Upper Limb Muscles Flashcards
Where is the pectoral region of the body
On the anterior chest wall
Which muscles are present in the pectoral region of the body? (4)
Pectoralis major
Pectoralis minor
Serratus anterior
Subclavius
Which is the most superficial muscle in the pectoral region?
Pectoralis major
The pectoralis major is large and ______ shaped
Fan
The pectoralis major consist of a ______________ and a _____________ head
Clavicular
Sternocostal
What is the distal attachment of both the clavicular and sternocostal head of the pectoralis major?
The intertubercular sulcus of the humerus
Where does the clavicular head of the pectoralis major originate?
The anterior surface of the medial clavicle
Where does the sternocostal head of the pectoralis major originate?
From the anterior surface of the sternum, superior six costal cartilages and the aponeuorsis of the external oblique muscle
What is the function of the pectoralis major?
Addicts and medially rotates the upper limb and draws the scapular anterioinferiorly
The clavicular head of the pectoralis major can act individually to flex the upper limb
What innervates the pectoralis major?
Lateral and medial pectoral nerves
Where does the pectoralis minor lie in relation to the pectoralis major?
Lies underneath the pectoralis major
Where does the pectoralis minor originate and attach?
Originates from the 3rd and 5th ribs
Attaches into the coracoid process of the scapula
What is the function of the pectoralis minor?
Stabilises the scapula by drawing it anteroinferiorly against the thoracic wall
What innervates the pectoralis minor?
Medial pectoral nerve
Where is the serratus anterior located in the body?
More laterally in the chest wall
The serratus anterior muscle consists of several ________
Strips
Where does the serratus anterior originate and attach?
Originates from the lateral aspects of ribs 1-8
Attaches to the costal surface of the medial border of the scapula
What is the function of the serratus anterior?
Rotates the scapula allowing the arm to be raised over 90 degrees
Holds the scapula against the ribcage
Which nerve innervates the serratus anterior?
Long thoracic nerve
Where is the subclavius located?
Located directly underneath the clavicle running horizontally
Where does the subclavius originate and attach?
From the junction of the 1st rib and its costal cartilage
Attaches into the inferior surface of the middle third of the clavicle
What is the function of the subclavius?
Anchors and depresses the clavicle
Which nerve innervates the subclavius?
Nerve to subclavius
What can result from damage to the long thoracic nerve?
Paralysis of the serratus anterior, scapula no longer held against the ribcage resulting in profusion out of the back - winged scapula
Winged scapula results from damage to which nerve?
Long thoracic nerve
Long thoracic nerve damage usually results from which kinds of injuries?
Traction injuries - where upper limb is stretched violently
Which wall of the axilla does the serratus anterior form?
Medial
The muscles of the shoulder can be divided into which 2 groups
Extrinsic
Intrinsic
What is common of the extrinsic muscles of the shoulder?
Originates from the torso and attach to the bones of the shoulder
What is common of the intrinsic muscles of the shoulder?
Originate from the scapula/clavicle and attach to the humerus
The intrinsic muscles of the shoulder originate from the…
and atttach to the…
Scapula and/or clavicle
Humerus
How many intrinsic muscles of the shoulder are there?
How many rotator cuff muscles are there?
6
4
Name the six intrinsic muscles of the shoulder
Deltoid Teres major Supraspinatus Infraspinatus Subscapularis Teres minor
Name the 4 rotator cuff muscles of the shoulder
Supraspinatus
Infraspinatus
Subscapularis
Teres minor
The deltoid muscle can be divided into which 3 parts?
Anterior
Middle
Posterior
Where does the deltoid originate and attach?
Originates from the scapula and clavicle
Attaches to the deltoid tuberosity on the lateral surface of the humerus
Which nerve innervates the deltoid?
Axillary nerve
What are the actions of the deltoid muscle?
Anterior fibres - flex the arm at the shoulder
Posterior fibres - extend the arm at the shoulder
Middle fibres - major abductor of the arm
The teres major forms which border of the quadrangular space?
Inferior border
Name two structures that pass through the quadrangular space
Axillary nerve
Posterior circumflex humeral artery
Where does the teres major originate and attach?
