Muscles Flashcards
Pectoralis minor
Med pectoral nerve: C8, T1
Stabilises scapula
Pectoralis major
Lat & med pectoral nerves:
Clavicular head: C5&6
Sternocostal head: C7&8, T1
Adducts & medially rotates humerus
Moves scapula ant & inf
Subclavius
Nerve to subclavius: C5&6
Anchors & depresses clavicle
Serratus anterior
Long thoracic nerve: C5-7
Protracts scapula (holds against thoracic wall) Rotates scapula
Biceps brachii
Musculocutaneous nerve: C5-7
Supinates forearm
Flexes forearm (when supine)
Shirt head resists shoulder dislocation
Coracobrachialis
Musculocutaneous nerve: C5-7
Helps flex & adduct arm
Resists shoulder dislocation
Brachialis
Musculocutaneous: C5&6
Lateral part - Radial: C5&7
Flexes forearm (all positions)
Triceps brachii
Radial: C6-8
Chief extensor of forearm
Long head - resists humerus dislocation
Aconeus
Radial: C7&8, T1
Assists triceps in extending forearm
Stabilises elbow joint
May abduct ulna in pronation
Pronator teres
Median nerve: C6&7
Pronates & flexes forearm @ elbow
Flexor carpi radialis
Median nerve (C6&7)
Flexes & abducts hand
Palmaris longus
Median nerve: C7&8
Flexes hand @ wrist
Tenses palmar aponeurosis
Flexor carpi ulnaris
Ulnar nerve: C7&8
Flexes & adducts hand @ wrist
Flexor digitorum superficialis
Median nerve (C7&8, T1)
Flexes middle phalanges @ proximal interphalangeal joints
& proximal phalanges @ metacarpophalangeal joints
Flexor digitorum profundus
Medial: ulnar nerve: C8, T1
Lateral: median nerve: C8, T1
Flexes distal phalanges 2-5 @ distal interphalangeal joints
Flexor pollicis longus
Median nerve: C8, T1
Flexes phalanges @ 1st digit
Pronator quadratus
Median nerve: C8, T1
Pronates forearm
Deep fibres bind radius & ulna together
Brachioradialis
Radial nerve: C5-7
Weak flexion of forearm
Extensor carpi radialis longus & brevis
Radial nerve: C7&8
Extend & abduct hand @ wrist joint
ECRL active during fist clenching
Extensor digitorum
Radial nerve: C7&8
Extends medial 4 digits & metacarpophalangeal (primary) & interphalangeal (secondary) joints
Extensor digiti minimi
Radial nerve: C7&8
Extends 5th digit @ metacarpophalyngeal (primary) & interphalangeal (secondary) joints
Extensor carpi ulnaris
Radial nerve: C7&8
Extends & adducts hand @ wrist joint
Active during fist clenching
Supinator
Radial nerve: C7&8
Supinates forearm (rotates radius)
Extensor indicis
Radial nerve: C7&8
Extends 2nd digit independently
Helps extend hand @ wrist
Abductor pollicis longus
Radial nerve: C7&8
Abducts thumb
Extends & carpometacarpal joint
Extensor pollicis longus
Radial nerve: C7&8
Extends distal phalynx of thumb
Extensor pollicis brevis
Radial nerve: C7&8
Extends proximal phalynx of thumb
Trapezius
Accessory nerve
Upper fibres elevate & rotate scapula during arm abduction
Middle fibres retract scapula
Lower fibres pull scapula inferorly
Latissimus dorsi
Thoracodorsal nerve
Extends, adducts & medially rotates upper limb
Levator scapulae
Dorsal scapular nerve
Elevates scapula
Rhomboids (major & minor)
Dorsal scapula nerve
Retracts & rotates scapula
Deltoid
Axillary nerve
Anterior fibres flex arm @ shoulder
Posterior fibres extend arm @ shoulder
Middle fibres major abductor of arm
(takes over from supraspinatus after 1st 15 degrees of abduction)
Teres major
Lower subscapular nerve
Adducts shoulder
Medially rotates arm
Supraspinatus
Suprascapular nerve
Abducts arm 0-15 degrees (then assists deltoid)
Infraspinatus
Suprascapular nerve
Laterally rotates arm
Subscapularis
Upper & lower subscapular nerves
Medially rotates arm
Teres minor
Axillary nerve
Laterally rotates arm
Opponens pollicis
Opposes the thumb, by medially rotating and flexing the metacarpal on the trapezium.
Median nerve.
Abductor pollicis brevis
Abducts the thumb.
Median nerve.
Flexor pollicis brevis
Flexes the MCP joint of the thumb.
Median nerve.
Opponens digiti minimi
rotates the metacarpal of the little finger towards the palm, producing opposition.
Ulnar nerve.
Abductor digiti minimi
Abducts the little finger.
Ulnar nerve.
Flexor digiti minimi brevis
Flexes the MCP joint of the little finger.
Ulnar Nerve.
