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
How can you attempt to stop bleeding if major artery/vein injured in upper limb?
compressing them against the humerus
Plexus
- ‘braid’ or ‘plait’
- complex networks of nerves or veins
Brachial plexus
- network of nerves that provides motor and senosry innervation to the upper limb
- formed by the spinal nerves that leave the lower cervical spinal cord segments and the first thoracic spinal cord segment (C5, 6, 7, 8, 9 and T1)
- the spinal nerves are mixed nerves which carry both motor and sensory fibres
What are the five segments of the brachial plexus?
- roots (spinal nerves C5-T1)
- trunks (also located in neck)
- divisions
- cords (named relative tot heir position around the second part of the axillary artery)
- branches
What are the three types of trunk?
- superior: C5 and C6
- middle: C7
- inferior: C8 and T1
Divisions of brachial plexus
- each trunk divides into an anterior and a posterior division under the clavicle
Cords of the brachial plexus
- anterior divisions of superior and middle trunks combine = LATERAL CORD
- posterior divisions of all trunks combine = POSTERIOR CORD
- anterior division of inferior trunk continues as MEDIAL CORD
Branches of the brachial plexus
- axillary (branch from posterior cord)
- radial (continuation of posterior cord)
- musculocutaneous (branch from lateral cord)
- ulnar (branch from medial cord)
- median (formed by branches from the lateral and medial cords)
True or false? the brachial plexus also gives rise to other nerves that innervate the shoulder and pectoral muscles)
True
What is the axillary nerve a branch of?
- posterior cord
- contains fibres from spinal nerves C5 and C6
- runs close to ther surgical neck of humerus and is vulnerable to injury in fractures of surgical neck of humerus or dislocations of humeral head
True or false? the radial nerve also innervates all the muscles in the posterior compartment of the forearm
true
- these muscles are extensors of the wrist and digits
- also innervates regiosn of skin over the forearm and hand
What is the radial nerve a branch of?
- continuation of posterior cord
- contaisn fibres C5-T1
- runs along the radial (spiral) groove on the posterior surface of the humerus and is vulnerable here in mid-shaft fractures of the humerus
Musculocutaneous nerve
- innervates muscles in the anterior arm
- arises from lateral cord
- contains fibres from spinal nerves C5-C7
- continues as sensory nerve that innervates a region of skin over the forearm
- becasue of its location it is rarely injured in isolation
Median and ulnar nerves
- do not innervate any muscles in arm
- innervate muscles in the forearm and hand
How is the median nerve formed?
- from contributions from both lateral and medial cords
- contains fibres from C6-T1
- innervates most of muscles of anterior forarm (which are flexors of wrist and digits)
- innervates small muscles of the thumb
- innervates skin over lateral aspect of palm and over lateral digits
- most vulnerable in arm as it crosses the anteriro aspect of the elbow in a region called Cubital Fossa
How is the ulnar nerve formed?
- formed by contribution of medial cord after it has given a contribution to median nerve
- contains fibres from spinal nerves C8-T1
- innervates most of small muscles in hand (therefore vital for moving digits)
- innervates skin over medial aspect of hand and medial digits
- vulnerable to injury behind the medial epicondyle (as it lies in a superficial position here)
Injuries to brachial plexus
- can result in different clinical presentations
- most catastrophic: when all roots are injured
What are the three muscles of the anterior arm?
- biceps brachii
- brachialis
- coracobrachialis
(all three act as plexors and are all innervated by musculocutaneous nerve)
Biceps brachii
- lies most superficially in the anterior arm
- two muscle bellies (long head and short head)
- proximally both heads are attached to the scapula (long to supraglenoid tubercle and short to coracoid process)
What is the name of the structure where the common tendon of the bellies of the biceps brachii converge?
- radial tuberosity of the radius
- the tendon of the long head peirces the capsule of the shoulder joitn and helps to stabilise the joint
True or false? Biceps is a flexor of the elbow joint
true
(also contributing to felxion of shoulder joint as it crosses the shoulder joint)
True or false? Biceps are also a powerful supinator of the forearm when the elbow is flexed
true
Supination is weaker when?…
the elbow is extended
Brachialis
- lies deep to the biceps
- proximally attached to anterior aspect of lower half of shaft of humerus
- also cross the elbow joint to insert distally upon the ulna tuberosity
True or false? the Brachialis is a powerful flexor of the elbow joint
true - but does not cross the shoulder joint so does not act on the shoulder
Coracobrachialis
- smaller muscle
- attaches proximally to coracoid process of scapula
- distally to medial aspect of middle part of humerus
- crosses the shoudler joint so acts upon it as a weak flexor
What is the cubital fossa?
