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Year 2 - LCRS - Anatomy of the Limbs > Session 2: The Shoulder and Arm (07.01.2020) > Flashcards

Session 2: The Shoulder and Arm (07.01.2020) Flashcards

1
Q

What are the important bones in the shoulder and arm area?

A
  • scapula
  • clavicle
  • humerus
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2
Q

What is the arm?

A
  • it is the region between the shoulder joint and the elbow joint
  • the area between the elbow and wrist is the forearm
  • now often referred to as upper arm and lower arm which is not fully correct anatomically
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3
Q

Scapula

A
  • triangular, flattish bone
  • has a spine that divides the scapula into a suoraspinous and infraspinous process
  • glenoid cavity -> socket for the humerus (joint)
  • acromion
  • coracoid process
  • three angles (lateral, superior, inferior)
  • three borders (medial, superior and inferior)
  • two surfaces (costal and posterior)
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4
Q

Glenoid cavity

A
  • cup/socket for the shoulder joint
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5
Q

Clavicle

A
  • small, long bone
  • S- shaped
  • the first bone to calcify in foetal development and one of the last bones to finish calcifying (age 20/22)
  • flattened at the acromial end
  • has a flattened facet at the sternal end where it articulates with the manubrium of the sternum
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6
Q

The Humerus

A
  • long bone
  • has an anatomical (true) and a surgical neck. Fractures are more common in the surgical neck.
  • ends have articular features
  • deltoid tuberosity where the muscle attaches
  • condyles and epicondyles
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7
Q

Acromion

A
  • bony process of the scapula
  • anterolateral projection of the spine over the glenohumeral joint
  • articulates (via small oval facet on its distal end) with the clavicle
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8
Q

Coracoid Process

A
  • hook-like structure that projects anterolaterally

- positioned directly inferior to the lateral part of the clavicle

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9
Q

Muscle attachments terminology

A
  • Old-fashioned terminology for muscle attachments is:
    origins and insertions. Now considered inaccurate.
  • For Limbs, the correct terminology is: proximal attachment and distal attachment. The proximal attachment is at, or closer to, the trunk.
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10
Q

What are the muscular compartments in that region?

A
  • anterior pectoral girdle muscles
  • posterior pectoral girdle muscles
  • intrinsic shoulder muscles
  • anterior compartment of the upper arm
  • posterior compartment of the upper arm
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11
Q

Name the Anterior Pectoral Girdle Muscles

A
  • Pectoralis major
  • Pectoralis minor
  • Subclavius
  • Serratus anterior* (runs between anterior and posterior)

=> chest muscles except for serrates anterior

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12
Q

Pectoralis major

A
  • anterior pectoral girdle muscle
  • broad attachment to medial 3rd of clavicle, sternum and some costal cartilages
  • 3 parts: clavicular head, sternocostal head, abdominal part); according to Gray’s there are 2 heads: clavicular and sternocostal
  • attaches to groove on lateral humerus (lateral lip of the inter tubercular sculls (groove))
  • developed with push-ups and punching/boxing
  • function: adducts and medially rotates the humerus, lesser actions on the scapula
  • most superficial muscle of the anterior wall
  • innervated by lateral and medial pectoral nerves (oroginating from brachial plexus, C5-T1)
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13
Q

Pectoralis minor

A
  • attaches to coracoid process of scapula
  • attaches to ribs 2,3,4 and 5
  • pulls scapula down (pulls tip of shoulder down) and possibly forward (protracts scapula)
  • innervated by medial pectoral nerve (C5,6,7,8, T1)
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14
Q

Innervation of Pec Major

A

Medial and lateral pectoral nerve

  • clavicular head (C5,C6)
  • sternocostal head (C6,7,8, T1)
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15
Q

Subclavius muscle

A
  • Attachment:
    Distally inferior part of the clavicle
    Proximally Rib 1 at the costochondrial joint
  • Function: Pulls tip of shoulder down; pulls clavicle medially to stabilise the sternoclavicular joint)
  • Innervation: Nerve to subclavius (C5,C6)
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16
Q