Originates from the posterior surface of the inferior angle of the scapula
Attaches to the intertubercular groove of the humerus
Which nerve innervates the teres major?
Lower subscapular nerve
What are the actions of the teres major?
Adducts at the shoulder
Medially rotates the arm
What are the 4 rotator cuff muscles?
Subscapularis
Infraspinatus
Supraspinatus
Teres minor
The rotator cuff muscles originate at the _________ and attach to the ________ _________
Scapula
Humeral head
How do the rotator cuff muscles provide stability to the glenohumeral joint?
The resting tone of the muscles act to pull the humeral head into the glenoid fossa
Where does the supraspinatus originate and attach?
Originate from the supraspinous fossa of the scapula
Attaches to the greater tubercle of the humerus
Which nerve innervates the supraspinatus?
Suprascapular nerve
What are the actions of the supraspinatus?
Abducts the arm 0-15 degrees and assists the deltoid for 15-90 degrees
Where does the infraspinatus originate and attach?
Originates from the infraspinous fossa of the scapula
Attaches to the greater tubercle of the humerus
Which nerve innervates the infraspinatus?
Suprascapular nerve
What does the infraspinatus do?
Laterally rotates the arm
Where does the subscapularis originate and attach?
Originates from the subscapular fossa of the scapula
Attaches to the lesser tubercle of the humerus
Which nerve innervates the subscapularis?
Upper and lower subscapular nerves
What is the action of the subscapularis?
Medially rotates the arm
Where does the teres minor originate and attach?
Originates from the posterior surface of the scapula
Attaches to the greater tubercle of the humerus
Which nerve innervates the teres minor?
Axillary nerve
What is the action of the teres minor?
Laterally rotates the arm
What is rotator cuff tendonitis? What usually causes it?
Inflammation of the tendons of the rotator cuff muscles
Repetitive use of the shoulder joint
Which muscle is most commonly affected by rotator cuff tendonitis? What happens?
Supraspinatus
During abduction, the supraspinatus rubs against the coraco-acromial arch
What treatments are given for rotator cuff tendonitis?
Rest
Analgesia
Physiotherapy
Steroid injections
Surgery
Extrinsic muscles of the shoulder originate from the…
and attach to the…
Where in the body are the extrinsic muscles of the shoulder located?
Torso
Bones of the shoulder (scapula, clavicle, humerus)
In the back
The extrinsic muscles of the shoulder are arranged in which 2 layers?
Superficial layer
Deep layer
How many extrinsic superficial muscles of the shoulder are there?
Name them
2
Trapezius
Latissimus dorsi
Which is the most superficial of all the back muscles?
Trapezius
Where does the trapezius originate and attach?
Originates from the skull, nuchal ligament and spinous processes of C7-T12
Attaches to the clavicle, acromion and the scapula spine
Which nerve innervates the trapezius?
Accessory nerve for motor innervation
Also receives proprioceptor fibres from C3 and C4 spinal nerves
What is the action of the trapezius?
Upper fibres - elevate scapula and rotate it during abduction of the arm
Middle fibres - retract the scapula
Lower fibres - pull the scapula inferiorly
What is the most common cause of accessory nerve damage?
Iatrogenic (as a result of a medical procedure)
Give an example of a medical procedure which has risks for damaging the accessory nerve
Cervical lymph node biopsy
How can the accessory nerve be tested?
By testing trapezius function - shrugging of the patient’s shoulders
What are some clinical features of accessory nerve damage? (3)
Muscle wasting, partial paralysis of the sternocleidomastoid, asymmetrical neckline
Where does the latissimus dorsi originate and attach?
Has a broad origin in the lower part of the back - arises from the spinous processes of T6-T12, iliac crest, inferior 3 ribs
Attaches at the intertubercular sulcus of the humerus
Which nerve innervates the latissimus dorsi?
Thoracodorsal nerve
What are the actions of the latissimus dorsi?
Extends, adducts and medially rotates the upper limb
How many deep extrinsic muscles of the shoulder are there? Name them. Where are they situated?
3
Rhomboid major
Rhomboid minor
Levator scapulae
In the upper back under the trapezius
Describe the levator scapulae. Where does it originate and attach?