- region anterior to elbow joint
- also known asa antecubital fossa ‘ACF’
- triangular shaped region with three borders
What are the three borders of the cubital fossa?
- lateral: brachioradialis (posterior forearm muscle)
- medial: prontor teres (anterior forearm muscle)
- superior/base: formed by imaginery line drawn between medial and lateral epicondyles of humerus
Contents of the cubital fossa
- tendon of biceps brachii (passes through)and is tapped with a tendon hammer to examine biceps reflex
- biceptal aponeurosis
- brachial artery (medial to biceps tendon) bifurcates here
- median nerve (only passing)
- radial nerve (deep to brachioradialis and only passing)
Biceptal aponeurosis
- fascial extension of biceps tendon
- separates superficial veins from deeper structures in fossa (brachial artery and median nerve)
What are the bifurcations of the brachial artery?
- radial and ulnar arteries
- bifurcates in the cubital fossa
Importance of the superficial veins that lie in the subcutaneous tissue over the cubital fossa
- venepuncture
- intravenous access
Axillary lymph node metastasis
- malignant axillary node may be felt as a lump in the armpit
- biopsy and can be removed
- removal can lead to fluid accumulation and swelling in upper limb
- risk to injury of two nerves: long thoracic nerve and thoracodorsal nerve
Long Thoracic nerve
- innnervates serratus anterior
- lies superficial on surface of muscle in medial wall of axilla
- injury can cause weakness or paralysis of serratus anterior
- function: hold medial border of scapula flat against the posterior chest wall
- if muscle paralysed the medial border lifts off the chest wall and appears to stick out
- called a winged scapula
Thoracodorsal nerve
- innervates latissimus dorsi
- vulnerable to injury when removing axillary nodes
- runs along the subscapularis muscle which forms the posterior wall of the axilla
Upper brachial plexus injury ‘Erb’s palsy’
- may involve C5-6 or C5-7
- paralysis of lateral rotators of shoulder and extensors of wrist is common
- affected limb appears medially rotated with the wrist flexed
- cause: trauma
Lower brachial plexus injury ‘Klumpke’s palsy’
- involves C8 and T1
- paralysis of small muscles of the hand
- trauma
Horner’s syndrome
- triad of drooping
- eyelid (ptosis)
- constricted pupil (miosis)
- lack of sweating (anhidrosis) on one side of the face
- sypathetic nerve supply to face is interrupted
- T1 spinal nerve carries sympathetic fibres whcih are destined to suply the face
Brachial plexus block
- form of regional anaesthesia
- alternative to general anaesthesia
- test senosry and motor functino before the surgery too
What are the two bones in the forearm?
- radius and ulna
How are the two bones in the forearm connected?
- by the interosseous membrane
Describe how the ulna and radius articulates with the humerus
- trochlea notch of ulna articulates with trochlea of humerus
- radial head of radius articulates with capitellum of humerus
(allows flexion and extension)
The radius and ulna also articulate with each other at the…
- proximal and distal radioulnar joints
What do the radioulnar joints allow for?
- pronation and supination of forearm and hand
- radius pivots around the ulna
- anterior compartment of forearm contains two muscles that act as pronators
Radiocarpal joint
- radius articulates with two of the small bones distally of the wrist (carpus)
Movement by radiocarpal joint
- flexion
- extension
- abduction
- adduction
- movements are achieved by muscles in anterior and posterior forearm
Describe the carpus
- comprised of 8 small bones that articulate with each other at small joints
- ~arranged in 2 rows of 4 bones (proximal and distal)
- distal radius articulates with two of the bones in proximal row to form the radiocarpal joint
What two bones of the proximal row does the radius articulate with in the carpal to form the radiocarpal joint?