Serrates Anterior Muscle

A

Attachment:

  • proximal: attaches to the lateral surfaces of the upper 8-9 ribs and deep fascia overlying the related intercostal spaces
  • distal: costal surface of the medial border of scapula

Function:

  • protraction and rotation of the scapula
  • keeps medial border and inferior angle of the scapula opposed to the thoracic wall

Innervation:
- Long thoracic nerve (C5, C6,C7)

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17
Q

Name the posterior pectoral girdle muscles

A
  • Trapezius
  • Latissimus dorsi
  • Levator scapulae
  • the Rhomboids
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18
Q

Trapezius Muscle

A

Attachment:

  • superior crest of the spine of the scapula, acromion, posterior border of the lateral one-third of clavicle
  • superior nuchal line, external occipital proturbance, medial margin of the ligament nuchae
  • spinous processes of C7 to T12 and related supraspinous ligaments

Innervation:

  • motor: spinal part of accessory nerve (XI)
  • sensory: (proprioception) anterior rami of C3 and C4

Function:

  • powerful elevation of scapula
  • rotates the scapula during abductionof humerus above horizontal
  • middle fibres retract scapula
  • lower fibres depress scapula

Other:
- there are 3 types of fibres: ascending (inferiorly), descending (superiorly) and middle fibres coming across

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19
Q

Latissimus dorsi muscle

A

Attachments:

  • floor of the inter tubercular sulcus (groove) of humerus (strap like muscle and tendon that attaches to the groove)
  • spinous processes of the lower 6 thoracic vertebrae and related interspinous ligaments; via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments, and iliac crest; lower 3-4 ribs.

Innervation:
- thoracodorsal nerve (C6,C7, C8)

Function:
- Adduction, medial rotation and extension of the arm at the glenohumeral joint

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20
Q

Rhomboid muscles

A

Attachment:
- Rhomboid minor: lower end of ligaments nuchae and spinous process of C7 and T1 vertebrae; posterior surface of medial border of the scapula at the root of the spine of the scapula

  • Rhomboid major: spinous processes of T2-T5 vertebrae and intervening supraspibous ligaments; posterior surface of medial border of the scapula at the root of the spine of the scapula to the inferior angle

[=medial border of scapula and spinous processes between C7 and T5]

Innervation: dorsal scapular nerve (C4,C5)

Function: Elevation and retraction of the scapula (retracts, rotates and fixes the scapula)

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21
Q

Levator Scapulae

A

Attachment:

  • transverse processes of C1 and C2 vertebrae and posterior tubercles of transverse processes of C3 and C4 vertebrae
  • posterior surface of medial border of scapula from superior angle to root of spine of the scapula

Innervation:
- branches directly form the anterior rami of C3 and C4 spinal nerves and by branches (C5) from dorsal scapular nerve

Function: elevates the scapula (duh) + rotation

22
Q

Name the intrinsic shoulder muscles

A
  • Deltoid
  • Teres Major
  • The rotator cuff muscles
    - supraspinatus
    - infraspinatus
    - teres minor
    - subscapularis
23
Q

Deltoid muscle

A

Attachements:

  • inferior edge of the crest of the spine of the scapula, lateral margin of the acromion, anterior border of the lateral 3rd of the clavicle
  • deltoid tuberosity of humerus

Innervation:
- axillary nerve (C5, C6)

Function:

  • major abductor of the arm
  • clavicular fibers assist in flexing the arm
  • posterior fibers assis in extending the arm

Other: there is a spinal (posterior) and a clavicular (anterior) part of the deltoid -> fibers can act separately but together they act as the major abductor of the shoulder joint

24
Q

Which muscle is the major abductor of the arm?

