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 There are several anatomical regions within the chest:
Mammary region (regio mammaria)
Inframammary region (regio inframammaria)
Sternal region (regio sternalis)

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) Clavicular part (pars clavicularis) Sternocostal part (pars sternocostalis) 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)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)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)



(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
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