Small strap-like muscle
From the transverse processes of the C1-C4 vertebrae
Medial border of the scapula
Which nerve innervates the levator scapulae?
Dorsal scapular nerve
What is the action of the levator scapulae?
Elevates the scapula
Where is the rhomboid minor situated compared to the rhomboid major muscle?
Rhomboid minor situated superiorly to rhomboid major
Which nerve innervates both the rhomboid major and rhomboid minor?
Dorsal scapular nerve
What is the action of both the rhomboid minor and rhomboid major muscles?
Retracts and rotates the scapula
What is the origin and attachment of the rhomboid major?
Originates from the spinous processes of T2-T5
Attaches to the medial border of the scapula - between the scapula spine and inferior angle
What is the origin and attachment of the rhomboid minor muscle?
Originates from the spinous processes of C7-T1
Attaches to the medial border of the scapula at the level of the scapula spine
Between which joints is the upper limb located?
How many muscles are there in the upper limb?
How many of these muscles are in the anterior compartment of the upper limb and how many in the posterior compartment?
Name them.
Between the shoulder joint and the elbow joint
4
Anterior - 3
Posterior - 1
Anterior - Biceps brachii, brachialis, coracobrachialis
Posterior - Triceps brachii
All the muscles of the anterior compartment of the upper limb are innervated by which nerve?
Musculocutaneous nerve
What is a pneumonic for the muscles in the anterior compartment of the upper limb?
BBC
Biceps, brachialis, coracobrachialis
Arterial supply to the anterior compartment of the upper arm is via branches of the…
Brachial artery
The biceps brachii consists of 2 ___________
Heads (long and short)
Do the biceps brachii have any attachments to the humerus?
No
Most of its muscle mass is located anterior to the humerus
What is the bicipital aponeurosis?
Which part of the cubital fossa is formed by the bicipital aponeurosis?
A connective tissue sheet given off as the biceps brachii enters the forearm
Roof of the cubital fossa
Where does the biceps brachii originate?
Long head originates from the supraglenoid tubercle of the scapula
Short head originates from the coracoid process of the scapula
Where does the biceps brachii attach?
Both heads insert into the radial tuberosity and the fascia of the forearm via the bicipital aponeurosis
What is the function of the biceps brachii?
Supination of the forearm
Flexes the arm at the elbow/shoulder
What nerve innervates the biceps brachii?
Musculocutaneous nerve
Where does the coracobrachialis lie in relation to the biceps brachii?
Deep to the biceps brachii in the arm
Where does the coracobrachialis originate and attach?
Originates from the coracoid process of the scapula
Attaches to the medial side of the humeral shaft at the level of the deltoid tubercle
What is the function of the coracobrachialis?
Flexion of the arm at the shoulder and weak adduction
Which nerve innervates the coracobrachialis?
Musculocutaneous nerve
Where does the brachialis lie in the upper arm?
Deep to the biceps brachii
Found more distally than the other muscles in the arm
What portion of the cubital fossa is formed by the brachialis?
Forms the floor of the cubital fossa
Where does the brachialis originate and attach?
Originates from the medial and lateral surfaces of the humeral shaft
Attaches at the ulna tuberosity
What is the function of the brachialis?
Flexion at the elbow
What nerve innervates the brachialis?
Musculocutaneous nerve with contributions from the radial nerve
Are complete ruptures of tendons relatively common or rare?
Which tendon in the upper limb is one of the most commonly ruptured?
Rare
Long head of the biceps brachii
How does a rupture of the biceps tendon clinically present?
A bulge where the muscle belly is on elbow flexion (Popeye’s sign)
Why does a patient with a ruptured biceps tendon not notice much weakness in the upper limb?
Due to the action of the brachialis and supinator muscles
The triceps brachii consists of how many heads?
In which compartment of the upper arm does the triceps brachii lie?
3 - Long head, lateral head, medial head
Posterior compartment
What is the relative positions of the three heads of the triceps brachii in the upper arm?
Medial head lies deeper than the other two which cover it
Which vessel supplies blood to the posterior compartment of the upper arm?
Profunda brachii artery
Where do the lateral, medial and long head of the triceps brachii originate?
