Muscles of the Pectoral Girdle

depression elevation lateral rotation medial rotation pectoral girdle retraction scapula rhythm scapulohumeral rhythm shoulder girdle trapezius

Muscles of the Pectoral Girdle Physiotherapy Solihull Simon Evans

Movements of the Shoulder Girdle

  • In order to optimise the positioning of the hand in pace the scapula can glide around the chest wall
  • Elevation / Depression - scapula is moved up / down on chest wall
  • Protraction / retraction - scapula glides anteriorly / posteriorly around chest wall
  • Lateral / medial rotation - refers to motion of the inferior angle relative to the chest wall (often as an integral part of upper limb elevation and lowering)

Muscles producing protraction

  • Serratus Anterior:
    • Situated over the lateral surface of the thorax between the ribs and the scapula
    • From the outer surfaces of the upper 8 or 9 ribs in the mid axillary line
    • to the costal surface of the medial border of the scapula
    • Its lower part interdigitates with the external abdominal oblique
    • N.S. : Long thoracic nerve (C5, 6 and 7) 

Muscles Producing Protraction

  • Pectoralis Minor:
    • Thin, flat muscle found on the anterior aspect of the chest deep to pectoralis major
    • From the outer surfaces of ribs 3, 4 and 5
    • To the upper and medial aspects of the coracoid process
    • NS: Medial pectoral nerve (C6, 7 & 8) 

    Muscles Producing Retraction

    • Rhomboid Major & Minor
      • Found deep on posterior thoracic wall
      • Arise from
        • R.Minor - Spinous processes of C7 & T1 and supraspinous ligament
        • R. Major - Spinous processes of T2 to T5 and supraspinous ligament
        • Both attach to the dorsal surface of the medial border of the scapula (Min. at root of spine of, Maj. below min. as low as inferior angle)
      • NS: Dorsal scapular nerve (C5) 


      • Large flat muscle overlying posterior thorax & neck - Functionally divided into upper (elevation), middle (retraction) & lower (depression)
      • From
        • Medial 1/3 of superior nuchal line
        • External occipital protruberance
        • Ligamentum nuchae
        • Spinous processes & supraspinous ligament of C7 to T12
        • To
          • Posterior aspect of lateral 1/3 of clavicle
          • Medial aspect of acromion process
          • Superior border spine of scapula
          • Root of spine of scapula
          • NS: accessory nerve (cranial XI) and ventral rami of C3, 4 & 5

        Muscle Producing Elevation & Depression

        • In addition to the UFT Levator scapulae also brings about elevation (deep to UFT)
        • From tendinous slips from posterior tubercles on transverse processes of C1-4 
        • To upper medial border of scapula (between superior angle and root of spine)
        • NS: Dorsal scapula nerve (C5) & ventral rami of C3 &4
        • Depression of the shoulder girdle is brought about by trapezius (and subclavius) and assisted by latissimus dorsi

        Lateral Rotation

        • Describes lateral motion of the inferior angle around chest wall
        • This is a rotation about a central axis perpendicular to plane of scapula
        • As tension increases in the coracoclavicular ligament the clavicle is pulled into posterior rotation (about long axis) 

        Medial Rotation

        • Also a force couple
        • Inferior angle moves medially around chest wall
        • Force couple consists of pectoralis minor, levator scapulae and the rhomboids

        Scapulohumeral Rhythm

        • Co-ordinated action of the movements of the shoulder girdle with the shoulder joint
        • Should be both in terms of magnitude and sequencing
        • Needed to achieve range of motion of the upper limb

        See More Articles on the Human Anatomy - Click HereMuscles of the Pectoral Girdle Physiotherapy Solihull Simon Evans

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