MUSCLE OF THE SHOULDER

=> Muscle of the Shoulder

1) UPPER LIMB + VERTEBRA :-

=> This muscle are connected with upper limb and vertebrae. There are 5 muscle of upper limb and vertebrae

1) Trapezius

2) Lattisimus dorsi

3) Levator scapular

4) Rhomboid major

5) Rhomboid minor

TRAPEZIUS

ORIGIN : External occipetal protuberance, Superior nuchal line of occipetal bone, Spinous processes of 7th cervical and All thoracic vertebrae

INSERTION: lateral 1/3 of clavicle, Medial margin of acromion, spine of scapula

ACTION: Elevates The Scapula , rotation of scapula, retraction of shoulder, draw the scapula
downwards and Abduction Of Shoulder Beyond 90°

NERVE SUPPLY : XI cranial nerve (SPINAL ACCESSORY Nerve)

LATISSIMUS DORSI

ORIGIN: posterior layer of thoraco lumbar fascia,
Spinous processes of lower 6 thoracic vertebrae and Caudal most 3-4 ribs, May attach to iliac crest.

INSERTION: Intertubercular groove of the humerus.

ACTION: extends, adducts and medial rotation of arm

NERVE SUPPLY : Thoraco Dorsal Nerve (C6,C7,C8)

LEVATOR SCAPULAE

ORIGIN: transvers processes of upper 4 cervical vertebrae.

INSERTION: medialborder of the scapula superior portion.

ACTION: elevation of sup.angle of scapula and draws it medially.

NERVE SUPPLY : C3,C4,C5 Nerves

RHOMBOIDUS MINOR

ORIGIN : ligamentum nuchae,spinous process of C7, T1 vertebrae

INSERTION : medial border of the scapula

ACTION : retracts, depress the scapula and fix it to thoracis wall

NERVE SUPPLY : Dorsal Scapular .N (C4,C5)

RHOMBOIDUS MAJOR

ORIGIN: Spinous process of T2, T5

INSERTION: medial border of the scapula, inferior sulcus

ACTION: retracts the scapula, depress the glenoid cavity and fix the scapula to the thoracis wall

NERVE SUPPLY : Dorsal Scapular .N (c4,c5)

2) SCAPULAR MUSCLE :-

There are five Scapular muscle.

1) Suprascapular

2) Infrascapular

3) Subscapularis

4) Teres major

5) Teres minor

6) Deltoid

Scapular Muscle (left side)

SUPRASPINATUS

ORIGIN: supraspinatous fossa of the scapula

INSERTION: superior facet on the gr.tubercle of the humerus

ACTION: initiation of abduction (15*) & lat.Rotation

NERVE SUPPLY: Suprascapular.N From Brachial Plexus (C5,C6)

INFRASPINATUS

ORIGIN: infraspinatous fossa of the scapula

INSERTION: middle facet on the gr.tubercle of the humerus

ACTION: lat.rotation of shoulder, strengthen the shoulder by bracing the head of humerus.

NERVE SUPPLY: Suprascapular Nerve of Brachial Plexus (C5,c6)

SUBSCAPULARIS

ORIGIN: medial 2/3 subscapular fossa, lateral border of the scapula

INSERTION: lesser tubercle of the humerus

ACTION: stabilise the shoulder & prevents anterior displacement of the shoulder (medial rotation, adduction of arm)

NEREV SUPPLY: Upper &Lower Subscapular Nerve (C5, C6)

TERES MINOR

ORIGIN: lateral borderof the scapula

INSERTION: inferio facet on the greater tubercle of the humerus

ACTION: external rotator & weak adductor

NERVE SUPPLY: Axillary nerve (C5,C6)

DELTOID

ORIGIN :- Lateral 1/3 clavicle, sup.surface of acromion, spine of the scapula.

INSERTION: deltoid tuberosity.

ACTION: abduction of arm, flx.&.ext of arm, med.& lat. rotation.

NERVE SUPPLY: Axillary nerve (C5,c6)

3) SCAPULAR MUSCLE :-