AP 1 M5 5.2: Anatomy of the Muscular System Part II: Muscles of the Upper and Lower Extremities Flashcards
muscles on the posterior thorax
The muscles on the posterior thorax assist in movement of the shoulder girdle. The trapezius is a large muscle that acts on the shoulder as well as the neck and upper spine. The trapezius is superficial to the remaining muscles shown
Muscles of the Shoulder Girdle Continued
The shoulder is a ball and socket joint, which permits many types of movement. The glenoid cavity of the scapula is very small compared to the head of the humerus. The large bony structure of the shoulder requires many ligaments and layers of muscle for stability.
rotator cuff
A muscle grouping known as the rotator cuff is necessary to stabilize the humeral head inside the shoulder joint.
Rotator cuff is made up of the “SITS” muscles
The rotator cuff is made up of the “SITS” muscles: supraspinatus, infraspinatus, teres minor, and subscapularis.
Muscles of the Lower Extremity
Several movements are important to clarify when discussing muscles of the lower extremity.
Hip extension
Hip extension involves moving the thigh posteriorly (or backward movement of the thigh)
Hip flexion
Hip flexion is moving the thigh anteriorly (or forward movement of the thigh)
Knee extension
Knee extension means to straighten the knee, or to increase the angle of the joint.
Knee flexion
Knee flexion is bending the knee (decreasing the angle of the joint)
Lateral rotation
Lateral rotation (external rotation) refers to rotation away from the center of the body.
Internal rotation
Internal rotation (medial rotation) refers to rotation towards the central axis of the body.
Gluteal Muscles of the Thigh
The gluteal muscles extend and rotate the hip joint. Gluteus maximus is a large, superficial muscle covering the posterior thigh.
hip
The hip is a ball and socket joint, permitting many ranges of movements, such as adduction, abduction, extension, flexion, and rotation. The “hip” refers to the ball and socket joint. Thigh movements refer to movement of the femur. A muscle can have multiple actions, depending on the location and orientation of the muscle fibers. For example, gluteus maximus can abduct and extend at the hip joint. In addition, a muscle may act on multiple joints. For example, the biceps femoris crosses the hip joint and knee joint. At the hip, biceps femoris enables hip extension, while at the knee it enables knee flexion.
Trapezius (upper, middle, lower)
Muscles of the Shoulder and Upper Extremity
Origin: occipital bone, spinous process of T1-12
Insertion: lateral clavicle, acromion, and scapular spine of scapula
Action: rotation, retraction, elevation, depression of scapula; extends neck and stabilizes shoulder
Innervation: Accessory nerve (Cranial Nerve 11)
Levator scapulae
Muscles of the Shoulder and Upper Extremity
Origin: transverse process of C1-4
Insertion: medial border of scapula
Action: elevates scapula
Innervation: dorsal scapular nerve
Rhomboids (major, minor)
Muscles of the Shoulder and Upper Extremity
Origin: spinous process (minor: C7-T1) (major: T2-5)
Insertion: medial border of scapula
Action: retraction of scapula
Innervation: dorsal scapular nerve
Pectoralis minor
Muscles of the Shoulder and Upper Extremity
Origin: ribs 3-5
Insertion: coracoid process of scapula
Action: elevates ribs, draws scapula down and medially
Innervation: medial pectoral nerve
Serratus Anterior
Muscles of the Shoulder and Upper Extremity
Origin: upper 8-9 ribs
Insertion: medial border of scapula
Action: protraction of scapula
Innervation: long thoracic nerve
Deltoid (anterior, posterior, middle)
Muscles of the Shoulder Girdle Continued
Origin: clavicle and scapula
Insertion: deltoid tuberosity of humerus
Action: abduction at shoulder (whole muscle)
Innervation: axillary nerve
Pectoralis major
Muscles of the Shoulder Girdle Continued
Origin: ribs 2-6, body of sternum
Insertion: greater tubercle of humerus
