Superficial muscles of the thoracic wall

Superficial muscles of the thoracic wall: Anatomy & FunctionAnatomy, function, blood supply and innervation of the superficial muscles of the thoracic wall
~ 5 min

In this pdf-note, we’ll start with the borders of the chest:

  • The superior border consists of the jugular notch of the sternum, superior border of the clavicle, and acromioclavicular joint

  • The inferior border consists of the xiphoid process of the sternum and the costal arch

  • The lateral border is the posterior median line

    Borders of the chest
    Borders of the chest

    There are several anatomical regions within the chest:

  • Mammary region (regio mammaria)

  • Inframammary region (regio inframammaria)

  • Sternal region (regio sternalis)

Anatomical regions within the chest
Anatomical regions within the chest

The muscles of the chest are located within these regions. They are arranged in two layers: superficial and deep. In this pdf-note, we will learn about the superficial muscles of the chest. These include:

  • Pectoralis major muscle (m. pectoralis major)

    Pectoralis major muscle (m. pectoralis major)
    Pectoralis major muscle (m. pectoralis major)
    Clavicular part (pars clavicularis)
    Clavicular part (pars clavicularis)
    Sternocostal part (pars sternocostalis)
    Sternocostal part (pars sternocostalis)
    Abdominal part (pars abdominalis)
    Abdominal part (pars abdominalis)
    Pectoralis major muscle
    (m. pectoralis major)

    Origin:

    Clavicular part (pars clavicularis) arises from the medial part of the anterior surface of the clavicle

    Sternocostal part (pars sternocostalis) arises from the anterior surface of the sternum, cartilages of the ribs 1-6

    Abdominal part (pars abdominalis) arises from the anterior wall of the sheath of the rectus abdominis muscle

    Insertion: crest of the greater tubercle of the humerus

    Function: adduction and pronation of the upper limb, flexion and partly extension (at the shoulder joint), pulls the scapula anteriorly and inferiorly, participates in the act of breathing

    Innervation: medial and lateral pectoral nerves (C5-Th1)

    Blood supply: thoraco-acromial artery, anterior and posterior intercostal arteries, lateral thoracic artery

  • Pectoralis minor muscle (m. pectoralis minor)

    Pectoralis minor muscle (m. pectoralis minor)
    Pectoralis minor muscle (m.pectoralis minor)
    Pectoralis minor muscle
    (m. pectoralis minor)

    Origin: anterior surface and cartilages of the ribs 3-5

    Insertion: medial margin and coracoid process of the scapula

    Function: pulls the scapula anteriorly and inferiorly, participates in the act of breathing

    Innervation: medial pectoral nerve (C8-Th1)

    Blood supply: thoraco-acromial artery, anterior intercostal arteries

  • Subclavius muscle (m. subclavius)

    Subclavius muscle (m. subclavius)
    Subclavius muscle (m. subclavius)
    Subclavius muscle
    (m. subclavius)

    Origin: cartilage and sternal end of the 1st rib

    Insertion: middle third of the clavicle

    Function: pulls the clavicle anteriorly and inferiorly

    Innervation: subclavian nerve (C5-C6)

    Blood supply: thoraco-acromial artery, transverse artery of the scapula

  • Serratus anterior muscle (m. serratus anterior)

Serratus anterior muscle (m. serratus anterior)
Serratus anterior muscle (m. serratus anterior)
Serratus anterior muscle (m. serratus anterior)
Serratus anterior muscle (m. serratus anterior)
Serratus anterior muscle (m. serratus anterior)
Serratus anterior muscle (m. serratus anterior)
Serratus anterior muscle
(m. serratus anterior)

Origin:

Superior part arises from the ribs 1-2

Middle part arises from the ribs 3-6

Inferior part arises from the ribs 7-10 and the external oblique muscles

Insertion:

Superior part inserts into the anterior and posterior surfaces of the superior angle of the clavicle

Middle part inserts into the anterior surface of the medial margin of the scapula

Inferior part inserts into the anterior and posterior surfaces of the inferior angle of the clavicle

Function: pulls the scapula anteriorly and laterally, rotates the scapula around the sagittal axis, lifts the ribs with a fixed scapula

Innervation: long thoracic nerve (C5-C7)

Blood supply: thoracodorsal artery, lateral thoracic artery, posterior intercostal arteries

Dictionary

Muscles of the thoracic wall

Mammary region
regio mammaria
Inframammary region
regio inframammaria
Sternal region
regio sternalis
Pectoralis major muscle
m. pectoralis major
Clavicular part
pars clavicularis
Sternocostal part
pars sternocostalis
Abdominal part
pars abdominalis
Pectoralis minor muscle
m.pectoralis minor
Subclavius muscle
m. subclavius
Serratus anterior muscle
m. serratus anterior
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