- scaphoid
- lunate
Describe the proximal row (carpal)
From lateral to medial:
- scaphoid
- lunate
- triquetral
- pisiform
Pisiform
- not a true carpal bone
- small bone that develops in tendon of flexor carpi ulnaris
Describe the distal row (carpal)
From lateral to medial:
- trapezium (base of thumb)
- trapezoid
- capitate (central and largest bone)
- hamate
Hamate
- bears a bony process anteriorly
- the hook
- obvious and palpable upon examination
Which bone of the carpal is the most commonly fractured?
- scaphoid
- usually by a fall onto an outsretched hand
Describe the hand
- metacarpals (lie distal to carpus)
- bones of the digits are phalanges, three in each finger and two in the thumb
Cubital fossa
- triangular shaped region anterior to elbow
- lateral: brachioradialis
- medial: pronator teres
- superior: line drawn between medial and lateral epicondyles of humerus
Pronator teres
- anterior forearm muscle
- it is a pronator
Brachioradialis
- posterior forearm muscle
How many muscles are there in the anterior compartment?
8
- arranged in three layers (superifical, middle, deep)
- most are flexors of wrist, middle or thumb
- most innervated by median nerve
Superficial layer of anterior compartment
4 lateral to medial:
- pronator teres
- flexor carpi radialis
- palmaris longus
- flexor carpi ulnaris
Attached proximally to medial epicondyle of humerus
therefore this region is referred to as common flexor origin
Flexor carpi radialis
- flexes and abducts wrist
- inserts onto radial side of wrist
Palmaris longus
- small muscle belly
- long, thin easily recognisable tendon
- tendon inserts into fascia of palm of hand
Felxor carpi ulnaris
- flexes and adducts wrist
- inserts onto ulna side of wrist
- innervated by ulnar nerve
- ulanr nerve and artery lie lateral side of tendon at wrist
Middle layer of anterior compartment
- one muscle: flexor difitorum superficialis (FDS)
- gives rise to four tendons
- flexor of digits
- innervated by median nerve (which travels between flexor digitorum superificialis and one of the deep muscles flexor digitorum profundus)
Deep layer of anterior compartment
3 muscles
- flexor digitorum profundus
- flexor pollicis longus
- pronator quadratus
Flexor digitorum profundus
- flexor of digits
- deep to flexor digitalis superficial
- gives rise to four tendons (travel to hand and fingers)
- tendons of superficialis and profundus are closely related
Innervation of flexor digitorium profundus
- has a dual innervation
- lateral half (gives rise to tendons travel to index and middle fingers): median nerve
- medial half (gives rise to tendons travel to ring and little fingers): ulnar nerve
Flexor pollicus longus
- flexes thumb
- pollex = thumb
Pronator quadratus
- deepest forearm muscle
- square-shaped
- lies over distal ends of radius and ulnar
- pronates the distal radioulnar joint
What is the carpal tunnel?
- narrow passageway at wrist
- floor and sides are formed by carpal bones
- fibrous band FLEXOR RETINACULUM completes the tunnel forming the roof (attached to scaphoid and trapezium laterally and to the hook of the hamate and pisiform medially)
What travels through the carpal tunnel?
- median nerve
- tendons of the anterior forearm muscles that insert onto the digits:
- flexor digitorum superificalis (4 tendons to digits 2-5)
- flexor digitorum profundus (4 tendons to digits 2-5)
- flexor pollicis longus (1 tendon to thumb)
Carpal tunnel syndrome
- carpal tunnel is already small and tighlty packed
- inflammation/swelling of tendons of arthiritus of the joints which increases pressure in tunnel
- compresses the median nerve
Presentation of carpal tunnel syndrome
- impaired/altered sensation over skin of hand supplied by median nerve
- tingling/numbness
- weakness of hand muscles supplied by median nerve esp. small muscles of thumb
Treatment of carpal tunnel syndrome
- alleviate compression by dividing the flexor retinaculum
Which artery bifurcates in the cubital fossa and what are the terminal branches?
- brachial artery bifurcates into radial and ulnar arteries
Radial artery
- travels along lateral aspect of forearm
- can easily be palpated at wrist
Ulnar artery
- travels along medial aspect of forearm
- can also be palpated at wrist but nto as easily as it is partly covered by tendon flexor of carpi ulnaris
What do the radial and ulnar arteries do at the palm of the hand and why?
