Objectives• Identify the bony components of the shoulder.
girdle including the Clavicle, Scapula and
Humerus.
• Describe how primary muscles are responsible
for the following shoulder motion: adduction,
abduction, flexion, extension.
1-Bones of the Pectoral Girdle: Clavicle and Scapula2- Arm : Humerus. 3-Forearm : Radius & Ulna.4-Wrist : Carpal bones 5-Hand: Metacarpals & Phalanges
Bones of the Upper Limb
Articulations of clavicle• Clavicle articulates
Medially with the manubrium of the Sternum at the Sternoclavicular joint .
• Laterally with the Scapula at the Acromioclavicular joint
• Inferiorly with the 1st rib at the Costoclavicular Joint
Pectoral (Shoulder) Girdle
• connects the upper limb to the axial skeleton
• formed of two bones: Clavicle and Scapula.• formed of two joints1. Sternoclacvicular joint2. Acromioclavicular joint
SA
Movements of the shoulder joint:
Abduction / adductionFlexion / extension
Rotation – internal (medial) -external (lateral)
Movements of the shoulder girdle: (increase range of movement of upper limb)
Protraction / RetractionElevation / Depression
Rotation:Superior / Inferior
Circumduction
Muscles of the (Pectoral) Region
• muscles of the pectoral region.Pectoralis major.Pectoralis minor.Subclavius.Serratus anterior.
Pectoralis Major
Clavicular head:Medial ½ of front of the clavicle.
Sternocostal head:Sternum.Upper 6 costal cartilages.
Lateral lip of bicipital groove.
• Nerve supply: medial & lateral pectoral nerve
• Action : Adduction and medial rotation of the arm. Clavicular head helps in flexion of arm (shoulder).
Pectoralis Minor
3
4
5
Coracoid process.
Nerve supply: medial pectoral nerveAction:• Depression & protraction
of the shoulder.• Elevate the ribs during
deep inspiration.
Subclavius
Nerve supply:• Nerve to subclaviusAction: • Fixes the clavicle during movement of
shoulder joint.
1st ribSubclavian groove in the inferior surface of clavicle.
Nerve supply: • Long thoracic nerve.Action:• Depression & protraction of
the scapula (boxing) • Raising the arm above 90
degree (climbing).• Accessory muscle of
respiration
Serratus anterior
Upp
er 8
ribs
Front of the medial border of scapula.
Injury of long thoracic nerve: Winged Scapula:
Subscapularis
Cause; Paralysis of serratus anterior as it is "big swing muscle" or "boxer's muscle”Antagonist of Rhomboids
Injury of long thoracic nerve
Deltoid
Nerve supply:Axillary nerve
Action:Anterior fibers : Flexion, medial rotation Middle fibers: abduct arm from 15°- 90°.Posterior fibers : Extension, lateral rotation
Lateral third of clavicle, acromion, spine of scapula
Deltoid tuberosity of humerus
Axillary nerve injury
Deformity: flat shoulderCause: fracture surgical neck of humerus.Clinical signs: 1. Paralysis of deltoid
and teres minor.2. Loss of abduction
from 15-90.
TRAPEZIUS External occipital protuberance.Ligamentum nuchae.Spine of C7Spine of T1-T12
Clavicle, acromion and spine of scapula
Nerve supply: Spinal part of accessory (11th cranial) nerve.
Action:Abduction > 90 (climbing)Upper fibers: elevate scapula.
Middle fibers: retract scapulaLower fibers: depress scapula.