Shoulder & Elbow Anatomy Flashcards
What are the bones of the pectoral girdle?
- Scapula
- Clavicle
What is the name of the joint at which the entire upper limb and pectoral girdle articulate?
Glenohumeral joint
What are the articulating surfaces of the shoulder joint?
- Head of Humerus
- Glenoid cavity of Scapula
What structures are associated with the shoulder joint and what are their functions?
Joint capsule - fibrous sheath which encloses the structures of the joint
Synovial membrane - Lines the joint capsule and produces synovial fluid to reduce friction between the articular surfaces
Synovial bursae - A synovial fluid-filled sac which acts as a cushion between tendons and other joint structures
What are the clinically important bursae found around the shoulder joint?
Subacromial
Subscapular
What type of joint is the shoulder joint?
Ball and socket synovial joint
What type of movements can occur at the shoulder joint?
Flexion
Extension
Abduction
Adduction
Internal rotation
External rotation
What factors contribute to the shoulder joint being so mobile?
- Shallow glenoid cavity and large humeral head (golf ball on tee)
- The joint capsule is lax
What structures give stability to the shoulder joint?
Rotator cuff muscles - Subscapularis, supraspinatus, infraspinatus and Teres Minor compress the humeral head into the glenoid fossa
Glenoid labrum - Deepends the glenoid cavity, reducing risk of dislocation
Ligaments - Strenthen the joint capsule
Bicep tendon - Depresses the humeral head into the glenoid fossa
What are the articulating surfaces of the elbow?
- Trochlear notch of the Ulna
- Trochlea of the Humerus
- Head of Radius
- Capitulum of Humerus
What are the clinically important bursae around the elbow joint?
Intratendinous
Subtendinous
Olecranon
What movements occur at the elbow joint?
Extension
Flexion
What are the 2 different locations of the radioulnar articulations?
Proximal radioulnar joint - articulation of the radial head and radial notch of the ulna
Distal radioulnar joint - articulation between the ulnar notch of the radius and head of ulna
How is movement produced at the proximal radioulnar joint and what movements are permitted?
- Head of radius rotates within the annular ligament
- Pronation and Supination movements permitted
What muscles perform pronation and supination at the proximal radioulnar joint?
Pronation - pronator quadratus and pronator teres
Supination - Supinator and biceps brachii
What is the articular disc and what are its functions?
- A fibrocartilaginous ligament
Functions:
- Holds the radius and ulna together during movement at the joint
- Seperates the distal radioulnar joint from the wrist joint
What type of joint is the distal radioulnar joint and what movements does it permit?
Type of joint - Pivot
Movements - Pronation & Supination
What muscles perform pronation and supination at the distal radioulnar joint?
Pronation - Pronator Teres, Pronator Quadratus
Supination - Supinator & Biceps Brachii
What is the Interosseus membrane and what are its functions?
Interosseus Membrane - A sheet of connective tissue that joins the radius and ulna together between the two radioulnar joints.
Functions:
- Holds the radius and ulna together during pronation and supination
- Acts as a site of attachment for muscles in the forearm
- Transmits forces from the radius to the ulna
What are the articulating surfaces of the wrist joint?
Distally - Proximal row of the carpal bones
Proximally - The distal end of the radius and the articular disk
What type of joint is the wrist joint?
Synovial Condyloid
What movements occur at the wrist joint?
Flexion
Extension
Abduction
Adduction
Which group of muscles perform flexion of the wrist joint?
Anterior forearm muscles
What is the combined action of extensor anf flexor carpi ulnaris muscles on the wrist joint?
Flexion and medial deviation
What muscles are responsible for abduction of the wrist?
Abductor Pollicis Longus
Flexor Carpi Radialis
Extensor Carpi Radialis Longus & Brevis
What is the action of the muscles in the posterior compartment of the forearm?
Extension of the wrist joint
What muscles produce extension at the shoulder joint?
