► Pectoral Region
► Learning Objectives
► At the end of this lecture the student should be able to:
• Know the role of muscles of pectoral region in stabilizing the pectoral girdle.
• Enumerate the muscle of pectoral girdle .
• Describe the attachments of muscle of pectoral girdle, nerve supply and actions ( Pectoralis Major
and minor,
• Subclavius,Trapezius,Latissimus Dorsi,Rhomboid major and minor,Levator Scapulae and Serratus
anterior).
• Discuss the clavi-pectoral fascia.
• Know the triangle of auscultation.
• Mention the nerves and blood vessels of this region.
► PECTORAL GIRDLE
► The pectoral girdle or shoulder girdle is the set of bones which connects the upper limb to the
axial skeleton on each side.
► Consists of the clavicle and scapula
► PECTORAL GIRDLE
► The only joints between the shoulder girdle and axial skeleton are the sternoclavicular joints
on each side.
► No joint exists between each scapula and the rib cage; instead the muscular connection
between the two permits relatively great mobility of the shoulder girdle in relation to the
pelvic girdle.
► Superficial Fascia
► It contains the moderate amount of fat—continuous with the fascia of surrounding region.
► Contents: cutaneous nerves—cervical plexus.
► Cutaneous branches from the thoracic and posterior intercostal arteries.
► Platysma .
► Breast
► Cutaneous Vessel
► The anterior cutaneous nerve are accompanied by perforating branches of internal thoracic
artery.
► The 2nd, 3rd and 4th branches enlarges in female—supply the breast.
► Lateral cutaneuos nerves accompanied the lateral cutaneous branches of posterior intercostal
arteries.
► Breast
► Most important structure present in the pectoral region.
► It is a modified sweat gland and ectodermal in origin.
► Deep Fasica (Pectoral Fasica)
► The deep fasica covering the pectoralis major muscle is called pectoral fascia .
► Thin and closely attached to the muscle by the numerous septa passing b/w the faciculi of the
muscle.
► It attached superiorly—clavicle & anteriorly to the sternum.
► Superiorlaterally—passes over the infraclavicular fossa and deltopectoral groove
► Inferiolaterally –facsia curve round the inferolateral border of the pectoralis major– cont. with
the axillary fascia.
► Inferiorly—cont. with the fascia of thorax and rectus sheath.
► PERCTORAL GIRDLE MUSCLES
► Muscles of the pectoral girdle broadly are divided into
► • Anterior axioappendicular group
► • Posterior axioappendicular group
► ANTERIOR AXIOAPPENDICULAR MUSCLES
► Also called
► Thoracoappendicular or
► pectoral muscles
► • Four muscles
► – Pectoralis major
► – Pectoralis minor
► – Subclavius
► Serratus anterior
► PECTORALIS MAJOR
• Large fan shaped
• Covers superior part of thorax
• Has clavicular and sternocostal heads
• Its inferior border forms Ant. Axillary fold
• Pectoralis major and adjacent deltoid forms the narrow
deltopectoral groove in which cephalic vein runs
• Pectoralis major along with clavicle forms clavipectoral or deltopectoral triangle
► PECTORALIS MINOR
• Lies beneath Pectoralis major
• An imp.landmark for structures in axilla
• With coracoid process makes a bridge beneath which vessels and nerves pass
► SUBCLAVIUS
► • Lies almost horizontally when the arm is in anatomical position
► • Located inferior to clavicle and affords some protection to the
► subclavian vessels and the superior trunk of brachial plexus if
► clavicle fractures
► SERRATUS ANTERIOR
► Saw toothed appearance, also called boxer’s muscle
► • Overlies lateral part of thorax and forms medial wall of axilla
► • Holds scapula against thoracic wall while doing push-ups
► Posterior Axioappendicular Muscles
► Also called scapulohumeral muscles
► • Divided into 3 groups
► • Superficial posterior Appendicular (extrinsic shoulder) muscles
► – Trapezius
► – Latissimus dorsi
► • Deep posterior Appendicular (extrinsic shoulder) muscles
► – Levator scapulae or rhomboids
► Scapulohumeral (intrinsicshoulder) muscles;
► – Deltoid
► – Teres major
► – 4 rotator cuff muscles (supraspinatus, infraspinatus, teres minor and subscapularis)