- anastomose to form palmar arches
- ensure hand remains adequately perfused in the event that either artery becomes occluded or injured
Venous drainage of the forearm
- superficial and deep veins in upper limb
- communicate
- ultimately all venous blood drains into axillary vein
Superficial veins of the forearm
- cephalic and basilic vein
- cephalic courses laterally
- basilic courses medially
- connected in the region of cubital fossa by medial cubital vein
- basilic vein recieves deep veins to form axillary vein
Deep veins of forearm
- accompany arteries and are often paired
- e.g. two brachial veins accompany the brachial artery
- ultimately drain into axillary vein
Because the ulna and radius are connected by joints, the interosseous membrane, ligaments and muscles…
- tend to act as one
- injuries often fracture bones bones OR fracture one and dislocate the other
Fracture of distal radius
- colles’ fracture
- common in older people esp. in females as osteoporosis is more common
Fracture of radial head
- common
- not always apparant on x-ray images
Medial epicondylitis
- inflammation of tendinous insertions of superficial forearm flexors at medial epicondyle
- tends to be caused by repetitive use and strain or muscles
- pain felt around medial epicondyle and may radiate down forearm
- also called golfer’s elbow
Injury to flexor tendons
- risk from lacerations over anterior forearm and wrist
Neurovascular injuries in anterior forearm
- radial and ulnar artery and ulnar nerve lies supferficially at wrist
- median nerve lies deep in forearm but may be injured in deep lacerations but at wrist it is more superifical so may be injured here
- median nerve damage: impairs funcitons of thumb muscles and skin over areas suppled by median nerve
- vessels and nerves may also be compressed or kined by fractures or dislocations of forearm or carpal bones
Ganglion
- cystic swelling commonly appears dorsum of wrist
- soft and typically non-tender
- contain synovial fluid
The carpus is composed of how many bones?
- 8 small bones
- articulate with each other at small joints
- two rows of four (proximal and distal)
Which carpal bones does the distal radius articulate with and what joint does it form?
- scaphoid and lunate
- forms radiocarpal joint
Which carpal bone is fractured commonly?
- scaphoid
- fall on outsretched hand
What may happen if the lunate dislocates?
- compression of median nerve
Which bones lie immedialty distal to the carpals?
- metacarpals
- 1-5 from lateral to medial
What are the bones of the digits called?
- phalanges
- three in each finger (proximal, medial and distal) and two in thumb (proximal and distal)
What are Carpometacarpal joints (CMCJs)?
- between distal row of carpal bones and proximal parts of metacarpals
What are metacarpophalangeal joints (MCPJs)?
- lie between distal parts (heads) of metacarpals and proximal phalanges
What are interphalangeal joints (IPJs)?
- lie between phalanges
- thumb contains 2 phalanges so it only has one of these joints
- fingers have 3 phalanges so they have 2: proximal interphalangeal joint and distal interphalangeal joint
What is power grip used for?
- hold/squeeze objects tightly
What is hook grip used for?
- important for carrying objects with handles e.g. bags
What is precision grip used for?
- hold objects between pads of thumb and index finger e.g. pen/needle
- can be performed with/without power
Movements of fingers
- flexion
- extension
- abduction
- adduction
Movements of thumb
- flexion
- extension
- abduction
- adduction
- opposition
Movements of fingers and thumb are controlled by…
- extrinsic and intrinsic muscles
Where are the extrinsic muscles that control movement of the fingers and thumb?
- in anterior and posterior forearm
- their tendons travel into the hand
Where are the intrinsic muscles that control movement of the fingers and thumb?
- lie within the hand
Which muscles of the anterior forearm are the prime flexors of the wrist?
- flexor carpi radialis
- flexor carpi ulnaris
- palmaris longus
Insertion of flexor carpi radialis
- inserts onto 2nd metacarpal
Insertion of flexor carpi ulnaris
- inserts onto 5th metacarpal
Insertion of palmaris longus
- inserts onto palmar fascia
True or false? Anterior muscles that flex the digits also flex the wrist as the tendons cross the wrist?
true
Where does the tendon of the flexor digitorum superficialis insert?
- it splits into 2
- inserts on either side of middle phalanx of digits 2-5
Where does the tendon of the flexor digitorum profundus insert?
- passes through the slit of the FDS tendon to insert onto the palmar aspect of the distal phalanx of digits 2-5
- only muscle capable of flexing the DIP joint
- it also flexes PIP joint and MCP joint of digits 2-5
Where does the tendon of the flexor policus longus insert?