Action: flexion, adduction and medial rotation at shoulder
Innervation: pectoral nerves
Supraspinatus (above spine of scapula)
Muscles of the Shoulder Girdle Continued
Origin: supraspinatus fossa of scapula
Insertion: greater tubercle of humerus
Action: abduction at the shoulder
Innervation: suprascapular nerve
Infraspinatus (below spine of scapula)
Muscles of the Shoulder Girdle Continued
Origin: infraspinatus fossa of scapula
Insertion: greater tubercle of humerus
Action: lateral rotation at shoulder
Innervation: suprascapular nerve
Teres Minor
Muscles of the Shoulder Girdle Continued
Origin: lateral border of scapula
Insertion: greater tubercle of humerus
Action: lateral rotation at shoulder
Innervation: axillary nerve
Teres Major – not part of the rotator cuff
Muscles of the Shoulder Girdle Continued
Origin: inferior angle of scapula
Insertion: intertubercular groove of humerus
Action: extension, adduction, and medial rotation at shoulder
Innervation: lower subscapular nerve
Subscapularis – along inner surface of the scapula
Muscles of the Shoulder Girdle Continued
Origin: subscapular fossa of scapula
Insertion: lesser tubercle of humerus
Action: medial rotation at the shoulder
Innervation: subscapular nerves
Latissimus Dorsi
Muscles of the Shoulder Girdle Continued
Origin: spinous process of inferior thoracic and lumbar vertebrae, ribs 8-12
Insertion: intertubercular groove of humerus
Action: extension, adduction, and medial rotation at shoulder
Innervation: thoracodorsal nerve
Coracobrachialis
Muscles of the Shoulder Girdle Continued
Origin: coracoid process of scapula
Insertion: medial shaft of humerus
Action: adduction and flexion at shoulder
Innervation: musculocutaneous nerve
Biceps brachii
Muscles of the Forearm and Elbow
Origin: short head- coracoid process; long head- supraglenoid tubercle of scapula
Insertion: tuberosity of radius
Action: flexion at elbow and shoulder; supination
Innervation: musculocutaneous nerve
Brachialis
Muscles of the Forearm and Elbow
Origin: anterior/distal surface of humerus
Insertion: tuberosity of ulna
Action: flexion at elbow
Innervation: musculocutaneous nerve and radial nerve
Brachioradialis
Muscles of the Forearm and Elbow
Origin: lateral epicondyle of humerus
Insertion: lateral aspect of styloid process of radius
Action: flexion at elbow
Innervation: radial nerve
Triceps (long head, lateral head, medial head)
Muscles of the Forearm and Elbow
Origin:
Lateral head – superior, lateral margin on humerus
Long head – infraglenoid tubercle of scapula
Medial head – posterior surface of humerus
Insertion: olecranon of ulna
Action: extension at elbow
Innervation: radial nerve
Pronator Teres
Muscles of the Forearm and Elbow
Origin: medial epicondyle of humerus
Insertion: mid-lateral surface of radius
Action: pronation
Innervation: median nerve
Flexor carpi radialis
Superficial Flexors
Action: wrist flexion, radial deviation of the hand
Innervation: median nerve
Supinator
Muscles of the Forearm and Elbow
Origin: lateral epicondyle of humerus
Insertion: anterolateral surface of radius
Action: supination
Innervation: deep radial nerve
Palmaris longus
Superficial Flexors
Action: wrist flexion
Innervation: median nerve
Flexor carpi ulnaris
Superficial Flexors
Action: wrist flexion, ulnar deviation of the hand
Innervation: ulnar nerve
Flexor digitorum superficialis (FDS)
Superficial Flexors
Action: flexion of the wrist and digits 2-5 (middle and proximal phalanx)
Innervation: median nerve
Flexor pollicis longus
Deep Flexors
Action: flexion of thumb
Innervation: median nerve
Flexor digitorum profundus (FDP)
Deep Flexors
Action: wrist flexion, flexion of digits 2-5 (distal phalanx)
Innervation: palmar interosseous nerve
Extensor carpi radialis brevis
Superficial Extensors of the Wrist
Action: extension, abduction of the wrist
Innervation: radial nerve
Extensor carpi radialis longus
Superficial Extensors of the Wrist
Action: extension, abduction of the wrist