Long head - infraglenoid tubercle
Lateral head - humerus, superior to the radial groove
Medial head - humerus, inferior to the radial groove
Where do the three heads of the triceps brachii converge and attach in the upper arm?
Into the olecranon of the ulna
What is the function of the triceps brachii?
Extension of the arm at the elbow
What is the innervation of the triceps brachii?
Radial nerve
A tap on the triceps tendon tests which spinal segment?
C7
A bicep tendon reflex test, tests which spinal cord segment?
C6
The muscles in the anterior compartment of the forearm are split into which categories?
3 categories
Superficial
Intermediate
Deep
In general, muscles in the anterior compartment of the forearm perform… (2)
Flexion at the wrist/fingers
Pronation
How many superficial muscles are there in the anterior compartment of the forearm? Name them
4
Flexor carpi ulnaris
Palmaris longus
Flexor carpi radialis
Pronator teres
All the superficial muscles in the anterior compartment of the forearm originate from…
A common tendon, which arises from the medial epicondyle of the humerus
Where does the flexor carpi ulnaris originate and attach?
Originates from the medial epicondyle and has a long origin from the ulna
Attaches to the pisiform
What are the actions of the flexor carpi ulnaris?
Flexion and adduction at the wrist
What nerve innervates the flexor carpi ulnaris?
Ulnar nerve
Which superficial anterior forearm muscle is absent in some of the population?
Palmaris longus - absent in ~15% of the population
In a dissection, what will you find directly underneath the palmaris longus?
Median nerve
Where does the palmaris longus originate and attach?
Originates - medial epicondyle
Attaches - flexor retinaculum of the wrist
What is the function of the palmaris longus?
Flexion at the wrist
What nerve innervates the palmaris longus?
Median nerve
Where does the flexor carpi radialis originate and attach?
Originates - medial epicondyle
Attaches - base of metacarpals II and III
What is the function of the flexor carpi radialis?
Flexion and abduction at the wrist?
Which nerve innervates the flexor carpi radialis?
Median nerve
The lateral border of the pronator teres forms the __________ border of the cubital fossa
Medial
What are the origins and attachments of the pronator teres?
Originates - medial epicondyle, coronoid process of the ulna
Attaches - laterally to the mid shaft of the radius
How do the superficial muscles of the anterior forearm appear medially to laterally?
Flexor carpi ulnaris
Palmaris longus
Flexor carpi radialis
Pronator teres
What is the action of the pronator teres?
Pronation of the forearm
Which nerve innervates the pronator teres?
Median nerve
How many muscles are there in the intermediate layer of the anterior forearm muscles?
Name them
Flexor digitorum superficialis
Which neurovascular structures pass between the two heads of the flexor digitorum superficialis?
Median nerve and ulnar artery and then travel posteriorly
Where does the flexor digitorum superficialis originate and attach?
Two heads, originates from the medial epicondyle of the humerus and from the radius
Attaches to the middle phalanges of the four fingers as it splits into four tendons at the wrists
What is the action of the flexor digitorum superficialis?
Flexes the metacarpophalangeal joints and proximal interphalangeal joints at the 4 fingers
Flexes at the wrist
Which nerve innervates the flexor digitorum superficialis?
Median nerve
How many muscles are there in the deep compartment of the anterior forearm?
Name them
Describe their relative positions
3
Flexor digitorum profundus
Flexor pollicis longus
Pronator quadratus
Flexor digitorum profundus lies most medially, then flexor pollicis longus more laterally and pronator quadratus found deep to the tendons of these two muscles
Where does the flexor digitorum profundus originate and attach?
Originates - ulna/interosseous membrane
Attaches - splits into 4 tendons and attaches to the distal phalanges of the four fingers
What is the action of the flexor digitorum profundus?
Flexes the distal interphalangeal joints of the fingers
Flexes at metacarpophalangeal joints of the fingers
Flexes at the wrist
What nerve innervates the flexor digitorum profundus?
The medial half (little and ring fingers) innervated by the ulnar nerve
The lateral half (middle and index) innervated by the anterior interosseous branch of the median nerve
Where does the flexor pollicis longus originate and attach?