A

Deltoid

25
Q

The rotator cuff

A
  • Rotator cuff group acts to fix the head of humerus in the glenoid fossa.
  • attach at superior head of the humerus
  • Their main activity is to act as a group to hold the head of the humerus inside the fossa, one of the main stabilising factors of the shoulfer joint
  • supraspinatus, infraspinatus, teres minor, subscapularis
  • Subscapularis = broad muscle
  • Supraspinatus important in initiating abduction of arm for first 15°, then deltoid takes over.
  • teres major is NOT one of the rotator cup muscles

innervation mainly C5,C6? suprascapular nerve for sup and infraspinatus and axillary nerve for teres minor)

26
Q

Teres latin

A

smooth, rounded

27
Q

Teres Major

A
  • NOT a rotator cuff muscle

Attachments:

  • elongate oval area of posterior surface of the inferior angle of the scapula
  • medial lip of the intertubercular sulcus on the anterior surface of the humerus
  • attaches at almost the same place as latissimus doors

Innervation: Inferior subscapular nerve (C5,C6.C7)

Function:

  • Medial rotation and extension of the arm at the glenohumeral joint;
  • stabilisation of the glenohumeral joint
28
Q

What are the muscles in the anterior compartment of the arm?

A
  • bicpes brachii
  • brachialis
  • coracobrachialis

=> all supplied by the musculocutaneous nerve

29
Q

Biceps brachii muscle

A

Attachments:

  • long head: supraglenoid tubercle of scapula; short head: apex of coracoid process.
  • insertion/proximal: tuberosity of radius

Innervation: Musculocutaneous nerve (C5,C6)

Function:
- powerful flexor of the forearm at the elbow joint and supinator of the forearm; accessory flexor of the arm at the glenohumeral joint

Other: Biceps means 2 heads

30
Q

Coracobrachialis Muscle

A

Attachments:

  • apex of the coracoid process
  • linear roughening of the humerus on medial side

Innervation: musculocutaneous nerve (C5,C6, C7)

Function:

  • Flexor of the arm at the glenohumeral joint
  • adducts arm
31
Q

Brachialis muscle

A

Attachments:

  • anterior aspect of humerus (medial and lateral surfaces) and adjacent intermuscular septae
  • tuberosity of the ulna

Innervation:

  • musculocutaneous nerve (C5, C6)
  • small contribution by the radial nerve (C7) to lateral part of muscle

Function: powerful flexor of the forearm at the elbow joint

Other: beneath the biceps brachia muscle; flattens to form a tendon which attaches to the ulna.

32
Q

What are the muscles of the posterior compartment of the arm?

A
  • triceps brachii
  • Anconeus

=> supplied by the radial nerve

33
Q

Triceps brachii

A

Attachments:

  • origin: long head: infraglenoid tubercle of scapula; medial head posterior surface of humerus; lateral head: posterior surface of humerus;
  • insertion: olecranon

Innervation: radial nerve

Function:
- extension of the forearm at the elbow joint; long head can also extend and adduct the arm at the shoulder joint.

Other: triceps = 3 heads

34
Q

Anconeus

A

Attachments:

  • origin: lateral epicondyle of humerus
  • insertion: olecranon and proximal posterior surface of ulna

Innervation:
- radial nerve (C6,7,8) via branch to medial head of triceps brachia

Funciton:

  • abduction of the ulna in pronation
  • accessory extensor of the elbow joint
35
Q

What are the joints in that region?

A
  • Sterno-clavicular joint
  • Acromio-clavicular joint
  • Gleno-Humeral joint (Shoulder joint)
  • Scapulo-thoracic joint (sometimes referred to as a “virtual” or “physiological” joint)
  • Elbow joint
  • The pectoral girdle = SCJ + ACJ + GHJ + STJ
  • GHJ is not truly in the pectoral girdle
36
Q

In what direction is shoulder dislocation likely to occur?

