Upper limb anatomy Flashcards
What are the components of the clavicle?
Clavicle is an S shaped structure that has 2 ends:
- Medial (sternal) end-quadrangular in shape
- Lateral (acromial) end- in contact with acromion of scapula
In the lateral 2/3 of the clavicle there is a conoid tubercle and trapezoid line for attachments of the conoid, trapezoid ligament (coracoclavicular ligament)
What are the components of the scapula?
Scapula has:
- 2 surfaces-anterior, posterior
- 3 borders-medial, superior, lateral
- 2 angles-superior and inferior angle
- suprascapular notch
It also has 3 processes:
- spine
- acromion
- coracoid process
It has 2 fossas:
- Supraspinous fossa
- Infraspinous fossa
- Subscapularis fossa
It has a glenoid cavity for attachment of the humerus (to form the glenohumeral joint). Above this, there is a supraglenoid tubercle, infraglenoid tubercle.
What are the components of the humerus?
What is the clinical significance of anatomical neck?
Humerus has a head, an anatomical neck. Below this there is a:
- Greater tubercle-that has 3 facets for attachments of the supraspinatus, infraspinatus, teres minor from top to bottom
- Lesser tubercle-for attachment of subscapularis
- Intertubercular sulcus-for tendon of long head of biceps brachii
Below this there is an anatomical neck between greater/less tubercles and shaft. Behind this, is the posterior circumflex humeral artery and axillary nerve. When the humerus fractures, it can cause damage to these areas.
Down the shaft you have a few other attachments:
- Laterally-deltoid attachment
- Medially-coracobrachialis attachment
What are the ligaments that hold the sternoclavicular joint together:
What are the ligaments that hold the acromioclavicular ligament together:
- Anterior and posterior sternoclavicular ligament
- Interclavicular ligament
- costoclavicular ligmanet
What are the ligaments that hold the glenohumeral ligament:
- Superior, middle and inferior glenohumeral ligament
- coracohumeral ligament
- transverse humeral ligament that holds the long head of biceps braachii.
What are the common fractures in the acromioclavicular and sternoclavicular joint:
- Sternoclavicular joint-atnerior/posterior disclocation
- Acromioclavicular-middle 3rd often affected. severe trauma can cause damage to coracoclavicular ligament causing upward subluxation of clavicle.
A 7-year-old Turkish girl with a history of a fall from a height of approximately 1.5 meters was seen on our ward. The patient had complaints of left shoulder pain and of being unable to move her shoulder. X ray showed this:
This is an anterior inferior dislocation of glenohumeral joint causing compression of axillary nerve therefore causing her to be unable to move her shoulder.
What is the origin, insertion and innervation and function of the trapezius and deltoid:
Trapezius:
- from C1 to T12, attaches to spine of scapulae.
- innervated S: C3, C4 and M: accezzory nerve (XI). upper fibres causes elevation of scapulae. Middle fibres cause retraction of scapulae. Inferior fibres cause depression of scapulae.
Deltoid:
- from spine of scapulae, to the inferior edge of acromion, and lateral edge of clavicle to deltoid process on humerus
- innervated by axillary nerve (C5, C6). Causes abduction of shoulder above 15 degrees (first 15 done by supraspinatus)
What is the origin, insertion and innervation and function of the levator scapulae, rhomboid minor, rhomboid major
Levator scapulae:
- from transverse process of C1 to C4, attaches to medial border of scapulae.
- innervated by dorsal scapular nerve and C3, C4. It causes elevation of scapulae
Rhomboid minor:
- from spinous process of C7, to medial border of scapulae.
- innervated by dorsal scapular nerve and causes elevation and retraction of scapulae.
Rhomboid major:
- from spinous process of T2-T5, to medial border of scapulae
- innervated by dorsal scapular nerve and causes elevation and retraction of scapulae.
What is the origin, insertion, innervation and function of the supraspinatus, infraspinatous and teres minor muscle?