Lumbricals
flex at the MCP joint, and extend at the IP joints of each finger.
medial two lumbricals (of the little and ring fingers):ulnar nerve.
lateral two lumbricals (of the index and middle fingers): median nerve
Dorsal interossei
Abduct the fingers at the MCP joint.
Ulnar nerve.
Palmar interossei
Adducts the fingers at the MCP joint.
Ulnar nerve.
Palmaris brevis
Wrinkles the skin of the hypothenar eminence and deepens the curvature of the hand, improving grip.
Ulnar nerve.
Adductor pollicis
Adductor of the thumb.
Ulnar nerve.
Iliopsoas
flexes the lower limb at the hip joint and assists in lateral rotation at the hip joint.
psoas major: anterior rami of L1-3
iliacus: femoral nerve.
Rectus femoris
only muscle of the quadriceps to cross both the hip and knee joints
flexes the leg at the hip joint, and extends at the knee joint.
Femoral nerve.
Sartorius
At the hip joint, it is a flexor, abductor and lateral rotator.
At the knee joint, it is also a flexor.
Femoral nerve.
Pectineus
Adduction and flexion at the hip joint.
Femoral nerve.
Adductor magnus
Adductor & hamstring part
both adduct the thigh
adductor component also flexes the thigh
hamstring portion extending the thigh.
Adductor part: obturator nerve (L2-L4),
hamstring part: tibial nerve (L4-S3).
Adductor longus
Adduction and medial rotation of the thigh.
Obturator nerve (L2-L4).
Adductor brevis
Adduction of the thigh.
Obturator nerve (L2-L4).
Obturator externis
Laterally rotates the thigh.
Obturator nerve (L2-L4).
Gracillis
Adduction of the thigh at the hip, and flexion of the leg at the knee.
Obturator nerve (L2-L4).
Biceps femoris
Mainly flexion at the knee
also extends the leg at the hip, and laterally rotates at the hip and knee.
Long head: tibial part of the sciatic nerve
short head: common fibular part of the sciatic nerve.
Semitendinosus
Flexion of the leg at the knee joint
Extension of thigh at the hip
Medially rotates the thigh at the hip joint and the leg at the knee joint.
Tibial part of the sciatic nerve.
Semimembranosus
Flexion of the leg at the knee joint
Extension of thigh at the hip
Medially rotates the thigh at the hip joint and the leg at the knee joint.
Tibial part of the sciatic nerve.
Gluteus maximus
main extensor of the thigh
and assists with lateral rotation
(only used when force is required, such as running or climbing)
Inferior gluteal nerve.
Gluteus medius
Abducts and medially rotates the lower limb
During locomotion, secures the pelvis, preventing pelvic drop of the opposite limb.
Superior gluteal nerve.
Gluteus minimus
Abducts and medially rotates the lower limb.
During locomotion, secures the pelvis, preventing pelvic drop of the opposite limb.
Superior gluteal nerve.
Piriformis
Lateral rotation and abduction.
Nerve to piriformis.
Obturator internis
Lateral rotation and abduction.
Nerve to obturator internus.
Gemelli (superior & inferior)
Lateral rotation and abduction.
The superior gemellus: nerve to obturator internus
inferior gemellus: nerve to quadratus femoris.
Quadratus femoris
Lateral rotation.
Nerve to quadratus femoris.
Rotator cuff muscles
Supraspinatus
Infrasoinatus
Teres minor
Subscapularis
Muscles extending upper limb
Posterior deltoid
Latissimus dorsi
Teres major
Muscles flexing upper limb
Biceps brachii
Pectoralis major
Anterior deltoid
Coracobrachalis
Muscles medially rotating upper limb
Subscapularis Pectoralis major Latissimus dorsi Teres major Anterior deltoid
Muscles laterally rotating upper limb
Infraspinatus
Teres minor
Muscles that abduct arm
Supraspinatus (15 – 20°)
Deltoid (90°)
Upper and lower fibres of the trapezius (above 90°)
Serratus anterior
Muscles flexing elbow (& nerves that innervate)
Brachialis – Musculocutaneous;
Biceps brachii – Musculocutaneous;
Brachioradialis – Radial nerve
6 movements of scapula & muscles that produce them
Protraction – Serratus anterior
Retraction – (Middle fibres of) trapezius, rhomboids
Elevation – (Upper fibres of) trapezius, levator scapulae
Depression – (gravity) (relaxation of elevator muscles)
Lateral rotation/upward rotation – upper and lower fibres of trapezius
Medial rotation/downward rotation – Latissimus dorsi, levator scapulae, rhomboids (tilt glenoid cavity inferiorly)
NB In lateral/upward rotation of the scapula, the glenoid cavity moving superiorly (i.e. when upper limb is abducted).
Converse is true for medial/downward rotation.
Movements of the wrist
Flexion - Produced mainly by the flexor carpi ulnaris, flexor carpi radialis, with assistance from the flexor digitorum superficialis.
Extension - Produced mainly by the extensor carpi radialis longus and brevis, and extensor carpi ulnaris, with assistance from the extensor digitorum.