Originates from the anterior surface of the radius and interosseous membrane
Attaches - base of the distal phalanx of the thumb
What is the function of the flexor pollicis longus?
Flexes the interphalangeal and metacarpophalangeal joint of the thumb
Which nerve innervates flexor pollicis longus?
Anterior interosseous branch of the median nerve
The pronator quadratus muscle takes which rough shape?
Square shape
Where does the pronator quadratus originate and attach?
Originates - anterior surface of the ulna
Attaches - anterior surface of the radius
What is the function of the pronator quadratus?
Pronates the forearm
Which nerve innervates the pronator quadratus?
Anterior interosseous branch of the median nerve
The muscles in the posterior compartment of the forearm are commonly known as the…
Extensor muscles
The general function of the posterior forearm muscles is to…
Produce extension at the wrist and fingers
The posterior forearm muscles are all innervated by the…
Radial nerve
The posterior forearm muscles are divided into which layers?
2 layers - superficial/deep
The two layers of muscles (superficial and deep) in the posterior compartment of the forearm and spared by…
A layer of fascia
How many superficial posterior forearm muscles are there?
Name them
7
Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor carpi ulnaris Aconeus Extensor digitorum Extensor digiti minimi
Which 4 of the superficial posterior forearm muscle share a common origin?
What is this origin?
Extensor carpi radialis brevis
Extensor digitorum
Extensor carpi ulnaris
Extensor digiti minimi
Lateral epicondyle
All the posterior forearm muscles are innervated by which nerve?
Radial nerve
In the distal forearm the __________ artery and _________ nerve are sandwiched between the ______________ and the deep flexor muscles.
Radial
Radial
Brachioradialis
Where does the brachioradialis originate and attach?
Originates - proximal aspect of the lateral supracondylar ridge of the humerus
Attaches - distal end of the radius, before the radial styloid process
What is the action of the brachioradialis?
Flexes at the elbow
Where are the extensor carpi radialis brevis and longus situated?
Lateral aspect of the posterior forearm
Where does the extensor carpi radialis longus originate and attach?
Originates from the supracondylar ridge
Attaches to metacarpal bones II and III
Where does the extensor carpi radialis brevis originate and attach?
Originates - lateral epicondyle
Attaches - metacarpals II and III
What is action of the extensor carpi radialis longus and brevis?
Extends and abducts the wrist
Which muscle is the main extensor of the fingers?
Extensor digitorum
How do you test the function of the extensor digitorum?
Pronate the forearm and extend the fingers against resistance
Where does the extensor digitorum originate and attach?
Originates - lateral epicondyle
Attaches - splits into 4, inserts into the extensor hood of each finger
What is the action of the extensor digitorum?
Extends the medial four fingers at the metacarpophalangeal and interphalangeal joints
Where does the extensor digiti minimi lie in the posterior forearm?
Medially to the extensor digitorum
Thought to originate from the extensor digitorum - two muscles are fused together in some individuals
Where does the extensor digiti minimi originate and attach?
Originates - lateral epicondyle of the humerus
Attaches - into the extensor hood of the little finger
What is the action of the extensor digiti minimi?
Extends the little finger and contributes to extension at the wrist
Where does the extensor carpi ulnaris lie in the posterior forearm?
On the medial aspect of the posterior forearm
Where does the extensor carpi ulnaris originate and attach?
Originates - lateral epicondyle of the humerus
Attaches - base of metacarpal V
What is the action of the extensor carpi ulnaris?
Extension and adduction of the wrist
Where is the aconeus situated in the posterior forearm?
Medially and superiorly
The aconeus is blended with the fibres of the ____________ _________
Triceps brachii
Where does the aconeus originate and attach?
Originates - lateral epicondyle
Attaches - posterior and lateral part of the olecranon
What is the action of the aconeus?
Extends and stabilises the elbow joint
Abducts the ulna during pronation
What is lateral epicondylitis? What is another term for it?
Inflammation of the periosteum of the lateral epicondyle
Tennis elbow
What is the peak age of onset of lateral epicondylitis?
40-50 years of age
What causes lateral epicondylitis?
