Pectoral & Thoracic Musculature-pp8

Question 1

What two bones does the SCAPULOTHORACIC “Joint” consist of? What types of movements does it permit?

Answer 1

Allows the SCAPULA to glide along the THORAX on a curved surface of connective tissue.

1. Elevation & depression
2. Protraction & Retraction (equivalent to Abduction & Adduction but used b/c of circular motion around ribs)
3. Upward & Downward rotation around Scapula.

Question 2

Joint, at which, the Glenoid Fossa of the Scapula and the Head of the Humerus meet? What type of joint is it?

Answer 2

GLENOHUMERAL Joint. Is a ball & socket joint, Meaning that it is multiaxial but prone to dislocation

Question 3

PECTORALIS MAJOR muscles produce movement at what joint?
What are its 3 heads of origin?
Where do ALL 3 heads of pectoralis major insert?
Innervation?

Answer 3

Fun: movement of arm at Glenohumeral Joint
Ori:
1. Clavicular Part: Medial half of the clavicle
2. Sternocostal part: Sternum and costal cartilages
3. Abdominal Part: Anterior layer of rectus sheath
Ins: Insert via a common tendon to the PROXIMAL HUMERUS
Inn: Pectoral Nerves & Brachial Plexus

Question 4

PECTORALIS MINOR & SERRATUS ANTERIOR produce movement at what joint?

Answer 4

Scapulothoracic Joint

Question 5

What muscle in the Rotator Cuff is most often indicted in rotator cuff injuries of non-throwers? Why?

Answer 5

SUPRASPINATUS, b/c supraspinatus is responsible for keeping your arm attached at the Glenohumeral joint, therefore it is Constantly fighting against gravity.

Question 6

What movements do Flexion and Extension refer to?

Answer 6

Flexion is forward movement and Extension is backwards movement (i.e. tilt head back or rotate arm back)

Question 7

What causes a dimpled appearence of the skin on a woman’s breast that is infected w/ breast carcinoma when she is standing?

Answer 7

Breast Carcinoma often invades the SUSPENSORY Ligaments that suspend the mammary glands from the pectoral fascia causing them to CONTRACT.

Question 8

What is the origin, insertion, function, and innervation of the PECTORALIS MINOR muscle?

Answer 8

Ori: Ribs
Ins: CORACOID Process of the Scapula
Fun: Draws Scapula anteriorly, downward, and protracts the scapula while assisting in respiration
Inn: Pectoral Nerves

Question 9

The Anterior Axillary Folds are formed by what two components? And overlies what fossa?

Answer 9

Pectoral muscles and overlying skin form the anterior axillary fold, which overlies the Axillary Fossa.

Question 10

What important structures lie within the Axillary Fossa? 3

Answer 10

1. Brachial Plexus (Innervates the entire arm)
2. Axillary Vessels (Blood supply to entire arm)
3. Lymph Nodes

Question 11

What is the origin, insertion, function, and innervation of the SERRATUS ANTERIOR muscle? (The boxers muscle)

Answer 11

Ori: Ribs
Ins: Scapula
Fun: Draws scapula laterally forward
Inn: Long Thoracic nerve

Question 12

Why is the Long Thoracic Nerve so vulnerable to destructive lesions?

Answer 12

The long thoracic nerve travels along the serratus anterior muscle SUPERFICIALLY. Usually, nerves received through deep tissues.

Question 13

There are three Important apertures in the Diaphragm transmitting structures b/t the thoracic and abdominal cavities…
1. Caval Foramen
2. Esophageal Hiatus
3. Aortic Hiatus
What does each transmit?
What is a good way to remember this and where, along the spine transmission occurs?

Answer 13

1. CAVAL Foramen: Inferior Vena CAVA
   –Diaphragmatic contraction increases pressure in chest cavity while dilating while dilating the inferior vena cava to allow blood to flow superiorly
   2: Esophageal Hiatus: Esophagus opening-will drain contents into stomach
2. Aortic hiatus: Inferior aortic artery (AORTA)
   I ATE(8) = Inferior Vena Cava @ T8 Vertebral Body
   10 Eggs = Esophagus @ T10 vertebral body
   At 12 = Aorta @ T12 vertebral body

Question 14

Why does the heart rise and fall with the contraction & relaxation of the diaphragm?

Answer 14

Because the fibrous pericardial sac containing the heart is fused to the cranial (superior) surface of the central tendon. Causes a position change of about 2 Vertebral Levels in quiet breathing.

Question 15

What is the insertion point of ALL diaphragm fibers arising from the Circumference of the body wall?

Answer 15

CENTRAL TENDON

Question 16

Diaphragm forms the floor of the thoracic cavity AND the roof of the Abdominopelvic Cavity. What is the diaphragm’s main function?

Answer 16

The diaphragm is the primary muscle of RESPIRATION

Question 17

What three muscle layers COMBINE to fill the intercostal spaces of the thoracic cavity? What is their main function?

Answer 17

1. External Intercostal
2. Internal Intercostal
3. Innermost Intercostal
   Fun: Keep the intercostal spaces rigid during breathing

Question 18

What is the orientation from origin to insertion of the External intercostals and the Internal Intercostals?
When are each most active?

Answer 18

Ext Int: Run AnteroInferiorly from the rib Above to the rib Below. Most Active during inspiration; elevate the ribs during forced inspiration.
Internal Intercostals: Run InferoPosteriorly form the floor of the Costal Grooves to the ribs below (Perpendicular to external intercostal). Must active during expiration.

Question 19

Each intercostal space contains a neurovascular bundle. B/t which layers of muscles? How are the veins, arteries, and nerves oriented in the bundle?

Answer 19

The Intercostal Neurovascular bundles are located in the plane b/t the second and third layers of muscle. They are order Superior to Inferior like...
Vein
Artery
Nerve
Think V.A.N.

Question 20

In what ways do the ribs move in order to increase respiration?

Answer 20

The upper ribs expand antero-posteriorly

The lower ribs move laterally to expand the volume of the thoracic cavity and help with inspiration.