Posterior Deltoid
Latissimus Dorsi
Teres Major
What muscles produce flexion at the shoulder joint?
Pectoralis Major
Anterior Deltoid
Coracobrachialis
What muscles produce abduction at the shoulder joint?
0-15 degrees - Supraspinatus
15-90 degrees - Middle fibres of Deltoid
90 degrees plus - Trapezius & Serratus Anterior
What muscles produce adduction at the shoulder joint?
Pectoralis Major
Latissimus Dorsi
Teres Major
What muscles produce internal rotation at the shoulder joint?
Subscapularis
Pectoralis Major
Latissimus Dorsi
Teres Major
Anterior Deltoid
What muscles produce external rotation at the shoulder joint?
Infraspinatus
Teres Minor
What muscles produce flexion at the elbow joint?
Brachialis
Biceps Brachii
Brachioradialis
What muscles produce extension at the elbow joint?
Triceps Brachii
Anconeus
What muscles produce pronation at the radioulnar joints?
Pronator quadratus
Pronator Teres
What muscles produce supination at the radioulnar joints?
Supinator
Biceps brachii
Which aspect of the spinal nerves make up the brachial plexus?
Anterior rami (motor & sensory)
Which spinal nerves make up the brachial plexus?
C5, C6, C7, C8, T1
Through which bony structure do the spinal nerves leave the spinal cord?
Intervertebral foramen
In the cervical portion of the vertebral column, what is the relationship between vertebral body and spinal nerve number?
The spinal nerve exits the spinal column above its corresponding vertebral body, i.e. spinal nerve C5 will exit between vertebral bodies C4 and C5
What is the mnemonic that can be used to remember the sub-divisions of the brachial plexus?
Read (Roots)
That (Trunk)
Damn (Divisions)
Cadaver (Cords)
Book (Branches)
What are the roots of the brachial plexus?
C5, C6, C7, C8, T1
What are the trunks of the brachial plexus?
Superior
Middle
Inferior
What are the divisions of the brachial plexus?
Each trunk seperates into anterior and posterior divisions
What are the cords of the brachial plexus?
Lateral
Posterior
Medial
What are the branches of the brachial plexus and their root values?
Musculocutaneous (C5, C6, C7)
Axillary (C5, C6)
Radial (C5, C6, C7, C8, T1)
Median (C5, C6, C7, C8, T1)
Ulnar (C8, T1)
What are the extrinsic muscles of the shoulder?
Trapezius
Latissimus Dorsi
Levator Scapulae
Rhomboids
What action does serratus anterior have on the pectoral girdle?
Protracts the pectoral girdle
Which muscles make up the intrinsic muscles of the shoulder?
Deltoid
Teres Major
Supraspinatus
Infraspinatus
Teres Minor
Subscapularis
What are the rotator cuff muscles?
Supraspinatus
Infraspinatus
Subscapularis
Teres Minor
In relation to the shoulder joint, which of the rotator cuff muscles lie posteriorly?
Supraspinatus
Infraspinatus
Teres Minor
In relation to the shoulder joint, which of the rotator cuff muscles lie anteriorly?
Subscapularis
Which of the rotator cuff muscles is responsible for abducting the arm at the shoulder joint?
Supraspinatus
Which of the rotator cuff muscles is responsible for laterally rotating the arm at the shoulder joint?
Infraspinatus
Teres Minor
Which of the rotator cuff muscles is responsible for medially rotating the arm at the shoulder joint?
Subscapularis
Which muscle is found posterior to the humerus?
Triceps Brachii
What is the action of triceps brachii?
Extension of the arm and forearm
Which muscle is the antagonist to triceps brachii?
Biceps Brachii
What bones does the biceps brachii attach to?
Scapula and Radius
What actions does the biceps brachii perform?
Flexion and supination of the forearm (due to its attachment to the radius)
At which joints does the radius move around the ulna?
Superior and Inferior Radioulnar joint
Which muscles are antagonists to biceps brachii?
Pronator Teres
Pronator Quadratus