What is the origin, insertion, innervation ,function of the subscapularis and teres major?
Subscapularis:
-in subscapularis fossa and attaches to lesser tubercle. Innervated by subscapular nerve, causes medial rotation of shoulder
Teres major:
-inferior edge of the scapula and attaches to lesser tubercle. Innervated by subscapular nerve, causes medial rotation of shoulder
What are the boundaries of the suprascapular foramen and quadrangular foramen? What does this contain
Suprascapular foramen is formed between the suprascapular notch and suprascapular ligament. It contains the suprascapular artery/nerve.
Quadrangular foramen is formed:
- Inferior border of the teres minor
- Superior border of teres major
- Long head of biceps
- anatomical neck of the humerus
It contains the axillary nerve and posterior circumflex humeral artery.
What are the arteries/nerves/veins associated with the posterior scapular region:
Nerves
- Suprascapular nerve from brachial plexus that enters posterior scapular region via suprascapular foramen. Innervates supraspinatus and infraspinatus
- Axillary nerve from brachial plexus that enters via quadrangular region. Innervates deltoid and teres minor
Arteries
- Suprascapular artery from the thyrocervical trunk of the subclavian artery
- Anterior and posterior circumflex artery from axillary artery (3rd part)
- Circumflex scapular artery from axillary artery
(OBQ10.233) A 24-year-old patient complains of vague right shoulder pain. On physical exam the patient is noted to have weakness with external rotation. EMG findings are consistent with quadrangular space syndrome. Along with the deltoid, what other muscle is affected?
Hypertrophy of the muscles can cause quadrangular space syndrome that compresses the axillary nerve and posterior circumflex humeral artery
The patient was a forty five year old male architect who additionally works in academia. His lifestyle is sedentary but he does play tennis and is right handed. He complained of pain locally over his right shoulder under the acromium. He stated the pain had come on gradually whilst playing tennis four weeks ago and went after playing
- Torn supraspinatous tendon-> unable to abduct the arm above 15 degrees
A sixty-two-year-old, right-hand-dominant man presented with a 5-day history of progressive pain and swelling of his right shoulder and a 48-hour history of fever and rigors. On examination, the patient was pyrexial with a temperature of 38 degrees. General examination was unremarkable. On inspection, the right shoulder was swollen, with erythema in the anterior and superior shoulder regions. This area was warm to touch, with acute tenderness in the subacromial region. The patient was unable to actively move his shoulder, and minimal passive movement elicited severe pain.
- Subacromion bursitis
Bursa is located around subacromion and contains a lot of synovial fluid to minimize friction. Inflammatoin-> causes pain in movement of shoulder joint
Anterior axilla
What is the origin, insertion, innervation and function of the pectoralis major, minor and subclavius?
Medial axilla
What is the origin, insertion, innervation and function of the serratus anterior?
What happens when you damage the long thoracic nerve?
Long thoracic nerve is commonly damaged in mastectomy-> causing winging of the scapula because serratus anterior can no longer protract scapula.
Posterior axilla
What is the origin, insertion, innervation and function of the subscapularis, teres major, latissimus dorsi and long head of triceps bracchi?
Contents of axillary inlet
What is the origin, insertion, innervation and function of the biceps brachii and coarcobrachialis?
Biceps brachii
-long head from the supraglenoid tubercle and short head from the coracoid process; attach to the radial tuberosity. Innervated by the musculocutaneous nerve (C5,C6). Causes flexion of forearm at elbow joint and supination of forearm.
Coracobrachialis
-from the coracoid process and attaches to the medial shaft of humerus. Innervated by musculocutaneous nerve (C5, C6,C7). Causes flexion of arm
What is the course of the axillary artery and when does it become the axillary artery/brachial artery?
What are the 3 parts of the axillary artery:
- Proximal to pectoralis minor
- Posterior to pectoralis minor
- Distal to pectoralis minor
Axillary artery is from the subclavian artery and starts at lateral edge of rib I, it terminates as the brachial artery at inferior border of teres major.
