Pectoral regionLecture 2

Muscle ActionEach muscle has: Origin Beginning. Insertion End. Body (belly).Law:When a muscle performs its action, its insertion, moves towards its origin.

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Pectoral Region

Spring 2016 3Dr. Maher Hadidi, University of Jordan

Pectoral RegionBreast region.Contents:1. Skin.2. Superficial fascia.3. Breast.4. Deep fascia.5. 3 Muscles:

a. Pectoralis major.b. Pectoralis minor.c. Subclavius.

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Pectoralismajor

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Origin: Clavicle (M ½) , Sternum and upper 6 ribs. Insertion: humerus, lateral lip of intertubercular groove. Nerve Supply: Medial & lateral pectoral nerves. Action: Adducts and medially rotate the arm.Spring 2016 Dr. Maher Hadidi, University of Jordan 5

Pectoralis Minor

O: 3rd, 4th, 5th ribs. Ins: Coracoid process. NS: Medial pectoral N. Action: Depress scapula downward and forward.Spring 2016 Dr. Maher Hadidi, University of Jordan 6

Subclavius Dr. Maher Hadidi

Origin: 1st rib. Ins: Clavicle inferior surface. NS: N. to Subclavius. Action: Protects the underlying structures.Spring 2016 Dr. Maher Hadidi, University of Jordan

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Clavipectoral fascia A sheet of CT that

connects clavicle to the floor of the axilla.

t n los su l v use c e bc a i n p tor l s m nora d ec a i i

and seals the gapDr. Maher Hadidibetween them.

Pierced by:• Thoracoacromial A.• Cephalic vein.• Lateral pectoral N.

Muscles connecting UL to vertebral col.

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DeltoidO: Clavicle, acromion and

spine of scapula. Ins: Deltoid tuberosity. Action: Its fibers runs in 3

directions• Ant. flex shoulder.• Post. extend should. Dr. Maher Hadidi• Middle Abduct arm

15-900.NS: Axillary N.

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TrapeziusO: Skull, spines of C1-T12 v. Ins: Its fibers runs in 3

directions• Down Clavicle.• Horizontal Acromion.• Up Spine of scapula.

Action: Upper F. Elevate arm. Middle F. adduct medial Dr. Maher

Hadidi Lower F. pull downward

Assist the serratus anterior muscle in abducting the arm 1800 above the head.

NS: Spinal accessory (IX) N.

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Latissmus dorsiO: T7-T12, L1- L5,

Sacrum & Iliac crest.Ins: Floor of biceptal

grooveAction: extends, adducts

and medially rotate humerus like incanoeing. Dr. Maher Hadidi

NS: Thoracodorsal N.

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Scapular muscles

Lecture 3

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Muscles connecting UL to scapula

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SupraspinatusO: Supraspinous fossa. Ins: Greater tubercle of

humerus.Action: Abducts arm S

i0-150. T

NS: Suprascapular N.Infraspinatus

O: Infraspinous fossa. Ins: Greater tubercle.Action: Lateral rotation

of arm. Dr. Maher Hadidi

NS: Suprascapular N.

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Teres Minor(L. Rounded)

O: Lat. border of Scapula. Ins: Greater tubercle.Action: Lateral rotation of

arm. Dr. Maher HadidiNS: Axillary n.

Teres MajorO: Lat. border of Scapula. Ins: Medial lip of i.t groove Action: Adduction & Medial rotation and of arm.NS: Lower subscapular n.

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Subscapularis

Origin: Subscapularfossa.

Ins: Lesser tubercle.Action: Medial rotation

of the arm.NS: Upper and lower

subscapular Ns.Dr. Maher Hadidi

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Serratus anterior Origin: upper 8 ribs. Ins: Medial border of

scapula. Act: Protraction of

scapula (pulls scapula forward over thoracic wall).It assists trapezius to elevate arm 1800 above shoulder.

NS: Long thoracic N.

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Rotator cuff muscles of shoulder Form of 4 muscles: n SupraspinatusInfraspinatus

n Teres minor iS

n Subscapularis T

Their tendons flatten attheir insertion and blend Dr. Maher Hadidiwith the capsule of theshoulder joint. They act asa handcuff that strengthen shoulder joint (superior,posterior & anterior).

But NOT inferior?Spring 2016 Dr. Maher Hadidi, University of Jordan 21

Spaces between scapular muscles Quadrangular space

Borders:• Sup. T. minor• Inf. T. major• Med. Triceps, long h.• Lat. humerus

Contents:• Axillary N.• Post. circ. hum. A,V.Triangular space Dr. Maher Hadidi

Borders:• Sup, T. minor• Inf, T. major• Lat. Triceps, long head

Contents:• Circumflex scapular A & V.

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