Innervation: radial nerve
Extensor digitorum
Superficial Extensors of the Wrist
Action: wrist extension, extension of digits 2-5
Innervation: deep radial nerve
Extensor digiti minimi (digit 5)
Superficial Extensors of the Wrist
Action: wrist extension, extension of digit 5
Innervation: deep radial nerve
Extensor carpi ulnaris
Superficial Extensors of the Wrist
Action: extension, adduction of the wrist
Innervation: deep radial nerve
Abductor pollicis longus (APL)
Deep extensors of the wrist
Action: abduction of wrist and thumb
Innervation: deep radial nerve
Extensor pollicis longus (EPL)
Deep extensors of the wrist
Action: thumb extension, wrist abduction
Innervation: deep radial nerve
Extensor pollicis brevis (EPB)
Deep extensors of the wrist
Action: thumb extension, wrist abduction
Innervation: deep radial nerve
Extensor indicis (EI)
Deep extensors of the wrist
Action: extension of wrist and digit 2
Innervation: deep radial nerve
Psoas Major
Muscles of the Lower Extremity
Origin: transverse bodies of all lumbar vertebra
Insertion: lesser trochanter of the femur (with iliacus)
Action: hip flexion (or trunk flexion if femur is stationary)
Innervation: lumbar plexus
Iliacus
Muscles of the Lower Extremity
Origin: iliac fossa of ilium
Insertion: lesser trochanter of femur
Action: hip flexion
Innervation: femoral nerve
Gluteus maximus
Gluteal Muscles of the Thigh
Origin: posterior gluteal line of the ilium, lower sacrum, side of the coccyx
Insertion: gluteal tuberosity
Action: abducts, extends, laterally rotates hip joint
Innervation: inferior gluteal nerve
Gluteus medius
Gluteal Muscles of the Thigh
Origin: gluteal surface of the ilium
Insertion: greater trochanter of the femur
Action: abducts thigh, stabilizes the hip joint
Innervation: superior gluteal nerve
Gluteus minimus
Gluteal Muscles of the Thigh
Origin: Gluteal surface of the ilium
Insertion: Greater trochanter of the femur
Action: Abducts thigh, stabilizes hip joint
Innervation: Superior gluteal nerve
TFL – tensor fascia latae
Gluteal Muscles of the Thigh
Origin: ASIS (anterior superior iliac spine)
Insertion: iliotibial tract
Action: abducts and internally rotates thigh, stabilizes hip and knee joints
Innervation: superior gluteal nerve
Obturator externus
Lateral Rotators of the Thigh (Deep)
Action: lateral rotation of thigh
Innervation: obturator nerve
Obturator internus
Lateral Rotators of the Thigh (Deep)
Action: lateral rotation of thigh
Innervation: spinal nerves S1-3
Superior gemellus
Lateral Rotators of the Thigh (Deep)
Action: lateral rotation, adduction, extension of hip joint
Innervation: spinal nerves L5, S1
Inferior gemellus
Lateral Rotators of the Thigh (Deep)
Action: lateral rotation, adduction, extension of hip joint
Innervation: spinal nerves L5, S1
Quadratus Femoris
Lateral Rotators of the Thigh (Deep)
Action: lateral rotation, adduction of hip joint
Innervation: spinal nerves L5, S1
Piriformis
Lateral Rotators of the Thigh (Deep)
Action: lateral rotation, adduction, extension of hip joint
Innervation: spinal nerves L5-S2
Biceps Femoris
Posterior, Hamstring Group
Origin: Long head, ischial tuberosity; short head, linea aspera of femur, lateral surface
Insertion: head of the fibula, lateral surface
Action: knee flexion, hip extension
Innervation: Long head - tibial nerve; Short head - common fibular nerve
Semitendinosus
Posterior, Hamstring Group
Origin: ischial tuberosity
Insertion: medial surface of tibia
Action: knee flexion
Innervation: tibial nerve
Semimembranosus
Posterior, Hamstring Group
Origin: ischial tuberosity
Insertion: medial condyle of tibia
Action: knee flexion
Innervation: tibial nerve
Rectus Femoris
Anterior, Quadriceps
Origin: AIIS (anterior inferior iliac spine)
Insertion: common tendon of the quadriceps to tibial tuberosity
Action: knee extension, hip flexion
Innervation: femoral nerve
Vastus Medialis
Anterior, Quadriceps
Origin: intertrochanteric line of femur
Insertion: patella via quadriceps tendon; tibial tuberosity