- inserts onto distal phalanx of the thumb
- flexes IP joint of thumb and is only muscle that can do so
What are flexor tendon sheaths?
- enclose long flexor tendons
- maintian position of felxor tendons in midline of each finger
- within the fibrous sheath, the tendons are enclosed in a synovial sheath (reduces friction and allows tendons to slide freely within their fibrous sheath during flexion and extension)
Tenosynovitis
- inflamation of the tendon and synovial sheath
What does the thick palmar aponeurosis protect?
- long flexor tendons, tendon sheaths and vessels in central palm
What are the four groups of intrinsic muscles of the hand?
- thenar eminence (3)
- hypothenar eminence (3)
- lumbricals (4)
- interossei (7)
- there is also one remaining muscle that does not fit in any group called Adductor pollicus of the thumb
Innervation of the intrinsic muscles of the hand
- ulnar and median nerves
Thenar eminence (3)
- fleshy mass on palm of hand at base of thumb
1. flexor pollicis brevis (FPB) - flexes thumb
2. abductor pollicus brevis (APB) - abducts thumb
3. opponens pollicus (OP) - opposes thumb - attached to carpal bones proximally
- innervated by recurrent branch of median nerve
Flexor pollicus brevis
Movement, insertion, innervation
- flexion
- proximal phalanx
- recurrent branch of median nerve
Abductor pollicus brevis
Movement, insertion, innervation
- abduction
- proximal phalanx (lateral aspect)
- recurrent branch of median nerve
Opponens pollicus
Movement, insertion, innervation
- opposition
- 1st metacarpal
- recurrent branch of median nerve
Recurrent branch of median nerve
- leaves median nerve after it has passed through the carpal tunnel
- therefore thenar eminence muscles can be affected by carpal tunel sundrome
- weak and atrophy
Adductor pollicius
- moves the thumb but differs from thenar eminence in 2 ways
- it is also attached to the 3rd metacarpal and to posterior phalanx of the thumb
- contraction of the muscle pulls the thumb towards the palm = adduction
What are the 2 ways adductor pollicis is different to the thenar eminence?
- It lies deep in the palm, not in the thenar eminence
- It is innervated by the ulnar nerve
What are the thenar muscles important for?
Precision grip
- thumb is abducted flexed and medically rotated at the CMC joint do it can oppose with one of the fingers
- can be performed with/without power
Hypothecate eminence
- fleshy mass on medial side of palm of hand, proximal to little finger
- contains three small muscles that act on the little finger and are attached to carpal bones proximally
- flexor digiti minimi
- abductor digiti minimi
- oppnonens digiti minimi
- all innervated by deep branch of ulnar nerve
Flexor digiti minimi
- flexion
- insert: proximal phalanx
-ulnar nerve
Abductor digiti minimi
- abduction
- insert: proximal phalanx
- ulnar nerve
Opponens digiti minimi
- opposes little finger
- insert: 5th metacarpal
- ulnar nerve
Lumbrical muscles
- four, one for each finger
- arise from tendons of flexor digitorum profundus
- travel along aspects of digits 2-5
- insert: dorsum of digits
- flex metacarpal joints and extend the interphalangeal joints
- lateral two (2,3) innervated by median nerve
- medial two (2,3) innervated by ulnar nerve
Interossei muscles
- attached to and lie between metacarpals
- insert onto dorsal aspects of of digits 2-5
- two groups: palmar + dorsal
- contribute to extension of interphalangeal muscles
Palmar interosseous muscles
- three
- arrangement and insertion point allows them to adduct the fingers when they contract
Dorsal interosseous muscles
- four
- arrangement and insertion points allow them to abduct the fingers when they contract
First palmar interosseous
- arises from medial side of 2nd metacarpal
- inserts: medial aspect of 2nd proximal phalanx
Second palmar interosseous
- arises from lateral side of 4th metacarpal
- inserts: lateral aspect of 4th proximal phalanx
Third palmar interosseous
- arises from lateral side of 5th metacarpal
- inserts: lateral aspect of 5th proximal phalanx
First dorsal interosseous
- arises from medial side of 1st metacarpal and lateral side of 2nd metacarpal
- inserts: lateral aspect of 2nd proximal phalanx
- moves index finger
Second dorsal interosseous
- arises from