PHTH 7101 Muscles Origin, Insertion, Innervation, Blood supply

Proximal attachment is also known as:

Origin

Distal attachment is also known as:

Insertion

Pec major

O: Sternal head (manubrium and body) and clavicular head ( medial part of clavicle)

I: lateral lip of bicipital groove of humerus

Innervation: Median/Lateral pectoral n

Blood supply: pectoral branch of thoracoacromial artery and perforating branches of internal thoracic artery

Pec major action

clavicular head: flexion of arm

sternal head: horizontal adduction of arm

both: medial rotators of arm

Pec minor

O: Ribs 3-5

I: Coracoid process of scapula

Innervation: Medial pectoral nerve

Blood supply: pectoral branch of the thoracoacromial artery

Pec minor action

scapular depression

Serratus Anterior

O: Ribs 1-8 or 9

I: Medial (vertebral) border of scapula

Innervation: Long thoracic nerve

Blood supply: lateral thoracic artery

serratus anterior action

scapular protraction (abduction)

Deltoid

O: acromion, crest of spine of scapula, lateral one third of clavicle

I: deltoid tuberosity of humerus

Innervation: axillary nerve

Blood supply: posterior circumflex humeral artery

Deltoid action

abduction of arm, flexion and internal rotation of arm (ant fibers), external rotation and extension (post fibers)

Subclavius

O: costal cartilage and 1st rib

I: Acromial end of clavicle

Innervation: "nerve to subclavian: C5-C6

Blood supply: clavicular branch of the thoracoacromial artery

subclavius action

may help protect the sternoclavicular joint from tractioninjuries, and to protect the subclavian vessels and brachial plexus inthe event of a fractured clavicle.

External intercostals

O: inferior margin of the superior rib

I: fibers insert medially downward into the superior margin of the inferior rib

Innervation: intercostal nerves (T1-T11)

Blood supply: anterior intercostal arteries, posterior intercostal arteries

External Intercostals action

elevates ribs during inspiration; stabilizes thoracic wall

Internal intercostals

O: lateral edge of the costal groove of inferior ribs

I: fibers insert medially upward into the inferior margin of superior ribs

Innervation: intercostal nerves (T1-T11)

Blood supply: anterior intercostal arteries, posterior intercostal arteries

Internal intercostals action

aids in expiration by depressing ribs; keeps the intercostal space stable

External Obliques

O: outer surface of the 5th to 12th ribs

I: linea alba, pubic crest and tubercle, ASIS, and iliac crest

Innervation: intercostal nerves, iliohypogastric nerve, and ilioinguinal nerve

Blood supply: musculophrenic artery, superior epigastric artery, inferior epigastric artery

External Obliques action

rotates trunk contralaterally, helps some in trunk flexion, aids in expiration

Internal Obliques

O: deep later of thoracolumbar fascia, anterior 2/3 of iliac crest, lateral 2/3 of inguinal ligament, iliopsoas fascia

I: costal margin, pubic crest, linea alba

Innervation: intercostal nerves (T7-T12), iliohypogastric nerve, and ilioinguinal nerve

Blood supply: musculophrenic artery, superior epigastric artery, inferior epigastric artery

Internal Obliques action

ipsilateral trunk rotation and lateral flexion of trunk

Transversus abdominis

O: inside rib cage above costal arch

I: linea alba, pubic crest, pecten pubis

Innervation: intercostal nerves (T7-T12), iliohypogastric nerve, and ilioinguinal nerve

Blood supply: musculophrenic artery, superior epigastric artery, superficial circumflex iliac artery, lumbar arteries

Transversus abdominis action

compresses abdomen, flexes and rotates trunk

Rectus abdominis

O: pubis and pubic symphysis

I: xiphoid process, costal cartilages of ribs 5-7

Innervation: anterior cutaneous intercostal nerves (T7-T11)

Blood supply: superior epigastric artery

Rectus abdominis action

compression of abdomen, flexion of trunk, posterior pelvic tilt

Sternocleidomastoid

O: anterior surface of manubrium (sternal), medial third of clavicle

I: mastoid process and lateral part of the superior nuchal line

innervation: motor - spinal accessory nerve CN XI ; sensation - brachial plexus from C2-3

blood supply: superior thyroid artery, occipital artery

Sternocleidomastoid action

Flexes and laterally rotates the head and neck

Platysma

O: pectoral fascia overlying pec major and deltoid

I: inferior border of mandible and parotid fascia

Innervation: Facial nerve CN VII

Blood supply: facial artery

Platysma action

depression of angles of mouth and mandible

infrahyoid (strap) muscles

superficial: sternohyoid and omohyoid

deep: sternothyroid and thyrohyoid

Sternohyoid

O: posterior surfaces of manubrium and sternal end of clavicle

I: Lower border of hyoid bone

Innervation: ansa cervicalis (C1-3)

Blood supply: superior thyroid artery

Sternohyoid action

depression and stabilization of hyoid bone and larynx; aids in phonation and swallowing

Omohyoid

O: superior belly -intermediate tendon ; inferior belly - upper border of scapula

I: superior belly - lower border of hyoid bone ; inferior belly - intermediate tendon

innervation: ansa cervicalis (C1-3)

blood supply: superior thyroid artery

Omohyoid action

depression and stabilization of the hyoid and larynx for phonation and swallowing

sternothyroid

O: posterior of the manubrium below the origin of the sternohyoid

I: oblique line of the thyroid cartilage

Innervation: ansa cervalis (C1-3)

Blood supply: superior thyroid artery

sternothyroid action

depression and stabilization of the hyoid bone for phonation and swallowing

thyrohyoid

O: oblique line of the thyroid cartilage

I: lower border of hyoid bone

Innervation: hypoglossal nerve (C1)

Blood supply: superior thyroid artery

thyrohyoid action

depression and stabilization of the hyoid bone for phonation and swallowing

cricothyroid

Has an oblique part and straight part

Innervation: external laryngeal nerve

inferior constrictor

O: oblique line of thyroid cartilage, cricoid cartilage

I: pharyngeal raphe

Innervation: external laryngeal nerve

Blood supply: superior thyroid artery; ascending pharyngeal artery