Repeated use of the superficial extensor muscles
How many deep muscles of the posterior forearm are there?
Name them
Supinator Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis
All the deep muscles of the posterior forearm excluding the supinator act on the…
Thumb and index finger
Name the deep muscles of the posterior forearm, laterally to medially
Supinator
Abductor pollicis longus
Extensor pollicis longus/brevis
Extensor indicis
The supinator forms the ___________ of the cubital fossa
The supinator consists of how many heads?
What passes between heads of the supinator?
Floor
2 heads
Deep branch of the radial nerve
Where does the supinator originate and attach?
Two heads
Originates - lateral epicondyle and posterior surface of the ulna
Attaches - posterior surface of the radius
What is the action of the supinator?
Supinates the forearm
The abductor pollicis longus is situated immediately _______ to the supinator muscle
Distal
The tendon of the abductor pollicis longus contributes to the lateral border of the…
Anatomical snuffbox
Where does the abductor pollicis longus originate and attach?
Originates - interosseous membrane and the posterior surfaces of the radius/ulna
Attaches - lateral side of the base of metacarpal I
What is the action of the abductor pollicis longus?
Abducts the thumb
Where is the extensor pollicis brevis found in relation to the abductor pollicis longus?
Medially and deep to the abductor pollicis longus
The tendon of the extensor pollicis brevis contributes to the ___________ border of the anatomical snuffbox
Lateral
Where does the extensor pollicis brevis originate and attach?
Originates - posterior surface of the radius and interosseous membrane
Attaches - base of the proximal phalanx of the thumb
What is the action of the extensor pollicis brevis?
Extends at the metacarpophalangeal and carpometacarpal joints of the thumb
The tendon of the extensor pollicis longus forms the ______________ border of the anatomical snuffbox
Medial
Where does the extensor pollicis longus originate and attach?
Originates - posterior surface of the ulna and interosseous membrane
Attaches - distal phalanx of the thumb
What is the action of the extensor pollicis longus?
Extends all joints of the thumb
Where does the extensor indicis originate and attach?
Originates - posterior surface of the ulna and interosseous membrane
Attaches - extensor hood of the index finger
What is the action of the extensor indicis?
Extends the index finger
Wrist drop is a sign of __________ nerve injury that has occurred…
It is caused by…
Radial
Proximal to the elbow
Unopposed flexion at the wrist joint
What are two common characteristic sites of damage of the radial nerve?
Axilla
Radial groove of the humerus
What can cause radial nerve damage in the…
I) axilla
II) radial groove of the humerus
I) humeral dislocations/fractures of the proximal humerus
II) humeral shaft fracture
Muscles acting on the hand can be divided into which 2 categories?
Extrinsic and intrinsic muscles
Describe the location and action of the extrinsic muscles of the hand
Located in the anterior and posterior compartments of the forearm
Control crude movements of the hand and produce a forceful grip
Describe the location and action of the intrinsic muscles of the hand
Located within the hand itself
Responsible for fine motor functions of the hand
How many thenar muscles are there? Where are they located?
3
Base of the thumb
The muscle bellies of thenar muscles produce a bulge in the hand known as the ________ _____________
What are these muscles responsible for?
Thenar eminence
Fine movements of the thumb
Which nerve innervates all the thenar muscles?
Median nerve
Name the three thenar muscles
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
What is the largest of all the thenar muscles? Where does the opponens pollicis lie in relation to the other thenar muscles?
Opponens pollicis
Lies underneath the other two
Where does the opponens pollicis originate and attach?
Originates - tubercle of the trapezium
Attaches - lateral margin of the metacarpal of the thumb
What is the action of the opponens pollicis?
Opposes the thumb
Where is the abductor pollicis brevis found in relation to the other thenar muscles?
Anteriorly to the opponens pollicis and proximal to the flexor pollicis brevis
Where does the abductor pollicis brevis originate and attach?
Originates - tubercles of the scaphoid and trapezium
Attaches - lateral side of proximal phalanx of the thumb
What is the action of the abductor pollicis brevis?
Abducts the thumb
Which is the most distal of all the thenar muscles?
Flexor pollicis brevis
Where does the flexor pollicis brevis originate and attach?