Adduction (ulnar deviation) - Produced by the extensor carpi ulnaris and flexor carpi ulnaris
Abduction (radial deviation) - Produced by the abductor pollicis longus, flexor carpi radialis, extensor carpi radialis longus and brevis.
Movements of the radio ulnar joint
Pronation: Produced by the pronator quadratus and pronator teres.
Supination: Produced by the supinator and biceps brachii.
Muscles extending the elbow
Triceps brachii
anconeus
Movements of the shoulder joint
Extension (upper limb backwards in sagittal plane)
Produced by the posterior deltoid, latissimus dorsi and teres major.
Flexion (upper limb forwards in sagittal plane)
Produced by the biceps brachii (both heads), pectoralis major, anterior deltoid and corocobrachialis.
Abduction (upper limb away from midline in coronal plane)
The first 0-15 degrees of abduction is produced by the supraspinatus. The middle fibres of the deltoid are responsible for the next 15-90 degrees. Past 90 degrees, the scapula needs to be rotated to achieve abduction – that is carried out by the trapezius and serratus anterior.
Adduction (upper limb towards midline in coronal plane)
Produced by contraction of pectoralis major, latissimus dorsi and teres major.
Medial Rotation (rotation towards the midline, so that the thumb is pointing medially) Produced by contraction of subscapularis, pectoralis major, latissimus dorsi, teres major and anterior deltoid.
Lateral Rotation (rotation away from the midline, so that the thumb is pointing laterally) Produced by contraction of the infraspinatus and teres minor.
Movements of hip & muscles responsible
Flexion: Iliosoas, rectus femoris, sartorius
Extension: Gluteus maximus, semimembranous,semitendinosus and biceps femoris
Abduction: Gluteus medius, gluteus minimus and the deep gluteals (piriformis, gemelli etc)
Adduction: Adductors longus, brevis and magnus,pectineus and gracillis
Lateral rotation: Biceps femoris, gluteus maximus, and the deep gluteals (piriformis, gemelli etc)
Medial rotation: Gluteus medius and minimus, semitendinosus and semimembranosus
Movements of the knee
Extension: Produced by the quadriceps femoris, which inserts into the tibial tuberosity.
Flexion: Produced by the hamstrings, gracilis, sartorius and popliteus.
Lateral rotation: Produced by the biceps femoris.
Medial rotation: Produced by five muscles; semimembranosus, semitendinosus, gracilis, sartorius and popliteus.
NB: Lateral and medial rotation can only occur when the knee is flexed (if the knee is not flexed, the medial/lateral rotation occurs at the hip joint).
Muscles of anterior leg & collective action
tibialis anterior
extensor digitorun longus
extensor hallucis longus
(fibularis tertius)
Dorsiflex & invert foot
Tibialis anterior
Deep fibular nerve
Strongest dorsiflexor
Foot inversion
Extensor digitorum longus (leg)
Deep fibular nerve
Extension of lateral 4 toes
Dorsiflexion of foot
Extensor hallucis longus
Deep fibular nerve
Extension of great toe
Dorsiflexion of foot
Fibularis tertius
Deep fibular nerve
Eversion & dorsiflexion
(Not present in all individuals
Arises from inferior part of EDL)
Muscles of lateral part of leg & their collective action
Fibularis longus (peroneal longus) Fibularis brevis (peroneal brevis)
Eversion
Finularis longus
Superficial fibular nerve
Eversion & plantar flexion
Supports lateral & transverse arches
Fibularis brevis
Superficial fibular nerve
Eversion of foot
Muscles of the posterior lower leg & their collective action & innervation
Superficial:
Gastrocnemius
Plantaris
Soleus
Deep: Popliteus Tibialis posterior Flexor digitorum longus Flexor hallucis longus
Plantar flex & invert foot
Tibial nerve
Gastrocnemius
Plantarflex @ ankle joint
Knee flexor
Tibial nerve
Plantaris
Plantarflexes @ ankle joint
Knee flexor
(Minor role)
Tibial nerve
Soleus
Plantarflexes @ ankle joint
Tibial nerve
Popliteus
Laterally rotates femur on tibia
(‘Unlocking’ the knee joint so flexion can occur)
Tibial nerve
Tibialis posterior
Inverts & plantarflexes the foot
Maintains medial arch of the foot
Tibial nerve
Flexor digitorum longus (of leg)
Flexes lateral 4 toes
Tibial nerve
Flexor hallucis longus
Flexes great toe
Tibial nerve
Insertion points of biceps brachii
Long head:
Supraglenoid tubercle on scapula
Short head:
Coracoid process
Both insert as biceps tendon on bicipital tuberosity on radius & biciptal aponeurosis on ulnar
Flexor retinaculum attachments
Turns the carpal arch into the carpal tunnel by bridging the space between the medial and lateral parts of the arch.
Originates on the lateral side and inserts on the medial side of the carpal arch.
(Formed laterally by the scaphoid and trapezium tubercles
Formed medially by the hook of the hamate and the pisiform)
