Anatomy - Upper Limbs Flashcards
Pectoral
shoulder
Pectoral girdle
the clavicle, the scapula and the muscles attached to these bones
Scapula
shoulder blade
Arm
- region between the shoulder and the elbow joints
- bone: humerus
- contains anterior and posterior muscle compartments
Forearm
- region between elbow and wrist joint
- bones of forearm are the radius and ulna
- contains anterior and posterior muscular compartments
- forearm compartments contain lots of muscles
Hand
- lies distal to wrist
- palm and dosrum
(palm is complex and contains many small muscles that move the digits
Joints of the upper limb
- glenohumeral joint
- elbow joint
- proximal and distal radioulnar joints
- radiocarpal joint
Glenohumeral joint
- the shoulder joint
- synovial ball and socket joint formed by articulation between the scapula and proximal humerus
- highly mobile (key to allowing us to position our hand)
Elbow joint
- allows flexion and extension of the forearm
- it is synovial hinge joint formed by articulation of the distal humerus with the ulna and radius
- extremely important in allowing us to bring things towards us and is crucial for activities of daily living, such as eating and washing ourselves
Proximal and distal radioulner joints
- synovial joints between the radius and ulna allow pronation and supination of the forearm and hand
Radiocarpal joint
- otherwise known as the wrist joint
- it is a synovial joint formed by articulation between the dital radius and two of the carpal bones (small bones of the wrist)
- allows flexion, extension, abduction and adduction
Why is the ‘joint’ between the scapula and the posterior chest wall not considered a traditional joint?
there is no bony articulation between these structures
(but this movement of the scapula over the chest wall is crucial for normal movement of the shoulder joint)
Movements of pectoral girdle
scapula moves:
- protraction
- retraction
- elevated
- depressed
- rotated
Example of protraction
reach out ouar arms to push a door
Example of retraction
squaring the shoulders
Movements of the shoulder joint
- flexion
- extension
- abduction
- adduction
- medial rotation
- lateral rotation
- circumduction
(almost always accompanied by movements of the scapula on the chest wall - when we raise our upper limb the scapula rotates)
Circumduction
circular
Movements of the elbow joint
- flexion
- extension
Movements of the radioulner joint
- pronation (palm down)
- supination (palm up)
Movements of the wrist joint
- felxion
- extension
- abduction
- adduction
Movements of the fingers
- flexion
- extension
- abduction
- adduction
The Clavicle
- slender, S-shaped bone
- easily palpable
- commonly fractured
- articulates with sternum at medial end (sternoclavicular joint) and with acromion of the scapula at its lateral end (acromioclavicular joint)
- holds the limb away fron the trunk so that it can move freely
What type of joints are sternoclavicular and acromioclavicular joints?
synovial joints
The Scapula
- mostly flat
- has some bony projections
- some parts can be easily palpated
- movemets can be seen upon examination
- posterior surface: bears a ridge of bone called: spine (easily palpable)
- lateral end of spine expands to form acromion
- clavicle, scapula and the attached muscles comprise the pectoral girdle
Acromion
- (lateral end of the spine of the scapula)
- this articulates with the lateral end of the clavicle
- can usually be palpated easily
What is the name and function of the shallow fossa at the lateral aspect of the scapula?
- glenoid fossa
- articulates with the proximal humerus to form the shoulder (gelnohumeral) joint
- shallow: making it poort fit for humerus (increases range of movement possible at shoulder, but comproses the stability of the joint)
- superior and inferior to glenoid fossa are two small projections of bone
Relationship between movement and stability of a joint
increased mobility = decreased stability
What are the names and functions of the two small projections of bone found superior and inferior to the glenoid fossa?
- supraglenoid tubercle (superior)
- infraglenoid tubercle (inferior)
- important sites for muscle attachments
Humerus
- long bone of the arm
- has a shaft and expanded proximal and distal ends
What does the head of humerus articulate with?
- glenoid fossa of the scapula
- head bears a groove called the anatomical neck
What is the name of the projection of bone on the proximal side of the humerus?
greater tubercle
What is the name of the smaller projection on the lateral side of the humerus?
lesser tubercle
Surgical neck
- the narrowed bone continuous with the shaft
- distal to the tubercles
Why is the surgical neck clinically important?
- commonly fractured esp. in elderley
- axilary nerve runs close to this region and can be injured as a result of fractures or dislocation of the humeral head
Deltoid tuberosity
- slight protuberance on upper lateral aspect of the humeral shaft
- site of attachment for the deltoid muscle
Radial (spiral) groove
- marks the path of the radial nerve over the posterior aspect of the upper part of humeral shaft
- radial nerve runs very close to the humerus here and can be injured in mid-shaft humeral fractures
True or false? there is no bony articulation between the scapula and the posterior thoracic wall
true - since the scapula is surrounded by muscles
Protraction
extends the upper limb
Retraction
squaring of the shoulders
Elevation
shrugging the shoulders
Depression
lowering the shoulders
Rotation
tilts the glenoid fossa cranially to aid elevation of the upper limb
Rotation of the scapula
- every 2 degrees of abduction of the shoulder, the scapula rotates 1 degree
What is they key muscle involved in protraction of the scapula?
serratus anterior
What are the two large superficial muscles of the posterior pectoral girdle?