3 parts of axillary artery
- Proximal to pectoralis minor
- superior thoracic artery
- Posterior to pectoralis minor
- thoracoacromial artery
- lateral thoracic artery
- Distal to pectoralis minor
- subscapularis artery
- anterior and posterior circumflex humeral artery
What is the course of the axillary vein and the tributaries it receives?
Axillary vein comes from the basilic vein at inferior margin of teres major and then continues to become subclavian at lateral edge of rib I.
It receives tributaries from cephalic vein and paired brachial veins.
An 18 year old boy isbrought to A&E following epileptic seizure. On recovery, he complains of pain in right shoulder. Examination shows arm to be medially rotated and adducted. What is your likely diagnosis?
- Posterior dislocation is uncommon often from epileptic seizure. Causes damage to the posterior rotator cuffs-supraspinatus, infraspinatus and teres minor; preventing external rotation therefore arm is medially rotated and adducted
- Anterior dislocation is much more common after fall on shoulder. Causes damage to anterior rotator cuff-subscapularis and teres major; preventing medial rotation; therefore arm is laterally rotated and abducted
What is the brachial plexus-roots, trunks, divisions, and cords?
Brachial plexus runs from anterior rami of C5, C6, C7,C8 and T1. Its course can be remembered by “rugby teams drink cold beer”
Roots-C5, C6, C7,C8 and T1
Trunk:
- superior trunk: C5, C6
- middle trunk: C7
- inferior trunk: C8, T1
Divisions:
-anterior and posterior divisions. Anterior often supplies the anterior compartment of arm; posterior often supplies the posterior compartment of arm.
Cord:
- lateral: anterior division of C5, C6, C7
- middle: anterior division of C8, T1
- posterior cord: posterior divisions of all
What are thr branches arising from the root?
- Dorsal scapular nerve from C5-> supplies rhomboid major and minor
- Long thoracic nerve from C5, C6, C7-> supplies serratus anterior
What are the branches arising from the superior trunk (hint S nerves):
- Suprascapular nerve-supplying the supraspinatus and infraspinatus
- Subclavian nerve-supplying subclavius
What are the major branches from the cords (my aunty raped my uncle)?
What are the branches from the lateral and medial cord?
- Musculocutaneous from the lateral cord-anterior flexors of arm
- Axillary and radial nerve from posterior cord-posterior extensors of arm
- Medial and ulnar from the medial cord-medial supplying anterior compartment of forearm; ulnar supply intrinsic muscles of hand
Lateral cord
- Musculocutaneous from the lateral cord-anterior flexors of arm; this terminates as the lateral cutaneous nerve
- Lateral pectoral nerve-pectoralis major
Medial cord (5)
- Medial and ulnar from the medial cord-medial supplying anterior compartment of forearm; ulnar supply intrinsic muscles of hand
- Medial cutaneous nerve of arm; medial cutaneous nerve of forearm
- Medial pectoral nerve-pectoralis minor
What are the major branches arising from the posterior cord (ULTRA)?
- Upper subscapularis-subscapular muscle
- Lower subscapularis-subscapular muscle and teres major
- Thoracodorsal-latissimus dorsi
- Radial nerve-posterior extensors of arm
- Axillary nerve-deltoid and teres minor
Describe the shaft and the distal end of the humerus?
Shaft
Below the head, neck and surgical neck of humerus (posterior):
- Attachment for lateral head of triceps brachii above the deltoid tuberosity
- Radial groove-where radial nerve and profunda brachii artery is behind
The humerus then expands to become the lateral and medial supraepicondylar ridge distally.
Distal humerus:
There are 2 epicondyles, 1 condyle and 3 fossas
- Medial and lateral epicondyle
- Condyle below for articulation of radial and ulnar bones. Capitulum (lateral) which articulates with radius. Trochlea (medial) which articulates with ulnar.
