the pectoral girdle e-learning

The Upper Limb:The Upper Limb:

Pectoral (Shoulder) GirdlePectoral (Shoulder) Girdle

Upper Limb DivisionsUpper Limb Divisions

1. Pectoral (Shouldar) Girdle

incomplete bony ring

formed by Scapula & Clavicle

2. Arm

between shoulder & elbow

contain the Humerus

3. Forearm

between elbow & wrist

contain Ulna & Radius

4. Hand

contain carpals, metacarpals

& phalanges

Bones of Pectoral GirdleBones of Pectoral Girdle

Clavicle: long bone

Scapula: flat bone

Bone of The ArmBone of The Arm

Humerus: long

Clavicle

“S” shaped bone (resilience)

medial 2/3 convex anteriorly , lateral 1/3 concave ant.

Sternal end (rounded) manubrium & 1st rib

Acromial end (flat) acromion

importance of the clavicle:importance of the clavicle:

Connects upper limb to axial skeleton (strut)

Protects neurovascular bundle that supply the upper limb

Transmits shocks from upper limb to axial skeleton

Clinical: Clinical: Fractures of ClavicleFractures of Clavicle

Common

indirect impact to upper limb

Between middle & lateral thirds

Medial part / lateral

-Shoulder drop

-Medial rotation of humerus

Scapula (shoulder blade)Scapula (shoulder blade)

Triangular flat boneTriangular flat bone

3 borders3 borders

3 angles3 angles

2 surfaces:2 surfaces:

Anterior (Anterior (costalcostal) surface) surface

22ndnd – 7 – 7thth ribs ribs

Posterior (Posterior (spinousspinous) surface) surface

Left Scapula (Posterior Aspect)Left Scapula (Posterior Aspect)

• 1.Coracoid Process

• 3. Superior border

• 4. Supraspinous Fossa

• 6. Scapular Spine

• 7.Medial border

• 8.Infraspinous Fossa

• 9.Inferior Angle

• 10.Lateral border

• 11.Glenoid Cavity Margin

• 12.Acromion Process

Humerus (brachial bone)Humerus (brachial bone)

The arm bone

Articulates with:

Scapula (shoulder joint)

Radius & Ulna (elbow joint)

Upper part Upper part

1. Head (1/3 of sphere)

2. Anatomical Neck

3. Lesser Tubercle

4. Intertubercular Groove

5. Greater Tubercle

6. Surgical Neck

7. Deltoid Tuberosity

Joints of Pectoral GirdleJoints of Pectoral Girdle

3 Joints:

Sterno-clavicular joint

Acromio-clavicular joint

Gleno-humeral joint

(Shouldar joint)

Joint QuestionsJoint Questions

1. What is the type of that joint?

2. What are the articular surfaces of that joint?

3. What are the supporting ligaments?

4. What kind of movement is available?

5. Any special characteristics of the joint?

Sterno-Clavicular JointSterno-Clavicular Joint

Type: Synovial (saddle shaped, or double plane)

Surfaces: sternal end of clavicle

Manubrium & 1st costal cartilage

Movements:

ant., post., sup. & inf.

Characteristics: Articular disc

Shock absorberShock absorber

GlenoHumeral (Shoulder) JointGlenoHumeral (Shoulder) Joint

Type: Synovial (ball & socket)

Articulations:

Head of humerus

Glenoid cavity of scapule

Ligaments:

1. Fibrous Capsule

2. Gleno-humeral lig.(3)

3. Coraco-humeral lig.

4. Transverse humeral lig.

Movements:

Circumduction

Includes??

Characteristics:

The fibrous capsule is Weak inferiorly

due to:

1. penetrated inferiorly by tendon of long head of triceps

2. Joint is surrounded (stabilized) by group of muscles called: Rotator Cuff muscles

*except inferiorly

Muscles of The Shoulder Region:Muscles of The Shoulder Region:

Thoraco-appendicular MusclesThoraco-appendicular Muscles& Scapulo-humeral Muscles& Scapulo-humeral Muscles

Anterior Thoracoappend. MusclesAnterior Thoracoappend. Muscles

Pectoralis Major

Pectoralis Minor

Serratus Anterior

Subclavius

Pectoralis MajorPectoralis Major

Fan shape muscle

Origin:

Clavicular & sternocostal heads

Insertion:

Humerus

Innervation:

Medial & Lateral pectoral nerves

Action:

Adduction of humerus

Pectoralis MinorPectoralis Minor

triangular shaped muscle

Origin:

3rd, 4th & 5th ribs

Insertion:

Coracoid process

Innervation:

Medial pectoral nerves

Action:

Depress scapula, elevate ribs

Pectoralis Major & MinorPectoralis Major & Minor

Serratus Anterior MuscleSerratus Anterior Muscle

Serrated border

Origin:Outer surfaces of upper 8 ribs

Insertion:Medial border of scapula

Innervation:Long thoracic n.

Action:Pulls scapula forward along the ribsKeeps the scapula in contact to thoracic cage

Clinical: Winged ScapulaClinical: Winged Scapula

Medial border of scapula hangs away from thoracic wall

1. Damage to serratus anterior m.

2. Injury to long thoracic n.

During fights

Winged Scapula

SubclaviusSubclaviusSmall muscle that extends:

Middle 1/3 of clavicle

1st costal cartilage

Innervation:

Nerve to subclavius

Action:

Depresses the clavicle

Posterior Thoracoappendicular MusclesPosterior Thoracoappendicular Muscles “Only names to be able to distinguish them in the lab”

Trapezius

Latissimus dorsi m.

Levator scapulae

Rhomboid major

Rhomboid minor

Scapulo-humeral MusclesScapulo-humeral Muscles“Read the table in your book for innervation, origin, insertion & “Read the table in your book for innervation, origin, insertion &

main action”main action”

Deltoid

Teres Major

Teres Minor

Supraspinatus

Infraspinatus

subscapularis

Rotator Cuff MusclesRotator Cuff Muscles

4 muscles that inserted around shoulder joint & form a musculotendinous cuff

Cover the joint from 3 directions:

Superior: supraspinatus

Anterior: subscapularis

Posterior: infraspinatus & teres minor

Fxn.

Stabilize shoulder joint

Anterior Superior

Posterior