- trapezius and latissimus dorsi
- large flat muscles with extensive attachments to the vertebral column
- trapezius attaches to the skull
- latissimus dorsi attaches to the anterior aspect of the proximal humerus, not the scapula (so it move the shoulder joint rather than the scapula) but often considered posterior pectoral muscles
What are the three smaller deeper muscles?
- levator scapulae
- rhomboid major
- rhomboid minor
Where doe these three smaller, deeper muscles attach?
to the medial border of the scapula to the vertebral column
Trapezius
movement of scapula:
- upper part: elevates
- middle part retracts
- lower part: depresses
- rotates the scapula
attachment origin: skull, cervical and throacic vertebrae
attachment insertion: clavicle and scapula (spine and acromion)
Latissimus dorsi
extends, adducts and medially rotates the humerus
attachment origin: lower thoracic vertebrae
attachment insertion: humerus (upper anterior)
Levator scapulae
movement of the scapula:
- elevates
attachment origin: upper cervical vertebrae
attachment insertion: scapula (medial border)
Rhomboid major
Movement of the scapula:
- retracts
attachment origin: C7 and T1
attachment insertion: scapula (medial border)
Rhomboid minor
Movement of the scapula:
- retracts
attachment origin: thoracic vertebrae
attachment insertion: scapula (medial border)
Brachial plexus
- complex network of nerves that innervates the upper limb
- most of the muscles of posterior pectoral region are innervated by branches stemming from this
Which posterior pectoral muscle is not innervated by the brachial plexus?
trapezius - innervated by the 11th cranial nerve the accessory nerve (its spinal root)
What is the name of the branch of the brachial plexus that innervates the latissimus dorsi?
thoracodorsal nerve
What 6 muscles attach the scapula to the humerus?
- deltoid
- supraspinatus
- infraspinatus
- subscapularis
- teres minor
- teres major
they move and stabilise the shoulder
Which four of the six muscles work together to provide stability to the shoulder joint?
- supraspinatus
- infraspinatus
- subscapularis
- teres minor
these are known as the rotator cuff
Deltoid
- large muscle over the lateral ascpect of the shoulder
-attaches the humerus to the lateral part of the clavicle and to the spine of the scapula - gives the shoulder its rounded contour
- inserts onto the humerus at a landmark called: deltoid tuberosity
- powerful abductor of shoulder joint
- deltoid CANNOT initiate abduction - another muscle initiate the first 20 degrees before the deltoid takes over
- anterior and posterior fibres of deltoid contribute to flexion and extension of the shoulder
- innervated by major branch of brachial plexus called: axillry nerve
What can occur from the injury of the axillary nerve?
- atrophy and weakness or even paralysis of deltoid
- impacts greatly on activities of daily life
Teres major
- arises from posterior aspect of scapula
- inserts onto the anterior aspect of humerus
- action: medial rotator and adductor of shoudler joint
The Rotator cuff
- all these are short muscles which attach scapula to the tubercles of the humerus
- supraspinatus, infraspinatus and teres minor originate from posteiror surface of scpular and insert onto the greater tubercle (tendons fuse with fibrous capsule that surrounds the shoulder joint)
Quadrilateral space
- square-shaped space bounded by teres minor (above), teres major (below), long head of triceps (medially), and surgical neck of humerus (laterally)
- axillary nerve travels through this space to enter posterior scapula region and innervate deltoid and teres minor
Subscapularis
- originates from anterior surface of scapula and inserts onto the lesser tubercle of the humerus
Deltoid (summary)
action at shoulder joint: abduction beyond 20 degrees
origin from scapula: spine and acromion (plus clavicle)
insertion (on humerus): deltoid tuberosity
Teres major (summary)
action at shoulder joint: medial rotation adduction
origin from the scapula: posterior surface, inferior part of lateral border
insertion (on the humerus): anterior humerus
Supraspinatus (summary)
action at shoulder joint: first 20 degrees of abduction
origin from the scapula: supraspinous fossa
insertion (on the humerus): greater tubercle (superior facet)
Infraspinatus (summary)
action at shoulder joint: lateral rotation
origin from the scapula: infraspinous fossa
insertion (on the humerus): greater tubercle (middle facet)
Teres minor (summary)
action at the shoulder joint: lateral rotation
origin from the scapula: lateral border
insertion (on the humerus): greater tubercle (inferior facet)
Subscapularis (summary)
action at the shoulder joint: medial rotation
origin from the scapula: subscapular fossa
insertion (on the humerus): lesser tubercle
Why is the Supraspinatus clinically important?
