7. Upper Limb Flashcards
What makes up the shoulder girdle?
- Clavicle
- Scapula
By what form of ossification does the clavicle develop?
Intramembraneous ossification
Describe the articulations and ligamental attachments of the clavicle.
Articulations:
- Medially -> With manubrium of the sternum (sternoclavicular joint)
- Laterally -> With acromion of scapula (acromioclavicular joint a.k.a. AC joint)
Ligaments:
- Coracoclavicular ligament -> Connects the clavicle to the coracoid process of the scapula. Made up of the trapezoid and conoid ligaments.
- Costoclavicular ligament -> Connects the medial clavicle to the first costal cartilage and first rib.
Where does the clavicle most commonly fracture?
- In the middle third.
- Following fractures, the medial portion is pulled superiorly by sternocleidomastoid whilst the lateral portion is pulled inferiorly by the weight of the upper limb.
Is this the anterior or posterior view of the scapula?
Posterior
Draw the coracoid process.
What does the scapula articulate with and what are the names of these joints?
- Humerus -> Glenohumeral joint
- Clavicle -> Acromioclavicular joint
What is involved in the glenohumeral joint?
- Glenoid fossa of the scapula
- Head of humerus
What is the glenoid labrum?
A fibrocartilaginous structure that deepens the glenoid fossa, stabilising the shoulder joint.
Describe the attachements of the capsule in the glenohumeral joint.
The joint capsule’s fibrous layer attaches to the circumference of the glenoid cavity and inserts into anatomical neck of the humerus. Inferiorly, near the armpit region, the capsule is lax, minimising impingement to motion.
How is the scapula involved in limb mobility?
Scapular movements assist the optimal movement of the glenohumeral joint as a result of interactions between the scapula and humerus (scapulohumeral rhythm).
What are the 4 rotator cuff muscles?
Subscapularis, infraspinatus, supraspinatus, teres minor
Where do the rotator cuff muscles attach?
- Supraspinatus, infraspinatus and teres minor attach to the greater tuberosity of the humerus
- Subscapularis attaches to the lesser tuberosity of the humerus (only one)
The other ends of the muscles attach to the scapula.
What movement does supraspinatus aid?
Assists with initial arm abduction.
What movement do infraspinatus and teres minor aid?
Lateral shoulder rotation
What movement does subscapularis aid?
Medial shoulder rotation
Draw the attachments of the rotator cuff muscles.
What muscles act at the glenohumeral joint?
- Trapezius -> Elevation, rotation (during abduction) and retraction of the scapula.
- Pectoralis major -> Flexes, adducts and medially rotates the upper limb.
- Latissimus dorsi -> Extends, adducts and medially rotates the upper limb.
- Serratus anterior -> Retracts the scapula against the chest wall.
- Deltoid -> Functions to flex (anterior fibres) and extend (posterior fibres) the arm at the glenohumeral joint. Middle fibres are the major shoulder abductors, taking over from the supraspinatus muscle after the first 15°.
What muscles are involved in shoulder abduction?
- First 15 degrees -> Supraspinatus
- Remainder -> Deltoid
What is the pectoralis major innervated by?
Pectoral muscles
What is latissimus dorsi innervated by?
Thoracodorsal nerve
What is serratus anterior innervated by?
Long thoracic nerve
Paralysis of which muscle can lead to winging of the scapula?
Serratus anterior
What is the most common direction for a shoulder dislocation? What are the complications?
- Anteriorly
- Anterior dislocations may cause damage to the nearby axillary nerve, causing paralysis of deltoid and impaired sensation in the badge patch area
Show the attachments of the main back muscles.
Where in the shoulder girdle do each of these attach:
- Trapezius
- Pectoralis major
- Latissimus dorsi
- Serratus anterior
- Deltoid
- Trapezius -> Scapula
- Pectoralis major -> Humerus
- Latissimus dorsi -> Scapula and humerus
- Serratus anterior -> Scapula
- Deltoid -> Scapula and humerus
Label a scapula.
What structures are found in the axilla?
- Axillary artery
- Axillary vein
- Brachial plexus
- Axillary lymph nodes
Describe the walls of the axilla.
- Anterior -> Pectoralis major and minor
- Posterior -> Subscapularis, teres major and latissimus dorsi
- Medial -> Thoracic wall
- Laterally -> Intertubercular sulcus of the humerus.
What does the humerus articulate with?
- Scapula (glenohumeral joint)
- Head of radius + Trochlear notch of ulna (elbow joint)
Label this:
Label this:
What does the radius articulate with?
Proximally:
- With capitulum of humerus (elbow joint)
- With radial notch of ulna (proximal radioulnar joint)
Distally:
- With head of ulna (distal radioulnar joint)
- With scaphoid and lunate (radiocarpal / wrist joint)
What does the ulna articulate with?
