expiration

Rhomboideus Major

Includes major and minor; lie deep to the trapezius; muscle of inspiration

Rhomboideus Minor

Includes major and minor; lie deep to the trapezius; muscle of inspiration

Latissimus Dorsi

Primarily responsible for other functions such as moving arm, pulling shoulder; muscle of inspiration and muscle of expiration

Levator Scapulae

Provides neck support and helps to elevate the scapula; muscle of inspiration

Sternocleidomastoid

Provides stability and control for neck flexion and extension in addition to assisting in respiration; muscle of inspiration

Inguinal Ligament

Thickened strand of aponeurosis running from anterior-posterior iliac spine to pubic symphysis

Line Alba

White line that runs from xiphoid process to the pubic symphysis; forms a midline structure for muscle attachment