- 3 fossas. Radial fossa and coronoid fossa above condyle. Olecranon fossa posteriorly above trochlea
Describe the proximal end of radius?
- Head
- Neck
- Radial tuberosity-where the biceps brachii tendon attaches to
- Benath radial tuberosity, oblique line
Describe the proximal end of ulna bone?
- Olecranon
- anteriorlateral projects to form trochlear notch that articulates with trochlea
- superior surface-roughening for triceps attachment
- posterior surface-tip of elbow
- Coronoid process anteriorly from ulnar, helps form the trochlear notch
- Radial notch which articulates with radius
- Below radial notch you have supinator crest- where supinator attaches to
- Ulna tuberosity-where brachialis attaches to
What is the origin, insertion, innervation and function of the coracobrachialis, biceps brachii, brachialis
What spinal cord segment does tapping on tendon of biceps brachii test?
Biceps brachii:
-long head from the supraglenoid tubercle; short head from coracoid process; attach onto the radial tuberosity of radius; innervated by musculocutaneous nerve (C5, C6, C7). Function: flexor of forearm at elbow joint and supinator
Brachialis:
-shaft of the humerus and attaches onto ulnar tuberosity. Innervated by musculocutaneous nerve (C5, C6, C7). Function: flexor of forearm at elbow joint and supinator
Coracobrachialis:
-coracoid process and attaches onto shaft of humerus. Innervated by musculocutaneous nerve. Function: flexion of shoulder at glenohumeral joint
Clinical relevance:
-tapping of biceps tendon on radial tuberosity test C5-C6
What is the significance of this?
- Biceps Brachii tendon rupture-> muscle belly protrudes to create “popeye sign”
What is the origin, insertion, innervation and function of the triceps brachii?
What does tapping on tendon of triceps brachii test?
Triceps brachii has 3 heads.
- Lateral head-posterior of humerus
- Long head-infraglenoid tubercle
- Medial head-posterior of humerus
Attaches to olecranon of ulna. Innervated by radial nerve (c6, C7, c8). Function-extension of forearm at elbow joint.
Clinical relevance:
- Tapping on triceps brachii on olecranon test C7-C8
What is the course of the brachial artery in the arm and what branches does it give off?
- Brachial artery comes from the axillary artery after the inferio margin of the teres major. It courses medially in the arm, and then goes in between the lateral/medial epicondyle at the elbow joint, where it splits into the radial and ulnar artery.
- It has a profunda brachii artery that goes to supply the posterior compartment of arm by passing around radial groove with radial nerve.
What is the course of brachial veins in the arm?
- There are 2 paired brachial veins lateral to the brachial artery that join the basilic vein. Basilic vein then continues to become axillary vein at inferior border of teres major. It also receives the cephalic vein (ceiling)
What is the course of the musculocutaneous/median/ulnar nerve?
- Musculocutaneous come from the lateral cord of brachial plexus and passes through the coracobrachialis in between the biceps brachii and brachialis. It gives off motor innervation to anterior muscles of arm. Lateral to the lateral epicondyle, it gives off the lateral cutaneous nerve of forearm (sensory innervation to skin of forearm)
- Median nerve is from the medial cord. It passes lateral to the brachial artery.
- Ulnar nerve is from medial cord. It passes medial to the brachial artery. It then passes posterior to medial epicondyle before entering anterior compartment of forearm.
What is the course of the radial nerve?
It enters the posterior compartment of the arm by passing around the radial groove with the profunda brachii. It then goes laterally in between the brachioradialis and brachialis to give off inferior lateral cutaneous nerve of arm and posterior cutaneous nerve of forearm.
After falling down on her arm, lady reported loss of sensation on the back of her hand. Her wrist seemed to drop.
What do you think has happened?
- Radial nerve injury due to radial groove damage in humeral fracture. Will cause wrist drop (affect extensors) and sensory changes over dorsum of hand.