- it travels from the supraspinous fossa to the greater tubercle UNDER the acromion
- tendon can become inflamed and pinched between the acromion and humerus during movements of the shoulder
- called|: impingement and typical finding on examination of pateint is ‘painful arc’
How does the rotator cuff provide vital stability?
- contraction of the rotator cuff muscles holds the head of the humerus in the shallow glenoid
- the rotator cuff tendons fuse with the capsule of the shoulder joint
What other structures contribute to the stability of the shoulder?
- glenoid labrum
- ligaments (reinforces the capsule)
- tendon of biceps brachii
Glenoid labrum
- rim of fibrocartilage around the margin of glenoid fossa
- deepens the shallow fossa and aids stability
Tendon of biceps brachii
- lies in anterior arm
- reinforces joint
What separates the arm into anterior and posterior compartments?
intermuscular septa
Triceps brachii
- single large muscle
- posterior compartment of arm
- three muscle bellies/heads which all converge via a common tnedon onto a single insertion point (olecranon of the ulna)
- cross the posterior aspect of the elbow joint
- when it contract it extends the elbow
What are the names of the three heads of triceps
- long head: infraglenoid tubercle of scapula (most medial part of tricep)
- lateral head: posterior humerus, proximal to radial groove
- medial head: posterior humerus, distal to radial groove
True or false? the long head is able to contribute to extension of the shoulder joint
true - because of its attachment to the scapula
True or false? all three heads are innervated by the radial nerve
true - terminal branch of brachial plexus
- winds around the posterior aspect of the humerus in the radial (spiral) groove between the medial and lateral heads of triceps
- nerve lies on the bone so fractures of the shat of the humerus can injure it
Adhesive capsulitis ‘frozen shoulder’
- pain, stiffness in shoulder
- capsule of joint becomes inflamed, stiff and tight
- adhesions may develop
- tends to be seen in middle aged people and is more common in women and people with diabetes
- cause not understood
- no cure
- supportive physio
- take up to three years to resolve
Rotator cuff injury
- acute/chronic
- tendons can also degenerate by age
- painful at rest and on movement and cause weakness
- is supraspinatus tendon becomes injured and inflamed it may become inpinged between the acromion and the humeral head as the space is small
- first part of abduction is not painful but rom 60-120 the inflamed tendon is compressed against the acromion
- painful arc
- inflamed tendon may rupture
Dislocation of shoulder
- humeral head moves out of the glenoid fossa
- anterior dislocation is common and amost all dislocations are anterior
- often caused by blunt trauma
- posterior dislocation very uncommon but associated with vigorous muscle contraction e.g. epileptic seizure
- x-ray imaging confirm direction of displacement of humeral head and whether there is an associated fracture
- both types can injure the axillary nerve
Axillary nerve injury
- close proximity to surgical neck allows damage from fractures or disclocation
- motor fibres of axillary nerve innervate deltoid and teres minor
- sensory fibres innervate a patch of skin over the upper lateral arm
- injury to axillary nerve can result in weakness or paralysis of deltoid (difficulty abducting shoulder)
- altered sensation or numbness over upper lateral limb
Radial nerve injury
- radial nerve lies very close o bone when it runs through the radial groove
- fractures or humeral shaft can injure the nerve
- leads to weakness or paralysis of muscles that are innervated by the radial nerve downstream of the point at which the nerve is injured
- causes weakness of triceps
- impaired elbow extension
- radial nerve lesion at level of mid arm also affects movements at wrist as radial nerve innervates all muscles of posterior forearm which extends to the wrist
What does the shaft of the humerus expands distally to form?
bony prominences called the medial and lateral epicondyles (these are palpable)
What are the prominenes on the distal humerus?
- trochlea and capitellum
- they articulate with the trochelar notch of the ulna and the head of the radius respectively at the elbow joint
Axilla
- anatomical term for the armpit
- pyramind-shaped and has six boundaries
Boundaries of the axilla
- anterior wall (pectoralis major and minor)
- posterior wall (subscapularis, teres major and latissimus dorsi)
- lateral wall (upper humerus)
- medial wall (serratus anterior and chest wall)
- apex (first rib, clavicle and scapula - it is the passage between the neck and the axilla)
- base (skin and fascia between the chest wall and arm)
What does the axilla contain?
- fat
- lymph nodes
- axillary artery
- axillary vein
- brachial plexus (specifically the cords and branches)
Axillary lymph nodes
- there are five groups
- drain upper limb, breast, chest wall, scapular region and abdominal wall as far as the umbilicus
- those located in the apec are the apical nodes (often involved in spread of cancer)
- particularly associated with cancer of the breast
- can expand in response to an infection
Axillary artery
- continuation of the subclavian artery
- subclavian travels under the clavicle and into the axilla
- axillary artery gives rise to several branches: one above pec minor, two behind it and three below
- continues into the arm as the brachial artery (when is crosses the inferior border of teres major)
Axillary vein
- drains upper limbs and is continuous wiht subclavian vein
- travels alongside the artery
- formed from the union of the deep veins of the arm with the basilic vein