Action: knee extension
Innervation: femoral nerve
Vastus Lateralis
Anterior, Quadriceps
Origin: greater trochanter of femur
Insertion: patella via quadriceps tendon; tibial tuberosity
Action: knee extension
Innervation: femoral nerve
Vastus Intermedius
Anterior, Quadriceps
Origin: anterior/lateral surfaces of femur
Insertion: common tendon of the quadriceps to tibial tuberosity
Action: knee extension
Innervation: femoral nerve
Adductor Brevis
Medial Compartment
Origin: superior and inferior rami of the pubis
Insertion: medial shaft femur, into the upper linea aspera
Action: adducts, medially rotates thigh
Innervation: obturator nerve
Adductor Longus
Medial Compartment
Origin: front of the pubis
Insertion: linea aspera
Action: adducts, medially rotates thigh
Innervation: obturator nerve
Adductor Magnus
Medial Compartment
Origin: inferior ramus of pubis
Insertion: adductor tubercle, medial condyle of the femur, linea aspera
Action: adducts, medially rotates thigh
Innervation: obturator nerve
Gracilis
Medial Compartment
Origin: lower half of pubic symphysis
Insertion: superior shaft of tibia
Action: adductor of the thigh, flexes knee
Innervation: obturator nerve
Pectineus
Medial Compartment
Origin: pectineal line
Insertion: posterior surface of the femur
Action: adducts thigh
Innervation: femoral nerve
Sartorius
Medial Compartment
Origin: ASIS (anterior superior iliac spine)
Insertion: superior shaft of tibia
Action: Hip: flexion, abduction, external rotation; Knee: flexion, internal rotation
Innervation: femoral nerve
Tibialis Anterior
Muscles of the Lower Leg
(Anterior)
Origin: lateral condyle of tibia
Insertion: base of metatarsal 1, medial cuneiform
Action: dorsiflexion, inversion of foot
Innervation: deep peroneal nerve
Extensor Digitorum longus
Muscles of the Lower Leg
(Anterior)
Origin: lateral condyle of tibia
Insertion: distal phalanges of digits 2-5
Action: extends digits 2-5, dorsiflexion of foot
Innervation: deep peroneal nerve
Extensor hallucis longus
Muscles of the Lower Leg
(Anterior)
Origin: anterior surface of fibula
Insertion: dorsal surface of digit 1 (great toe)
Action: extension of digit 1, dorsiflexion of foot
Innervation: deep peroneal nerve
Peroneus Brevis
Muscles of the Lower Leg
(Anterior)
Origin: lateral, distal fibula
Insertion: lateral side of 5th metatarsal
Action: plantarflex and evert foot (pronate)
Innervation: superficial peroneal nerve
Peroneus Longus
Muscles of the Lower Leg
(Anterior)
Origin: posterior surface of tibia, superior fibula
Insertion: base of metatarsal 1
Action: plantarflex and evert foot (pronate)
Innervation: superficial peroneal nerve
Gastrocnemius
Muscles of the Lower Leg
(Posterior)
Origin: medial and lateral heads: posterior surfaces of medial and lateral femoral condyles
Insertion: posterior surface of calcaneus via Achilles tendon
Action: plantarflexion of foot, knee flexion
Innervation: tibial nerve
Soleus
Muscles of the Lower Leg
(Posterior)
Origin: posterior surface of fibula, medial region of posterior tibia
Insertion: posterior surface of calcaneus via Achilles tendon
Action: plantarflexion of foot
Innervation: tibial nerve
Tibialis Posterior
Muscles of the Lower Leg
(Posterior)
Origin: posterior surface of tibia, interosseous membrane, medial surface of fibula
Insertion: navicular bone, cuneiforms (3), cuboid, and metatarsals 2-4
Action: plantarflexion, inversion and adduction of foot
Innervation: tibial nerve
Flexor hallucis longus
Muscles of the Lower Leg
(Posterior)
Origin: posterior fibula
Insertion: inferior surface of distal phalanx of digit 1 (great toe)
Action: flexion of digit 1, inversion and plantarflexion of foot
Innervation: tibial nerve (deep peroneal branch)
Flexor digitorum longus
Muscles of the Lower Leg
(Posterior)
Origin: posterior surface of tibia
Insertion: inferior surface of distal phalanges 2-5
Action: flexion of digits 2-5; inversion and plantarflexion of foot
Innervation: deep peroneal nerve