Originates - tubercle of the trapezium
Attaches - base of the proximal phalanx of the thumb
What is the function of the flexor pollicis brevis?
Flexes the metacarpophalangeal joint of the thumb
What is the hypothenar eminence? Which set of muscles produces this eminence?
The muscular protrusion on the medial side of the palm
Hypothenar muscles
Which nerve innervates all the hypothenar muscles?
Ulnar nerve
How many hypothenar muscles are there?
Name them
3
Opponens digiti minimi
Abductor digiti minimi
Flexor digiti minimi brevis
Where does the opponens digiti minimi lie compared to the other hypothenar muscles?
Deep to the other hypothenar muscles
Where does the opponens digiti minimi originate and attach?
Originates - hook of the hamate
Attaches - medial margin of metacarpal V
What is the action of the opponens digiti minimi?
Rotates the metacarpal of the little finger towards the palm - producing opposition
Which is the most superficial of all the hypothenar muscles?
Abductor digiti minimi
Where does the abductor digiti minimi originate and attach?
Originates - pisiform and tendon of the flexor carpi ulnaris
Attaches - base of the proximal phalanx of the little finger
What is the action of the abductor digiti minimi?
Abducts the little finger
Where does the flexor digiti minimi brevis lie in relation to the abductor digiti minimi?
Lateral to the abductor digiti minimi
Where does the flexor digiti minimi brevis originate and attach?
Originates - hook of the hamate
Attaches - base of the proximal phalanx of the little finger
How many lumbricals are there in each hand?
4 - one associated with each finger
The lumbricals are crucial to movement of the…
Fingers
The lumbricals link the __________ tendons to the __________ tendons
Flexor
Extensor
Where does each lumbrical originate and attach?
From a tendon of the flexor digitorum profundus
Attach into the extensor head of each finger
How does each lumbrical pass around the fingers?
Pass dorsally and laterally around each finger
What is the action of the lumbricals?
Flex at the metacarpophalangeal joint
Extend at the interphalangeal joints of each finger
What nerves innervate the lumbricals?
Medial two lumbricals - ulnar nerve
Lateral two lumbricals - median nerve
Which of the lumbricals are unipennate and which are bipennate?
Unipennate - lateral two lumbricals
Bipennate - medial two lumbricals
Where are the interossei muscles located?
Between the metacarpals
The interossei muscles can be divided into which two groups?
Dorsal interossei
Palmar interossei
Which are the most superficial of all the dorsal muscles?
Dorsal interossei
How many dorsal interossei are there?
4
What are the origins and attachments of the dorsal interossei?
Each interossei originates from the lateral and medial surfaces of the metacarpals
Attach - into the extensor hood and proximal phalanx of each finger
What is the function of the dorsal interossei?
Abducts the fingers at the MCP joint
Which nerve innervates both the dorsal and palmar interossei?
Ulnar nerve
On what aspect of the hand are the palmar interossei muscles located?
How many palmar interossei muscles are there?
Anteriorly
3
Where do the palmar interossei originate and attach?
Originate - medial or lateral surface of a metacarpal
Attach - extensor hood and proximal phalanx of the same finger
What is the function of the palmar interossei?
Adducts the fingers at the MCP joint
What two other muscles in the hand are not lumbricals/interossei or part of the thenar or hypothenar muscle groups?
Palmaris brevis
Adductor pollicis
Where is the palmaris brevis found?
Very superficially in the subcutaneous tissue of the hypothenar eminence
Where does the palmaris brevis originate and attach?
Originates - palmar aponeurosis
Attaches - dermis of the skin on the medial margin of the hand
What is the action of the palmaris brevis?
Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand (improving grip)
Which nerve innervates the palmaris brevis?
Ulnar nerve
Describe the structure of the adductor pollicis?
Large triangular muscle with two heads
Which neurovascular structure passes anteriorly between the two heads of the adductor pollicis?
Radial artery
Where does the adductor pollicis originate and attach?
Originates - metacarpal III and capitate
Attaches - base of the proximal phalanx of the thumb
What is the action of the adductor pollicis?
Adductor of the thumb
Which nerve innervates the adductor pollicis?
Ulnar nerve