Proximally:
- Trochlea of humerus (elbow joint)
- Head of radius (proximal radioulnar joint)
Distally:
- Ulnar notch of radius (distal radioulnar joint)
What are the main landmarks and attachments of the humerus?
Landmarks:
- Head -> Glenohumeral joint
- Greater tuberosity (lateral) -> Supraspinatus, Infraspinatus, Teres minor
- Lesser tuberosity (anterior) -> Subscapularis
- Bicipital groove (a.k.a. intertubercular groove) -> Tendon of long head of biceps passes through this, Latissimus dorsi, Pectoralis major and Teres major attaches here
- Deltoid tuberosity (lateral side of shaft) -> Deltoid
- Radial groove (diagnal on posterior surface) -> Radial nerve and profunda brachii artery run through this
- Medial and lateral supracondylar ridge -> Lateral is rough and provides attachment for forearm extensor muscles
- Medial and lateral epicondyles -> Medial is larger and features a groove where the ulnar nerve passes through
- Trochlea (more medial) -> Articulates with trochlear notch of ulna
- Capitulum (more lateral) -> Articulates with head of radius
- Radial and coronoid fossa -> Receive forearm bones during flexion
- Olecranon fossa -> Receives olecranon of ulna during extension
Other muscle attachments along shaft:
- Anteriorly: Coracobrachialis, deltoid, brachialis, brachioradialis.
- Posteriorly: Medial and lateral heads of triceps
Ligaments:
- Medial collateral
- Lateral collateral
- Glenohumeral ligaments
What are the main landmarks and attachments of the radius?
Landmarks:
- Head -> Site of elbow joint (with capitulum of humerus)
- Radial tuberosity -> Biceps brachii
- Shaft
- Styloid process (lateral) -> Radial collateral ligament of the wrist + Site of radiocarpal joint
- Ulnar notch -> Site of distal radioulnar joint (with head of ulna)
Other muscles:
- Pronator teres
- Pronator quardatus
- Supinator teres
- Finger and thumb flexors and extensors
- Brachioradialis
Other ligaments:
- Radial collateral ligament (at elbow)
- Radial collateral ligament (at wrist)
- Radiocarpal ligaments
Note the intraosseous membrane between the radius and ulna.
What are the main landmarks and attachments of the ulna?
Landmarks:
- Trochlear notch - Site of elbow joint (with trochlea of humerus)
- Olecranon - Triceps brachii
- Coronoid process - Brachialis + Ulnar collateral ligament of elbow
- Ulnar tuberosity - Brachialis
- Radial notch - Site of proximal radioulnar joint + Annular ligament
- Styloid process - Ulnar collateral ligament of wrist
- Head - Site of distal radioulnar joint (with ulnar notch of radius)
Other muscles:
- Supinator
- Anconeus
- Finger and thumb flexors and extensors
Other ligaments:
- Radiocarpal ligaments
- Ulnar collateral ligament (wrist)
What is a supracondylar fracture? Which vessels and nerves may be damaged?
- One of the most common of all fractures in children and is usually caused by a fall on an outstretched hand.
- The shaft of the humerus is broken just above the condyles and the lower fragment is pushed and tilted backward.
- Nerves: Median nerve and brachial artery
Describe the structure of the elbow joint.
- It is formed of two joints:
- Medially -> Trochlea of the humerus articulates with the trochlear notch of the ulna.
- Laterally -> Capitulum of the humerus articulates with the head of the radius.
- The olecranon fossa on the posterior side of the humerus provides a site for the olecranon of the ulna during extension.
Describe the capsule around the elbow joint.
- The joint capsule attaches superior to the olecranon fossa and coronoid fossa of the humerus and inferiorly inserts distal to the proximal radioulnar joint.
- The capsule is strengthened medially and laterally by the ulnar and radial collateral ligaments
Where are the origins and insertions of the biceps muscle?
Origins:
- Long head: Supraglenoid tuberosity (of scapula)
- Short head: Coracoid process (of scapula)
Insertions:
- Distal biceps tendon: Radius (at radial tuberosity)
What are the origins and insertions of the triceps muscle?
Origins:
- Scapula
- Humerus
Insertions:
- Olecranon process of the ulna
What are the two radioulnar joints? What are they between?
- Proximal RUJ -> Located between the head of the radius and the radial notch of the ulna.
- Distal RUJ -> Located between the ulnar notch of the radius and head of the ulna.
What important structure is present in the proximal radioulnar joint?
- Annular ligament
- It allows the pivoting/rotation of pronation and supination - the joint capsule is attached to this rather than directly to the radius, allowing the freedom of movement between the radius and ulna.
What important structure is present in the distal radioulnar joint?
- Articular disc
- Binds the radius and ulna together and separates the joint from the wrist joint
What are the main supinators and pronators of the forearm?
Supinators:
- Supinator
- Biceps brachii
Pronator:
- Pronator teres