A
  • inferiorly
37
Q

Shoulder joint

A
  • Gleno-humeral joint
  • Ball-and-socket synovial joint.
  • The glenoid fossa (the socket) is shallow, but slightly deepened by a cartilaginous labrum. (it is not that deep)
  • However, muscles required for joint stability. (eg. Rotator cuff group) -> many muscles and ligaments hold the head in.
  • the joint is prone to dislocation (mainly inferiorly)
38
Q

The rotator cuff and the shoulder joint

A
  • Main function is to hold the humeral head within the glenoid
  • The rotator cuff depresses the humeral head (depress =. hold it in the glenoid fossa)
39
Q

What are the possible movements of the shoulder joint?

A
  • abduction (deltoid, supraspinatus)
  • adduction (pectoralis major, latissimus dorsi, teres major, triceps long head)
  • flexion (pectoralis major, coracobrachialis, deltoid)
  • extension (deltoid, teres major, latissimus dorsi, long head triceps)
  • lateral rotation (deltoid, infraspinatus, teres minor)
  • medial rotation (deltoid, pec major, teres major, subscapularis, latissimus dorsi)
40
Q

Movements of the scapulothoracic joint

A
  • Elevation / Depression of the scapula
  • Protraction / Retraction of the scapula
  • Rotation of the scapula
  • The contact between the scapula and the thoracic wall, not a proper joint
41
Q

Contents of the axilla

A
  • Arteries – axillary artery and its branches
  • Veins – axillary vein and its tributaries
  • Lymphatic vessels and lymph nodes (important!) - also re breast cancer
  • Nerves – the brachial plexus
42
Q

Shape and function of the axilla

A
  • pyramid
  • goes down until the 5th rib
  • The gateway for nerves and blood vessels to enter and leave the upper limb
  • transition between shoulder and arm
43
Q

Name the arteries of the region

A

Subclavian artery
- passes over the first rib to become…

Axillary artery
- at the lower border of teres major becomes the…

Brachial artery
- gives off a large branch in the arm – profunda brachii

Divides as the level of the elbow into…
Ulnar and Radial arteries

44
Q

Name the veins of the region

A
  • In limbs, venous return is via superficial and deep vessels
  • Dorsal venous network on the hand -> forms to veins: cephalic and basilic
  • Cephalic vein (superficial) runs up lateral border of arm
  • Basilic vein (superficial) runs up the medial border of arm
  • Basilic veins joins venae comitantes to form the axillary vein in the arm
  • Cephalic vein joins axillary vein in the axilla
  • Axillary vein becomes the subclavian vein at the level of the first rib
45
Q

Lymphatic drainage of the region

A
  • Superficial and deep systems, run with veins
  • Cubital lymph nodes
  • Delto-pectoral lymph nodes
  • Axillary lymph nodes – important! (Axillary lymph nodes also very important in draining the breast; removing axillary lymph nodes in breast cancer treatment can lead to lymphedema of the arm, forearm and hand.)
  • Subclavian lymph trunk
  • Long thoracic nerve and thoraco-dorsal nerve!
  • lots of nodes in the axilla including the ones draining the breast
46
Q

Nerves of the region

A
  • Brachial plexus

- nerve fibres to and from the spinal roots, more than 1 spinal root

47
Q

Brachial Plexus

A
  • passes under clavicle

- some terminal nerves branch off e.g. long thoracic nerve

48
Q

What are the largest nerves of the brachial plexus?

A
  • Axillary nerve (C56)
  • Musculocutaneous nerve (C567)
  • Ulnar nerve (C8T1)
  • Median nerve (C678T1)
  • Radial nerve (C5678T1)
49
Q

Radial nerve

A
  • supplies all posterior muscles of arm and forearm
50
Q

Medial and ulnar nerve

A

Do not supply the arm

51
Q

Profunda brachii A

A

= deep artery of the arm

  • large vessel which arises from the lateral and posterior part of the brachial artery, just below the lower border of the teres major.

Year 2 - LCRS - Anatomy of the Limbs (9 decks)

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